Risk Management Series

Primer for Design Professionals 
Communicating with Owners and Managers of New Buildings on Earthquake 
Risk 


 
FEMA 389 / January 2004




TABLE OF CONTENTS


1 INTRODUCTION  1-1


1.1	 Impetus for Updating the Prior Documents in the 
FEMA Seismic Considerations Series 1-3

1.2	 Objectives and Scope of this Document    1-5

1.3	 Document Contents and Organization   1-6

1.4  Document Formatting and Icons   1-8





2 SEISMIC RISK MANAGEMENT   2-1


2.1	 Seismic Risk: An Overview   2-1

2.2	 Seismic Risk Management: A Holistic Approach for 
Reducing Earthquake Impacts   2-4

2.3	 Evaluating Seismic Risk Consequences as a Basis for 
Developing a Risk Management Plan    2-6

2.4	 First Cost or Design Strategies   2-9

2.5	 Operating Cost or Business Strategies    2-13

2.6	 Event Response Strategies   2-16

2.7	 Choosing an Optimal Combination of Risk Reduction 
Strategies   2-18

2.8	 Example Implementation of a Risk Management 
Program   2-21

2.9	 Seismic Risk Management Advocacy   2-22





3	IDENTIFYING AND ASSESSING EARTHQUAKE-
RELATED HAZARDS   3-1


3.1	 Introduction   3-1

3.2	 Earthquake Ground Shaking Hazard    3-1

3.3	 Collateral Seismic Hazards   3-8

3.4	 Other Collateral Hazards   3-10

3.5	 Guidance for Assessing Earthquake-Related Hazards    3-16

3.6	 References and Further Reading    3-21





4	PERFORMANCE-BASED ENGINEERING:
AN EMERGING CONCEPT IN SEISMIC DESIGN   4-1


4.1	 Seismic Design Provisions in Building Codes   4-1

4.2	 Expected Performance when Designing to Current 
Codes    4-3

4.3	 Current Specifications for Performance-Based 
Seismic Design   4-6

4.4	 Impact of Performance-Based Strategies on
Future Design Codes   4-18

4.5	 Guidance for Design Professionals    4-23

4.6	 References and Further Reading    4-24





5	IMPROVING PERFORMANCE TO REDUCE 
SEISMIC RISK  5-1


5.1	 Introduction   5-1


5.2	 Selection of Structural Materials and Systems  .5-2

5.3	 Selection of the Architectural Configuration  5-5

5.4	 Consideration of Nonstructural Component 
Performance  5-6

5.5	 Quantifying the Benefits of Improved Performance    5-11

5.6	 Costs of Improved Performance    5-19

5.7	 Case Studies of Cost and Performance 
Considerations    5-23

5.8	 Quality Control During the Construction Process    5-30

5.9	 Recommendations for Improving Seismic 
Performance   5-31





6	DESIGN AND PERFORMANCE ISSUES RELATING
TO COMMERCIAL OFFICE BUILDINGS    6-1


6.1	 Introduction   6-1

6.2	 Ownership, Financing, and Procurement   6-2

6.3	 Performance of Office Buildings in Past Earthquakes    6-2

6.4	 Performance Expectations and Requirements   6-5

6.5	 Seismic Design Issues    6-5





7	DESIGN AND PERFORMANCE ISSUES RELATING
TO RETAIL COMMERCIAL FACILITIES  . 7-1


7.1	 Introduction   7-1

7.2	 Ownership, Financing, and Procurement   7-2

7.3	 Performance of Commercial Retail Facilities in 
Past Earthquakes    7-3

7.4	 Performance Expectations and Requirements   7-4

7.5	 Seismic Design Issues    7-4





8	DESIGN AND PERFORMANCE ISSUES RELATING TO
LIGHT MANUFACTURING FACILITIES   8-1


8.1	 Introduction   8-1

8.2	 Ownership, Financing and Procurement    8-2

8.3	 Performance of light Manufacturing Facilities in 
Past Earthquakes    8-3

8.4	 Performance Expectations and Requirements   8-4

8.5	 Seismic Design Issues    8-4





9	DESIGN AND PERFORMANCE ISSUES RELATING
TO HEALTHCARE FACILITIES . 9-1


9.1	 Introduction   9-1

9.2	 Ownership, Financing, and Procurement   9-2

9.3	 Performance of Healthcare Facilities in Past 
Earthquakes   9-3

9.4	 Performance Expectations and Requirements   9-5

9.5	 Seismic Design Issues    9-6





10	DESIGN AND PERFORMANCE ISSUES RELATING
TO LOCAL SCHOOLS (K-12)  10-1


10.1  Introduction   10-1

10.2  Ownership, Financing, and Procurement   10-2

10.3  Performance of Local Schools in Past Earthquakes  10-2

10.4  Performance Expectations and Requirements   10-3

10.5  Seismic Design Issues    10-4





11	DESIGN AND PERFORMANCE ISSUES RELATING
TO HIGHER EDUCATION FACILITIES (UNIVERSITIES)   11-1


11.1  Introduction   11-1

11.2  Ownership, Financing, and Procurement   11-2

11.3  Performance of Higher Education Facilities 
(Universities) in Past Earthquakes  11-2

11.4  Performance Expectations and Requirements   11-4

11.5  Seismic Design Issues    11-5






12	RESPONSIBILITIES FOR SEISMIC CONSIDERATIONS
 WITHIN THE DESIGN TEAM   12-1


12.1  Responsibilities of the Structural Engineer, Architect, 
and MEP Engineer   12-1

12.2  Developing a Unified Approach Within the Design 
Team   12-1

12.3  Engineering Services for Added Value of Risk 
Management   12-2

12.4  Communicating Seismic Considerations Issues to 
the Building Owner    12-2

12.5  Design and Construction Quality Assurance   12-10

 

REFERENCES  13-1



PROJECT PARTICIPANTS   14-1





INTRODUCTION 1

Seismic risk management tools, including new seismic engineering 
technology and data, are now available to assist with evaluating, predicting, 
and controlling financial and personal-injury losses from future damaging 
earthquakes. These tools have evolved as a result of scientific and engineering 
breakthroughs, including new earth-science knowledge about the occurrence 
and severity of earthquake shaking, and new engineering techniques for 
designing building systems and components to withstand the effects of 
earthquakes. As a result, design and construction professionals can now 
design and construct new buildings with more predictable seismic 
performance than ever before. 

Seismic risks can be managed effectively in a number of ways, including the 
design and construction of better performing buildings as well as the 
employment of strategies that can result in risk reduction over the 
life of the building. Risk reduction techniques include the use of new 
technologies, such as seismic isolation and energy dissipation devices for 
both structural and non-structural systems; site selection to avoid hazards such 
as ground motion amplification, landslide, and liquefaction; and the use of 
performance-based design concepts, which enable the engineer to better 
estimate building capacity and seismic loading demand and to design 
buildings for enhanced performance (beyond that typically provided by current 
seismic codes). The implementation of risk reduction strategies by building 
owners and managers is critically important, not only for reducing the likelihood 
of life loss and injury, but also for reducing the potential for losses associated 
with earthquake damage repair and business interruption. 

The Federal Emergency Management Agency (FEMA) has commissioned and 
funded the development of this document to facilitate the process of educating 
building owners and managers about seismic risk management tools that can 
be effectively and economically employed by them during the building 
development phase - from site selection through design and construction - as 
well as the operational phase. 

This document also recognizes that seismic design professionals (architects 
and engineers) throughout the United States have varying levels of technical 
knowledge and experience pertaining to the seismic design of buildings. In 
areas of moderate and high seismicity, the knowledge and experience is 
substantially greater than in areas of low seismicity. In many cases, design 
professionals rely extensively, if not exclusively, on local building seismic 
codes for specifications and instruction for incorporating seismic resistance in 
buildings that they design. In other cases, design professionals supplement 
their design experience and knowledge by using technical resource 
documents on seismic-design related issues prepared by professional 
structural engineering organizations and institutions, in many cases with funding 
from state and federal agencies 
(e.g., FEMA). As a result, many design professionals are likely to have 
substantial knowledge about concepts and approaches for reducing seismic 
risk in new buildings, the special focus of this document. 

Regardless of their level of knowledge and experience in seismic design, 
seismic design professionals are likely to have little knowledge regarding non-
engineering-related strategies and options that could be 
employed by building owners and managers to reduce their seismic risk. This 
document has therefore also been written to educate the seismic design 
professional on these non-engineer-ing-related risk management approaches, 
including risk transfer through insurance, risk reduction through earthquake 
response planning, and risk reduction through other non-engi-neering-related 
means. While the methods described are general in nature and apply to most 
building uses, the document specifically addresses six occupancy types: 

      	commercial office facilities, 

      	retail commercial facilities, 

      	light manufacturing facilities, 

      	healthcare facilities, 

      	local schools (kindergarten through grade 12), and 

      	higher education (university) facilities. 


The intended audience for this document consists of those design 
professionals (architects and engineers) who typically work with building 
owners and managers in developing new building projects. The document is 
intended to be used in conjunction with a set of six companion FEMA-funded 
brochures for building owners and managers, written to encourage the use of 
seismic risk management tools and strategies in the design and construction 
of new buildings. A brochure has been prepared for each of the six facility types 
identified above, and each is limited in 
scope and content so that it can be quickly read and easily understood by 
building owners and managers. The brochures identify a number of issues, 
many of them posed in the form of questions, that relate to seismic risk and the 
benefits that seismic risk management, including performance-based design, 
can provide to building owners and managers. Each brochure is amply 
illustrated with photographs, charts, and tables that demonstrate important 
concepts in seismic risk management and seismic design and construction. 

This document and set of brochures were preceded approximately fifteen years 
ago with a series of FEMA documents, known as the Seismic Considerations 
Series, which were written for a broad range of professionals and stakeholders 
interested in and concerned about building seismic performance issues. 




1.1 	IMPETUS FOR UPDATING THE PRIOR DOCUMENTS IN THE FEMA 
SEISMIC CONSIDERATIONS SERIES 

The initial publications in the FEMA-funded Seismic Considerations Series, 
prepared by the Building Seismic Safety Council and published in the time 
period, 1988-1990, provided guidance on seismic safety and design-related 
issues to owners, managers, and designers of selected building types. The 
series consisted of the following documents: 

      Seismic Considerations, Elementary and Secondary Schools 
(FEMA 149 Report) 

      Seismic Considerations, Health Care Facilities 
(FEMA 150 Report) 

      Seismic Considerations, Hotels and Motels (FEMA 151 Report) 

      Seismic Considerations, Apartment Buildings 
 (FEMA 152 Report) 


      Seismic Considerations, Office Buildings (FEMA 153 Report) 
The documents were written to address seismic performance issues and cost-
effective strategies for improving building seismic performance through 
engineering approaches and procedures laid out in the then state-of-the-art 
NEHRP Recommended Provisions for the Development of Seismic Regulation 
for New Buildings 
(BSSC, 1988). 

Since 1990, a considerable amount of new knowledge and information has 
been developed and published under the National Earthquake Hazards 
Reduction Program (NEHRP), a broad multidisciplinary and Congressionally-
mandated research and development program, administered by four Federal 
agencies and funded at the level of approximately $100 million per year. The 
purpose of NEHRP is to improve the capacity of the nation's built environment 
to resist the effects of earthquake induced ground shaking and the collateral 
hazards of landslide, liquefaction, ground failure, inundation, and 
postearthquake fires. 

Major new seismic hazard mitigation tools and strategies developed in the 
1990s include: 

      	new seismic hazard maps, published by the U. S. Geological Survey, 
that incorporate (1) state-of-the-knowledge earthquake occurrence models, (2) 
state-of-the-knowledge ground motion attenuation relationships, and (3) new 
probability-of-occurrence levels that better characterize expected ground 
motions in regions of large, infrequent earthquakes; 

      	new performance-based seismic design concepts, criteria, and 
procedures, funded by FEMA and published in the FEMA 273 NEHRP 
Guidelines for the Seismic Rehabilitation of Buildings (ATC, 1997a), and its 
successor document, FEMA 356, Prestandard and Commentary for Seismic 
Rehabilitation of Buildings (ASCE, 2000), that enable the building owner and 
design engineer to evaluate and upgrade buildings to meet specific 
performance levels (e.g., collapse prevention, life safety, immediate occupancy, 
continued operation) for defined levels of earthquake ground shaking; and 

      	new seismic risk management strategies, developed largely by the 
private sector, which enable building owners and managers to reduce the 
financial impacts of earthquakes by diversifying the locations of operations, by 
obtaining higher levels of earthquake insurance, and by using securitization 
instruments, such as Catastrophic Bonds. 

These new technological developments provide the necessary tools for 
building owners and managers, with the assistance of design professionals, 
to make and implement cost-effective decisions regarding seismic safety and 
seismic hazard mitigation. They also provide the impetus and justification for 
updating the original Seismic Considerations Series documents, which are 
based on seismic hazard information and engineering knowledge and 
concepts developed in the 1970s and 1980s.





1.2 OBJECTIVES AND SCOPE OF THIS DOCUMENT 

The objectives of this report are fourfold: (1) to summarize, in a qualitative 
fashion, important new concepts in performance-based seismic design and 
new knowledge about the seismic hazard facing the United States (in a way 
that can be easily communicated to building owners and managers); (2) to 
describe a variety of concepts for reducing seismic risk, including the means to 
reduce economic losses that are not related to engineering solutions; (3) to 
provide illustrative examples and graphical tools that can be used by the 
design community to more effectively "sell" concepts of seismic risk 
management and building performance improvements; and (4) to establish a 
means by which seismic engineering and financial risk management can be 
integrated to 
form a holistic seismic risk management plan. The overarching goal of the 
document is to provide a means to facilitate communications between building 
owners/managers and design professionals on the important issues affecting 
seismic risk decision making during the design and construction of new 
facilities, as well as the operational phase. 


Stated another way, this report may be considered as a framework for 
integrating seismic risk management into already well established project 
planning, design, and construction processes used by most owners and 
designers. The report is intended to be used in: 

      	the initial project planning stages to address siting, general building 
performance considerations, and how the design process can incorporate 
performance-based design principles; 

      	the budgeting phase of a project to identify the resources that can 
be allocated to manage risk;

      	the design phase of a project to assist in the layout of structural 
systems, define performance objectives, and perform benefit-cost analyses of 
various building options; and 

      	the construction administration phase of a project to achieve a high 
level 
of quality assurance and control, thereby increasing the likelihood that the 
facility, as constructed, will perform as expected. 


In addition, the report provides information that pertains to risk management 
strategies that are not directly part of the project planning, design, and 
construction processes, but that owners and managers can use to mitigate 
earthquakes losses. These strategies, applicable to newly constructed 
buildings as well as existing facilities, should be considered in conjunction 
with engineering design and construction strategies when developing a holistic 
seismic risk management plan for a new building. Thus the report is intended 
to also be beneficial in: 

      	evaluating the benefits of earthquake insurance and quantifying 
coverage needs;

      	developing a postearthquake response and recovery program that 
may reduce down-time and potential loss of business following a 
major event;

      	calculating the benefits of diversifying operations geographically or 
among different buildings within a single campus; and 
      	dealing with the risks associated with other types of hazards, both 
natural and man-made.






1.3 DOCUMENT CONTENTS AND ORGANIZATION 
This document has been written and organized to assist building design 
professionals (architects and structural engineers) in communicating with 
building owners on earthquake risk, that is, to advise building owners on 
methods that could be employed to reduce their seismic risk.  It is recognized 
that many design professionals may not be familiar with emerging concepts in 
(1) seismic risk management, (2) performance-based seismic design, and (3) 
seismic design and performance issues related to the specific occupancies 
discussed in this report-commer-cial office facilities, retail commercial 
facilities, light manufacturing facilities, healthcare facilities, local schools 
(kindergarten through grade 12), and higher education (university) facilities. 
These topics are therefore discussed in detail, including illustrations and 
tables designed to be used by the building design professionals when 
communicating with building owners on the means to reduce their seismic 
risk. 

Seismic risk management is introduced and discussed in Chapter 2, including 
an overview discussion on seismic risk and discussions on a range of risk 
reduction strategies.  This chapter also describes issues to be considered 
when developing a risk management plan, addressed in the context of the 
likelihood of potential losses.  The identified risk reduction strategies consist 
of: (1) first cost or design strategies; (2) operating cost or business 
strategies, 
and (3) event response strategies.  Also included are discussions on the 
selection of an optimal combination of risk reduction strategies, example 
applications of seismic risk management strategies on real buildings, and 
advocacy of seismic risk management. 

The means for identifying and assessing earthquake-related hazards during 
the site selection process are described in Chapter 3.  The chap-ter begins 
with a discussion of current approaches for seismic shaking hazard 
determination and assessment in the United States, followed by discussions 
on the collateral seismic hazards of surface fault rupture, soil liquefaction, 
soil 
differential compaction, landsliding, and inundation. Chapter 3 also discusses 
other earthquake-related hazards affecting building performance, including 
vulnerable transportation and utility systems (lifelines), the hazards posed by 
adjacent structures, the release of hazardous materials, and postearthquake 
fires. Specific guidance for assessing these earthquake related hazards during 
the site selection process, including a checklist for use by design 
professionals, is provided at the end of this chapter. 

In Chapter 4, emerging concepts in performance-based seismic design are 
described. This chapter includes a discussion on (1) expected building 
performance when designing new buildings to current codes; and 
(2) state-of-the-art concepts in performance based seismic design, which were 
developed for the seismic rehabilitation of existing buildings and are beginning 
to be applied on a volunteer basis in the seismic design of new buildings. The 
chapter concludes with a description of next-generation performance-based 
seismic design products and tools for engineers and building 
owners/managers expected to become available over the next decade or so. 
Chapter 5 focuses on ways to reduce seismic risk by improving building 
performance, a first cost or design risk reduction strategy.  This chapter 
describes and discusses performance attributes of various structural systems 
and materials, selection of the architectural configuration, and the interaction 
of 
nonstructural components and systems with the building structure.  Also 
included is a discussion of the costs and benefits associated with improved 
performance, as well as actual case studies describing structural system cost 
and performance considerations. 

Building and expanding on the ways to improve seismic performance 
discussed in Chapter 5, the next six chapters (Chapters 6 through 11) briefly 
identify specific design issues associated with each of the six occupancy types 
considered in this document. In addition, each of these chapters provides 
examples of earthquake performance for that facility type and discusses 
performance expectations and requirements, and specific vulnerabilities.  
Chapters 6 and 7, respectively, address commercial office buildings and 
commercial retail buildings; Chapter 8 addresses light manufacturing facilities; 
Chapter 9 focuses on health-care facilities; and Chapters 10 and 11, 
respectively, address local schools (kindergarten through grade 12) and higher 
education facilities (universities). 

Chapter 12 addresses the various responsibilities of members of the design 
team, including the building owner, architect, structural engineer, and 
mechanical/electrical/plumbing engineers. This chapter also includes 
discussions on the added value of risk management and design and 
construction quality assurance. 

Following Chapter 12 are a list of references and a list of individuals who 
participated in the development of this report.





1.4 DOCUMENT FORMATTING AND ICONS 

Several icons, shown below, are used in highlighted portions of this document 
to emphasize pertinent information. 

The Definition icon defines key terms and acronyms. 

The Case Study icon provides practical and relevant information based on past 
experience. 

The Resources icon provides supplemental information from FEMA and other 
organizations that may impact design considerations and decision-making. 

The Cost Consideration icon identifies a value or investment cost that needs to 
be considered in decision-making. 

The Risk Consideration icon identifies a potential or real risk that needs to be 
considered in decision-making. 

The Design Consideration icon identifies a design issue that needs to be 
considered in decision-making.





SEISMIC RISK MANAGEMENT 2

Chapter 2 introduces and describes seismic risk management, beginning with 
an overview of seismic risk, followed by discussions on the holistic nature of 
seismic risk management and on strategies for reducing seismic risk.  These 
strategies fall into three categories:  (1) first cost or design strategies; (2) 
operating cost or business strategies, and (3) event response strategies.  Also 
included in this chapter are discussions on the selection of an optimal 
combination of risk reduction strategies, and example applications of seismic 
risk management strategies, including cost and performance considerations, 
described in three case studies. The chapter concludes with a discussion of 
the importance of seismic risk management advocacy. 


2.1 SEISMIC RISK: AN OVERVIEW 

the likelihood of adverse consequences resulting from the occurrence of an 
earthquake.  Seismic risk is typically defined as a function of three elements: 
(1) the seismic hazard or likelihood of occurrence of an earthquake and the 
associated severity of shaking, (2) the seismic vulnerability or expected 
damage to buildings and other structures given the occurrence of an 
earthquake, and (3) the expected consequences or losses resulting from the 
predicted damage. The third term, the expected consequences, is typically 
used to quantify the seismic risk to an individual facility, a group of 
facilities, or 
a region.  For a building, these consequences or expected losses can be 
broadly categorized as: 

      	Casualties - the death or injury of building occupants or passersby 
resulting from the building collapse, blockage of exits, or failure of
life safety systems;

      	Capital - the value of a building's structural and nonstructural sys-
tems, including the structural framing elements, partitions, clad-
ding, and mechanical, electrical, and plumbing systems;

      	Contents - the value of, for example, a building's fixed and movable
equipment, goods for sale, laboratory and manufacturing equip-
ment;

      	Business Interruption - the financial cost resulting from loss of 
operations; this consequence can be expressed in a variety of ways, 
depending on the use of the facility, e.g., lost revenue, inability to treat 
patients, 
teach students or conduct research; and 
      	Market Share - the future costs of losing a competitive edge; this 
consequence can also be expressed in a variety of ways, including loss of 
clients to competitors, having staff leave to work for competitors, and losing 
"prestige" and the business associated with an orga-nization's reputation.

 

Seismic risk, as defined above, can be reduced by a reduction in any of the 
three elements - seismic hazard, seismic vulnerability, and expected 
consequences.  Seismic hazard can only be reduced by relocation of the 
building itself, as the likelihood of an earthquake occurring at a site and the 
severity of shaking is a function of the regional seismicity and local geology. If 
the building site is a fixed variable, seismic hazard and seismic vulnerability 
are often considered as one factor - the likelihood that the building will sustain 
earthquake damage.  The combination of this factor, with the expected 
consequences given the occurrence of the earthquake damage, results in a 
measure of seismic risk.  Thus seismic risk can be reduced by decreasing the 
likelihood of building damage (e.g., by relocating the building or by increasing 
the earthquake resisting capacity of the structure) or by decreasing the 
expected consequences (e.g., by developing a response plan, geographically 
diversifying operations, or purchasing insurance). 

The concept of seismic risk, expressed as a function of the likelihood of 
damage and the expected consequences, is illustrated in Figure 2-1.  The 
likelihood of damage is shown along the horizontal axis, increasing from left to 
right.  As mentioned above, the likelihood of damage is a function of the 
seismic hazard level (expected earthquake occurrences and severity of ground 
shaking) and the seismic vulnerability (earthquake resisting capacity of the 
building).  The consequences or losses resulting from the earthquake damage 
(or "consequence" in the more general risk term) are depicted on the vertical 
axis, increasing from bottom to top.  The quantification of seismic risk is not a 
simple task; however, the graph shown in Figure 2-1 is simplified qualitatively 
as four distinct quadrants, each of which is described below with example 
scenarios. 

Quadrant I, Low Risk: low likelihood of damage and low consequences; 
examples include: 

      	A national chain retail store in seismically active northern California; 
the 
building has been designed to perform well during severe earthquake ground 
motions and potential loss of use of one building out of hundreds would not 
disastrously affect the owner's business. 

      	An abandoned warehouse in Texas; the seismic hazard is extremely 
low and the value to the owner is small. Quadrant II, Moderate Risk: low 
likelihood of damage and high consequences; an example is: 

      	A well-designed hospital in South Carolina; the probability of severe 
earthquake ground motions is low but the hospital has 100 critical care beds 
and an occupancy of 2,000. 


Quadrant III, Moderate Risk: high likelihood of damage and low consequences; 
an example is: 

      	A small storage facility for a national distributor located in a high 
seismic zone and designed to pre-1950 standards. The building is 
vulnerable to damage but the loss would likely be relatively unim-
portant to the owner.

Quadrant IV, High Risk: high likelihood of damage and high consequences; 
examples include: 
      	A private day care center designed by an inexperienced engineer
two miles from an active fault in a highly seismic region. Lack of
knowledge of the hazards associated with near fault sites could 
result in injury to dozens of children.

      	A high-tech chip manufacturing plant in southern California, designed 
and built to the minimum requirements of the current code.  The likelihood that 
a code-minimum building will experience extensive non-structural damage is 
high and business interruption could be devastating to the owner.




2.2 	SEISMIC RISK MANAGEMENT: A HOLISTIC APPROACH FOR 
REDUCING EARTHQUAKE IMPACTS 

Seismic risk management is simply the act of managing activities and 
One of the purposes of this document is to provide building design 
professionals with tools and strategies to help owners and managers make 
cost-effective seismic-risk management decisions. The document therefore 
describes and compares various strategies, including reducing the likelihood 
of earthquake damage and reducing consequences, or both.  The document 
also provides information on estimating future costs resulting from earthquake 
damage and other impacts as well as the costs to improve performance in 
future earthquakes. 

The likelihood of earthquake damage is a function of the seismic hazard at the 
site and the seismic vulnerability of the building.  Seismic hazard is addressed 
in the context of site selection and evaluation of site-specific earthquake-
related 
hazards, as discussed in Chapter 3.  Seismic vulnerability is addressed in the 
context of performance-based design, a relatively new tool (discussed in 
Chapter 4) that engineers can use to adjust up or down the earthquake 
resisting capacity of a building, depending on the desired performance in future 
earthquakes. 
Design variables and issues affecting seismic performance, along with 
guidance for calculating the cost of improving performance, are provided in 
Chapter 5.  Chapter 5 also discusses the cost of improved seismic 
performance versus the cost of future earthquake damage and loss, including 
indirect costs resulting, for example, from time out of service. The means to 
quantify these costs are also discussed. The key to making wise investment 
decisions, as discussed in Chapter 5, can be found in a three-step process 
that consists of: 

      	quantifying the amount and likelihood of losses that buildings may 
suffer 
in future earthquakes, 

      	estimating the expected reduction in future losses that can be 
achieved through various risk management programs, including 

performance-based design, and

      	calculating the costs of implementing these programs, and comparing them 
to the estimated reduction in losses. As with any other investment, the 
building owner weighs the expected return against the possible risk of not 
achieving that return.  Equally important is the need to weigh the cost of the 
lost 
opportunity if the investment is not made.  Examples abound in decision 
making involving such trade-offs, whether they relate to earthquake risk or other 
matters. Specific seismic risk management strategies that focus on reducing 
the consequences or losses associated with earthquake damage are 
addressed later in this chapter, in terms of financial or business strategies and 
response planning strategies.  Examples of these strategies include: 

      	diversifying operations so that all of an owner's opera-
tions are not concentrated in vulnerable buildings,

      	obtaining insurance or other financial instruments to 
cover potential losses,

      	establishing options to lease or buy replacement space 
after an event, or to immediately bring in contractors for
repairs, and 

      	implementing pre-event planning and developing post-
earthquake response and recovery programs to speed the 
process of business resumption.


It is often more effective, but typically more costly, to reduce seismic risk by 
reducing the likelihood that the earthquake damage will occur. By reducing 
seismic vulnerability, the uncertainties associated with estimating 
consequences of the expected damage and responding after a significant 
event are lessened.  However, the initial costs of providing improved 
performance may never be recovered if an earthquake doesn't occur during the 
functional life of the facility. Reducing seismic risk by reducing the estimated 
consequences of a damaging earthquake often involves lower spending on an 
annual basis or incurring costs to repair or restore functionality once the event 
occurs.  Large investments are not needed up front.  In this case, while the 
likelihood of damage is not reduced, the intent is to reduce seismic risk by 
enabling a quicker response and recovery. 

The move to a performance-based design philosophy is a significant advance 
that can assist in seismic risk management, if it can be efficiently implemented 
into the building code development and design process.





2.3 	EVALUATING SEISMIC RISK CONSEQUENCES AS A BASIS FOR 
DEVELOPING A RISK MANAGEMENT PLAN 

The first step in developing a seismic risk management plan is to determine 
the nature and magnitude of the current risks.  For a building or group of 
buildings, structural analysis procedures can relate potential damage to the 
intensity of shaking for a certain size earthquake.  As the size of the earthquake 
increases, so does the total potential direct and indirect loss.  Although the 
size 
of the loss increases with increasing magnitude, the likelihood of experiencing 
the loss decreases with increasing magnitude as the probability of earthquake 
occurrence also decreases with increasing magnitude.  

Based on the likelihood of potential losses, one can determine the presumed 
capability to manage loss.  Some owners and managers might rely on 
government assistance in combination with in-house resources to cover 
potential losses.  The limit of these funds to pay for recovery costs would define 
current manageable loss.  Losses in excess of this limit would be catastrophic 
and threatening to the business or institution.  Figure 2-2 demonstrates this 
concept; the horizontal line defines the boundary between manageable and 
catastrophic loss.  The intersection of the horizontal manageable loss line with 
the potential total loss curve defines the likelihood or risk of catastrophic 
loss. If 
this risk is too high, it can be reduced by increasing the capability to manage 
loss (moving the horizontal line up in Figure 2-2) and by reducing the potential 
loss curve with a higher performance objective for the building.  Note that in 
Figure 2-2, the likelihood of the potential loss occurring is directly related to 
the 
probability of the earthquake, i.e., a smaller magnitude event corresponds to a 
high potential for occurrence and a larger magnitude event corresponds to a 
low potential for occurrence. 

The capability to manage risks depends on the combination of several 
investment strategies on the part of facilities owners and managers.  The first 
source of recovery funding is out-of-pocket expenses using in-house resources to 
cover losses.  This may be supplemented by some sort of 
government disaster assistance.  For example, Stanford University covered all 
of its costs resulting from the 1989 Loma Prieta earthquake with its own funds, 
supplemented by funds from the Federal Emergency Management Agency and 
the California State Office of Emergency Services. Small businesses may be 
able to obtain low interest recovery loans to increase their own resources. 
Conventional insurance is a fairly common means of increasing manageable 
loss levels.  This may be appropriate for smaller owners, whereas capacity 
might be a problem for a large institution such as a major university or hospital 
organization.  Insurance rates fluctuate with the perceived market, and 
settlement delays can be quite costly in some cases. The capital markets may 
offer the flexibility to design financial instruments directly to suit an owner's 
specific needs using catastrophe bonds, which are effectively a combination of 
a loan and insurance.  Conventional insurance and capital market investments 
can be used to increase the capability to manage loss. As discussed in 
Section 2.5, the optimal combination of these alternatives depends on 
insurance market conditions, interest rates, bonding capacity of the building 
owner, and other factors.  Increasing the manageable loss level reduces the 
risk of catastrophic loss by elevating the horizontal loss limit line as 
illustrated 
in Figure 2-3. 

Other strategies that can increase the level of manageable risk include the 
establishment of postearthquake response and recovery programs, which may 
reduce the amount of lost operations time through rapid engineering 
inspection and construction or repairs, or by obtaining alternate operating 
space quickly after an event.  This is discussed further in Section 2.6. 
Another important element of a risk management plan involves increasing the 
expected earthquake performance of the building, thereby lowering the 
potential loss curve.  Mitigation reduces the risk of catastrophic loss by 
lowering the likelihood that the design earthquake would cause losses that 
exceed the manageable loss limit. The implementation of a mitigation strategy 
may include, as described in Section 2.4, designing new facilities to higher 
performance objectives, in order to limit losses over the building's life.  This 
can apply to the replacement of outdated facilities or new facilities required as 
a result of company expansion needs. 

The technical and financial parameters of a risk management plan all have 
associated uncertainties.  Selecting the optimal combination of risk 
management strategies requires consideration of these uncertainties to 
assess the reliability of the decision making process.  In addition, an integrated 
financial and technical model is necessary to test alternative strategies.  The 
end result is a risk management plan that maximizes the return on investment 
to manage losses and reduce risk to an acceptable level over a fixed future 
time period.  The flowchart shown in Figure 2-4 illustrates the various 
strategies that comprise a typical risk management plan and the options, or 
steps, for evaluating the strategies to select the optimal risk reduction 
solution. 
 
These three
 groups of strategies and related steps (outlined in Figure 2-4) are 
discussed in the next three sections.





2.4 FIRST COST OR DESIGN STRATEGIES 

First cost or design risk reduction strategies are techniques that reduce the 
likelihood of damage to a structure.  The term "first cost" is generally defined 
as 
an investment requiring a large capital outlay, whether or not it is truly spent 
near the start of a project. A capital investment of $10 million on a new building 
will most likely be amortized over some length of time, typically much longer 
than that actually required to construct the building. The owner is still 
responsible for the entire debt principal once the loan is secured, and often the 
debt goes "on the books" as a reduction in the amount of capital available for 
other investments. 

First cost strategies reduce damage potential by either reducing the site 
hazards associated with a building or by increasing the expected performance 
of the building. 


Reduce Site Hazards 

An owner can reduce site hazards by reducing the intensity of earthquake 
shaking expected at the building site over the life of the structure, and by 
eliminating or reducing the potential for other seismic hazards, such as fault 
rupture, liquefaction, landslide, and inundation.  Several techniques for 
accomplishing this are described below. 


Locate the building in a region of lower seismicity, where earthquakes 
occur less frequently or with typically smaller intensities.  This option is 
generally the most effective strategy solely in terms of reducing the potential 
for earthquake damage to a facility, whether it be caused by ground shaking, fault 
rupture, liquefaction, landslide, or inundation.  Locating a building in Dallas, 
Texas, for example, will almost guarantee that it will never be damaged by an 
earthquake.  Of course, this option isn't possible for many building owners. 
While certainly less desirable, and possibly quite costly from a market share 
and cost of operations standpoint, universities, manufacturing facilities, 
commercial offices and, to some degree, commercial retail owners, can use 
this strategy to manage their risks.  Although it may not be practical for a 
university to build a new classroom facility across the country, locating some 
services off the main campus may be an option.  For example, a university on 
the San Francisco peninsula located near the San Andreas Fault has 
considered siting a rare books depository approximately 75 miles south of 
campus, in an area of significantly less seismicity. It is also fairly common for 
high technology manufacturing plants to be located far from their headquarter 
locations, at sites with low seismicity such as Texas, Massachusetts, or Idaho. 
While it would be very rare for a retail establishment to make a siting decision 
based on seismic risk over the demographics of the market in a particular 
region, moving a store even a few miles in some cases can make a 
measurable difference in seismic hazard, e.g., moving a proposed building 
location from within a mile of a major fault to five miles away. 

Locate the building on a soil profile that reduces the hazard. Local soil 
profiles can be highly variable, especially near water, on sloped surfaces, or 
close to faults. In an extreme case, siting on poor soils can lead to 
liquefaction, 
landsliding, or lateral spreading.  Often, as was the case in the 1989 Loma 
Prieta earthquake near San Francisco, similar structures located less than a 
mile apart each performed in dramatically different ways because of differing 
soil conditions. Even when soil-related hazards are not present, the amplitude, 
duration, and frequency content of earthquake motions that have to travel 
through softer soils can be significantly different than those traveling through 
firm soils or rock. 

An owner who is concerned about the effects of soil properties on risk should 
be encouraged to consult geotechnical and structural 
engineers to gauge the potential hazards associated with differing site 
conditions.  These should be weighed against the costs, both direct and 
indirect, of locating the facility on soils that will result in better 
performance. 

Engineer the soil profile to increase building performance and reduce 
vulnerability.  If relocating to a region of lower seismicity or to an area with a 
better natural soil profile is not a cost effective option, the soil at the 
designated 
site can often be re-engineered to reduce the hazard. On a liquefiable site, for 
instance, the soil can be grouted or otherwise treated to reduce the likelihood 
of liquefaction occurring. Soft soils can be excavated and replaced, or 
combined with foreign materials to make them stiffer. The building foundation 
itself can be modified to account for the potential effects of the soil, reducing 
the 
building's susceptibility to damage even if liquefaction or limited landsliding 
does occur. 

The owner should weigh the additional costs of modifying the soil profile or the 
building foundation (which may be quite significant in certain cases) with the 
expected reduction in damage and loss.



Improve Building Performance 

An owner can reduce vulnerability by increasing the performance of the 
building, thereby reducing the damage expected in earthquakes.  There are two 
methods by which this is typically accomplished: 

Reduce the response of the building to earthquake shaking. An 
earthquake generates inertial forces in a building that are a function of the 
structure's mass, stiffness, and damping, and of the acceleration and 
frequency of the earthquake motion.  The parameters associated with the 
earthquake can only be altered by reducing hazards, as described above. While 
the actual mass of the building (the weight of the structure, contents, and 
people) typically cannot be significantly altered, the effective mass can be 
changed by providing special devices, such as passive or active mass 
dampers, that can effectively reduce the overall mass that is accelerated by the 
earthquake.  Stiffness can be altered by modifying the structural system (e.g., 
concrete shear wall, steel moment frame) or by using braces and seismic 
dampers.  The building's fundamental period, which is an important parameter 
in determining building response, can be significantly increased (and resulting 
forces reduced) by providing seismic isolating devices at the building 
foundation. 

Engineers familiar with the use of these response-modifying devices can 
relatively easily quantify both the costs and benefits of employing them in 
buildings.  When these types of products were new to the building industry, they 
were generally expensive.  Today, with competition in the marketplace, they are 
much more common and costs have dropped dramatically. 

Increase the capacity of the building to resist earthquake forces.  The 
most traditional method for decreasing vulnerability of buildings is to make 
them "stronger." By increasing the forces that a building can resist, such as by 
providing larger structural elements or increasing the amount of bracing for 
nonstructural systems, less damage would be expected.  This strategy can be 
costly and, in some cases, may not be the most efficient means of increasing 
performance. Another option is to increase the ductility of the structural or 
nonstructural systems, improving their ability to absorb the energy of the 
earthquake without permanent damage. 

Increasing the capacity of the building may be the most difficult strategy to 
quantify reliably because of the inherent complexity of most structural and 
nonstructural systems.  However, the range of possible solutions (and costs) 
for increasing capacity is relatively large, thus this strategy is the often 
employed because it allows the engineer to fine-tune a design approach to 
meet an owner's budget and risk management criteria.





2.5 OPERATING COST OR BUSINESS STRATEGIES 

Operating cost or business risk reduction strategies are techniques that 
primarily enhance the capacity to manage losses, by effectively reducing the 
consequences of damage.  The term "operating cost" is generally defined as 
an investment made on an annual or other regular basis.
 
Diversify Operations 

An owner with geographically-dispersed buildings, or with an inventory 
consisting of buildings of various ages and seismic performance 
characteristics, can reduce overall earthquake risk by moving certain 
operations to buildings located in regions of lower seismic hazard or to 
buildings of higher seismic performance.  This strategy can be fine-tuned when 
different operations carry different earthquake risks in terms of business 
disruption, loss of contents, or other impacts. For example, high resource 
operations, such as manufacturing or administration, can be relocated to new, 
higher performing buildings, while archival storage can be moved to older, 
more vulnerable ones.  This can be done incrementally as new buildings are 
brought on line or over a defined timeframe so as to minimize the impact on 
operations.
 
Consider the following example of two manufacturing businesses.  One runs 
100% of its production from a single building in San Francisco. The other runs 
50% each from one building in San Francisco and from one building in Seattle. 
There is a one percent annual chance in each city of an earthquake large 
enough to cause complete loss to the buildings. 


Company A 

100% operations in San Francisco 1% annual risk of complete loss to San 
Francisco building 
Overall result:  a 1% annual risk of complete business loss 

Company B 

50% operations in San Francisco 50% operations in Seattle 1% annual risk of 
complete loss to San Francisco building 1% annual risk of complete loss to 
Seattle building 
Overall result: 

      a 1% annual risk of 50% business loss due to San Francisco event
 
      a 1% annual risk of 50% business loss due to Seattle event
 
      a 2% annual risk of 50% business loss 

      a 0.01% annual risk of complete business loss (1% 1%) 


As the number of sites grows, the risk of suffering a catastrophic loss to the 
business drops exponentially, even though the risk of suffering some loss 
grows. This assumes, of course, that the sites are independent. Having two 
similar buildings in San Francisco, within a mile of each other might not 
decrease the risk as substantially since a single earthquake could affect both. 
This methodology is used by insurance companies regularly to spread out their 
risk and reduce the potential for a single disaster causing more claims than 
they can settle.



Obtain Higher Levels of Insurance 

An organization should ensure that it has a sufficient amount, and type, of 
insurance coverage to adequately protect against losses.  This determination 
is typically made by an owner's risk manager (or the insurance broker, acting 
on behalf of the owner).  The risk manager must assess the cost of insurance 
relative to the potential costs of accepting the risk without insurance coverage.  
In most cases, investments in risk reduction (e.g., improving building 
performance or relocating to a lower risk area) will also result in insurance 
premium reductions. The risk manager must balance these different options by 
assessing the life cycle costs and benefits of each option.  In order for the 
overall risk management plan to be effective, it is important for the 
organization's risk manager to become an integral part of the management 
team making facility decisions, and that communications with the facility 
manager and the design team be open and complete.


Using Securitization Instruments 

Conventional insurance is typically best suited for incidents that occur 
regularly, 
although possibly infrequently, such as fire and worker injury.  Conventional 
insurance is also appropriate for losses that are easily quantifiable, such as 
losses to capital and inventory. For very rare or catastrophic losses, however, 
obtaining insurance coverage can often be cumbersome or costly.  It becomes 
difficult to price insurance when the rates of incidents are uncertain and when 
coverage for indirect losses from business interruption or loss of market share 
is needed. 

A newer instrument, commonly called a Catastrophe Bond (Cat Bond) has 
recently garnered some attention.  Sold on the open market, the proceeds of 
these bonds (typically in the range of $10 million to $100 million) are held in a 
financially secure trust.  If an earthquake occurs within the period of the bond, 
and if the earthquake meets certain criteria in terms of size, location, or loss, 
some or all of the bond's principal or interest is forfeited to the seller to 
assist 
recovery.  While generally limited to reinsurance companies, a small number of 
large, private corporations have started offering Cat Bonds.  When insurance 
rates are low, Cat Bonds are generally less attractive.  However, when 
insurance rates are high, as is common after a disaster, bonds become more 
economical. 

Large investment banks are generally the best source to help an owner explore 
securitization options.  The owner should have adequate understanding of his 
or her expected losses in different events, however, so that the amount of the 
bond and the interest payments can be as small as possible and yet still cover 
potentially catastrophic damage.  Design team members well versed in 
performance-based design, risk assessment, and loss estimation, can be a 
valuable resource to owners in this effort.




2.6 EVENT RESPONSE STRATEGIES

The goal of event response risk reduction strategies is to manage potential 
losses through quick recovery and response to damage caused by 
earthquakes.  Similar to operating cost or business strategies, event response 
focuses on reducing the consequence of damage and loss, rather than 
reducing the likelihood of damage and loss occurring. Relative to first cost or 
design strategies, event response typically requires much lower initial costs, 
as well as lower annual operational costs.  While event response does not 
typically reduce capital losses or the amount of repair that may be needed, it 
can speed up the process of recovery through effective pre-event planning. 


Emergency Response Procedures and Materials 

The simplest form of an event response strategy can consist of maintaining 
procedures, equipment, and materials on-site for aiding the evacuation of 
building tenants.  Most companies and institutions have at least a basic 
emergency kit and response procedures for evacuating people from a 
potentially hazardous building after an earthquake or during a fire. This level of 
planning can be implemented at a minimal cost. It may aid in the evacuation of 
the building and the treatment of injuries, but will not reduce capital or 
business interruption losses.


Pre-Event Disaster Training and Inspection Services 

A second strategy is to develop and provide formal disaster training for 
employees and building personnel. Many large companies have instituted 
basic emergency response training for their employees, which includes basic 
safety and medical training.  It may also include primer level education on how 
buildings respond in earthquakes and what telltale signs of building damage 
might indicate potential safety or operational hazards.  These programs are 
generally not technically sophisticated, and are not intended to be a substitute 
for professional emergency response or engineering personnel.  They can, 
however, reduce lost time in the event that damage is minimal and if building 
occupants are efficiently organized in the recovery effort. 

A key component of event response is the ability to adequately identify what 
building damage means in terms of occupant safety and building functionality. 
To be done reliably, this requires the use of professional engineers and 
architects who have taken comprehensive training in the evaluation of 
earthquake damaged structures.  Building owners and tenants can not 
reasonably be expected to accept the liability of deciding whether a building is 
safe to occupy.  Thus, post-event engineering inspections are an important tool 
in an overall event response strategy. Large organizations will typically keep 
architects or structural, mechanical,
and electrical engineers on retainer to quickly respond after a major event.  They 
will be authorized to make safety 
inspections of owner's 
facilities using guidelines typically established by the local jurisdiction, such 
as 
the ATC-20 post-earthquake building safety evaluation procedures (ATC, 1989, 
1995, 1996).  They will then make recommendations to the building owner and 
put up signs noting whether the building is safe to enter, unsafe, or has 
restricted access in some fashion. 
 
For owners or tenants of several buildings, this strategy should include the 
entire network of buildings that could be affected by an earthquake.  Inspectors 
will be used most efficiently if they are sent to the buildings that are most 
severely damaged. For critical facilities, such as hospitals, it is advantageous 
to predict in advance the expected safety inspection postings-INSPECTED 
(green placard), RESTRICTED USE (yellow placard), and UNSAFE (red 
placard)-for all buildings on site. Procedures to be followed in developing and 
using such posting predictions are provided in the ATC-51-1 report, 
Recommended U.S.-Italy Collaborative Procedures for Earthquake Emergency 
Response Planning for Hospitals in Italy (ATC, 2002)



On-Retainer Temporary Space and Repair Contractors 

A relatively new strategy being employed by some businesses is to obtain 
disaster lease or repair options for their facilities.  Organizations may execute 
agreements with local contractors and property owners to provide them with a 
choice of available temporary space and for the labor necessary to repair 
damaged facilities.  If an organization's buildings are damaged to the point that 
they are not functional and need significant repair, the owner would have the 
first right of refusal on any available space that a landlord has, at an agreed-
upon set of pre-event prices, and on the use of personnel from local 
contractors.  The organization, in return, provides a yearly retainer for the 
service. 
Contingency planning companies offer building owners a service referred to as 
a "hot site." This is typically a fully equipped and functional facility (usually 
office 
space) that can be occupied fairly rapidly, whenever the owner's facility 
becomes unusable as the result of a natu-ral or man-made disaster.  Such a 
service can significantly reduce or eliminate the costs of business disruption 
resulting from earthquake damage.  The service does not usually include the 
repair of the owner's damaged facility.


Facility and Data Mirroring 
A formal business occupancy resumption program may include developing 
procedures by which critical information and the ability to conduct business are 
backed up or duplicated at alternate sites. This can range from electronically 
backing up and storing computer data at an off-site location to supplying 
company-wide transportation assistance to and from the employees' place of 
business, to having a plan to swiftly relocate operations to other offices or 
locations. Depending on the nature of the business, one or more of these 
options may be applicable.


Emergency Operations Centers 

An emergency operations center is typically a hardened facility in which 
managers can conduct the emergency response and recovery effort. This 
facility will be constructed or located so that it can be operational after a 
major 
event. It should house emergency communications equipment, information on 
buildings and their contents, and have access to maps and information 
detailing the extent of damage both to the owner's facilities and the surrounding 
areas.  The emergency operations center should be stocked so as to remain 
operational for at least 72 hours. For owners with large inventories of buildings 
or where a complex network of inspection and recovery is needed, the creation 
of an emergency operations center can be an effective strategy to ensure that 
building safety is rapidly evaluated and business resumption can occur as 
soon as it is safe and possible to do so. 



2.7 CHOOSING AN OPTIMAL COMBINATION OF
RISK REDUCTION STRATEGIES

Choosing an optimal combination of risk reduction strategies among those 
described above involves weighing the costs and potential savings associated 
with each option. The goal is to determine which combination results in the 
best return on investment.  The basic steps that should be taken to identify an 
optimal combination of risk reduction strategies include the following. 

1.	Identify potential losses. These losses include, as described earlier, 
capital, contents, casualties, business interruption, and market share. A 
qualitative description of the type of damage that could be suffered is an 
appropriate starting point.  This should include the use of engineering 
evaluation and performance-based design (see Chapter 4).  For a range of 
earthquake scenarios or probabilities, a description of the type of capital and 
contents damage, estimates of casualties, and estimates of the duration of 
business interruption can be made by evaluating the structural and 
nonstructural behavior of the building under the given shaking intensity (See 
Section 
5.7 for additional discussion). The design team and facilities staff should work 
as a team to identify, as examples, how long building operations will be shut 
down if shear walls in a building are cracked to the extent that structural repair 
is necessary, or what the average continuous occupancy of a classroom is over 
the course of a month. 

2.	Quantify losses. After the losses are qualitatively identified, they need to 
be translated into a common quantitative measure.  The total value of both 
anticipated direct and indirect losses should be determined.  In some cases, 
indirect losses will need to be converted into a direct cost equivalent through a 
value-based conversion; e.g., total manufacturing days lost, or hospital bed 
days lost.  

3.	Identify risk reduction strategies. Once losses have been quantified, the 
design team and owner's representatives should explore methods for reducing 
these losses, using the strategies described above; i.e., first cost or design 
strategies, operating cost or business strategies, or event response strategies.  
The team should identify as many options within each method as practical, 
estimating the cost to implement each and the expected savings in terms of 
reduced losses. 

For first cost or design strategies, various performance objectives should be 
considered for the new building.  For example, the baseline scheme would be 
a building that meets the minimum provisions of the applicable building code.  
A higher performance objective might be one in which the building is not 
necessarily functional after the design event, but in which operations can be 
restored within a relatively short period of time. A still higher performance 
objective may be a building that is designed to remain fully functional in the 
design event. For each higher performance option, a conceptual level of 
structural and nonstructural design should be performed to determine an 
approximate cost difference above the baseline option.  It is generally sufficient 
to make rough order approximations of costs. 

For each design strategy, the performance of the building is then translated into 
an expected loss (both direct and indirect) in a range of earthquake scenarios 
with different probabilities of occurrence. To facilitate comparisons, these 
should be translated into an expected annual loss and converted to a present 
value at an assumed discount rate. 

For operating cost or business strategies, different options such as insurance, 
securitization, and lease/repair options should be explored.  The annual 
premiums to obtain specified amounts of insurance can be calculated with the 
help of the owner's insurance brokers.  It is important to understand whether 
the insurance will also cover business interruption losses, or only capital and 
contents.  For larger owners, catastrophe linked securities can also be 
considered.  Typically, the coverage provided by such securities ranges from 
$10 million to $100 million, so smaller entities would not find these products 
appropriate. Lease/repair options can be developed with contractors and 
landlords in the nearby vicinity of the building, typically for an annual retainer 
fee. For all of these options, annual costs should be converted to a present 
value in order to facilitate a comparison with the other strategies. 

For event response strategies, the design team should develop an outline of 
some specific options, such as a post-earthquake inspection program or the 
establishment of an emergency operations center. Annual or initial costs can 
be relatively easily estimated from this, as they will typically be small relative 
to 
the other strategies. The main benefit of this strategy will be to reduce down 
time as a result of better pre-event planning.  The resulting savings should be 
approximated in terms of the daily cost of lost operations, multiplied by the 
expected reduction in lost time.  These costs and savings should also be 
annualized and converted to a present value for comparison purposes. 

4.	Select and implement strategies.  Once the various options within each 
strategy group have been evaluated and quantified, the team should consider 
permutations of each to determine the ones with the overall greatest benefit-to-
cost ratios.  Other factors may make certain strategies less desirable (such as 
the difficulty of a local school commission passing a bond measure for a 
seismic improvement capital outlay).  Where appropriate, each option should 
be given a weight-ing factor to express its desirability apart from purely 
economic factors. Once the optimal combination of strategies is selected, the 
owner and design team should develop a plan to implement them 
as part of the overall design process.




2.8 EXAMPLE IMPLEMENTATION OF A RISK MANAGEMENT PROGRAM 
2.9 
The following example illustrates how a hypothetical company might develop a 
risk management program. 

Description of company 

A Hayward, California company manufactures computer memory boards for 
large computer makers. The company's annual revenues are $100 million. All 
manufacturing is done in a single building with administration in a separate 
facility located in the same office park about three miles from the Hayward 
Fault. The company is planning to expand in the next three years, to double its 
annual revenues. It will buy a second manufacturing facility and construct a new 
office building. 

Establishment of risk tolerance 

Because the company currently has only four major clients it has determined 
that the risk of losing a substantial amount of revenue due to being dropped by 
a client is intolerable. It has decided to permit no more than 5% annual chance 
that lost client revenue exceed 10% of its revenue. Being near the Hayward 
Fault, the company concludes that it should not arbitrarily tolerate a large 
earthquake risk. 

Current seismic risks 

The company has conducted an engineering analysis of its current buildings 
and calculated the seismic risk. In a Hayward Fault event with a 5% annual 
chance of exceedence, capital and contents losses could reach $10 million. 
Loss of operations could cost another $25 million. The total direct losses of 
$35 million exceeds 10% of the company's revenue. 

Risk Management Strategies 

First cost / design strategies - The company can either buy new properties in 
the same office park or across the San Francisco Bay. By grouping all the 
buildings in the same location, the seismic hazard remains unchanged. 
However, the consequence of an earthquake on the Hayward Fault is 
increased because all of the buildings are likely to be affected. By separating 
the buildings geographically, the vulnerability of all four buildings being 
damaged by an earthquake in a year becomes negligible, although the chance 
that at least two of them will be affected by any event goes up. Engineers 
calculate that diversifying the regional location of operations reduces the 
overall 
risk most effectively. This results in reduced capital, contents and business 
interruption losses associated with a 5% annual chance of exceedence to $31 
million, or 15.5% of the now doubled $200 million annual revenues. 
Operating cost / business strategies - The company considers two operating 
cost options to further reduce the risk to its target tolerance. It can either 
obtain 
insurance to cover the remaining losses not managed by the improved first 
cost strategies, or it can implement a program of incremental retrofit of the two 
manufacturing buildings, to reduce their vulnerability. The company decides 
that the most cost effective option is to obtain insurance to cover (after 
deductibles) $5,000,000 of remaining potential losses above its tolerance. This 
represents 2.5% of the company's annual revenues 
Event response strategies - The company decides to establish a post-
earthquake response program, whereby it contracts with local engineers and 
contractors to provide immediate post-event inspections and repair design. 
The annual cost of developing and maintaining the program is $40,000 per 
year for the four buildings. The company conservatively estimates that in a 
moderate-to-large earthquake it could save at least a week-and-a-half of lost 
operations by having an engineer on board immediately. This equates to $6 
million, or 3% of the annual revenue. 

The three strategies together result in the following risk management program 
that meets the company's tolerance. 

Vulnerability assumes hazard with 5% annual chance of exceedence: 

First cost strategy: Total losses = $31 million (15.5% of revenues) 

Operating cost strategy: Reduces total losses by $5 million, to $24 million 
(11% of revenues) 

Event response strategy: Reduces business interruption and total losses 
by $6 million, to $20 million (10% of reve
nues)




2.9 SEISMIC RISK MANAGEMENT ADVOCACY
 
Corporate cultures, especially those related to perception and tolerance of risk, 
are difficult to change.  As a result, encouraging a corporate or institutional 
mindset to place a higher emphasis on seismic risk man-agement will usually 
require one or more "champions" who can work from both within and outside 
the organization. 

From within an organization, the organization's risk manager or a top level staff 
member from the facilities department is the likely most appropriate in-house 
champion, as these individuals are likely to have both a broad understanding of 
the company's corporate and business goals, and detailed knowledge of the 
design and construction process. The in-house champion will be expected to 
introduce seismic risk management standards, establish design priorities, 
quantify the consequences of losses, develop ongoing risk reduction 
processes, and keep the facilities department staff aware of their activities and 
findings.  This champion must also be able to persuade upper level 
management of the need for such changes in policies and procedures.  This 
will often require that the in-house champion "speak" in two languages - one 
technical and the other financial. 

The design team should also act to champion the seismic risk management 
cause at early stages of discussion regarding a new building.  In current 
practice, most design teams are organized under the direction of the project 
architect, who typically has a direct relationship to the building owner. 
Therefore, the external champion may be someone from within the project 
architect's office. 

It is important that both internal and external champions believe that seismic 
risk management truly adds value to their services and to the overall design 
process.  Additionally, the external champion should establish a relationship 
with the internal champion, in order to leverage and support each others efforts, 
and to further the risk management process. 




IDENTIFYING AND ASSESSING EARTHQUAKERELATED HAZARDS 3 

3.1 INTRODUCTION 

This chapter provides an overview of earthquake-related hazards affecting 
buildings as well as guidance on how to consider these hazards in the site 
selection process for new buildings. While seismic shaking is potentially the 
greatest threat, the collateral seismic hazards of fault rupture, liquefaction, 
soil 
differential compaction, landsliding, and flooding (inundation) could also 
potentially occur at a site. In addition, there are other hazards associated with 
the built environment that may affect building performance in the earthquake 
aftermath.  These include:  (1) hazards arising from external conditions to the 
site, such as vulnerable lifelines (transportation, communication, and utility 
networks) and hazardous adjacent structures, including buildings close 
enough to pound against the building that is to be constructed at the site; (2) 
storage and distribution of hazardous materials, and (3) postearthquake fires. 
Section 3.2 discusses seismic shaking hazards, including the current technical 
and code approaches for quantifying the shaking hazard. Section 3.3 identifies 
and discusses the collateral seismic hazards that should be considered in 
selecting an appropriate site for a new building (fault rupture, liquefaction, 
soil 
differential compaction, landsliding, and flooding). The other collateral hazards 
that could affect site selection decisions (vulnerable lifelines, hazardous 
adjacent structures, storage and distribution of hazardous materials, and 
postearthquake fires) are discussed in Section 3.4. Specific guidance on 
actions to be taken to assess earthquake-related hazards during the site 
selection process, including a checklist for site analysis, are provided in 
Section 3.5. Resources for further reading are provided in Section 3.6.  All 
sections are written in technical terminology appropriate for design 
professionals to aid in communicating with building owners and managers. 


3.2 EARTHQUAKE GROUND SHAKING HAZARD 

The effects of ground shaking on building response are well known and 
extensively documented.  Severe ground shaking can significantly damage 
buildings designed in accordance with seismic codes (Figures 3-1 and 3-2) 
and cause the collapse of buildings with inadequate seismic resistance 
(Figures 3-3 and 3-4).  

Figure 3-1	Six-story concrete-moment-frame medical building that was 
severely damaged by the magnitude-6.8 Northridge, California, earthquake of 
January 17, 1994. The building was subsequently demolished without 
removing contents. (photo courtesy of the Earthquake Engineering Research 
Center, University of California at Berkeley) 
Figure 3-2	Eight-story reinforced-concrete-frame office building in Kobe, 
Japan that partially collapsed during the magnitude-7.8 earthquake of January 
17, 1995. Note that the sixth floor is missing, due to collapsed columns at that 
level. Seismic codes in Japan are essentially equivalent to those in the United 
States. (photo courtesy of C. Rojahn) 

Quantifying the Earthquake Ground Shaking Hazard 

Seismic shaking is typically quantified using a parameter of motion, such as 
acceleration, velocity, or displacement.  In current seismic codes, seismic 
design forces are defined in terms that relate to acceleration in the horizontal 
direction.  A typical acceleration time-history of strong ground shaking is shown 
in Figure 3-5. 

The earthquake ground shaking hazard for a given region or site can be 
uncertainty in the assessment, at the building site for a selected or scenario 
earthquake.  Typically, that earthquake is selected as the maximum-magnitude 
earthquake considered to be capable of occurring on an identified active 
earthquake fault; this maximum-magnitude earthquake is termed a 
characteristic earthquake. A deterministic analysis is often made when there is 
a well-defined active fault for which there is a sufficiently high probability of 
a 
characteristic earthquake occurring during the life of the building.  The known 
past 
occurrence of such an earthquake, or geologic evidence of the periodic 
occurrence of such earthquakes in the past, are often considered to be 
indicative of a high probability for a future repeat occurrence of the event. 

Probabilistic hazard assessment expresses the level of ground shaking with a 
specific, low probability of being exceeded in a selected time period, for 
example 10% probability of being exceeded in 50 years, or 2% probability of 
being exceeded in 50 years, where 50 years is commonly chosen as the 
building design life.  The seismic loading criteria in current U.S. building codes 
define design force levels based on ground motions specified in probabilistic 
seismic hazard maps.  Such maps include those showing expected peak 
ground acceleration and those showing expected peak spectral acceleration 
response at different building periods of vibration. Figure 3-6, which was 
prepared by the 
U.S. Geological Survey National Seismic Hazard Mapping Project, illustrates a 
probabilistic seismic hazard map showing the regional variation of ground 
shaking hazard in the contiguous United States. 

This map indicates that, although the level of earthquake activity is high in 
California, most parts of the United States are also exposed to a sig
Missouri, Arkansas, South Carolina, Nevada, Idaho, Montana, Washington, 
Alaska, and Hawaii.  Furthermore, current geologic studies have shown 
increasing evidence for large earthquake potential in areas that are popularly 
believed to be relatively quiet.  Examples include the now-recognized 
subduction zones in Oregon and Washington, the Wasatch fault 
zone in Utah, and the Wabash Valley seismic zone in Illinois and Indiana. 

Probabilistic estimates of ground shaking at a given site can also be 
determined from a probabilistic ground shaking analysis for the site (often 
termed a "probabilistic seismic hazard analysis" or PSHA), whereby a 
geotechnical engineer determines and integrates contributions to the 
probability of exceedance of a ground motion level from all earthquake faults 
and magnitudes that could produce potentially damaging ground shaking at 
the site.  Figure 3-7 illustrates relationships, termed "hazard curves," which 
indicate the level of peak ground acceleration and annual frequency of 
exceedance for specified locations in seven major cities in the United States 
(which have been obtained from the USGS National Seismic Hazard Mapping 
Project).  From relationships such as those shown in Figure 3-7, ground 
motions can be readily obtained for any selected probability of exceedance and 
building design life. 

For applications in performance-based design (see Chapter 4), both a 
probabilistic approach and a deterministic approach for the ground shaking 
hazard assessment may be used.  Using a probabilistic approach, the seismic 
hazard can be integrated with the building resis-tance characteristics to 
estimate expected damage or loss, or the probability of exceeding some level 
of damage or loss, during a time period of significance such as the anticipated 
building life or the period during which the building will have a particular use.  
Using a deterministic approach, the expected damage or loss, or the 
probability of exceeding either a specified damage level or a specified loss, 
may be assessed for an earthquake considered to be sufficiently likely that 
satisfactory building performance during the earthquake is desired. 


Determining Design Ground Motions for a Specific Site 

Design ground motion for a given site can be obtained from national ground 
motion maps, such as the map shown in Figure 3-6, which defines ground 
shaking for a reference (standard) rock condition.  When using the national 
ground motion maps (e.g., Figure 3-6) to define design ground motions for a 
given site, published soil factors are used to adjust the mapped values to 
reflect the soil conditions at the site.  National ground motion maps include 
purely probabilistic hazard representations (peak acceleration response with a 
2% probability of exceedance in 50 years, or 10% probability of exceedance in 
50 years), as developed by the U.S. Geological Survey (Frankel et al., 1996; 
Frankel et al., 2000; Frankel and Leyendecker, 2000). Maps of modified levels 
of these hazards incorporate deterministic bounds on ground motions near 
highly active faults.  Maps containing deterministic bounds, which are termed 
Maximum Considered Earthquake (MCE) maps, are found in the 2000 NEHRP 
Recommended Provisions for Seismic Regulations for New Buildings and 
Other Structures (FEMA 368 report) and its companion Commentary (FEMA 369 
report), or in the 2000 International Building Code (IBC). Site factors to adjust 
the level of ground shaking from the reference rock condition to various softer 
soil conditions are also contained in the FEMA 368 NEHRP Recommended 
Provisions for Seismic Regulations for New Buildings and Other Structures 
(BSSC, 2001) and the IBC (ICC, 2000). 

Site-specific studies can also be done to supplement or bypass the national 
ground motion maps.  Such studies are most often undertaken for sites having 
soft soil conditions not covered by site factors published in the EMA 368 
NEHRP Recommended Provisions for Seismic Regulations for New Buildings 
and Other Structures or the IBC, for sites close to earthquake faults, and for 
buildings considered to be of sufficient importance to warrant additional focus 
on regional and area-specific factors affecting ground shaking.  Site-specific 
studies offer the potential for a more detailed analysis of the uncertainty in the 
seismic ground shaking hazard, as discussed below. If site-specific studies 
are conducted, they should be comprehensive and be subjected to detailed 
peer review. 


Uncertainty in Hazard Assessment 

Whether the seismic shaking hazard is estimated probabilistically or 
deterministically, there is always uncertainty in the hazard assessment and in 
the assessment of building performance. To provide a robust assessment of 
hazard, it is important to incorporate the uncertainty in aspects such as: 

magnitude of the largest (i.e., characteristic) earthquake that can 
occur on an earthquake fault;

recurrence rates of earthquakes of different magnitudes on a fault; 

the most applicable ground-motion-estimation relationship for a 
particular site, given the available models published in the technical literature; 
and 

site response effects. Each of these examples of uncertainty will have a 
different impact on a seismic ground shaking hazard assessment, and studies 
to assess the sensitivity of the hazard uncertainty on building performance are 
often conducted by multidisciplinary teams containing both seismologists and 
engineers. 




3.3 COLLATERAL SEISMIC HAZARDS 

compaction, landsliding, and flooding (inundation) - that are potentially so 
severe that they could impact development costs to such a degree as to cause 
the site to be rejected.  Although such a severe condition is uncommon, the 
potential occurrence of these hazards during earthquakes should be 
considered during the site selection process.  It should be 
noted that most current seismic design codes are not intended to prevent 
damage due to collateral seismic hazards.  The codes provide minimum 
required resistance to earthquake ground-shaking without consideration of 
settlement, slides, subsidence, or faulting in the immediate vicinity of the 
structure. Following are brief descriptions of these collateral hazards and their 
potential consequences. 

California, earthquake (a thrust fault earthquake). (Photo cour
tesy of the Earthquake Engineering Research Institute.) 
Surface Fault Rupture. Surface fault rupture is the abrupt shearing 
displacement that occurs along a fault that extends to the ground surface when 
the fault ruptures to cause an earthquake (Figure 3-8).  Generally, a fault 
rupture extends to the ground surface only during earthquakes of magnitude 6 
or higher.  Surface fault shear displacements typically range from a few inches 
to a foot or two for a magnitude 6 earthquake, to 10 feet or more for a 
magnitude 7.5 earthquake.  Because fault displacements tend to occur along a 
relatively narrow area defining the fault zone, large displacements may have 
catastrophic effects on a structure located directly astride the fault. 
Soil Liquefaction.  Soil liquefaction is a phenomenon in which a loose granular 
soil deposit below the ground water table may lose a substantial amount of 
strength due to earthquake ground shaking. There are many potential adverse 
consequences of liquefaction, including small building settlements, larger 
settlements associated with reduction of foundation bearing strength, and 
large lateral ground displacements that would tend to shear a building apart.  
An often cited soil liquefaction failure is shown in Figure 3-9. 

Soil Differential Compaction.  If a site is underlain by loose natural soil 
deposits, or uncompacted or poorly compacted fill, earthquake ground shaking 
may cause the soil to be compacted and settle, and differential settlements 
may occur due to spatial variations in soil properties. 

Landsliding. Hillside and sloped sites may be susceptible to seismically-
induced landslides.  Landslides during earthquakes occur due to horizontal 
seismic inertia forces induced in the slopes by the ground shaking.  Buildings 
located on slopes, or above or below slopes but close to either the top or the 
toe of the slope, could be affected by landslides. Landslides having large 
displacements have devastating effects on a building. An example of a building 
damaged by a landslide is shown in Figure 3-10. 

Inundation. Earthquake-induced flooding at a site can be caused by tsunami 
(coastal waves caused by some large offshore earthquakes), seiche (waves in 
bounded bodies of water caused by ground motion), landslides within or 
entering bodies of water, and the failure of dams. Such hazards are uncommon 
but need to be considered because of the potentially devastating 
consequences for sites located in inundated areas. The tilting of a structure 
caused by tsunami is shown in Figure 3-11.


 
3.4 OTHER COLLATERAL HAZARDS 

In addition to the seismic shaking hazards described in Section 3.2 and the 
collateral seismic hazards described in Section 3.3, there are other 
hazards that are indirectly related to earthquake events. In general, 
building owner and the site selection team.  These include: 

(1) hazards such as vulnerable lifelines (transportation, communication, and 
utility networks) and hazardous adjacent structures, including buildings close 
enough to pound against the building that is to be constructed at the site; (2) 
the storage and distribution of hazardous materials, and (3) postearthquake 
fires.  These other collateral hazards and 
their potential impacts are described below. 

Vulnerable Lifeline Systems. Earthquake damaged lifeline systems 
(transportation, communication, and utility networks) may impede the provision 
of necessary utility functions, or access to the building site in the 
postearthquake aftermath.  Such eventualities are largely outside the control of 
building designers and managers.  The loss of potable water as a result of 
damage to water storage and distribution systems would make most facilities 
unusable, as would loss of power due to damage to electric power generation 
facilities and electric power regional and local distribution lines.  Access to 
certain facilities, such as hospitals, can also be problematic, as for example, in 
the case of a hospital that is otherwise operable but is inaccessible because of 
damage to access highways and bridges.  

There are numerous examples of transportation lifeline failures during 
earthquakes and the consequent disruption to facility access.  These include 
freeway bridges damaged during the 1989 Loma Prieta earthquake near San 
Francisco, and freeway bridges damaged during the 1971 San Fernando and 
1994 Northridge earthquakes near Los Angeles.  One of the most serious 
lifeline losses in recent years was the collapse of an upper-deck span on the 
Oakland-San Francisco Bay bridge during the Loma Prieta earthquake, which 
resulted in the closure of the bridge for one month for damage repair.  This 
closure impacted the economy on both sides of the San Francisco Bay, 
because the 250,000 daily users of the bridge had to find alternative routes or 
postpone the transportation of goods and services, commuting to work, and 
traveling for other purposes, such as to schools, medical facilities, shopping 
centers, and other business operations. 

Pounding and Hazardous Adjacent Structures. In dense urban settings, there 
exists the potential for closely spaced buildings to pound against each other 
(Figure 3-12).  Pounding occurs when buildings with different dynamic response 
characteristics, which are governed by building stiffness 
(period of vibration), floor height, and number of stories, 
buildings are dissimilar. Pounding has caused severe damage and even 
collapse in urban earthquakes, such as during the magnitude-8.1 earthquake 
that affected Mexico City in 1985.  Although building codes call attention to this 
problem, building designers are often reluctant to provide the necessary space 
between buildings to eliminate the problem, principally because the required 
space would reduce available square footage in the building being developed. 
Consequently, adequate seismic gaps between buildings are seldom 
implemented in densely populated urban areas of seismically hazardous 
regions of the United States. In Japan, even with the acute shortage of space in 
its largest cities, the problem is taken seriously, with new buildings seldom 
built closer than a meter or so from adjacent structures.  In suburban or 
campus-type site planning in which building sites tend to be much larger, the 
problem seldom arises. 

Closely spaced buildings in dense urban environments are also subjected to 
the failure of hazardous adjacent buildings or building components.  The 
problem is most acute if there is an older adjacent building, built to less 
stringent seismic codes, that is taller than the new building being constructed.  
Designers should carefully assess neighboring structures and design against 
possible falling objects from them (e.g., unreinforced parapets, walls, or 
chimneys).  In the 1989 Loma Prieta earthquake, several fatalities were caused 
when a large portion of an unreinforced masonry building collapsed onto the 
roof of a lower adjoining building. A typical failure is shown in Figure 3-13. 
Storage and Distribution of Hazardous Materials.  Hazardous materials, such 
as stored toxic chemicals in industrial buildings, laboratories, and other 
facilities, can be extremely dangerous to building occupants and neighboring 
facilities if released during an earthquake due to the fall and failure of 
containment vessels.  The release of natural or liquefied petroleum gas from 
earthquake damaged storage or pipeline distribution systems can also be 
potentially hazardous, not only from the toxic standpoint but because of the 
potential for postearthquake fires (see below).  

Postearthquake Fires.  Historically, fires have been one of the most common 
and damaging hazards associated with earthquakes.  Extensive fire damage 
occurred following the San Francisco earthquake of 1906, and the destruction 
and life loss in 1923 in Tokyo were largely the result of postearthquake fires 
(Figure 3-14).  More recently, entire neighborhoods were destroyed by fire after 
the 1995 earthquake in Kobe, Japan. 

The potential for postearthquake fires depends on the number and proximity of 
ignition sources, the availability of fuel, and the fire-fight-ing capability, 
which 
relates to available manpower, available fire-fight-ing equipment, and available 
water for fighting fires.  Building codes in the United States have extensive 
provisions ensuring that the materials of construction reduce the fuel content of 
buildings and that building planning and construction, including the provision of 
space around buildings for vehicular access and for fire-fighting equipment, 
provides for the safety of occupants. Modern construction codes have 
significantly reduced the risk for steel and reinforced concrete buildings, but 
wood-frame construction, the most dominate type of construction in the United 
States, remains extremely vulnerable to postearthquake fires because of the 
flammability of the material.  Sources of ignition include overturned gas water 
heaters and earthquake damaged gas distribution pipelines, which often 
occurs during moderate and large earthquakes, together with sparks or fires 
from damaged electrical distribution lines and other sources.  The earthquake 
aftermath may result in special impediments to fire-fighting that do not exist in 
the ordinary course of events, including wide-spread and multiple fires, 
damage to fire stations and equipment, injuries to personnel, impeded access 
to the building sites, and failures in the water supply system. 





3.5 GUIDANCE FOR ASSESSING EARTHQUAKERELATED HAZARDS 

The design team, which consists of the architect, structural engineer, 
geotechnical engineer and possibly others, has the responsibility for advising 
the owner on important earthquake-related hazards, including those affecting 
site selection and those that can be reduced in the design and construction 
process.  The owner has final authority on site selection, but likely needs 
advice on earthquake hazard reduction.  All members of the team have roles to 
play in determining and mitigating earthquake-related hazards for the site. The 
roles merge and become less rigid depending, for example, on the knowledge, 
experience, authority, and confidence of the owner and the individuals on the 
design team. 

The assessment of potential earthquake-related hazards should be carried out 
during the site evaluation process.  The evaluation of a site for a new building 
should consider: (a) zoning restrictions and the local authority's planning 
restrictions; (b) regional geology and its associated regional seismicity, on a 
scale that spans, for example, from tens to hundreds of miles, providing 
information on the regional ground shaking hazard, and locations of historically 
active faults; (c) site soil conditions, on a scale that spans, for example, from 
tens to hundreds of yards, providing information for foundation support and the 
local ground shak-ing hazard; (d) the earthquake survivability of service 
utilities, 
transportation infrastructure, other lifelines, and access for employees; and (e) 
hazards from outside the property boundary, including unfavorable topography 
(e.g., potential landslides), the potential for inundation due to tsunami or dam 
failure, neighboring buildings that are so close that pounding is a potential 
hazard, adjacent buildings that have potentially hazardous components that 
may fail and fall on the building, and hazardous building contents.  The design 
team's report to the owner should include the impact of the sum of all these 
evaluations on the desired performance level attained by the completed 
building in future earthquakes. 

A site evaluation checklist is provided in Figure 3-15. A complete evaluation 
should address the issues shown in this checklist.  This checklist is intended 
to assist in identifying those issues with which the individuals on the design 
team should be familiar, and the areas where further consultant help may be 
necessary. 

It is clear from the checklist in Figure 3-15 that a geotechnical engineer, and 
other specialists, should participate in evaluation of the following seismic-
related hazards: 

ground shaking hazard; 

seismogeologic hazards that could result, for example, in ground
failure beneath the building; and

collateral on-site and off-site hazards, such as damage to utilities or 
transportation infrastructure that results from ground failure and could 
adversely affect an organization's operations. 

Specific guidance on the evaluation of strong ground shaking, the evaluation of 
collateral seismic hazards, and the evaluation of other collateral hazards 
follows. 

Evaluating the Ground Shaking Hazard 

Although ground shaking is the primary hazard affecting building performance 
at most sites, it is often not explicitly considered in site selection because it 
does not provide the site with a fatal flaw.  That is, the cost to design to a 
higher, or the maximum, ground shaking level would generally not cause a site 
to be rejected outright.  Nevertheless, if alternative sites are being considered, 
it is desirable to have a geotechnical engineer evaluate the differences in 
estimated levels of ground shaking among sites because of the potential 
influence on project costs. The level of shaking is influenced by the 
characteristics of the faults in the site region, the distance of the site from 
the 
faults, source-to-site ground motion attenuation characteristics, and site soil 
conditions.  Ground motion attenuation is, in turn, influenced by the source-to-
site geology. If alternative sites are located at sufficiently different distances 
from seismic sources in the same region or are located in different regions, 
the primary factor causing differences in ground shaking levels is the local soil 
condition. Resources such as national or state ground shaking maps and site 
factors, for example in the NEHRP Recommended Provisions for Seismic 
Regulations for New Buildings and Other Structures (BSSC, 2001) and the 
International Building Code (ICC, 2000), enable an experienced geotechnical 
engineer to make an  assessment of differences in expected ground shaking 
levels among sites. 

Evaluating Collateral Seismic Hazards 

lateral seismic hazards (surface fault rupture, soil liquefaction, soil 
differential 
compaction, landslide, and inundation) are presented in a number of 
publications including the FEMA 273 report, NEHRP Guidelines for the Seismic 
Rehabilitation of Buildings (ATC/BSSC, 1997a), the companion FEMA 274 
report, Commentary on the NEHRP Guidelines for the Seismic Rehabilitation of 
Buildings (ATC/ BSSC, 1997b), the FEMA 356 report, Prestandard and 
Commentary for the Seismic Rehabilitation of Buildings (ASCE, 2000) and the 
U.S. Army Corps of Engineers publication TI809-04 for the seismic design of 
buildings (USACE, 1998). 

Surface Fault Rupture. Generally, it is not feasible to design a building to 
withstand large fault displacements. Sites transected by active faults should 
generally be avoided unless the probability of faulting during the building life 
is 
sufficiently low. 

Soil Liquefaction.  The assessment of the vulnerability of a site to soil 
liquefaction must address the hazard severity, the potential effects on the 
building and utility connections, and any need for design measures to mitigate 
the hazard.  The hazard consequences may range from essentially no adverse 
effects and no increase in development costs to catastrophic effects that 
cannot be economically mitigated. 

Soil Differential Compaction.  In general, seismically-induced soil differential 
settlements will not be large enough to have a major effect on site development 
or building design costs.  Unusual sites may contain thick layers of 
uncompacted or poorly compacted fill, where seismic (and static) differential 
settlements could be large and difficult to predict. Even for such sites, building 
settlements can be minimized, for example, by using deep pile foundations 
extending below the fill. 

Landsliding. During site selection, the focus should be on identifying unstable 
or marginally stable hillside slopes that could experience large landslide 
displacements and require significant cost to mitigate.  Slopes having pre-
existing active or ancient landslides are especially suscepti
be considered, recognizing that tsunami, seiche, landslides within or entering 
bodies of water, and the failure of dams are uncommon.  Such hazards may 
exist in coastal areas, near large bodies of water, and in the region 
downstream from large dams.  Guidance on tsunami run-up elevations is 
available in publications such as the U.S. Geological Survey Professional 
Paper 1360.  Guidance on the potential for landslides within or entering bodies 
of water should be obtained from a geotechnical engineer.  Locations of large 
dams and the potentially affected downstream area should dam failure occur 
are typically available from dam regulatory agencies. 

Evaluating Other Collateral Hazards 

The existence of other collateral hazards that emanate from outside the 
property boundary, such as neighboring buildings that are so close that 
pounding is a potential hazard, adjacent buildings that have potentially 
hazardous components that may fail and fall on the building, and hazardous 
building contents, should be identified as part of a site selection study if 
alternative sites are under consideration, and the hazards are evaluated in 
terms of both the probability of occurrence within a certain period and their 
consequences. Possible collateral hazards related to a selected site should be 
identified and procedures for their mitigation should form part of the 
postearthquake building emergency response plan. 

In particular, building owners and the design team responsible for site 
selection should be familiar with hazardous materials stored and used on the 
building site, as well as the potential for storage in nearby facilities. 
 
Planning for the release of hazardous materials is essential if investigation 
shows that 
the building site is vulnerable to such hazards. Similarly, building owners and 
the design team responsible for site selection should consider the potential for 
damage caused by adjacent structures, either by pounding or the collapse of 
nearby hazardous buildings or their components. 

The means for reducing lifeline system seismic hazards, which could result in 
the failure of transportation and utility systems as well as the means for 
reducing the potential for regional fires following earthquakes, are generally 
outside the control of the building owner and design team. 





3.6 REFERENCES AND FURTHER READING 

The following publications are suggested resources for further information. 
Guidelines, Pre-Standards, and Codes with Information on Evaluating Ground 
Shaking and Collateral Hazards 
ASCE, 2000, Prestandard and Commentary for the Seismic Rehabilitation of 
Buildings, prepared by the American Society of Civil Engineers; published by 
the Federal Emergency Management Agency, FEMA 356 Report, Washington, 
DC. 

ATC/BSSC, 1997a, NEHRP Guidelines for the Seismic Rehabilitation of 
Buildings, prepared by the Applied Technology Council (ATC-33 project) for the 
Building Seismic Safety Council; published by the Federal Emergency 
Management Agency, FEMA 273 Report, Washington, DC. 

ATC/BSSC, 1997b, Commentary on the NEHRP Guidelines for the Seismic 
Rehabilitation of Buildings, prepared by the Applied Technology Council (ATC-
33 project) for the Building Seismic Safety Council; published by the Federal 
Emergency Management Agency, FEMA 274 Report, Washington, DC. 

BSSC, 2001, The 2000 NEHRP Recommended Provisions For New Buildings 
And Other Structures, Part I, Provisions and Part 2, Commentary, prepared by 
the Building Seismic Safety Council, published by the Federal Emergency 
Management Agency, FEMA 368 Report, Washington, DC. 

ICC, 2000, International Building Code, International Code Council, Falls 
Church, VA. 

USACE, 1998, Seismic Design of Buildings, TI-809-04, U.S. Army Corps of 
Engineers, Washington, DC. 

Earthquake Reconnaissance Reports (All Published by the Earthquake 
Engineering Research Institute: www.eeri.org) 

Benuska, L., Ed., 1990, Loma Prieta Earthquake of October 17, 1989: 
Reconnaissance Report, Supplement to Earthquake Spectra Volume 6, 450 
pp. 

Comartin, C.D., Ed., 1995, The Guam Earthquake of August 8, 1993: 
Reconnaissance Report, Supplement to Earthquake Spectra Volume 11, 175 
pp. 

Comartin, C.D., Greene, M., and Tubbesing, S.K., Eds., 1995, The Hyogoken 
Nanbu Earthquake, January 17,1995: Preliminary Reconnaissance Report, 116 
pp. 

Chung, R. Ed., 1995, Hokkaido-nansei-oki, Japan, Earthquake of July 12, 1993: 
Reconnaissance Report, Supplement to Earthquake Spectra Volume 11, 166 
pp. 

Cole, E.E. and Shea, G.H., Eds., 1991, Costa Rica Earthquake of April 22, 1991: 
Reconnaissance Report, Special Supplement B to Earthquake Spectra Volume 
7, 170 pp. 

EERI, 1985, Impressions of the Guerrero-Michoacan, Mexico, Earthquake of 19 
September 1985: A Preliminary Reconnaissance Report, Published in 
cooperation with the National Research Council of the National Academy of 
Sciences, 36 pp. 

Hall, J., Ed., 1995, Northridge Earthquake of January 17, 1994: 
Reconnaissance Report, Vol. I, Supplement to Earthquake Spectra Volume 11, 
523 pp. 

Hall, J., Ed., 1996, Northridge Earthquake of January 17, 1994: 
Reconnaissance Report, Vol. II, 280 pp. 

Malley, J.O., Shea, G.H., and Gulkan, P. Eds., 1993, Erzincan, Turkey, 
Earthquake of March 13, 1992: Reconnaissance Report, Supplement to 
Earthquake Spectra Volume 9, 210 pp.
 
Schiff, A.J., Ed., 1991, Philippines Earthquake of July 16, 1990: 
Reconnaissance Report, Special Supplement A to Earthquake Spectra Volume 
7, 150 pp. 

Wyllie, L.A. and Filson, J.R., Eds., 1989, Armenia Earthquake of December 7, 
1988: Reconnaissance Report, Supplement to Earthquake Spectra Volume 5, 
175 pp.






 
PERFORMANCE-BASED ENGINEERING:
AN EMERGING CONCEPT IN SEISMIC DESIGN 4

Performance-based seismic design, the focus of this chapter, is a relatively 
new concept that reflects a natural evolution in engineering design practice. It 
is 
based on investigations of building performance in past earthquakes and 
laboratory research, and is enabled by improvements in analytical tools and 
computational capabilities.  Performance-based seismic design concepts 
have been made possible by the collective intellect of an interested profession 
and significant financial resources provided in large part by the federally funded 
National Earthquake Hazards Reduction Program.
  
To introduce the subject, we begin with a description of the process by which 
seismic codes are developed and implemented (Section 4.1), followed by a 
discussion of the expected performance of new buildings designed in 
accordance with current seismic codes (Section 4.2). Interestingly enough, as 
discussed in Section 4.3, currently applied concepts in performance-based 
seismic design were developed for the rehabilitation of existing buildings, as 
opposed to the design of new buildings.  These concepts, however, apply 
equally well to new buildings, and model codes for new building seismic 
design are beginning to adopt and adapt the performance-based concepts 
created for seismic rehabilitation of existing buildings.  As described in Section 
4.4, work is also underway to develop next-generation performance-based 
seismic design guidelines for new and existing buildings. 


4.1 SEISMIC DESIGN PROVISIONS IN BUILDING CODES 

Building design codes for cities, states, or other jurisdictions throughout the 
United States are typically based on the adoption and occasional modification 
of a model building code.  Up until the mid-1990s, there were three primary 
model building code organizations: Building Officials and Code Administrators 
International, Inc. (BOCA), International Conference of Building Officials (ICBO), 
and Southern Building Code Congress International, Inc. (SBCCI).  In 1994, 
these three organizations united to found the International Code Council (ICC), 
a nonprofit organization dedicated to developing a single set of comprehensive 
and coordinated national model construction codes.  The first code published 
by ICC was the 2000 International Building Code (IBC; ICC, 2000). 
 
Building code adoption is a complicated process, especially in regions with 
significant exposure to natural hazards such as earthquake, wind, or flood.  In 
some earthquake-prone regions of the United States, the seismic design 
provisions outlined in the 2000 IBC have not been adopted. Instead, the 
provisions of the Uniform Building Code (UBC), the model building code 
published by IBCO from 1949 through 1997 (ICBO, 1997), are still used.  The 
seismic provisions in the UBC are based primarily on the provisions contained 
in the Structural Engineers Association of California (SEAOC) Recommended 
Lateral Force Requirements and Commentary, known as the Blue Book and 
published from 1959 through 1999 (SEAOC, 1999).  In addition, the 1997 UBC 
relies on the provisions contained in the 1994 edition of the NEHRP 
Recommended Provisions for Seismic Regulations for New Buildings (BSSC, 
1995), while the 2000 IBC relies on the more recent 1997 edition of the NEHRP 
Recommended Provisions for Seismic Regulations for New Buildings and 
Other Structures (BSSC, 1998). 

The NEHRP Provisions have been published regularly since the National 
Earthquake Hazards Reduction Program (NEHRP) was created in 1978 as a 
response to Congress passing P.L. 95-124, the Earthquake Hazards 
Reduction Act of 1977.  The Federal Emergency Management Agency (FEMA) 
was mandated to implement P.L. 95-124 and NEHRP, and the Building 
Seismic Safety Council (BSSC) was formed to provide a broad consensus 
mechanism for regularly updating the NEHRP Recommended Provisions for 
Seismic Regulations for New Buildings (hereinafter referred to as the NEHRP 
Recommended Provisions), first published in 1978 by the Applied Technology 
Council as Tentative Provisions for the Development of Seismic Regulations 
for Buildings, (ATC-03 Report; ATC, 1978).  The most recent version of the 
NEHRP Recommended Provisions is the 2000 edition (BSSC, 2001) and a 
2003 edition is currently in development, as discussed later in this chapter. 
The remainder of this chapter explores seismic design issues related to 
current building codes, specifically the intent of current codes with respect to 
the performance of structural and nonstructural building systems. The current 
codes include the 2000 IBC and the 1997 UBC (and the NEHRP 
Recommended Provisions and SEAOC Blue Book on which they rely), as these 
are most commonly used, although it should be noted that a few jurisdictions 
have adopted the recently published National Fire Protection Agency (NFPA) 
5000 Building Construction and Safety Code (NFPA, 2003) in conjunction with 
the American Society of Civil Engineers (ASCE, 2002) ASCE 7-02 publication, 
Minimum Design Loads for Buildings and Other Structures, for earthquake 
loading requirements.  

Performance-based engineering, an emerging design tool for managing 
seismic risk, and the impact that the emergence of performance-based design 
strategies will have on future buildings and their seismic performance, 
discussed later in this chapter. 


4.2 	EXPECTED PERFORMANCE WHEN DESIGNING TO CURRENT 
CODES 

The basic intent of current seismic design provisions is best summarized by 
the SEAOC Recommended Lateral Force Requirements and Commentary 
(SEAOC, 1999), which states: 

These Requirements provide minimum standards for use in build-
ing design regulation to maintain public safety in the extreme 
ground shaking likely to occur during an earthquake. These 
Requirements are primarily intended to safeguard against major
failures and loss of life, not to limit damage, maintain 
functions, or provide for easy repair.

In other words, current seismic design codes are essentially aimed at the 
preservation of life and safety for the benefit of the community. The 
recommended provisions express 
expectations and provide no guarantees; they assume that there may be 
damage to a building as a result of an earthquake.  For example, the SEAOC 
Recommended Lateral Force Requirements and Commentary includes a 
general set of performance statements to qualify the nature of expected 
damage, as follows: 

Structures designed in accordance with these recommendations should, in 
general, be able to: 

Resist a minor level of earthquake ground motion without damage 

Resist a moderate level of earthquake ground motion without structural 
damage, but possibly experience some nonstructural damage. 

Resist a major level of earthquake ground motion having an intensity 
equal to the strongest either experienced or forecast for the building site 
without collapse, but possibly with some structural as well as nonstructural 
damage. 

It is expected that structural damage, even in a major design level earthquake, 
will be limited to a repairable level for most structures that meet these 
Requirements. In some instances, damage may not be economical to repair. 
The level of damage depends upon a 
number of factors, including the intensity and duration of ground shaking, 
structure configuration, type of lateral force resisting sys
Designers use codes as a resource, as they provide minimum acceptable 
consensus standards.  Codes provide no guidance on the selection of 
materials and systems, rather only criteria for their use once selected.  Codes 
also do not 
provide the designer with the difference in performance between systems; for 
example, the difference between the stiffness of shear walls and frames and 
the importance of this characteristic for the overall seismic performance of the 
building.  Lastly, codes do not discuss that the use of some structural systems 
will result in more nonstructural damage than others, even though the 
structural systems perform equally well in resisting the earthquake forces.  The 
following sub-sec-tions describe the expected performance of structural and 
nonstructural components, respectively. 

As mentioned earlier, current seismic design provisions for non-essential 
facilities are intended to provide life safety, i.e., no damage in a minor 
earthquake, limited structural damage in a moderate earthquake, and 
resistance to collapse in a major earthquake (typically the design ground 
motion). Resistance to collapse means that the structure may have lost a 
substantial amount of its original lateral stiffness and strength, but the 
gravity-
load-bearing elements still function and provide some margin of safety against 
col
lapse.  The structure may have permanent lateral offset and some elements of 
the seismic-force resisting system may exhibit substantial cracking, spalling, 
yielding, buckling, and localized failure. Following a major earthquake, the 
structure is not safe for continued occupancy until repairs are done.  Shaking 
associated with strong aftershocks could threaten the stability of the structure.  
Repair to a structure in this state is expected to be feasible, however it may not 
be economically attractive to do so.  Section 4.3 includes further discussion of 
the seismic behavior of specific structural systems in the context of describing 
performance-based design objectives.  

Expected Performance of Nonstructural Components 

While current seismic design provisions provide minimum structural 
performance standards in terms of resistance to collapse, they typically do not 
address performance of nonstructural components, such as room partitions, 
filing cabinets and book cases, hung lighting and ceilings, entryway canopies, 
and stairwells; nor do they address perfor
electrical panels or transformers.  The vast majority of damage and resulting 
loss of building functionality during recent damaging earthquakes has been the 
result of damage to nonstructural components and systems (Figure 4-1).  Many 
building owners have been surprised when a building withstands the effects of 
a moderate earthquake from a structural perspective, but is still rendered 
inoperable from a nonstructural standpoint. 

Current seismic design provisions typically require that nonstructural 
components be secured so as to not present a falling hazard; however, these 
components can still be severely damaged such that they can not function. 
Loss of electric power, breaks in water supply and sewer out-flow lines (see 
Figure 4-2), or non-functioning heating or air conditioning will render a building 
unusable by tenants.  Breaks in fire sprinklers will cause flooding within all or 
part of a building, soaked carpets and walls, inundated files and records, and 
electrical shorts or failures in electrical equipment and computers.  Other 
examples of nonstructural damage that can be expected in a code-compliant 
building subjected to strong ground shaking include extensive cracking in 
cladding, glazing, partitions, and chimneys; broken light fixtures; racked doors; 
and dropped ceiling tiles.  Section 4.3 includes further discussion of the 
seismic behavior of specific nonstructural systems in the context of describing 
performance-based design objectives.  



4.3 CURRENT SPECIFICATIONS FOR PERFORMANCE-BASED SEISMIC DESIGN

As described earlier, an important yet emerging concept in the successful
implementation of seismic risk management strategies is the application of 
performance-based seismic design approaches.  The primary function of 
performance-based seismic design is the ability to achieve, through analytical 
means, a building design that will reliably perform in a prescribed manner 
under one or more seismic hazard condi-tions.  The fact that alternative levels 
of building performance are being defined and can be chosen as performance 
objectives is a relatively new development in seismic design.  Some of its 
origins lie in studies of building performance during recent earthquakes, in 
which owners of buildings that suffered hundreds of thousands of dollars in 
damage were surprised to learn that the buildings met the intent of the life-
safety provisions of the seismic code under which they were designed, since 
no one was killed or seriously injured.  Out of these experiences came the 
realization that design professionals need to be more explicit about what 
"design to code" represents and what seismic design in general can and can 
not accomplish.  At the same time, studies of damaged buildings, together with 
laboratory research and computer analyses, have led to a much more 
sophisticated understanding of building response under the range of 
earthquake ground motion that can be expected to occur. 

This section describes some of the key concepts of performance-based 
seismic design.  These concepts have emerged from a series of studies, 
funded by FEMA, that focused on the development of performance-based 
seismic design guidelines for existing buildings.  The first study, published in 
the FEMA 237 report, Seismic Rehabilitation of Buildings - Phase I: Issues 
Identification and Resolution (ATC, 1992), identified and resolved a wide variety 
of scope, format, socio-economic, and detailed technical issues that needed to 
be considered during the subsequent development of practical guidelines for 
the seismic rehabilitation of buildings.  During that initial study, the concept 
of 
performance goals was introduced, effectively commencing the move toward 
performance-based seismic design.  The follow-on study, an $8-million FEMA-
funded effort carried out jointly by the Applied Technology Council, the Building 
Seismic Safety Council, and the American Society of Civil Engineers, resulted 
in the formulation of detailed guidelines, written for practicing structural 
engineers and building officials, that specify the means to use performance-
based design concepts to rehabilitate existing buildings to improve their 
seismic resistance.  The final set of products of that effort consists of three 
documents:  FEMA 273, NEHRP Guidelines for the Seismic Rehabilitation of 
Buildings (ATC/BSSC, 1997a); FEMA 274, NEHRP Commentary for the 
Guidelines for Seismic Rehabilitation of Buildings (ATC/ BSSC, 1997b); and 
FEMA 276, Example Applications of the NEHRP Guidelines for the Seismic 
Rehabilitation of Buildings (ATC, 1997).  In order to speed the implementation 
of the FEMA 273 Guidelines in structural engineering practice, the Guidelines 
were converted, with funding from FEMA, to a Prestandard and Commentary for 
the Seismic Rehabilitation of Buildings (FEMA 356) by the American Society of 
Civil Engineers (ASCE, 2000).  The conversion process maintained the 
performance levels and performance descriptions, as described below, and 
other concepts developed for the FEMA 273 Guidelines. 

Midway through the long-term FEMA effort to develop the FEMA 273 Guidelines 
and FEMA 356 Prestandard, the Structural Engineers Association of California 
(SEAOC) developed Vision 2000, Performance Based Seismic Engineering of 
Buildings, which describes a framework for perfor
detailed procedures manual for the seismic evaluation and rehabilitation of 
concrete buildings using performance-based seismic design concepts.  All of 
the documents described above are important, state-of-the-art resources for 
the structural engineering community. 

The application of performance-based seismic design can be highly technical, 
and requires that the design engineer have a good understanding of seismic 
hazards, and the dynamic and inelastic behavior of buildings and materials.  
Unlike the application of building codes, performance-based seismic design is 
not typically prescriptive in nature, and often requires significantly more 
detailed 
building analysis than might otherwise be required.  However, as discussed 
earlier, the advantages of performance-based seismic design in the 
development of an overall risk management plan is usually worth the extra 
effort spent by the design team.  It is the challenge of the design team to convey 
this level of importance to the owner and the owner's representatives. 
Building Performance Objectives 

A fundamental concept behind the implementation of performance-based 
seismic design is the development of a consensus set of perfor
to an earthquake hazard of a defined intensity (e.g., a maximum credible event 
or an event with a certain return period).  As earthquake intensity increases, 
building performance generally decreases. The goal of specifying a 
performance objective is to achieve a reliable estimate of 
performance under one or more earthquake hazard scenarios.  A 
representation of different performance objectives is shown in Table 4-1, which 
is taken from FEMA 356 Prestandard and Commentary for Seismic 
Rehabilitation of Buildings ((ASCE, 2000), a prestandard for performance-
based seismic rehabilitation of existing buildings.  Although FEMA 356 pertains 
to seismic rehabilitation, the same concepts apply to new design. 
As shown in Table 4-1, FEMA 356 defines two basic earthquake hazard levels - 
Basic Safety Earthquake 1 (BSE-1, corresponding to 475-year return period 
event, or ground motions having a 10% probability of being exceeded in 50 
years) and Basic Safety Earthquake 2 (BSE-2 corresponding to 2475-year 
return period event, or ground motions having a 2% probability of being 
exceeded in 50 years).  The Basic Safety Objective (BSO) is then defined as 
meeting the target building performance level of Life Safety for BSE-1, and the 
target building performance level of Collapse Prevention for BSE-2 (cells k and 
p in Table 4-1). FEMA 356 states, 
The BSO is intended to approximate the earthquake risk to life 
safety traditionally considered acceptable in the United States.  Buildings 
meeting the BSO are expected to experience little dam
age from relatively frequent, moderate earthquakes, but signifi
cantly more damage and potential economic loss from the most 
severe and infrequent earthquakes that could affect them. 
Performance objectives higher than the BSO are defined as Enhanced 
Objectives, which are achieved by designing for target building performance 
levels greater than those of the BSO at either the BSE-1 or BSE-2 hazard levels 
or by designing for the target building performance levels of the BSO using an 
earthquake hazard level that exceeds either the BSE-1 or BSE-2 (see Table 4-1 
notes).  The possible combinations of target building performance and 
earthquake hazard level corresponding to design for an enhanced performance 
objective are limitless - the goal is simply to provide building performance 
better than that intended by the BSO and mandated in most current design 
codes. 

Note also that certain cells of the matrix (Table 4-1) are referred to as Limited 
Objectives.  While this lower performance objective may be applicable to 
certain partial or reduced seismic rehabilitation designs, it does not apply to 
new design as it falls below current code standards.
 

Building Performance Levels 

Building performance can be described qualitatively in terms of the: 

safety afforded building occupants, during and after an earthquake. 

cost and feasibility of restoring the building to pre-earthquake 
conditions. 

length of time the building is removed from service to conduct
repairs.

economic, architectural, or historic impacts on the community at large. These 
performance characteristics will be directly related to the extent of 
damage sustained by the building during a damaging earthquake. As shown in 
Table 4-1, FEMA 356 defines four basic Target Building Performance Levels, 
which differ only slightly in terminology from the four levels described in FEMA 
369, The 2000 NEHRP Recommended Provisions for New Buildings and Other 
Structures, Part 2: Commentary (BSSC, 2001). These performance levels, 
illustrated graphically in Figure 4-3, are: 

Operational Level: The lowest level of overall damage to the building. 
The structure will retain nearly all of its pre-earthquake strength and stiffness. 
Expected damage includes minor cracking 
of facades, partitions, and ceilings, as well as structural elements. 
All mechanical, electrical, plumbing, and other systems necessary 
for normal operation of the buildings are expected to be functional, 
possibly from standby sources.  Negligible damage to nonstructural 
components is expected.  Under very low levels of earthquake 
ground motion, most buildings should be able to meet or exceed 
this performance level.  Typically, however, it will not be economi
cally practical to design for this level of performance under severe 
levels of ground shaking, except for buildings that house essential 
services. 

Immediate Occupancy Level: Overall damage to the building is 
light.  Damage to the structural systems is similar to the Operational 
Performance Level; however, somewhat more damage to nonstruc-
tural systems is expected.  Nonstructural components such as clad-
ding and ceilings, and mechanical and electrical components 
remain secured; however, repair and cleanup may be needed.  It is 
expected that utilities necessary for normal function of all systems 
will not be available, although those necessary for life safety systems 
would be provided.  Many building owners may wish to achieve this 
level of performance when the building is subjected to moderate
levels of earthquake ground motion.  In addition, some owners may 
desire such performance for very important buildings, under severe 
levels of earthquake ground shaking.  This level provides most of 
the protection obtained under the Operational Building Perfor-
mance Level, without the associated cost of providing standby utilities and 
performing rigorous seismic qualification to validate equipment 
performance. 

Life Safety Level: Structural and nonstructural damage is signifi
quake lateral strength and stiffness, but the gravity-load-bearing elements 
function.  Out-of-plane wall failures and tipping of parapets are not expected, 
but there will be some permanent drift and select elements of the lat-eral-force 
resisting system may have substantial cracking, spalling, yielding, and 
buckling.  Nonstructural components are secured and not presenting a falling 
hazard, but many architectural, mechanical, and electrical systems are 
damaged. The building may not be safe for continued occupancy until repairs 
are done.  Repair of the structure is feasible, but it may not be economically 
attractive to do so. This performance level is generally the basis for the intent 
of 
code compliance. 

Collapse Prevention Level or Near Collapse Level: The structure 
sustains severe damage.  The lateral-force resisting system loses most of its 
pre-earthquake strength and stiffness. Load-bearing columns and walls 
function, but the building is near collapse. Substantial degradation of structural 
elements occurs, including extensive cracking and spalling of masonry and 
concrete elements, and buckling and fracture of steel elements.  Infills and 
unbraced parapets may fail and exits may be blocked.  The building has large 
permanent drifts. Nonstructural components experience substantial damage 
and may be falling hazards.  The building is unsafe for occupancy. Repair and 
restoration is probably not practically achievable. This building performance 
level has been selected as the basis for mandatory seismic rehabilitation 
ordinances enacted by some municipalities, as it results in mitigation of the 
most severe life-safety hazards at relatively low cost. 

Building performance levels typically comprise a structural performance level 
that describes the limiting damage state of the structural systems, plus a 
nonstructural performance level that describes the limiting damage state of the 
nonstructural systems and components.  Table 4-2, from FEMA 356, illustrates 
this concept.  A Target Building Performance Level is designated by the 
number corresponding to the Structural Performance Level (identified as S-1 
through S-6) and the letter corresponding to the Nonstructural Performance 
Level (identified as N-A through N-E).  Note that in Tables 4-1 and 4-2, the four 
Target Building Performance Levels discussed above are each designated as 
follows. 

Note also that in Table 4-2, there are several combinations of structural and 
nonstructural performance levels that are not recommended for rehabilitation; 
the same lack of recommendation applies to new design.  The six structural 
performance levels and five nonstructural performance levels are described in 
the following subsections.

Structural Performance Levels 

For the rehabilitation of existing buildings, the Structural Performance Levels 
most commonly used are the Immediate Occupancy Level, the Life Safety 
Level, and the Collapse Prevention Level (S-1, S-3, and S-5, respectively, in 
Table 4-2).  These levels are discrete points on a continuous scale describing 
the building's expected performance or, alternatively, how much damage, 
economic loss, and disruption may occur following the design earthquake.  
Intermediate levels are often used to assist in quantifying the continuous scale.  
For example, Table 4-2 lists Structural Performance Levels of Damage Control 
Range (S-2), Limited Safety Range (S-4), and Not Considered (S-6). 
Structural Performance Levels relate to the limiting damage states for common 
elements of the building's lateral force resisting systems. Table 4-3 and Table 
4-4, taken from FEMA 356, provide descriptions of the damage associated with 
the three Structural Performance Levels of Collapse Prevention, Life Safety, and 
Immediate Occupancy for specific types of horizontal (Table 4-3) and vertical 
(Table 4-4) structural elements and systems. 
  
Nonstructural Performance Levels 

The four Nonstructural Performance Levels most commonly used are the 
Operational Level, the Immediate Occupancy Level, the Life Safety Level, and 
the Hazards Reduced Level (N-A, N-B, N-C, and N-D, respectively, in Table 4-
2).  Table 4-2 also includes the additional performance level of Not Considered 
(N-E). Nonstructural components addressed by these performance levels 
include architectural components (e.g., partitions, exterior cladding, and 
ceilings) and mechanical and electrical components (e.g., HVAC systems, 
plumbing, fire suppression systems, and lighting).  Occupant contents and 
furnishings (such as inventory and computers) are often included as well. 

Nonstructural Performance Levels relate to the limiting damage states for 
common elements of the building's architectural features, utility systems, and 
contents and other equipment. Tables 4-5, 4-6, and 4-7 taken from FEMA 356, 
provide descriptions of the damage associated with the four Nonstructural 
Performance Levels of Hazards Reduced, Life Safety, Immediate Occupancy, 
and Operational for specific types of architectural components (Table 4-5); 
mechanical, electrical, and plumbing system components (Table 4-6); and 
contents (Table 4-7). 



4.4 	IMPACT OF PERFORMANCE-BASED STRATEGIES ON FUTURE 
DESIGN CODES 

While current design codes explicitly require life safety design for only a single 
level of ground motion, it is expected that future design codes will provide 
engineers with the necessary guidelines to design and construct buildings that 
meet a number of performance criteria when subjected to earthquake ground 
motion of differing severity.  The current (2000) version of the NEHRP 
Recommended Provisions for Seismic Regulations for New Buildings and 
Other Structures (BSSC, 2001) has initiated a move towards incorporating 
performance-based strategies through the use of three "Seismic Use Groups."  
These groups are categorized based on the occupancy of the structures and 
the relative consequences of earthquake-induced damage to the structures as 
follows: 

Group III structures are essential facilities required for 
postearthquake 
recovery, and those structures that contain significant amounts of hazardous 
materials.  An example is a medical facility with emergency treatment facilities. 
      	
Group II structures are those having a large number of occupants 
and those where the occupants ability to exit is restrained. An 
example is an elementary school.

Group I structures are all other structures, basically those with a 
lesser 
life hazard only insofar as there is expected to be fewer occupants in the 
structures and the structures are lower and/or smaller. An example is a low-
rise commercial office building. 

The 2000 NEHRP Recommended Provisions for Seismic Regulations of New 
Buildings and Other Structures specify progressively more conservative 
strength, drift control, system selection, and detailing requirements for 
structures contained in the three groups, in order to attain minimum levels of 
earthquake performance suitable to the individual occupancies.  The design 
criteria for each group are intended to produce specific types of performance in 
design earthquake events, based on the importance of reducing structural 
damage and improving life safety.  Figure 4-4, taken from the Commentary to 
the 2000 NEHRP Provisions, illustrates this concept. \

Next-Generation Performance-Based Seismic Design Guidelines 

Incorporation of performance-based engineering concepts in future design 
codes will also be aided by a major effort recently initiated by the Applied 
Technology Council (ATC) with funding from the Federal Emergency 
Management Agency (FEMA).  The project, known as ATC-58, Development of 
Performance-Based Seismic Design Guidelines, is currently in Phase I, Project 
Initiation and Performance Characterization. FEMA has provided funding for 
Phase I of a planned multi-year program to develop the guidelines, following 
the general approach outlined in FEMA 349, Action Plan for Performance Based 
Seismic Design (EERI, 2000).  It is expected that the successful development 
of the guidelines will require a multi-year effort entailing financial and 
technical 
participation from the four NEHRP agencies as well as private industry. 
FEMA 349 identifies six products essential to the creation and implementation 
of comprehensive, acceptable Performance-Based Seismic Design 
Guidelines: 

1.	A Program Management Plan that incorporates a broadly based 
oversight group to shepherd and promote the development of the Guidelines 
(over an extended period of time, say up to 10 years), and an education and 
implementation strategy to facilitate the use of the Guidelines. 

2.	Structural Performance Products that characterize building performance, 
specify how to evaluate a building's performance capability for a specified level 
of seismic hazard and with a defined reliability or level of confidence, and 
provide guidance on how to design a structure to provide desired performance 
(with defined reliability). 

3.	Nonstructural Performance Products that provide engineers with the 
capability to evaluate and design nonstructural components, such as partitions, 
piping, HVAC (heating, ventilation, and air conditioning) equipment, with the 
goal of ensuring that such components will provide desired performance (with 
defined reliability).  

4.	Risk Management Products that provide methodologies for calculating 
the benefits of designing to various performance objectives and to make 
rational economic choices about the levels of performance desired, the levels 
of confidence desired, and the comparative costs to reach those levels. 

5.	Performance-Based Seismic Design Guidelines that provide 
methodology and criteria for design professionals, material suppliers, and 
equipment manufacturers to implement performance-based design 
procedures. 

6.	A Stakeholders Guide that explains performance-based seismic design 
to nontechnical audiences, including building owners, managers, and lending 
institutions.  




4.5 GUIDANCE FOR DESIGN PROFESSIONALS 

It is clear that performance-based strategies will be included in future seismic 
design codes. Regardless of when this actually occurs, design professionals 
can utilize the information in this document, as well as those referenced below, 
to provide owners and managers with a much clearer picture of what may be 
expected in terms of damage, downtime, and occupant safety for a given 
building under various intensities of ground motion. 
When communicating with building owner representatives during the 
development of seismic performance criteria for a new building, it would be 
useful to: 

1.	Explain the concepts of performance-based seismic design using the 
concepts and materials provided in this document and the references cited. 

2.	Help the owner to determine if a performance level higher than life safety 
is needed for the design earthquake; if so, use these materials and the 
references cited to assist the owner in developing a design that would be 
accepted by the governing regulatory agency (e.g., local building department). 




4.6 REFERENCES AND FURTHER READING 

ASCE, 2000, Prestandard and Commentary for the Seismic Rehabilitation of 
Buildings, prepared by the American Society of Civil Engineers, published by 
the Federal Emergency Management Agency, FEMA 356 Report, Washington, 
DC. 

ATC, 1996b, Seismic Evaluation and Retrofit of Concrete Buildings, Volumes 1 
and 2, Applied Technology Council, ATC-40 Report, Redwood City, California. 
ATC, 2004a (in preparation), Improvement of Inelastic Seismic Analysis 
Procedures, prepared by the Applied Technology Council for the Federal 
Emergency Management Agency, FEMA 440, Washington, D.C. 

ATC, 2004b (in preparation), Program Plan for Development of Performance-
Based Seismic Design Guidelines, prepared by the Applied Technology 
Council for the Federal Emergency Management Agency, FEMA 445, 
Washington, D.C. 

ATC, 2004c (in preparation), Characterization of Seismic Performance for 
Buildings, prepared by the Applied Technology Council for the Federal 
Emergency Management Agency, FEMA 446, Washington, D.C. 

ATC/BSSC, 1997a, NEHRP Guidelines for the Seismic Rehabilitation of 
Buildings, prepared by the Applied Technology Council (ATC-33 project) for the 
Building Seismic Safety Council, published by the Federal Emergency 
Management Agency, FEMA 273 Report, Washington, DC. 

ATC/BSSC, 1997b, NEHRP Commentary on the Guidelines for the Seismic 
Rehabilitation of Buildings, prepared by the Applied Technology Council (ATC-
33 project) for the Building Seismic Safety Council, published by the Federal 
Emergency Management Agency, FEMA 274 Report, Washington, DC.
 
BSSC, 2001, NEHRP Recommended Provisions for Seismic Regulations for 
New Buildings and Other Structures, Part I: Provisions, and Part II, 
Commentary, 2000 Edition, prepared by the Building Seismic Safety Council, 
published by the Federal Emergency Management Agency, Publications, FEMA 
368 Report and FEMA 369 Report, Washington, DC. 

SEAOC, 1995, Vision 2000: Performance-Based Seismic Engineering of 
Buildings, Structural Engineers Association of California, Sacramento, 
California. 

SEAOC, 1999, Recommended Lateral Force Requirements and Commentary, 
prepared by the Structural Engineers Association of California, published by the 
International Conference of Building Officials, Whittier, California. 




IMPROVING PERFORMANCE TO REDUCE SEISMIC RISK 5 

5.1 INTRODUCTION 

Improving performance to reduce seismic risk is a multi-faceted issue that 
requires consideration of a broad range of factors. Previous chapters in this 
document have introduced and described the overarching concept of seismic 
risk management (Chapter 2) and two of the fundamental factors affecting 
improved seismic performance: consideration of the seismic hazards affecting 
the site (Chapter 3); and consideration of the desired seismic performance of 
structural and nonstructural components for the range of earthquakes of 
concern (Chapter 4).  

This chapter identifies and addresses related seismic design issues that are 
fundamentally important to improved seismic performance, regardless of the 
occupancy type: 

selection of the structural materials and systems (Section 5.2); 

selection of the architectural/structural configuration (Section 
5.3);

consideration of the expected performance of nonstructural components, 
including ceilings, partitions, heating, ventilation, and air condition equipment 
(HVAC), piping and other utility systems, and cladding (Section 5.4); 

cost analysis, including consideration of both the benefits and costs of 
improved seismic performance (Sections 5.5 through 5.7); 

and quality control during the construction process (Section 5.8). 

Considerable attention is given to the quantification of benefits and costs of 
improved seismic performance, given the underlying importance of cost 
considerations.  Benefits include reduced direct capital losses and reduced 
indirect losses, which are related to the time that a given building is 
operationally out of service.  Cost issues are demonstrated through several 
means, including the use of (1) graphics showing the relationship between the 
cost of various options for improving seismic performance versus the resulting 
benefits; and (2) case studies demonstrating best practices in earthquake 
engineering. 

The Chapter concludes with a set of general recommendations for improving 
seismic performance during the seismic design and construction process, 
regardless of occupancy type.  The subsequent six chapters focus on seismic 
design and performance issues related to spe-cific occupancy types:  
commercial office buildings (Chapter 6): retail commercial facilities (Chapter 
7); light manufacturing facilities (Chapter 8); healthcare facilities (Chapter 9); 
local schools, kindergarten through grade 12 (Chapter 10); and higher 
education (university) facilities (Chapter 11). 



5.2	   SELECTION OF STRUCTURAL MATERIALS AND SYSTEMS 

An earthquake has no knowledge of building function, but uncovers 
weaknesses in the building that are the result of errors or deficiencies in its 
design and construction.  However, variations in design and construction will 
affect its response, perhaps significantly, and to the extent that these 
variations 
are determined by the occupancy, then each building type tends to have some 
unique seismic design determinants.  A building that uses a moment-frame 
structure will have a different ground motion response than a building that uses 
shear walls; the frame structure is more flexible, so it will experience lower 
earthquake forces, but it will deflect more than the shear wall structure, and 
this 
increased motion may cause more damage to nonstructural components such 
as partitions and ceilings. The shear wall building will be much stiffer but this 
will attract more force: the building will deflect less but will experience higher 
accelerations and this will affect acceleration-sensitive components such as 
air conditioning equipment and heavy tanks. 

These structural and nonstructural system characteristics can be deduced 
from the information in the seismic code, but the code is not a design guide 
and gives no direct guidance on the different performance characteristics of 
available systems or how to select an appropriate structural system for a 
specific site or building type. 

Table 5-1 illustrates the seismic performance of common structural systems, 
both old and new, and gives some guidance as to the applicability of systems 
and critical design characteristics for good performance. The different structural 
performance characteristics mean that their selection must be matched to the 
specific building type and its architecture.  Table 5-1 summarizes a great deal 
of information and is intended only to illustrate the point that structural 
systems 
vary in their performance.  The table is not intended as the definitive tool for 
system selection; this requires extensive knowledge, experience and analysis. 
Table 5-2 shows structural system selections that are appropriate for different 
site conditions, for different occupancies and various building functions. For 
example, an important aspect of the building site is that a major structure must 
be "de-tuned," that is, designed such that its fundamental period differs 
sufficiently from that of the ground so that dangerous resonance and force 
amplification are not induced.  Thus, for a soft, long-period site; it is 
appropriate 
to use a rigid short period structural system; this need in turn must be related 
to other requirements of occupancy and function. 

Table 5-2 also illustrates that structures must be matched to the build-ing's 
use. For example, a concrete shear wall structure is appropriate for an 
apartment house because the strong cross walls are an economical way to 
provide the necessary seismic resistance and, at the same time, provide good 
acoustics between the apartments. While the purpose of Table 5-2 is to 
illustrate the way in which structural systems may be matched to the site 
condition and building design and use, the table is not intended as the 
definitive tool for system selection; this also requires extensive knowledge, 
experience, and analysis. 



5.3 SELECTION OF THE ARCHITECTURAL CONFIGURATION 

The architectural configuration-the building's size, proportions and three-
dimensional form-plays a large role in determining seismic performance.  
This is because the configuration largely determines the distribution of 
earthquake forces, that is, the relative size and nature of the forces as they 
work 
their way through the building.  A good configuration will provide for a balanced 
force distribution, both in plan and section, so that the earthquake forces are 
carried directly and easily back to the foundations. A poor configuration results 
in stress concentrations and torsion, which at their worst are dangerous. 

Configuration problems have long been identified, primarily as the result of 
extensive observation of building performance in earthquakes. However, many 
of the problem configurations arise because they are useful and efficient in 
supporting the functional needs of the building or accommodating site 
constraints.  The design task is to create configuration alternatives that satisfy 
both the architectural needs and provide for structural safety and economy. This 
requires that the architect and engineer must cooperate from the outset of the 
design process: first to arrive at an appropriate structural system to satisfy 
building needs, and then to negotiate detailed design alternatives that avoid, or 
reduce, the impact of potential problem configurations. 

Seismic codes now have provisions intended to deal with configuration 
problems.  However, the code approach is to accept the problems and attempt 
to solve them either by increasing design forces, or requiring a more 
sophisticated analysis.  Neither of these approaches is satisfactory, for they do 
not remove the problem.  In addition, many of the code provisions apply only to 
buildings that are five stories or over 65 feet in height, which leaves a large 
number of buildings unregulated by the code.   The problem can only be solved 
by design and not by a prescriptive code. 

Design solutions for a soft first story condition that the architect and engineer 
might explore together include (see Figure 5-1): 

The architectural implications of eliminating it (which solves the 
structural problem);

Alternative framing designs, such as increasing the number of columns 
or increasing the system stiffness by changing the design, to  alleviate the 
stiffness discrepancy between the first and adjacent floors; and 

Adding bracing at the end of line of columns (if the site constraints 
permit this). 

A more general problem is the increasing unpredictability of building response 
as the architectural/structural configuration increasingly deviates from an ideal 
symmetrical form.  This has serious implications for Performance Based 
Design, which depends for its effectiveness on the ability of the engineer to 
predict structural performance. 

Tables 5-3 and 5-4 illustrate the above points by identifying the common 
configuration problems- termed "irregularities" that are dealt with in the seismic 
code. These are classified as vertical or plan irregularities.  The tables show a 
diagram of each condition, illustrates the failure pattern and describes its 
effects.   The designations and numbers of the conditions are identical to the 
code: the diagrams are not contained in the code but are interpretations of the 
descriptions of each condition that the code defines. 




5.4 	CONSIDERATION OF NONSTRUCTURAL COMPONENT 
PERFORMANCE 

As discussed in Section 4.2, the majority of the damage that has resulted in 
building closure following recent U.S. earthquakes has been the result of 
damage to nonstructural components and systems. A building designed to 
current seismic regulations may perform well structurally in a moderate 
earthquake, but be rendered nonfunctional due to non-structural damage. 

Nonstructural components may also, however, influence structural per-
formance in response to ground shaking.  Structural analysis to meet code 
requirements assumes a bare structure. Nonstructural components that are 
attached to the structure, and heavy contents, depending on their location, may 
introduce torsional forces.  Characteristic examples of structural/nonstructural 
interaction are as follows: 

Heavy masonry partitions that are rigidly attached to columns and under 
floor slabs, can, if asymmetrically located, introduce localized stiffness and 
create stress concentrations and torsional forces. A particular form of this 
condition, that has caused significant structural damage, is when short column 
conditions are created by the insertion of partial masonry walls between 
columns.  The addition of such partial walls after the building completion is 
often treated as a minor remodel that is not seen to require engineering 
analysis. The result is that the shortened columns have high relative stiffness, 
attract a large percentage of the earthquake forces, and fail (Figure 5-2). 

In smaller buildings, stairs can act as bracing members between
floors, introducing torsion; the solution is to detach the stair from 
the floor slab at one end to allow free structural movement.

In storage areas or library stacks, heavy storage items can introduce 
torsion into a structure.  The structure may have been calculated to
accommodate the maximum dead load but consideration be lack-
ing for the effect of nonsymmetric loading over time as, for exam-
ple, when library books are acquired (Figure 5-3).



5.5 QUANTIFYING THE BENEFITS OF IMPROVED PERFORMANCE 

The benefits of improved performance are the reduced losses resulting from 
improved performance.  These reduced losses include not only the reduction in 
capital losses (as described below), but also the reduction in financial impacts 
resulting from the loss of operations. 

The benefits of improved earthquake performance of a building are quantified 
differently by the various types of building owners and users. For example, an 
owner occupant, an owner of a tenant-occupied building, and a tenant will all 
have different priorities and views regarding the cost-benefit trade-offs 
associated with improved earthquake performance of the building. 

From the point of view of an owner occupant, earthquake performance of a 
building can be quantified in terms of reducing the probability of: 

deaths and injuries in and around the building caused by an earthquake, 
and the resultant liability; 

collapse of the building or damage to the building that reduces the 
building's value; 

disruption of building services (HVAC, plumbing, electrical) and 
the resultant loss of use of the building or portions of it;

damage to building contents such as furniture, files, and inventory; and 

disruption of building operation and business as a result of the above. From the 
point of view of an owner of a tenant-occupied building, earthquake performance of 
a building can be quantified in terms of reducing 
the probability of: 

deaths and injuries in and around the building caused by an earthquake, 
and the resultant liability; 

collapse of the building or damage to the building that reduces the 
building's value; and 

disruption of building services (HVAC, plumbing, electrical) and 
the resultant loss of use of the building or portions of it (tenant 
business interruption).


From the point of view of a tenant who is not the owner, earthquake 
performance of a building can be quantified in terms of reducing the probability 
of:

disruption of building services (e.g., HVAC, plumbing, electrical) 
and the resultant loss of use of the building or parts of it;

damage to building contents such as furniture, files, and contents; and 

disruption of building operation and business as a result of the above. 




Quantifying Expected Capital Losses

Capital losses consist of the cost of replacing or repairing earthquake-
damaged structural and nonstructural components as well as damaged 
building contents. When quantifying capital value of damaged building 
components and contents, the first distinction that needs to be made is 
between the depreciated value of an asset, its market value, and its 
replacement cost.  The assumption is generally that damaged capital will be 
replaced.  If a 50-year-old building or piece of equipment is damaged to the 
extent that it is a total loss, it is unlikely that an owner can have a 
replacement 
building constructed or purchase a new piece of equipment for the same price 
as the original cost, nor for the depreciated value of the building or equipment 
(which may be very low, or zero). One may purchase a replacement building or 
piece of equipment that is 50 years old.  Still, the price of that building or 
equip-
ment will be based not on the depreciated value, but on the current market 
value of the asset. When the cost of losing an asset is evaluated, the owner 
must therefore determine what the cost to replace the asset will be, whether it 
is new or used. 

An owner can use various means to estimate the replacement cost of a 
building or its contents.  Realtors, manufacturers, engineers, and other 
specialists can research market conditions to estimate costs.  If the owner has 
a large number of facilities or buildings, he/she may have a database of recent 
capital projects from which to draw information. 

If structural and nonstructural building elements suffer less than total
loss in an earthquake, they can often be repaired without being
replaced.  Theoretically, one would never spend more than the replacement 
cost of the building to repair structural and nonstructural damage.  Practically, 
most owners consider the limit of repair costs to be on the order of 40 to 60 
percent of the replacement cost.  The older the building or equipment, typically 
the lower the threshold.  The reasoning is that if a building or piece of 
equipment is old and outdated, repairing it leaves the owner with something 
that, although functional, is still old and possibly outdated. 

Owners may have other constraints which raise or lower this threshold.  If short 
on cash or credit, an owner may have no choice but to repair a heavily 
damaged building rather than replace it.  If the operations within the building 
are so valuable that losses from down time far exceed the building's 
replacement cost, then even if very expensive repairs can be done more quickly 
than replacement, the threshold of repairable damage may also be high.  On 
the other hand, if an owner has been looking to get rid of an old, poorly 
configured, structure even
small amounts of damage may provide a convenient excuse to replace
the building.

It should be clear that unit repair costs are rarely equal to the unit costs of 
new 
construction.  The cost of building partition walls in a new building, for 
example, 
may be on the order of five dollars per square foot.  Repairing heavily damaged 
partition walls may cost more than twice this amount.  Removing and replacing 
a damaged steel brace within a building may cost several times the cost of 
installing the brace in a new building. 

A key to estimating the cost of repairing structural and nonstructural damage is 
understanding what the nature of the damage may look like. This is often 
defined as the "fragility" of the building system.  Fragility presents the 
likelihood 
of damage as a function of the forces or deformations imposed on the building. 
 Damage may be described in terms that include cracking or spalling of 
concrete elements; fracturing or buckling of steel beams, columns, or braces; 
glazing breakage; and partition cracking or failure. Estimating how much 
damage occurs at a specific stress or deformation has been and continues to 
be the subject of research.  Once estimates of the damage are made, 
contractors and cost estimators can provide valuable assistance to owners and the 
design
team in estimating repair costs.

Damage to contents and inventory is usually quantified in terms of the amount 
of each that needs to be replaced. In some cases, with very expensive 
equipment or inventory, one might consider repairing damage.  In most 
instances, however, damaged items are typically replaced.  Damage to non-
fixed items typically occurs as a result of high accelerations "flinging" items 
off 
shelves or overturning them. Earthquake-induced accelerations vary over the 
height of a building so that items in upper stories may be more prone to 
damage than at lower stories. Estimating the amount of damage to contents 
and inventory involves calculating the acceleration at each level and estimating 
the capacity of elements at each story to withstand these accelerations. 
Shelving should be evaluated as to its overturning capacity and the potential 
damage of items that are spilled. 

Contents such as desks and cabinets are fairly resilient to damage from 
sliding or falling, and are typically considered as losses only when they cannot 
be recovered because of substantial structural damage. Therefore, one might 
consider a threshold of structural damage (say when the building is 
condemned following an earthquake, or when it reaches its replacement 
threshold) at which point most of the contents are considered lost. 


Quantifying Loss of Operations 

Structural and nonstructural damage may require that a building's operations 
be curtailed or cease altogether for some period during repair or replacement.  
The loss of operations will have a direct effect on the revenue or "value" of the 
services or goods that the business produces. It will also, presumably, have a 
broader impact on its employees, on the customers that it serves, and possibly 
on the community or region as a whole.  Business interruption may also be a 
factor in how soon, if ever, the business can recover lost opportunities and 
markets. 

The primary impacts caused by loss of operations include: 

Direct loss of revenue or value; 

Indirect losses to employees, customers, and the community at 
large; and

Long term business losses. 


All three of these impacts are dependent on how long and to what extent the 
business is out of operation. This is usually a function of structural and 
nonstructural damage, and may also be a function of contents loss.  The 
impact of loss of operations on two facility types are demonstrated in the  two 
example case studies described on the following page. 
The loss of function of any single building is unlikely to cause devastating 
consequences to people in the affected region; nonetheless, these losses can 
be severe if the affected facilities are critical to community functions or the 
local 
or regional economy. Following are example situations where the loss of a 
critical facility can negatively affect the community as a whole or have far-
reaching consequences: 

In August, the only high school in a city is damaged to the point where 
it 
must be replaced. Where do the students go to school for the coming year or 
more while a new facility is designed and built? 

The only county hospital with a trauma center is rendered non-func-
tional during an event that causes dozens of life-threatening injuries
within the community.

A pharmaceutical manufacturing plant that produces a popular
drug for which the company owns the patent is destroyed in an 
earthquake.  How will patients continue to get the drug?

An automotive parts manufacturer that provides "just-in-time" sup-
plies to an automobile maker cannot function for three months.
How will this affect the automobile company's ability to produce 
cars and its ability to keep its employees busy?


It is almost impossible to put a dollar value on the cost of these losses 
because, like many other events, the repercussions can be difficult to 
completely define.  It is therefore unrealistic to develop a pure cost-benefit 
study equating additional dollars spent on better performance with savings in 
terms of these reduced indirect effects. 

One can, however, make comparative studies with respect to other types of risks 
and establish an equivalent value of 
tolerating them.  In any of the examples above, the building owner will likely 
have liability insurance to protect against claims that could have a devastating 
impact on the entity.  A private school might have a catastrophic insurance 
policy to protect against a student being killed in a sporting event; a public 
school may have locally- or state-granted legal protections.  A hospital certainly 
has malpractice insurance and an automotive plant will have worker's 
compensation insurance.  However, insurance policies all have limits on 
coverage. If losses exceed the coverage limit the result could be bankruptcy. 
Yet the owner in all cases makes a decision to limit coverage and therefore to 
accept the remaining risk of catastrophic loss. 

Considering the example of the school injury, if a family of an injured student 
wins a judgment exceeding the school's insurance policy, the school may have 
to declare bankruptcy and close its doors. The school may be able to avert this 
consequence if it buys additional insurance. However, at some point it makes 
the decision that it is not going to spend more in premiums and is willing to 
accept the risk of a catastrophic loss. The process to arrive at this limit may 
have been explicitly or implicitly thought out. Regardless, it can be used as a 
guide for making other decisions about risk management for earthquakes. The 
case study icon (see next page) illustrates this hypothetical situation. 
When determining the level of performance for which a building should be 
designed, an owner may want to consider involving those outside the business 
who will be indirectly affected by the potential loss of operations.  A community 
might be willing to contribute to the cost of a higher performance design of a 
school if it considers the value of having the building usable after an 
earthquake sufficiently high.  Similarly, an auto maker might contribute to the 
performance-based design of one of its parts suppliers if it considers an 
uninterrupted supply of parts crucial to its own operations. 


Social and Political Factors Affecting Seismic Risk Management
 
Emotion and politics are often important factors in the seismic risk 
management decision-making process. Parents of school children may say, 
"No price is too high to pay for the safety of my child."  Politicians or business 
leaders may proclaim, "We have a zero tolerance policy for placing the 
occupants of our buildings at risk." While well intended, these positions are not 
often achieved in practice.  

The concept of placing a quantified (dollar) value on the life or safety of each 
person is a controversial issue that impacts benefit-cost analysis.  This 
approach is implemented by comparing the value of saved lives (the benefit) to 
the cost of protecting those lives.  Political or emotional constraints often make 
this extremely difficult.  If an owner looks beyond life safety, however, and 
focuses on capital losses or down time, then it is practical and possibly 
necessary to quantify these losses in terms that can be compared directly to 
the costs to reduce them. The fact that most new U.S.-code-designed buildings 
are expected to provide life safety (for the range of earthquakes that may occur 
over the life of the building) renders the need to assign dollar values to human 
lives less imperative. 





5.6 COSTS OF IMPROVED PERFORMANCE 

Building owners incur costs to obtain specified levels of building performance. 
These costs are considered "first costs" if incurred at the time of building 
design and construction or purchase.  They are considered "operating costs" if 
incurred over the period of use of the building. 

It should be noted that the period of use of a building by its owner might differ 
from the life of the building. The life of a building may be 60 years or more, 
while the owner's use could be much shorter. When considering societal costs 
of a building, for example energy use, soci-ety's interest in operating costs are 
spread over the life of the building, regardless of owner turnover.  The life of 
the 
building is also of interest in the operating cost considerations of certain types 
of owners, particularly institutional owners such as schools and universities.  
However, for most commercial owners considering making an investment in a 
building, operating costs are of interest only over the period that the owner 
anticipates owning the building. 

First Costs 

The following are typical of first costs: 

The costs of site selection, including the cost of physical and eco-
nomic analysis of alternative sites.

The costs of planning and programming a new building, including the 
costs of consultants. 

The costs of architectural and engineering design and construction 
management, in the case of the construction of a new building, or 
the transaction costs (e.g., inspection and appraisal), in the case of the 
acquisition of an existing building. 


The disruption of operations resulting from the move from a cur
rently used building to a new building. Except for the last item, there is 
generally 
a direct relationship between cost and building performance (including seismic 
performance) - a higher first cost investment typically results in improved 
performance. 

Operating cost analyses often categorize the costs of construction or purchase 
as first costs. This is short sighted in most cases, since these costs are 
usually financed through mortgages or bonds, which converts them into 
continuous operating costs. 


Operating Costs 

The following are typical operating costs: 

Operation and maintenance of the building, including costs of 
earthquake response and recovery.

Replacement of building components and systems, including the cost of 
disruption of operation related to these activities, both of which can be 
annualized if converted to a payment into a replacement reserve fund. 

Changing the building to accommodate new functions or technology, 
and the disruption of operation resulting from such activities (which is 
analogous to churn rate). 

Insuring the building. Higher costs in this category may improve 
building 
performance by reducing unrecoverable losses or they may be inversely related 
to it, depending on insurance company underwriting practices. 

Building and contents damage resulting from unpredictable events, 
such as natural and man-made disasters, which can be expressed as a 
probability of incurring an annual cost. 

Disruption of operation due to building damage resulting from 
unpredictable events, which can be also expressed as a probability of incurring 
an annual cost. 

Liability for deaths and injuries from building damage resulting 
from unpredictable events.




The Relationship Between Cost and Performance 

An advantage of performance-based design is that it provides a means for the 
design team to create a relationship between construction cost and 
performance.  Traditionally (i.e., using existing seismic codes for new building 
design), to achieve better performance an engineer might simply increase the 
importance (I) factor from 1.0 to 1.25, thereby raising the design seismic forces 
by 25%. This may make a building perform better; however, the benefit is not 
easily quantifiable, even if the cost in increased steel tonnage or concrete 
volume can be estimated. 

A more refined way of achieving a specified performance in a cost efficient 
manner is to develop "learning curve" type relationships between the two. 
Consider the example in Figure 5-4.  A hypothetical precast concrete tilt-up 
manufacturing facility is to be constructed in a moderately high seismic zone. 
The lowest cost for the building is that which meets the minimum requirements 
of the building code. At this design level, the building will be expected to 
suffer 
some loss in the "worst case" earthquake, however that is defined. Additional 
investments in improved performance might be considered by the design team 
and owner. If the cost for each investment is added cumulatively as each is 
included in the construction budget then the expected worst case loss should 
decrease. As this example shows, investments in postearthquake response 
and nonstructural bracing result in a relatively large benefit in terms of reduced 
losses. Adding interior shear walls results in a moderate benefit. Increasing 
diaphragm strength and changing the entire structural system to unbonded 
braces produce a relatively low benefit. 

This example can be taken further by computing the benefit-cost ratio (BCR) for 
each performance strategy. Suppose the likelihood of the worst case event 
occurring over a 50-year life of the building is 25%, 
which corresponds to a 0.58% annual probability of occurrence2, and that the 
code minimum cost is equal to the replacement cost. Assuming a 5% discount 
rate (rate of return), the resulting benefits and costs are as summarized in 
Table 5-5. 


The example suggests that, in this case, the incorporation of a post-earthquake 
recovery program with a BCR of 2.1 is clearly a good investment. Improving 
nonstructural bracing in addition results in a BCR of 
0.85 suggesting that it is possibly a good investment. The other performance 
strategies appear not to be economically beneficial. 

A careful study of possible design strategies may lead to several cost-per-
formance curves, such as Figure 5-4, incorporating different combinations of 
performance strategies.  These will then allow the owner and the design team 
to select the one that achieves the greatest expected return on the investment. 






5.7 CASE STUDIES OF COST AND PERFORMANCE CONSIDERATIONS 

The following five case studies illustrate how different owners have addressed 
cost and performance considerations in seismic risk management decisions. 

Case Study 1: Computer Graphics Equipment Maker in Salt Lake City, Utah 


Salt Lake City, Utah is the headquarters of a small computer graphics 
equipment maker, as shown in Figure 5-5. The company's main prod
ucts are high-end simulation systems that sell for nearly $10 million 
each. Its new corporate office was to include a large assembly floor in which 
eight to ten of these devices would be assembled at one time, as 
well as a floor of office space above. All of the company's manufactur
ing would be housed within the building. The loss of a single simula
tion device as a result of an earthquake would have caused a 
catastrophic loss for the company, resulting in possible bankruptcy. 
The local structural engineer of record was skilled in performance-
based design and well known in Salt Lake City because of his efforts to 
expand awareness of seismic issues. The engineer was able to develop a 
relationship with the owner directly, although he was part of a design 
team headed by an architect. This "access" to the owner was crucial in 
providing an opportunity for the engineer to explain concepts of per-
formance-based seismic design. He and the owner discussed critical 
structural issues that could affect building performance and impact 
repair costs and business restoration. 

The code in force at the time of construction would likely have protected the 
building against most earthquakes. The seismicity in the Salt Lake City region 
during a typical 30-50 year building life is relatively low. However, considering 
the consequence of damage and lost functionality, even the relatively low 
vulnerability still resulted in an intolerably high risk to the owner. 
Because of the extremely high value of contents and cost of lost opera
tions, a performance objective was established to limit structural and 
nonstructural damage in a rare event to a level that would protect the 
contents and allow operations to continue unimpeded. 

To achieve this performance objective, the building was base isolated. The 
project team justified the additional cost associated with a base isolated 
building over a conventional structure by noting that the cost of the isolated 
structure was still less than the value of a single simulator. The vulnerability 
of 
the enhanced building was substantially lower than would be for a similar 
conventional structure. Much of the equipment, including the simulator devices, 
was braced to prevent tipping or sliding. The overall reduction in risk achieved 
was dramatic and met the owner's risk threshold. To reduce the risk any 
further, the building would likely have to have been re-sited to a region of lower 
seismicity. 


Case Study 2: Salt Lake City, Salt Lake City K-12 School District 

The Salt Lake City School District consists of 30-40 sites and contains 
buildings more than 70 years old, as shown in Figure 5-6. The District 
embarked upon a program of seismically upgrading its buildings to ensure that 
they would be safe and usable following a major seismic event. The District 
made the determination that it wanted to achieve a 70-year additional life for its 
structures. 

Its study of the existing school facilities found that when nonstructural 
rehabilitation costs (e.g., heating, electrical, roofing, and deferred 
maintenance) 
were added to the structural costs necessary to achieve the high performance 
objective, many of the rehabilitations would cost more than the replacement 
cost of the building. In these cases the decision was made to replace the 
facilities with new designs such as that shown in Figure 5-7. 

Recognizing that building codes can change dramatically even over the course 
of ten to twenty years, the District asked its engineering consultant to evaluate 
the performance needs with its long lifetime in mind. The engineer crafted 
simple yet effective graphics similar to the plot shown in Figure 5-8 to help the 
District determine its risk tolerance. A site hazard curve (see discussion in 
Section 3.2) was developed (see Figure 5-8) to show the expected ground 
accelerations plotted against their probability of exceedence in 50 years. Salt 
Lake City is in Uniform Building Code (UBC) Seismic Zone 3, and the vertical 
line at 10% show the design ground motion specified by the UBC. Over a 70-
year period, the probability of exceedence of this level of ground shaking 
increases from 10% to 14%. Another vertical line is drawn at 2% probability of 
exceedence in 50 years, representing perhaps the maximum credible event in 
the area. Over a period of 70 years, the probability of exceedence of this level 
of 
ground shaking increases from 2% to approximately 3%. Most notable is the 
dramatically higher ground motions that would be expected in the 2% 
probability of exceedence in 50-year event. This analysis showed that 
designing only for ground motions having a 10% probability of exceedence in 
50 years meant there was still a risk of much higher ground motions that could 
seriously damage the facilities. The District wanted to achieve a higher level of 
confidence than 14% over the 70-year lifetime that damage would be kept to a 
minimum. The design forces for the 2% probability of exceedence in 50-year 
event compared well to the UBC Seismic Zone 4 design forces. Therefore, the 
District decided to design all its new facilities to Zone 4 requirements for 
forces 
and detailing, pending a cost analysis of the upgraded performance. 

The consulting engineer estimated that to enhance a new facility's design from 
Zone 3 to Zone 4 compliance would add a cost on average of 1/4 to 1% of the 
construction budget. The District quickly realized that amortized over the length 
of its construction financing and certainly over the length of the 70-year 
assumed lifetime, this additional cost was negligible and therefore adopted the 
enhanced design strategy. 

Key factors in the owner's decision to use an enhanced performance objective 
were the expected longevity of the facilities and the number of buildings in the 
portfolio. The importance to the community of the school district, the large 
capital investment that was being made over the entire inventory, and the not 
inconsiderable likelihood of a damaging event occurring over the lives of the 
buildings were also important considerations in the District's decision. 


 
Case Study 3:  Prosthesis Manufacturing Company in Memphis, Tennessee 

A prosthesis manufacturing company in Memphis, Tennessee was nearing 
completion of a 100,000 square foot manufacturing plant in early 2002. The 
products manufactured within the building generate revenues of nearly 
$500,000 per day. The building operations are insured against down time by a 
large international insurance company. 

The building was built to the structural and nonstructural requirements
of the 1997 Southern Building Code (SBCCI, 1997). The insurer offered
to reduce the building's insurance premiums significantly if the nonstructural 
bracing was brought into conformance with the more severe requirements in 
the 2000 International Building Code (ICC, 2000). The International Building 
Code (IBC) requires that nonstructural bracing be designed to consider site 
conditions including soil and proximity to faults, and the location of the 
equipment within the building. 

A New York based manufacturer and supplier of mechanical equipment 
bracing products was hired to assess the additional cost of bracing the 
equipment to the higher standard. Typically, the IBC design required only larger 
elements (e.g., anchor bolts, clevises, rods) and not a substantial change to 
the design configuration. 

The manufacturer performed a detailed comparison of the two codes and 
prepared a side-by-side comparison of the cost premium for the IBC design. 
An excerpt from the comparison is shown in Table 5-6. 
The results of the study showed that the additional cost of upgrading the 
seismic bracing was negligible as a percentage of the overall non-structural 
costs. The company decided, based on the benefit of reduced insurance 
premiums, to implement the higher standard. 

This example suggests that improving the seismic nonstructural bracing in 
new buildings located in moderate seismic zones can be very cost efficient in 
terms of reducing losses. It may also result in the direct benefit of reduced 
annual insurance costs. 



Case Study 4: Stanley Hall, University of California Berkeley 

The University of California (UC) at Berkeley is one of the nation's premier 
research institutions. In 2003 the university broke ground for a state-of-the-art 
bio-engineering laboratory building as shown in Figure 5-9. The estimated cost 
of the project is nearly $200 million. The building will contain high-end 
laboratory facilities and house researchers working annually on nearly $40 
million in grants. UC Berkeley sits astride the active Hayward Fault. In the next 
thirty years, the USGS predicts there is nearly a 30% likelihood of a magnitude 
7 or greater earthquake occurring on the fault (Working Group on California 
Earthquake Probabilities, 2003). 

The University considered the protection of its massive investment in this 
facility to be extremely important. It asked the engineer of record to consider a 
higher performance objective than would have been required by the building 
code in force at the time. The goal was that the facility should remain 
occupiable after a design level event, and repair time to restore full operability 
should be measured in weeks not months. The engineer employed a state-of-
the-art buckling restrained (unbonded brace) braced frame system to ensure 
that damage would be kept to a minimum even in a large event that might 
rupture the entire length of the Hayward Fault. 

In order to obtain financing for the project, the University had to justify the 
added 
expense of the enhanced structural scheme. The school hired a second 
engineering firm expert in risk analysis, to help them provide the necessary 
rationale. The firm developed a "baseline" structural scheme that met only the 
minimum requirements of the building code. This system employed 
conventional concentric braced frames. The difference in cost between the two 
schemes was approximately $1.2 million, or roughly 1/2% of the building cost. 
They then used nonlinear performance-based engineering and risk 
assessment tools to calculate the expected losses due to earthquakes over 
the life of the building. The analysis showed that losses were substantially 
reduced using the enhanced scheme. The overall return on the $1.2 million 
investment, considering reduction of capital, contents and business 
interruption losses was approximately 11%. Figure 5-10 shows that the 
reduction in business interruption provided the majority of the projected 
benefits. Using a 5% discount rate as a benchmark, the benefit-cost ratio 
(BCR) for the enhancements was over 2 considering a fifty year life. At that dis-
count rate, the BCR reached one at a building life of about 15 years as shown 
in Figure 5-11. 

This example suggests that performance-based design can be a very cost 
effective risk management strategy for buildings that generate substantial 
revenue and for which the owner has a long-term interest. 







5.8 QUALITY CONTROL DURING THE CONSTRUCTION PROCESS 

Quality control is an important aspect of assuring satisfactory seismic 
performance: the building must be constructed as designed and specified.  

Building owners often interpret construction quality primarily in relation to 
interior and exterior finishes and materials because these are important for 
"marketing' in the private sector.  It is generally assumed that design and 
construction to meet the applicable building codes will assure a durable and safe 
structure. Since structural elements are usually 
invisible-concealed behind a suspended ceiling, gypsum board or exterior 
cladding-they have little bearing on the perception of building quality.  The 
exterior and interior appearance of the building will typically adhere to a 
company or institutional philosophy; this may be very functional for an industrial 
facility owner, but market trends or institutional objectives may influence 
others. The appearance of all facilities may also be influenced by local community 
design requirements. Decisions about image and quality have a major impact 
on construction cost, both initial and lifetime.  See Section 12.5 for additional 
guidance on assuring design and construction quality. 






5.9 RECOMMENDATIONS FOR IMPROVING SEISMIC PERFORMANCE 

In addition to the specific seismic design issues relating to siting, structural 
systems, and nonstructural systems, there are some general measures that 
can be employed to help manage seismic risk by reducing either the 
vulnerability of the facility to earthquake damage, or the consequences of the 
damage should it occur. These measures include the following. 

Consideration should be given to performance-based design to a level 
beyond Life Safety (typically the level of performance provided by provisions of 
the current seismic design codes) to a level of Immediate Occupancy, as 
discussed in Section 4.3. Institutional, public and corporate owners usually 
have long-term ownership of their facilities and a desire for continued operation 
in the post-event period. 

The design professionals in charge of the structural and nonstructural 
component installation should specify quality assurance requirements; the 
contractor should be required to exercise a high degree of quality control; and 
independent inspection should be used to ensure conformance to 
requirements. 

The design engineer should advise facility owners and manager on 
technical  aspects of obtaining insurance to cover potential losses including 
service interruption.  It may be possible to negotiate reduced premiums with 
the insurance carrier on the basis of any seismic mitigation measures 
provided beyond the code-minimum requirements. 

Retainer agreements should be established with engineers and 
architects to provide building inspection services immediately following an 
earthquake (see Section 2.6 for additional information). 

Personal protection and evacuation plans should be developed for all 
staff and students. Regular drills and educational sessions should be 
conducted to ensure proper execution (see Section 2.6 for additional 
information). 







DESIGN AND PERFORMANCE ISSUES RELATING TO COMMERCIAL OFFICE 
BUILDINGS 6 

6.1 INTRODUCTION 

Commercial office buildings represent a large building segment and house the 
core of American business operations. Corporate headquarters, banks, law 
firms, consulting firms, accountants, insurance companies, non-profit 
organizations - the list is almost endless - use office space in buildings 
around the country to house their operations. As these companies make 
decisions about the buildings that they construct or office space that they lease, 
seismic considerations can easily be factored into the decision process. 
The following are some unique issues associated with commercial office 
buildings that should be kept in mind during the design and construction 
phase of new facilities:  

Protection of building occupants is a very high priority.

Occupants are predominantly work-force, with high daytime "8 am to 5 
pm" occupancy. 

Most office building occupants are generally familiar with the 
characteristics of their building; a small percentage of occupants may be 
disabled to some degree and visitors will generally not be familiar 
with the building. 

Office buildings change their interior layouts frequently, to respond to 
tenant needs, fluctuations in work-force or organizational changes. 

Ensuring the survival of business records, whether in electronic or 
written form, is essential for continued business operation. 

Closure of the building for any length of time represents a serious 
business problem. 



6.2 OWNERSHIP, FINANCING, AND PROCUREMENT 

Commercial buildings may be owner operated, particularly if owned by national 
or global corporations, but many are developer owned (at least initially) 
housing tenant (lease holder) operations. In many instances the developer and 
building designers provide an empty "shell," which is fitted out according to the 
tenants' planning, spatial and environmental needs; design and construction is 
generally undertaken by the tenant's consultants and contractors.  This tends to 
split the responsibility for interior nonstructural and other risk reduction 
design 
and construction measures between the building designers and contractor, 
and a multiplicity of tenant designers and contractors. 

Financing for these facilities is typically through private loans.  The effective 
life 
of an office building is 20 to 30 years, after which major renovation and 
updating is normally necessary. Interior renovation is usually on a much 
shorter interval, particularly for rental office structures. 



6.3 PERFORMANCE OF OFFICE BUILDINGS IN PAST EARTHQUAKES 

The seismic performance of modern office buildings designed to recent codes 
(adopted since the late 1970s) has been good as far as providing life safety.  
However, the recognition by building owners that satisfactory life-safety code-
level performance may still encompass considerable damage (see Figure 6-
1), along with repair costs and possible business interruption of the building 
for weeks or even months, even in a moderate earthquake, suggests that 
some performance-based design strategies may be useful. 


Where severe structural damage has occurred in commercial office buildings, 
it has generally been to older buildings, often the result of configuration 
irregularities. Figure 6-2 shows an older medical office building, which had a 
vertical irregularity that caused one floor to pancake during the 1994 Northridge 
earthquake in Southern California; a failure resulting from inadequate 
attachment of heavy nonstructural walls in an older 5-story office building is 
shown in Figure 6-3. 

Newer office buildings have also been damaged, most notably the more than 
100 welded steel moment-frame buildings (healthcare and residential 
structures as well as commercial, higher education  and industrial buildings) 
that failed during the 1994 Northridge earthquake.  The damage occurred 
primarily at welded beam-to-column connections, which had been designed to 
act in a ductile manner and to be capable of withstanding repeated cycles of 
large inelastic deformation. 

While no casualties or collapses occurred as a result of these failures, the 
incidence of damage was sufficiently high in regions of strong motion to cause 
wide-spread concern by structural engineers and building officials.  Initial 
investigations showed that in some cases, 50% of the connections were 
broken and very occasionally the beam or column was totally fractured. 
Possible causes focused on incorrect connection 
design, incorrect fabrication, poor welding techniques and materials, 
struction techniques. 

As a result, a large research program was initiated, sponsored primarily by 
FEMA, to identify the problems and arrive at solutions.  Many structural 
specimens were tested in university laboratories.  New guidelines for these 
types of structures have been developed (SAC, 2000a, b), but remedial 
measures have resulted in more costly designs and extended approval 
procedures, with the result that many engineers have avoided welded steel 
moment-resistant frames in recent projects. 




6.4 PERFORMANCE EXPECTATIONS AND REQUIREMENTS 

The following guidelines are suggested as seismic performance objectives for 
commercial office buildings: 

Persons within and immediately outside the building must be pro-
tected to at least a life safety performance level during design-level  
earthquake ground motions.

Persons should be able to evacuate the building quickly and safely 
after the occurrence of design-level earthquake ground motions.

Emergency systems in the facility should remain operational after 
design-level earthquake ground motions. 

Emergency workers should be able to enter the building immedi-
ately after the occurrence of design-level earthquake ground
motions, encountering minimum interference and danger.





6.5 SEISMIC DESIGN ISSUES 

The information in this section summarizes the characteristics of commercial 
office buildings, notes their relationship to achieving good seismic 
performance, and suggests seismic risk management solutions that should 
be considered. 

Seismic Hazard and Site Issues 

Unusual site conditions, such as a near-source location, poor soil 
characteristics, or other seismic hazards, may lead to lower performance than 
expected by the code design.  If any of these other suspected conditions are 
geologic hazards, a geotechnical engineering consultant 
stabilization, foundation and structural design approaches should be employed 
to reduce consequences of ground motion beyond code design values, or 
costly damage caused by geologic or other seismic hazards (see Chapter 3 for 
additional information).  If possible, avoid sites that lack redundant access and 
are vulnerable to bridge or highway closure. 

Structural System Issues 

Office buildings are typically low- to mid-rise in suburban locations and 
occasionally high-rise in downtown locations of larger cities or in satellite 
suburban office complexes. Office buildings are intrinsically simple, and often 
are of simple rectangular configuration, not least because economy is usually 
a prime concern for commercial structures. Thus, their seismic design can be 
economical and use simple equivalent lateral force analysis procedures with a 
good probability of meeting code performance expectations as far as life safety 
is concerned. The protection of nonstructural components, systems and 
concepts requires structural design to a higher performance level.  
Configuration irregularities may be introduced for image reasons or site 
constraints in odd-shaped urban lots, and the structural design may become 
more complex and expensive. To assist the protection of nonstructural 
components, special attention should be paid to drift control. 

The need for planning flexibility requires minimization of fixed interior 
structural 
elements and a preference for column-free space. Need for flexibility in power 
and electronic servicing has resulted in increasing use of under floor servicing 
to work cubicles, and structural systems have been developed to provide this. 
Office buildings typically employ steel or reinforced concrete frames to permit 
maximum planning flexibility.  Steel or reinforced concrete moment frames 
provide maximum flexibility, but tend to be expensive in high and moderate 
seismic zones.  New guidelines for the design of welded moment-frame 
connections, noted above, have increased the cost of these types of structural 
system, increasing the already common use of steel braced frames.  Elevator 
cores duct shafts and toilet rooms, being permanent, can be used as shear 
walls if of suitable size and location.  Since these elements are much stiffer 
than a surrounding frame they may be a source of stress concentration and 
torsion, if asymmetrically located.  If severe asymmetry of core locations is 
essential for plan-ning reasons, the cores should not form part of the lateral-
force resisting system. 

Nonstructural System Issues 

The extensive use of frame structures for commercial office buildings, together 
with the tendency for them to be designed to minimum code standards, has 
resulted in structures that are subject to considerable drift and motion (sway).  
The result has been a high level of nonstructural damage, particularly to 
partitions, ceilings and lighting.  This kind of damage is costly and its repair 
is 
disruptive. 

In addition, storage units, free standing work stations and filing cabinets are 
subject to upset. Excessive drift and motion may also lead to damage to roof-
top equipment, and localized damage to water systems and fire suppression 
piping and sprinklers; thus the likelihood of water damage is greater. 
The responsibilities within the design team for nonstructural component 
support and bracing design should be explicit and clear. The checklist for 
responsibility of nonstructural design in Chapter 12 (see Figure 12-5) provides 
a guide to establishing responsibilities for the design, installation, review and 
observation of all nonstructural components and systems 






DESIGN AND PERFORMANCE ISSUES RELATING TO RETAIL COMMERCIAL 
FACILITIES 7 

7.1 INTRODUCTION 

Retail commercial facilities house shops and stores, which contribute a 
signficiant portion of the nation's economic output. Department store malls, 
big-box retailers, grocery stores and strip malls are but a few of the almost 
endless list of retail operations housed in these types of facilities. As these 
companies make decisions about the buildings that they construct or spaces 
that they lease, seismic considerations can easily be factored into the decision 
process. 

The following are some unique issues associated with retail commercial 
buildings that should be kept in mind during the design and construction 
phase of new facilities:  

Protection of building occupants is a very high priority.
 
Occupants are predominantly work-force and shoppers; shopping malls 
and large retail stores typically are open from about 10 am to 9 pm for 7 days a 
week, typically with higher occupancy at weekends.
 
"Big box" stores also have a high evening occupancy. 

Most shoppers are generally familiar with the characteristics of the 
shopping malls stores they frequent, but large retail stores are confusing to the 
first-time shopper. Familiarity with exit locations and egress routes is 
questionable. 

Retail stores, particularly department stores, change their interior 
layouts 
frequently to respond to market changes and retailing fashions. Big box stores 
generally retain a simple aisle layout, though some large electronic and 
furniture stores employ subdivided and clustered layouts related to groups of 
merchandise. 

Ensuring the survival of business records, whether in electronic or 
written form, is essential for continued business operation. 



7.2 OWNERSHIP, FINANCING, AND PROCUREMENT 

Retail malls are generally developer sponsored.  Department stores and "big 
boxes" are developed by regional or national owners; their design and 
construction are independent of the retail mall developments in which they may 
be located. In retail malls, the mall developer designs and constructs "shell" 
structures in which space is leased to retail store owners who use their own 
design and subcontracting teams to fit out the space to their requirements. 
This tends to split the responsibility for interior nonstructural and other risk-
reduction design and construction measures between the building designers 
and contractor, and a multitude of tenant store designers and contractors. 
Financing for these facilities is typically through private loans.  The effective 
life 
of a retail mall or store is about 20 years, after which major renovation and 
updating is necessary. Interior renovation is usually on a much shorter interval. 
Shopping malls and stores are generally constructed using a single contractor 
selected by competitive bid.  Large shopping malls may have a number of 
contractors working on the site because each department store will usually 
have its own general contractor and subcontractors.  Low cost and very rapid 
construction with reliable achievement of construction schedules are prime 
considerations.  The opening of new retail facilities is often timed to meet key 
shopping periods such as Christmas or opening of the school year. 




7.3 	PERFORMANCE OF COMMERCIAL RETAIL FACILITIES IN PAST 
EARTHQUAKES 

There has been considerable damage to retail facilities of all sizes in recent 
earthquakes. 

In the Northridge earthquake of 1994 near Los Angeles, a large regional 
shopping mall with 1.5 million sq.ft. of retail space suffered severe damage 
and was closed for 18 months.  Some 200 mall stores were closed and six 
department stores under independent ownership received varying amounts of 
damage. One department store suffered a partial collapse, and was 
demolished and replaced (Figure 7-1). The other stores were repaired. Other 
shopping malls in the area suffered damage, 
but their performance was considerably better.  The Topanga Plaza Mall in 
Canoga Park, approximately 5 miles from the epicenter, was built in the early 
60's but was seismically upgraded in 1971.  Structural damage was confined 
to cracking of reinforced masonry shear walls and damage to concrete 
columns in infilled shear walls. Nonstructural damage was significant, 
however, ranging from damage to floor, ceiling and wall finishes to frequently 
shattered or dislodged store-front glass panels. 




7.4 PERFORMANCE EXPECTATIONS AND REQUIREMENTS 

The following guidelines are suggested as seismic performance objectives for 
retail facilities: 

Staff and shoppers within and immediately outside retail stores must be 
protected to at least a life-safety performance level during design-level 
earthquake ground motions. 

Emergency systems in the facility should remain operational after 
the occurrence of design-level earthquake ground motions.

Shoppers and staff should be able to evacuate the building quickly and 
safely after the occurrence of design-level earthquake ground motions. 

Emergency workers should be able to enter the building immedi-
ately after the occurrence of design-level earthquake ground 
motions, encountering minimum interference and danger.




7.5 SEISMIC DESIGN ISSUES
 
The information in this section summarizes the characteristics of retail 
facilities, notes their relationship to achieving good seismic performance, and 
suggests seismic risk management solutions that should be considered. 

Seismic Hazard and Site Issues
 
Unusual site conditions, such as a near-source location, poor soil 
characteristics, or other seismic hazards, may lead to lower performance than 
expected by the code design.  If any of these other suspected conditions are 
geologic hazards, a geotechnical engineering consultant should conduct a 
site-specific study. If defects are encountered, an alternative site should be 
considered (if possible) or appropriate soil stabilization, foundation and 
structural design approaches should be employed to reduce consequences of 
ground motion beyond code design values, or costly damage caused by 
geologic or other seismic hazards (see Chapter 3 for additional information).  If 
possible, avoid sites that lack redundant access and are vulnerable to bridge 
or highway closure. 

Structural System Issues 

Retail facilities are usually one or two stories; mall structures and "big boxes" 
are usually light steel frames or mixed steel frame/wood/con-crete/concrete 
masonry structures.  Reinforced concrete block masonry perimeter walls often 
provide lateral resistance; for these systems, connections of roof diaphragms 
to walls are critical. The large building size and long-span light-frame load 
bearing structures of many of these facilities often lead to large drifts (or 
sway) 
during earthquake shaking.  When designed to code minimums these drifts 
may be excessive and cause nonstructural damage, particularly to ceilings and 
partitions. 

Retail buildings are intrinsically simple in their architectural/structural 
configuration, and basically are large open box-like structures with few interior 
walls and partitions. This enables their structural design to be simple and their 
seismic design can be carried out using the basic equivalent lateral force 
analysis procedures with a good probability of meeting code performance 
expectations as far as life safety is concerned. The desire for low cost, 
however, coupled with a tendency to meet only the minimum code 
requirements, sometimes results in inadequately engineered and poorly 
constructed structures. The protection of non-structural components, systems 
and contents requires structural design to a higher performance level.  
Configuration irregularities are sometimes introduced for image reasons and 
the structural design may become more complex and expensive. 

Nonstructural System Issues 

The extensive use of light-steel-frame structures for retail facilities, together 
with the tendency for them to be designed to minimum codes and standards, 
has resulted in structures that are subject to considerable drift and motion.  
The result has been a high level of nonstructural damage, particularly to 
ceilings and lighting.  This kind of damage is costly and its repair is 
disruptive. 

In most "big box" stores the building structure forms only a weatherproof cover 
and is lightly loaded. Often there is no suspended ceiling and light fixtures are 
hung directly from the building's structure. The merchandise is stacked on 
metal storage racks, which provide vertical and lateral support.  These racks 
are supplied and installed by specialist vendors.  The correct sizing and 
bracing of these racks is critical because the merchandise is often heavy and 
located at a high elevation. Even if the racks remain, material may be displaced 
and fall on the aisles, which are often crowded. 

More upscale department stores have complete suspended ceilings and often 
have elaborate settings for the display of merchandise.  These can be 
hazardous to staff and shoppers. 

Excessive drift and motion (building sway) may also lead to damage to roof-top 
equipment and localized damage to water systems and fire suppression 
piping and sprinklers. 

The responsibilities within the design team for nonstructural component 
support and bracing design should be explicit and clear. The checklist for 
responsibility of nonstructural design in Chapter 12 (see Figure 12-5) provides 
a guide to establishing responsibilities for the design, installation, review and 
observation of all nonstructural components and systems. 








DESIGN AND PERFORMANCE ISSUES RELATING TO LIGHT 
MANUFACTURING FACILITIES 8 

8.1 INTRODUCTION 

This chapter addresses a broad range of facilities used for industries engaged 
in the manufacturing assembly, testing and packaging of specialized products 
within workbench production areas. Much of this manufacturing is associated 
with the electronics, or "high-tech" industry, and in some cases, special 
environments such as "clean-rooms" are required. Most light manufacturing 
operations are relatively new and take place in recently designed and 
constructed buildings using modern equipment installations. 

The following are some unique issues associated with light manufacturing 
facilities that should be kept in mind during the design and construction phase 
of new facilities: 

Protection of building occupants is a very high priority. 

Building occupancy is relatively low, except in buildings with major 
production or assembly functions.  Occupants are predominantly work-force, 
with high daytime "8 am to 5 pm" occupancy, although favorable market 
conditions may entail the use of additional work-shifts. Visitors are few in 
number. 

Ensuring the survival of production, testing and other expensive 
equipment is an important economic concern. 


Closure of the building for any length of time represents a very serious 
business problem, which will involve loss of revenue and possibly loss of 
market share. 

Most manufacturing building occupants are generally familiar with the 
characteristics of their building; a small percentage may be disabled to some 
degree. 

Frequent provision must be made for the production of new products 
and the removal of existing equipment and its replacement. 

Ensuring the survival of business records, whether in electronic or 
written form, is essential for continued business operation. 



8.2 OWNERSHIP, FINANCING AND PROCUREMENT 

Many light manufacturing facilities are owner developed, particularly if owned by 
national or global corporations, but some are also developer owned providing 
for tenant operations.  Some large corporations may use a developer to build 
facilities that suit their operations, and thus avoid becoming involved in 
possibly troublesome development and building operations.  Buildings that are 
constructed by developers as speculation tend to be occupied by start-up or 
young companies. In these instances the developer and building designers 
provide an empty "shell," which is fitted out according to the tenants' planning, 
spatial and environmental needs; design and construction is generally 
undertaken by the tenant's designers and subcontractors.  This tends to split 
the responsibility for interior nonstructural and other risk-reduction design and 
construction measures between the building designers and contractor, and the 
tenant designers and contractors. 

Financing for these facilities is typically through private loans.  The effective 
life 
of the building may be about 50 years, particularly in the electronic industry. 
Light manufacturing buildings are generally constructed using a single 
contractor selected by competitive bid.  Low cost and very rapid construction, 
with reliable achievement of construction schedules, are prime considerations.


 
8.3 	PERFORMANCE OF LIGHT MANUFACTURING FACILITIES IN PAST 
EARTHQUAKES 

Starting in the late 1950s larger light manufacturing buildings have been 
predominantly tilt-up structures, particularly in California.  In seismic regions 
the perimeter precast walls were used as shear walls and roof structures were 
generally glued-laminated beams and plywood diaphragms. In the 1964 
Alaska earthquake and the 1971 San Fernando (Los Angeles) event, 
performance of these buildings was poor, with considerable damage being 
sustained.  The most common type of failure was to the wall/diaphragm 
anchors, but large out-of-plane movement of the panels, out-of-plane bending 
cracks in pilasters at mezzanine levels, and roof separations were all 
encountered and many roof collapses occurred.  Due to the relatively large size 
of these buildings roof collapses were localized, rarely extending beyond one 
or two bays, and the buildings were sparsely occupied, so casualties were few. 

Following the 1971 San Fernando earthquake code changes were introduced, 
with the result that subsequent performance was improved. During the 1994 
Northridge earthquake near Los Angeles, there were a number of failures of tilt-
up structures and there were some collapsed wall panels along the sides of 
buildings resulting in partial roof collapse. 

Changes to wall anchorage requirements were introduced in the 1997 Uniform 
Building Code. 




8.4 PERFORMANCE EXPECTATIONS AND REQUIREMENTS 

The following guidelines are suggested as seismic performance objectives for 
light manufacturing facilities: 

Persons within and immediately outside manufacturing facilities must 
be protected at least to a life-safety performance level during design-level 
earthquake ground motions.
 
Building occupants should be able to evacuate the building quickly and 
safely after the occurrence of design-level earthquake ground motions. 

Emergency systems in the facility should remain operational after 
the occurrence of design-level earthquake ground motions. 

Emergency workers should be able to enter the building immedi-
ately after the occurrence of design-level earthquake ground 
motions, encountering minimum interference and danger.

Key manufacturing equipment, supplies and products  should be
protected from damage.

In "high-tech" manufacturing facilities most services and utilities 
should 
be available within three hours of  the occurrence of design-level earthquake 
ground motions. 

There should be no release of hazardous substances as a result of
the occurrence of design-level earthquake ground motions.




8.5 SEISMIC DESIGN ISSUES 

The information in this section summarizes the characteristics of light 
manufacturing facilities, notes their relationship to achieving good seismic 
performance, and suggests seismic risk management solutions that should 
be considered. 

Seismic Hazard and Site Issues

Unusual site conditions, such as a near-source location, poor soil 
characteristics, or other seismic hazards, may lead to lower performance than 
expected by the code design.  If any of these other suspected conditions are 
geological hazards, a geotechnical engineering consultant should conduct a 
site-specific study. If defects are encountered, an alternative site should be 
considered (if possible) or appropriate soil stabilization, foundation and 
structural design approaches should be employed to reduce consequences of 
ground motion beyond code design values, or costly damage caused by 
geologic or other seismic hazards (see Chapter 3 for additional information). If 
possible, avoid sites that lack redundant access and are vulnerable to bridge 
or highway closure. 

Structural System Issues 

Light manufacturing facilities are usually one story; sometimes office/ 
administrative accommodation is provided in a mezzanine space.  There has 
been increasing use of light steel frames and steel deck structure for roofs and 
mezzanines. Most large buildings now use braced steel frame structures.  
Exteriors may be of masonry or metal insulated panels. 

Manufacturing buildings are intrinsically simple in their architectural/ 
structural 
configuration, and basically are large open box-like structures with few interior 
walls and partitions. This enables their structural design to be simple, and their 
seismic design can be carried out using the basic equivalent lateral force 
analysis procedures with a good probability of meeting code performance 
expectations as far as life safety is concerned. The desire for low cost, 
however, coupled with a tendency to meet only the minimum code 
requirements sometimes results in inadequately engineered and poorly 
constructed structures, The protection of valuable equipment and contents 
requires structural design to a higher performance level.  

The large building size and long-span light frame load bearing structures of 
many of these facilities often lead to large drifts (or sway). When designed to 
code minimums these drifts may be excessive and cause nonstructural 
damage, particularly to ceilings and partitions. 

Nonstructural System Issues 

Continued operation is particularly dependent on nonstructural components 
and systems, including purchased equipment, much of which is often of great 
sensitivity and cost. Many specialized utilities must be provided, some of which 
involve the storage of hazardous substances, such as pharmaceuticals, or 
hazardous gases.  These must be protected against spillage during an 
earthquake.  Distribution systems for hazardous gases must be well supported 
and braced.  

The extensive use of light-steel-frame structures for manufacturing facilities, 
together with the tendency for them to be designed to minimum codes and 
standards, has resulted in structures that are subject to considerable drift and 
motion.  As a result, recent earthquakes have caused a high level of 
nonstructural damage, particularly to ceilings and lighting.  This kind of 
damage is costly and its repair is disruptive. 

Research and production areas may need special design attention to 
specialized equipment services and materials to ensure continued production 
and delivery. 

In most manufacturing facilities the building structure forms only a 
weatherproof cover and is lightly loaded. Often there is no suspended ceiling 
and light fixtures are hung directly from the building's structure. In storage 
areas, materials are stacked on metal storage racks that provide their own 
vertical and lateral support.   These racks are supplied and installed by 
specialist vendors.  The correct sizing and bracing of these racks are critical if 
the materials are heavy and located at a high elevation. Even if the racks 
remain stable, material may be displaced and fall on the aisles or on 
equipment.
 
Storage units, free standing work stations, and filing cabinets are also subject 
to upset. Excessive drift and motion may lead to damage to rooftop equipment 
and localized damage to water systems and fire suppression piping and 
sprinklers. 

The responsibilities within the design team for nonstructural component 
support and bracing design should be explicit and clear. The checklist for 
responsibility of nonstructural design in Chapter 12 (see Figure 12-5) provides 
a guide to establishing responsibilities for the design, installation, review and 
observation of all nonstructural components and systems. 






DESIGN AND PERFORMANCE ISSUES RELATING TO HEALTHCARE 
FACILITIES 9 

9.1 INTRODUCTION 

Healthcare facilities are the places where America goes for treatment for most 
of its healthcare and are the places that need to be available to them after 
being injured in an earthquake. Regional or local hospitals, outpatient clinics, 
long-term care facilities are all examples of health-care facilities that serve in 
this role. As healthcare companies make decisions about the buildings that 
they construct, seismic considerations can easily be factored into the decision 
process. 

The following are some unique issues associated with healthcare facilities that 
should be kept in mind during the design and construction phase of new 
facilities: 

Protection of patients and healthcare staff is a very high priority. 

Healthcare occupancy is a 24 hour/7 day-per-week function. 

Acute-care hospitals have a large patient population that is immobile 
and helpless, for whom a safe environment is essential. This particularly 
requires a safe structure and prevention of falling objects. 

Hospitals are critical for emergency treatment of earthquake victims and 
recovery efforts. 

Medical staff has a crucial role to play in the immediate emergency and 
during the recovery period. 

Ensuring the survival of all equipment and supplies used for emergency 
diagnosis and treatment is essential for patient care. 

Ensuring the survival of medical and other records, whether in 
electronic 
or written form, is essential for continued patient care. 

Closure of hospitals for any length of time represents a very serious 
community problem exacerbated by the possibility of the loss of healthcare 
personnel who are in high demand or unable to work because of personal 
earthquake-related consequences (e.g., their own injury). 

Many hospitals are not only service providers but also profit or 
nonprofit 
businesses and, since their operating costs and revenues are high, every day 
that the facility is out of operation represents serious financial loss.  




9.2 OWNERSHIP, FINANCING, AND PROCUREMENT 

Healthcare facilities are typically developed by a private non-profit or for-
profit 
hospital corporation or an HMO (health maintenance organization). Many are 
also developed by a local, state or federal government agency. Financing of 
privately owned facilities is typically by private loan, possibly with some state 
or 
federal assistance; for-profit hospitals may issue stock when access to capital 
is required, and hospitals also conduct fund-raising activities, a large part of 
which assist in capital improvement program financing. State and local public 
institutions are financed by state and local bond issues. Non-profit hospitals 
sometime issue bonds to the public. 

Private institutions have no restrictions on methods of procurement; projects 
may be negotiated, conventionally bid, use construction management or 
design-build.  Public work must be competitively bid. Typically, contracts are 
placed for all site and building work (structural and nonstructural). Medical 
equipment and furnishings and their installation are purchased separately 
from specialized vendors. 
Hospitals typically emphasize high quality of design and construction and long 
facility life, though all institutions are also budgeting conscious.  An 
attractive 
and well equipped hospital site and building cam-pus are seen as an 
important asset, particularly by private institutions that are in a competitive 
situation. 



9.3 	PERFORMANCE OF HEALTHCARE FACILITIES IN PAST 
EARTHQUAKES 

The most significant experience of seismic performance of healthcare facilities 
in recent earthquakes was that of the Northridge (Los Angeles), California, 
earthquake of 1994.  The San Fernando, California, earthquake of 1971 
seriously damaged several medical facilities, including the then brand-new 
Los Angeles County Olive View Hospital.  Most of the fatalities in this 
earthquake occurred in hospitals, principally the result of the collapse of an 
older unreinforced masonry Veterans Hospital building. In response to the 
recognized need for superior seismic performance by hospitals, the California 
Legislature enacted the Alfred 
E. Alquist Hospital Facilities Seismic Safety Act, which became effective in 
1973. This Act mandated enhanced levels of design and construction.  The Act 
proved very effective in limiting structural damage in the Northridge earthquake; 
no post-Act hospitals were red-tagged (posted with a red UNSAFE 
postearthquake safety inspection placard) and only one was yellow-tagged 
(posted with a yellow RESTRICTED USE placard). However, nonstructural 
damage was extensive, resulting in the temporary closure of several of the 
post-1973 buildings and the evacuation of patients. 

Long-term closure only occurred in hospitals affected by the 1994 Northridge 
earthquake when there was structural damage; this only affected some pre-
1973 hospitals. While structural damage can cause severe financial losses, 
the more important loss of ability to serve the community during the hours 
following the earthquake is more likely to be caused by nonstructural damage.  
At Holy Cross Medical Center, for example, damage to the air handling system 
and water damage from broken sprinklers and other piping required 
evacuation, but most services were restored within a week and paramedic 
units opened within 3 weeks (Figure 9-1). At Olive View Hospital (the 
replacement for the hospital damaged in the 1971 San Fernando earthquake) 
the structure was virtually undamaged (Figure 9-2), even though it was subject 
to horizontal ground accelerations approaching 1 g (g = acceleration of gravity).  
Broken piping and leakage, however, caused the evacuation of all patients and 
closure for one week. 

During the 1994 Northridge earthquake, most nonstructural damage in 
healthcare facilities occurred to water related components. Damage was 
caused by leakage from sprinklers and domestic water and chilled water lines; 
water shortages were caused by lack of sufficient on-site storage. Twenty-one 
buildings at healthcare facilities suffered broken non-sprinkler water lines with 
most of the damage in small lines, less than 2-1/2 inches in diameter, for 
which bracing was not required by code. Sprinkler line breakage occurred at 35 
buildings, all of which was caused by small unbraced branch lines. 
Following the 1994 Northridge earthquake, a new state law was passed that 
required all hospitals that are deemed at "significant risk of collapse" to be 
rebuilt, retrofitted or closed by 2008, and all acute care hospitals to meet 
stringent safety codes by 2030.  All hospital plans are to be reviewed by the 
Office of Statewide Health Planning and Development (OSHPD).  The 1972 and 
1994 hospital legislation is similar in scope to the 1933 and 1976 Field 
legislation enacted to protect schools, which is generally regarded to have 
been very successful in achieving its objectives of providing earthquake-safe 
schools. 



9.4 PERFORMANCE EXPECTATIONS AND REQUIREMENTS 

The following guidelines are suggested as seismic performance objectives for 
healthcare facilities: 

Patients, staff and visitors within and immediately outside health-care 
facilities must be protected at least to a life-safety performance level during 
design-level earthquake ground motions. 

Safe spaces in the facility (which, depending on climatic conditions, 
may 
be outside) should be available for emergency care and triage activities within 
two hours of the occurrence of design-level earthquake ground motions. 

Most hospital services should be available within three hours of the 
occurrence of design-level earthquake ground motions. 

Emergency systems in the facility should remain operational after 
the occurrence of design-level earthquake ground motions. 

The facility services and utilities should be self-sufficient for four 
days after the occurrence of design-level earthquake ground 
motions.

Patients and staff should be able to evacuate the building quickly 
and safely after the occurrence of design-level earthquake ground 
motions.

Emergency workers should be able to enter the building immediately 
after the occurrence of design-level earthquake ground motions, encountering 
minimum interference and danger. 

There should be no release of hazardous substances as a result of the 
occurrence of design-level earthquake ground motions. 




9.5 SEISMIC DESIGN ISSUES
 
The information in this section summarizes the characteristics of healthcare 
facilities, notes their relationship to achieving good seismic performance, and 
suggests seismic risk management solutions that should be considered. 
Unusual site conditions, such as a near-source location, poor soil 
characteristics, or other seismic hazards, may lead to lower performance than 
expected by the code design.  If any of these other suspected conditions are 
geologic hazards, a geotechnical engineering consultant should conduct a 
site-specific study. If defects are encountered, an alternative site should be 
considered (if possible) or appropriate soil stabilization, foundation and 
structural design approaches should be employed to reduce consequences of 
ground motion beyond code design values, or costly damage caused by 
geologic or other seismic hazards (see Chapter 3 for additional information).  If 
possible, avoid sites that lack redundant access and are vulnerable to bridge 
or highway closure. 

Structural System Issues 

Healthcare facilities are of great variety and size, encompassing all types of 
structure and services.  Large hospitals accommodate several occupancy 
types. Acute care is a highly serviced short-term residential occupancy, and 
many diagnostic, laboratory and treatment areas require high-tech facilities and 
services.  Service areas such as laundry, food service receiving, storage and 
distribution are akin to industrial functions, and administration includes typical 
office, communication and record-keeping functions. 

Smaller healthcare facilities may encompass one or more functions such as 
predominantly longer residential care, or specialized treatment such as 
physical rehabilitation or dialysis.  This functional variety influences some 
structural choices but the structure, as in all buildings, plays a background role 
in providing a safe and secure support for the facility structural integrity and 
drift 
control need special attention to provide an added level of reliability for the 
nonstructural components and systems. 

The heavy and complex service demands of hospitals require greater floor-to-
floor heights than for other buildings (such as offices) to provide more space 
above a suspended ceiling to accommodate the services.  A number of 
hospitals have been designed with "interstitial" service space-a complete 
floor inserted above each functional floor to accommodate the services and 
make their initial installation and future change easier to accomplish (see 
Figure 9-3). 

Because of their functional complexity, hospitals often have complex and 
irregular configurations.  Broadly speaking, smaller hospitals are planned as 
horizontal layouts; large hospitals often have a vertical tower for the patient 
rooms elevated above horizontally planned floors for the diagnostic, treatment 
and administrative services.  Emergency services are generally planned at the 
ground floor level with direct access for emergency vehicles. The structural 
design should focus on reducing configuration irregularities to the greatest 
extent possible and ensuring direct load paths. Framing systems need careful 
design to provide the great variety of spatial types necessary without 
introducing localized irregularities. 

Nonstructural System Issues 

As noted above excessive structural motion and drift may cause damage to 
ceilings, partitions, light fixtures, and glazing.  In addition, storage units, 
library 
shelving, and filing cabinets may be hazardous if not braced. Excessive drift 
and motion may also lead to damage to roof-top equipment, and localized 
damage to water systems and fire suppression piping and sprinklers.  Heavy 
equipment such as shop machinery, kilns and heavy mechanical and electrical 
equipment may also be displaced, and be hazards to occupants in close 
proximity. 

Continued operation is particularly dependent on nonstructural components 
and systems, including purchased equipment, much of which is often of great 
sensitivity and cost. Many specialized utilities must be provided, some of which 
involve the storage of hazardous substances, such as pharmaceuticals and 
oxygen in tanks.  These must be protected against spillage during an 
earthquake. Distribution systems for hazardous gases must be well supported 
and braced.  Water must be provided to many spaces, unlike an office building, 
where the provision is much more limited, and thus the likelihood of water 
damage in healthcare facilities is greater. 

The responsibilities within the design team for nonstructural component 
support and bracing design should be explicit and clear. The checklist for 
responsibility of nonstructural design in Chapter 12 (see Figure 12-5) provides 
a guide to establishing responsibilities for the design, installation, review and 
observation of all nonstructural components and systems. 






DESIGN AND PERFORMANCE ISSUES RELATING TO LOCAL SCHOOLS (K-
12) 10 

10.1 INTRODUCTION 

Primary and secondary (kindergarten through grade 12) schools house 
thousands of America's children every school day. These buildings come in a 
variety of configurations and sizes and are constructed from all types of 
structural materials like steel, concrete, masonry and wood. As school districts 
make decisions about the buildings that they construct, seismic considerations 
can easily be factored into the decision process. 

The following are some unique issues associated with kindergarten through 
grade 12 (K-12) schools that should be kept in mind during the design and 
construction phase of new facilities: 

Protection of children is an emotional societal issue and has very
high priority.

Occupancy density is one of the highest of any building type (typically 
1 person per 20 square feet by code), with the exception of summer months, and 
after an earthquake, children are likely to be very frightened, creating 
difficulties for evacuation of a damaged structure. 

Occupancy by children is required by law, thus the moral and legal 
responsibilities for properly protecting the occupants are very great. 

School facilities are critical for immediate earthquake disaster shelter 
and recovery efforts. 

Closure of schools for any length of time represents a very serious 
community problem, and major school damage can have long-term economic 
and social effects. 



10.2 OWNERSHIP, FINANCING, AND PROCUREMENT 

Public schools are programmed and developed by the local school district.  
Financing is typically by local or state bond issues, possibly with the addition 
of 
federal assistance. 

Public work must be competitively bid. Typically, contracts are placed for all 
site 
and building work, both structural and nonstructural.  Equipment and 
furnishings and their installation are purchased separately from specialized 
vendors. 

School districts typically try to emphasize high quality of design and 
construction and long facility life, though all districts are necessarily very 
budget 
conscious. 



10.3 PERFORMANCE OF LOCAL SCHOOLS IN PAST EARTHQUAKES 

There has been surprisingly little severe structural damage to schools, except 
in the Long Beach, California, earthquake of 1933, and there have been very 
few casualties.  In California, no school child has been killed or seriously 
injured since 1933.  This good fortune results primarily because all major 
California earthquakes since 1925 have occurred outside school hours.
 
Damage in the Long Beach earthquake was so severe that it was realized that 
if the schools had been occupied there would have been many casualties.  As 
a result, the State passed the Field Act within a month after the earthquake.  
This act required that all public school buildings be designed by a California 
licensed architect or structural engineer, all plans must be checked by the 
Office of the State Architect, and construction must be continuously inspected 
by qualified independent inspectors retained by the local school board. The 
State Architect set up a special division, staffed by structural engineers, to 
administer the provisions of the Act. While time of day limited casualties, the 
Field Act, which is still enforced today, has greatly reduced structural damage. 
In the Northridge, California, earthquake of 1994, State inspectors posted red 
UNSAFE placards on 24 school buildings, and yellow RESTRICTED USE 
placards on 82, although this was later considered overly conservative.  No 
structural elements collapsed. There was, however, considerable nonstructural 
damage as shown in  Figure 10-1. This was costly to repair, caused closure of 
a number of schools and, if the schools had been in session, would have 
caused casualties.  The Field Act focused on structural design and 
construction, and only recently were nonstructural components included in the 
scope of the Act. 



10.4 PERFORMANCE EXPECTATIONS AND REQUIREMENTS 

Students and teachers within and outside elementary and secondary school 
buildings must be protected during an earthquake.  Any damage that 
jeopardizes the provision of educational services impacts not only the facility 
but also the community, since the school is an important community center.  
Primary and secondary educational establishments are important community 
service providers and service interruption is a major problem. In addition to 
these general seismic performance expectations, the following guidelines are 
suggested as seismic performance objectives for elementary and secondary 
schools: 

The school should be capable of substantial use for shelter purposes 
within 3 hours of the occurrence of earthquake design-level ground motions. 

Emergency systems in the school should remain operational after 
the occurrence of earthquake design-level ground motions. 

Students and teachers should be able to evacuate the school quickly 
and safely after the occurrence of earthquake design-level ground motions. 

Emergency workers should be able to enter the school immediately after 
the occurrence of earthquake design-level ground motions, encountering 
minimum interference and danger. 



10.5 SEISMIC DESIGN ISSUES 

The information in this section summarizes the characteristics of local schools 
(K-12), notes their relationship to achieving good seismic performance, and 
suggests seismic risk management solutions that should be considered.

Seismic Hazard and Siting Issues

Unusual site conditions, such as a near-source location, poor soil 
characteristics, or other seismic hazards, may lead to lower performance than 
expected by the code design.  If any of these suspected conditions are geologic 
hazards, a geotechnical engineering consultant should conduct a site-spe-cific 
study. If defects are encountered, an alternative site should be considered (if 
possible) or appropriate soil stabilization, foundation and structural design 
approaches should be employed to reduce consequences of ground motion 
beyond code design values, or costly damage caused by geologic or other 
seismic hazards (see Chapter 3 for additional information). If possible, avoid 
sites that have restricted access. 

Structural System Issues 

Schools are a wide variety of sizes, from one-room rural school houses to 
2000-student high schools.  Each size will have its own code requirements and 
cost implications.  A wide variety of structural approaches are available and 
careful selection must be made to meet the educational and financial program. 
Traditional schools with rows of standard classrooms are relatively simple 
buildings, with few partitions since the structural walls can provide much of the 
space division.  Classroom walls can act efficiently as shear walls but the 
school is likely to have very limited flexibility for space changes. The 
structure, 
as in all buildings, plays a background role in providing a safe and secure 
support for the facility activities.  The structural problems are, however, 
relatively 
simple, and a well designed and constructed school should provide a safe 
environment. 

Newer schools are usually one or two stories with light steel frame or mixed 
steel frame, wood and concrete or concrete masonry structures.  When 
designed to code minimum requirements, these light and relatively long-span 
structures may have excessive drift characteristics.  Excessive motion and drift 
may cause damage to ceilings, light fixtures, partitions, glazing, roof-top 
equipment, utilities and fire suppression piping. The structural design should 
pay special attention to drift control and to appropriate support of vulnerable 
nonstructural components and systems. 

Urban schools are sometimes mid-rise (up to 4 stories), with reinforced 
masonry, reinforced concrete, or steel frame structures. For these structures, 
configuration irregularities, such as soft stories, may become critical.  The 
structural design should focus on reducing configuration irregularities and 
ensuring direct load paths. 

Larger schools may have long-span gymnasia or multi-use spaces in which 
wall-to-diaphragm connections are critical.  These larger spaces may be used 
for post-disaster shelters.  Seismic resistance must typically be provided by 
perimeter frames or walls. The structural design should pay special attention to 
reducing perimeter opening irregularities, and providing direct load path and 
appropriate structural connections. Larger schools also often tend to become 
more complex in layout because of new program needs, and the desire to 
provide a more supportive and attractive environment. The complexities in 
layout may introduce irregularities in plan shapes and require complicated 
fram-ing.  The structural design should focus on reducing plan irregularity, and 
providing appropriate structural connections. 

Nonstructural System Issues 

School occupants are particularly vulnerable to nonstructural damage.
Although school children may duck under desks and be safe from falling objects 
such as light fixtures and ceiling tiles, ceiling components that fall 
in hallways and stairs can make movement difficult, particularly if combined 
with power failure and loss of lighting. As discussed in the Structural System 
Issues Section, most traditional primary and elementary school buildings are 
relatively simple buildings, with few partitions since the structure provides the 
space division.  Excessive motion and drift (sway) may cause damage to 
ceilings, partitions, light fixtures, and glazing. In addition, storage units, 
library 
shelving, and filing cabinets may be hazardous if not braced. Excessive drift 
and motion may also lead to damage to roof-top equipment, and localized 
damage to water systems and fire suppression piping and sprinklers. Heavy 
mechanical and electrical equipment may also be displaced.  

Falling nonstructural components and systems present a significant potential 
for injuries to building occupants as shown in Figure 10-1. In addition to the 
injury potential and economic loss resulting from repair and clean-up costs, 
excessive service interruption can result from light-
be designed for enhanced drift control to limit nonstructural damage. 
Lightweight hung ceilings should be avoided in light frame or large structures, 
and the safety of suspended lighting fixtures should always be verified. In 
general, the responsibilities within the design team for nonstructural 
component support and bracing design should be explicit and clear (Use  
Figure 12-5 responsibility checklist to facilitate this process). 






DESIGN AND PERFORMANCE ISSUES RELATING
TO HIGHER EDUCATION FACILITIES (UNIVERSITIES) 11

11.1 INTRODUCTION 

University campuses generally consist of many different types of buildings, in a 
broad variety of sizes, housing many different functions. As a result, higher 
education facilities are, in many ways, a microcosm of the larger community. In 
addition to teaching classrooms, university facilities include auditoriums, 
laboratories, museums, stadiums and arenas, libraries and physical plant 
facilities, to name a few. As universities make decisions about the buildings 
that they construct, seismic considerations can easily be factored into the 
decision process. 

The following are some unique issues associated with higher education 
facilities that should be kept in mind during the design and construction phase 
of new facilities: 

Protection of students, faculty and staff is a very high priority. 

Higher education facilities have a high daytime occupancy and some 
evening use, with reduced use in the summer months.  Classrooms in 
particular often have high intensity usage. 

Closure of higher education facilities represents a very serious 
problem, 
and major college and university damage can have long-term economic and 
social effects.  

Ensuring the survival of records, whether in electronic or written 
form, is essential for continued operation.

Protection of valuable contents such as library inventories, research 
equipment and materials is a high priority. 



11.2 	OWNERSHIP, FINANCING, AND PROCUREMENT 

Higher education facilities are typically developed by the institution, which may 
be privately, state or local-community owned.  Financing of privately owned 
facilities is typically by private loan, possibly with some state or federal 
assistance; large universities also have large endowments and fund-raising 
activities, a large part of which assist in capital improvement program 
financing. Public institutions may also be financed by state and local bond 
issues.  

Private institutions have no restrictions on methods of procurement; projects 
may be negotiated, conventionally bid, use construction management or 
design-build.  Public work must be competitively bid.  Typically, contracts are 
placed for all site and building work, both structural and nonstructural. 
Equipment and furnishing and their installation are purchased separately from 
specialized vendors. 

Higher education institutions typically emphasize high quality of design and 
construction and long facility life, though all institutions are also budget 
conscious.  An attractive campus is seen, particularly by institutions which are 
in a competitive situation, as an important asset. 



11.3 	PERFORMANCE OF HIGHER EDUCATION FACILITIES (UNIVERSITIES) 
IN PAST EARTHQUAKES 

The most significant experiences of seismic performance of higher education 
facilities in recent earthquakes has been those related to the Whittier (Los 
Angeles region) earthquake of 1987, the Loma Prieta (San Francisco Bay 
region) earthquake of 1989, and the Northridge (Los Angeles) earthquake of 
1994.  During the Whittier earthquake, a number of buildings at the California 
State University at Los Angeles suffered some structural damage and 
extensive nonstructural disruption.  One student was killed by a concrete 
facade panel that fell from a parking structure. During the Loma Prieta 
earthquake, the Stanford University campus experienced considerable 
damage, forcing the closure of a dozen buildings.  Subsequently, Stanford 
convened a special committee to review steps that should be taken to protect 
the campus against future events. One result was to set up its own seismic 
safety office with structural engineering staff to determine, in concert with 
departmental and university representatives, performance objectives for 
buildings and to review proposed designs. The university played a strong role 
in the early application of performance-based design strategies for its capital 
programs. 

In the Northridge earthquake, the California State University at Northridge was 
forced to close for a month and re-open in temporary buildings. Severe 
damage was done to the welded steel frame of the University Library (Figure 
11-1), and buildings on the University of California at Los Angeles (UCLA) 
campus were slightly damaged. For the most part the serious structural 
damage to all these campuses was experienced by older reinforced buildings 
or to unreinforced masonry structures. 
The implications of the above-described damage caused a number of 
universities to become concerned about the ability of their facilities to support 
continued teaching and research following a more severe event. 
In 1997 the University of California at Berkeley committed $1 million to intensify 
campus planning and developed a 10-point action plan that included a high-
level administrative restructuring to focus on campus planning and 
construction, with extensive focus on seismic safety.  The 10-point plan 
included: 

Creation of a new Chancellor's cabinet-level position of Vice Chancellor 
to oversee all aspects of the program. 

Determination of the need for full or partial closure of any facilities 
deemed an unacceptable risk. 

Development of plans for a variety of temporary relocation or 
"surge" space, sites and buildings.

Development and initiation of a multi-source financing plan to 
implement the master plan and implement a seismic retrofit pro-
gram. 

Conduct of  a comprehensive emergency preparedness review, 
including mitigating nonstructural hazards, assuring that emergency and 
critical facilities are available, and providing emergency response training. 

This plan is now being implemented; a number of key facilities have been 
retrofitted, and others are in process, with priorities based on a seismic 
evaluation of all the campus buildings.  New buildings are subject to a peer-
review process of the proposed seismic design. 



11.4 PERFORMANCE EXPECTATIONS AND REQUIREMENTS 

The following guidelines are suggested as seismic performance objectives for 
higher education facilities: 

Students, faculty, staff and visitors within and immediately outside the 
facilities must be protected at least to a life safety performance level during 
design-level earthquake ground motions. 

Emergency systems in the facilities should remain operational after the 
occurrence of design-level earthquake ground motions. 

All occupants should be able to evacuate the school quickly and 
safely after the occurrence of design-level earthquake ground
motions.


Emergency workers should be able to enter the facility immediately after 
the occurrence of design-level earthquake ground motions, encountering 
minimum interference and danger. 



11.5 SEISMIC DESIGN ISSUES 

The information in this section summarizes the characteristics of higher 
education facilities, notes their relationship to achieving good seismic 
performance, and suggests seismic risk management solutions that should 
be considered. 

Seismic Hazard and Site Issues 

Unusual site conditions, such as a near-source location, poor soil 
characteristics, or other seismic hazards, may lead to lower performance than 
expected by the code design.  If any of these other suspected conditions are 
geologic hazards, a geotechnical engineering consultant should conduct a 
site-specific study. If defects are encountered, an alternative site should be 
considered (if possible) or appropriate soil stabilization, foundation and 
structural design approaches should be employed to reduce consequences of 
ground motion beyond code design values, or costly damage caused by 
geologic or other seismic hazards (see Chapter 3 for additional information). If 
possible, avoid sites that lack redundant access and are vulnerable to bridge 
or highway closure.
 
Structural System Issues 

Higher education facilities are of great variety and size, encompassing all types 
of structure and services. The basic occupancies are teaching, research and 
administration, but assembly facilities may range from a small rehearsal 
theater to a multi-thousand seat sports stadium.  A large student center may be 
a cross between a small shopping mall and a community center with retail 
stores, food service and places of recreation and assembly. As universities 
become more competitive to attract a wider audience, student-life facilities are 
tending to become larger and more complex. In addition, many universities 
provide extensive dormitory facilities. 

Teaching requires spaces for small seminar groups, classrooms that are often 
larger in size than those of a grade school, and large lecture halls with sloped 
seating and advanced audio-visual equipment. Science teaching requires 
laboratories and support spaces with services and equipment related to 
traditional scientific and engineering fields, such as chemistry, biology, physics 
and computer sciences. 
 
The administration function includes all office functions, including extensive 
communication services and extensive record keeping.  Science research 
requires laboratories and other special facilities (e.g., 
greenhouses) that can accommodate a variety of unique spatial, service and 
utility needs required by researchers; some laboratories such as material 
sciences, physics, and engineering require heavy equipment with large power 
demands.  Departmental buildings in the humanities may encompass a small 
administrative function, a variety of teaching facilities, many of them small.  
Departmental buildings in the sciences may include laboratories and their 
support space within the same building, and faculty offices may include direct 
access to research laboratories. Departmental buildings may also include a 
departmental library. Teaching and research in the biological sciences may 
include the storage, distribution and use of hazardous substances. 

The library is a major campus facility, and a large campus may have several 
campus-wide libraries.  Notwithstanding the rapid advance of computerized 
information technology and information sources such as the internet, the hard-
copy resources of the library continue to be of major importance, and the library 
is a distinct building type with some specific structural and service demands, 
such as the ability to safely accommodate heavy dead loads, and to provide a 
high level of electronic search and cataloging functions. 

Because of their functional complexity, large higher education facilities often 
have complex and irregular architectural/structural configurations. In addition, 
the spatial variety within many higher education buildings influences some 
structural choices, and structural design tends to be complex in its detailed 
layout with a variety of spans and floor-to-floor heights. Some laboratory 
equipment requires a vibration free environment, which entails special 
structural and mechanical equipment design. The structural design should 
focus on reducing con-figuration irregularities to the greatest extent possible 
and ensuring 
direct load paths. Framing systems need careful design to 
provide the great variety of spatial types necessary without 
introducing localized irregularities.  
Since continued operation is a desirable performance objective, structural 
design beyond life safety is necessary and design for both structural integrity 
and drift control need special attention to provide an added level of reliability 
from the nonstructural components and systems. 

Nonstructural System Issues 

As noted above, excessive structural motion and drift may cause damage to 
ceilings, partitions, light fixtures, and glazing.  In addition, storage units, 
library 
shelving, and filing cabinets may be hazardous if not braced.  Excessive drift 
and motion may also lead to damage to roof-top equipment, and to localized 
damage to water systems and fire suppression piping and sprinklers.  Heavy 
laboratory equipment and heavy mechanical and electrical equipment may also 
be displaced, and be haz-ards to occupants in close proximity. Continued 
operation is particularly dependent on nonstructural components and systems, 
including purchased scientific equipment, much of which is often of great 
sensitivity and cost.  Many specialized utilities must be provided, some of which 
involve the storage of hazardous substances.  These must be protected 
against spillage during an earthquake.   Distribution systems for hazardous 
gases must be well supported and braced.  Water must be provided to many 
spaces, and thus the likelihood of water damage is greater. Cosmetic wall and 
ceiling damage that can easily be cleaned up in an office building may shut 
down a research laboratory. 

Laboratory and research areas may need special design attention to 
nonstructural components and systems to ensure continued operation of 
critical experiments and equipment. 
The responsibilities within the design team for nonstructural component 
support and bracing design should be explicit and clear. The checklist for 
responsibility of nonstructural design in Chapter 12 (see Figure 12-5) provides 
a guide to establishing responsibilities for the design, installation, review and 
observation of all nonstructural components and systems. 








RESPONSIBILITIES FOR SEISMIC CONSIDERATIONS WITHIN THE DESIGN 
TEAM 12 

12.1 	RESPONSIBILITIES OF THE STRUCTURAL ENGINEER, ARCHITECT, 
AND MEP ENGINEER 

Seismic considerations should apply to every building system, subsystem, and 
component, and the performance of each component or system is often 
interdependent.  The traditional organization of the design team and the 
assignment of responsibilities to the architect, structural engineer, MEP 
(mechanical, electrical, and plumbing) consultants, and other specialty 
consultants (e.g., geotechnical engineer, curtain wall consultant, elevator 
consultant, or security consultant) is critically important to address cross-
cutting seismic design issues or problems. 

For example, the seismic design and performance of glazing systems, 
windows, and curtain walls have improved significantly in recent years through 
the adoption of improved code provisions for these building systems.  These 
improvements can impact both life safety in an earthquake (broken glass can 
kill or seriously injure) and immediate occupancy following an earthquake 
(integrity of the building envelope). The trade-offs involve drift limits, curtain 
wall 
clearances and design details, and glazing design.  In this example, the 
architect, structural engineer, and curtain wall consultant must work together 
closely to arrive at the appropriate designs. 



12.2 DEVELOPING A UNIFIED APPROACH WITHIN THE DESIGN TEAM 

The first step in the design process should be the development, with active 
participation of the owner, of a set of clear performance objectives that address 
how the building is expected to perform before, during, and following an 
earthquake.  These performance objectives should be based on owner needs 
and decisions, and should be expanded into detailed performance statements 
that apply to every subsystem of the building. Throughout the design 
development, there should be explicit reviews of each element of the design 
against the performance statements in order to assure that the completed 
building meets the expectations articulated in the original performance 
objectives. In addition, the owner should be encouraged to develop and carry 
out a risk management plan compatible with the performance objectives. 
The term "performance objective," discussed in Chapters 2 and 4, should 
include a statement regarding the seismic performance that is expected of the 
building, subsystem, or component that is being addressed. Wherever 
possible, it should include quantifiable performance criteria that can be 
measured.  For example, an objective may be that a subsystem (such as the 
HVAC system) should be operable following an earthquake of a certain 
magnitude.  The specific criteria related to this may specify how long the 
system is expected to operate, under what operating conditions, and with what 
resulting interior environmental conditions. 



12.3 ENGINEERING SERVICES FOR ADDED VALUE OF RISK MANAGEMENT 

The owner should establish a process in which the risk management function 
and the facilities management function are fully coordinated 
facility-related risks.  In order to do so, the risk manager should have an 
understanding of seismic risks.  Once the risk manager gains such an 
understanding, the risk manager should be educated to prepare a return-on-
investment analysis for investments in seismic performance. The design team 
has an opportunity to offer the owner a service of educating the risk manager 
on the details of seismic risk in buildings.  This service could be independent 
of any specific capital improvement or design project, or it can be offered as a 
pre-design orientation activity that is linked to a design project. 
Issues of building performance should be communicated to a building owner 
in terms that relate how the building is expected to perform following an 
earthquake, and the potential impacts that this level of performance may have 
on the postearthquake functionality of the building. In order to accomplish this, 
the design team must learn to communicate using terminology that is familiar 
to the owner. This can best be accomplished through interaction with the 
owner's facilities or risk manager. 

It is typically more difficult to explain earthquake risk issues to a building 
owner, 
since such considerations are probabilistic in nature, and less specific with 
respect to magnitude, location, or even how often they will occur.  The design 
team must understand the owner's extent of risk aversion or risk tolerance. The 
more risk neutral the owner is, the simpler the communication is likely to be, in 
that various outcomes can be multiplied by their respective probabilities and 
then communicated directly to the owner. This process, however, becomes 
more complicated with a more risk averse or tolerant owner.  The best way this 
communication can be accomplished is through close interaction and 
coordination with the owner's risk or facilities manager. 

As the member of the design team who initiates the design concept and 
develops it through design development and the preparation of construction 
documentation, the architect should play a key role in the seismic design 
process.  To ensure that consideration of seismic issues occurs with the right 
degree of priority, and at the right time in the design process, the architect 
should have a clear conceptual understanding of seismic design issues that 
impact the design. 

The structural engineer's role is to provide the structural design for a building.  
While the structural engineer must play the major role in providing an 
earthquake-resistant design, the overall design responsibility is shared 
between the architect and engineer, because of architectural decisions that 
may impact the effectiveness of the engineer's design solution and hence the 
building's seismic performance.  The use of per-formance-based design can 
reinforce the importance of the recommendation that the architect and 
structural engineer work together from the inception of a design project, and to 
discuss seismic issues before and during the conceptual design stage.  Many 
of the critical architectural decisions occur at the conceptual design stage, at 
which point the building configuration is set and issues such as the nature of 
the structure and structural materials and architectural finishes are identified. 
The concept of structural engineers participating with architects during the early 
conceptual design phase of a project is not new, yet it is often confined to a 
cursory conversation or does not occur at all, for a variety of economic, 
cultural, 
and professional reasons.  Developmental projects often require a partial 
design in order to procure project financing; at this point, the owner typically 
attempts to minimize upfront costs and the architect will not involve, or only 
peripherally involve, structural consultants.  Some architects see the structural 
engi-neer as providing a purely service role in enabling the architect to achieve 
the forms and spaces that are desired.  In a successful project, the architect 
and structural engineer typically collaborate on layout and design issues from 
the inception of the project, in order to ensure that the architectural and 
structural objectives are achieved. 

As the servicing needs of contemporary buildings continue to increase, the 
impact of the MEP (mechanical, electrical, and plumbing systems) consultant's 
work on seismic design becomes increasingly important. An example of this is 
the need for penetrations or blockouts in the structure to 
gration of the structural and mechanical system, and their size and location 
should be carefully worked out between the architect, structural, and 
mechanical engineers.  There are many instance of damage to buildings in 
earthquakes caused by structural member penetrations that have not been 
adequately coordinated with the structural design. 

design of mechanical equipment supports the responsibility of the equipment 
vendor, the mechanical engineer, or the structural engineer?  Similarly, is the 
design of the connections for precast concrete cladding the responsibility of the 
precast element vendor or the building structural engineer? And, is the layout 
and design of bracing for ductwork the responsibility of the mechanical 
contractor or the building structural engineer?  If these responsibilities are not 
called out at the outset of the job, the result will be disputes, extra costs, and 
potentially serious omissions. 


Design-Build and Fast-Track Projects 

Large projects are often "fast-tracked" to some degree, with the construction 
contract separated into a number of bid packages that may be sole-source 
negotiated or competitively bid.  The objective here is to speed the project's 
overall completion, but the process can substantially complicate coordination 
of tasks.  Among the reasons for this are the following. 

      	The complete design team may not be in existence before the 
preparation of construction documents has begun.  This arrangement can 
create problems when decisions early in the project determine design 
approaches and delegate responsibility to entities who are not yet under 
contract, or who have had no input into such early decisions. 

      	Communication among designers during fast-track projects is usually 
more difficult because the development of separate bidding packages means 
that the design process is fragmented, rather than one which undergoes 
continuous evolution.  At any stage during design development and contract 
document preparation stages of a project, a complete set of drawings of the 
project may not exist. 

      	Because of demands in the project schedule, the design and fabrication, 
or preparation of shop drawings, many items are not always thoroughly 
reviewed by the architect or engineer, and in some cases projects and for design 
teams that have a track record in working together, but 
for more complex projects and for design teams that have not previously 
worked together, both the design and construction phases of a project will 
need special attention.  The assignment of roles and responsibilities is critical 
if the performance objectives are to be adequately defined and for integrated 
seismic design and construction to be achieved. 



Checklists to Facilitate the Design and Construction Process 

A useful aid for the development of performance objectives and the 
coordination of the design and construction process within the design team is 
the use of checklists.  These may be maintained by hand for smaller jobs, or 
computerized for larger or more complicated ones.  Checklists can highlight 
key seismic design issues that require consideration and resolution, and can 
serve to ensure that all issues are adequately dealt with.  The checklists 
discussed below are suggested as models that may be modified to suit the 
nature of the design team and the construction delivery process. 

Figure 12-1 provides a seismic performance checklist, intended to focus the 
building owner and the design team on issues related to seismic performance 
expectations.  The checklist presents a set of questions that are used to help 
the client focus on available seismic performance alternatives, leading to a 
recorded statement of the client's expectations of seismic performance goals 
that, hopefully, are in line with available resources.  Agreement on such goals 
and expectations forms the beginning of a performance-based design 
procedure and can limit future "surprises" due to unanticipated earthquake 
damage.  The checklist statements can become a part of the project's building 
program, in a manner similar to statements about acoustical or thermal 
performance, and can serve as the basis for the use of more formal 
performance-based design procedures during the design. 

Figure 12-2 provides a checklist intended to facilitate a discussion between the 
architect and the structural engineer on the importance of various building 
siting, layout, and design issues.  The checklist identifies a number of issues 
that should be discussed and resolved by the architect and structural engineer 
at the early stages of a new project. The checklist should be used when a 
conceptual design has been prepared and transmitted to the structural 
engineer.  The checklist is intended primarily to provoke a discussion, and is 
not intended to be filled in and used as a document of record.  Most of the 
items in the checklist will need varying levels of discussion; the checklist is 
only 
intended to identify the existence of a potential problem and indicate the 
importance and priority, or significance, of the problem. 
Figure 12-2 also ensures that all significant issues are covered, and that the 
architect and structural engineer have reached mutual understanding on the 
resolution of problems.  This is the point at which the structural engineer 
should explain any issues that are not clear.  Similarly, if planning or other 
constraints appear to have resulted in a questionable seismic configuration or 
a building with other undesirable seismic characteristics, the use of this 
checklist will ensure the identification of these characteristics fairly early in 
the 
design process, and should open the way to their resolution. 

Figure 12-3 provides a list of structural and nonstructural components which 
are typically included in a building project.  It is intended to define the 
responsibilities within the design team for various aspects of the design, and 
establishes the scope of work among the major consultants and suppliers.  
The checklist provides the basis for consultant agreements between the 
architect, construction manager, and specialist consultants.  In most projects, 
costs and a competitive market tend to limit the time and money available for 
design.  Working within a limited budget and timeframe, current practice is for 
architects and structural engineers to leave some design tasks to engineers 
employed by subcontractors and vendors (e.g., the design of precast concrete 
panels and their connections, prefabricated stairs, and truss assemblies). This 
checklist can be used to identify where and when these procedures will be 
used. 

Figure 12-4 provides an example that shows how the checklist in Figure 12-3 
may be completed for a representative project. This example shows a 
traditional design and construction process in which the architect plays the key 
role in design management and project coordination.  The assigned 
responsibilities would vary depending on the nature of the project, the 
composition of the project team, and the proposed design and construction 
procedures. 

Figure 12-5 provides a list of typical building non-structural components and, 
similar to Figure 12-2, is intended to delineate the roles and responsibilities of 
design team members for the design and installation of nonstructural 
components and systems.  In current practice, this area is often unclear and 
important non-structural protective measures may become the subject of 
dispute; in some extreme cases, they may be omitted altogether.  Both this 
checklist and that shown in Figure 12-2 are expected to play an important role 
in establishing the total scope of work for the various project consultants, and 
in ensuring that important tasks do not fall between the cracks of the various 
involved design and construction parties. 



12.5 DESIGN AND CONSTRUCTION QUALITY ASSURANCE 

Building codes require that "special inspections" be carried out for specific 
critical elements of a building during construction.  These inspections are 
intended to assure that a high degree of quality has been achieved in 
constructing the approved design, and in the manner in which it is intended.  As 
related to seismic design, special inspections typically apply to important 
construction and fabrication considerations, such as ensuring the use of pre-
certified weld procedures and adequate weld quality. 

Performance-based seismic design also requires specific performance from 
nonstructural systems and components in the building.  In order to obtain the 
intended seismic performance in these areas, additional quality assurance 
activities are needed, above and beyond those typically required by code or 
employed on normal non-seismic construction projects. The following is a 
partial list of some nonstructural system components in need of special 
consideration or inspection. 


Inspection of the anchorage and bracing of architectural and 
mechanical elements.

Labeling of fenestration products to ensure that they have been pro-
vided as specified, and inspection to ensure proper installation.

Inspection of ceiling and partition attachments. 

Inspection of special equipment. 

The report, ATC-48, Built to Resist Earthquakes: The Path to Quality Seismic 
Design and Construction (ATC/SEAOC, 1999), provides comprehensive guidance on 
issues pertaining to the quality design and construction of wood-frame, concrete, 
and masonry buildings, and anchorage and bracing of non-structural 
components. 






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PROJECT PARTICIPANTS

Principal Investigator 

Christopher Rojahn Applied Technology Council 201 Redwood Shores 
Parkway, Suite 240 Redwood City, California  94065 


FEMA Project Officer 

Milagros Kennett Federal Emergency Management Agency 500 "C" Street, SW, 
Room 416 Washington, DC   20472 


Senior Review Panel 

John Ashelin Project Engineer - Corporate Engineering Anheuser-Busch 
Companies, Inc. One Busch Place St. Louis, Missouri  63118 

Deborah B. Beck Beck Creative Strategies LLC 531 Main Street - Suite 313 
New York, New York  10044 

Clifford J. Carey AIA University of Illinois Project Planning & Facility 
Management 807 S. Wright Street, Suite 320 Champaign, Illinois 61820 

Edwin T. Dean1 Nishkian Dean 319 SW Washington Street, Suite 720 Portland, 
Oregon  97204 


1. ATC Board Contact 

Randal C. Haslam AIA CSI Director of School Construction Jordan School 
District 9150 South 500 West Sandy, Utah  84070 

Roger Richter California Healthcare Association 1215 K Street, Suite 800 
Sacramento, California  95814 



Project Working Group 

Chris Arnold Building Systems Development 
P.O. Box 51950 Palo Alto, California  94303 

Craig D. Comartin Comartin-Reis Engineering 7683 Andrea Avenue Stockton, 
California  95207-1705 

David B. Hattis Building Technology Inc. 1109 Spring Street Silver Spring, 
Maryland  20910 

Patrick J. Lama Mason Industries 350 Rebro Drive Hauppauge, New York  
11788 

Maurice S. Power Geomatrix Consultants, Inc. 2101 Webster Street, 12th Floor 
Oakland, California  94612 

Evan Reis Comartin-Reis Engineering 345 California Ave, Suite 5 Palo Alto, 
California  94306