Guidelines for 

Performance-Based 

Seismic Design of

Buildings 

FEMA P-58-6 / December 2018 

FEMA P-58-6 / December 2018

Guidelines for Performance-Based 

Seismic Design of Buildings

Prepared by

APPLIED TECHNOLOGY COUNCIL

201 Redwood Shores Parkway, Suite 240

Redwood City, California 94065

www.ATCouncil.org

Prepared for

FEDERAL EMERGENCY MANAGEMENT AGENCY

Michael Mahoney, Project Officer

Robert D. Hanson, Technical Monitor

Washington, D.C.

APPLIED TECHNOLOGY COUNCIL

Christopher Rojahn

Jon A. Heintz (Project Executive)

Ayse Hortacsu (Project Manager)

PROJECT MANAGEMENT COMMITTEE

Ronald O. Hamburger (Project Technical Director)

John Gillengerten 

William T. Holmes

John D. Hooper

Stephen A. Mahin

Jack P. Moehle

Khalid Mosalam

Laura Samant 

Steven R. Winkel

PROJECT STEERING COMMITTEE

William T. Holmes (Chair)

Lucy Arendt

Deborah Beck

Christopher Deneff 

H. John Price

Jonathan C. Siu 

Jeffrey R. Soulages

Eric Von Berg

Williston Warren (ATC Board Contact)

STAKEHOLDER PRODUCTS TEAM

Laura Samant (Team Leader)

David Mar

Lori Peek 

Maryann T. Phipps

Sharyl Rabinovici

L. Thomas Tobin

PERFORMANCE PRODUCTS TEAM

John Gillengerten (Team Leader)

David R. Bonneville

Dominic Campi

Vesna Terzic

PRODUCTS UPDATE TEAM

John D. Hooper (Team Leader)

Russell Larsen

Peter Morris
STAKEHOLDER PRODUCTS 

CONSULTANTS

Sandra L. Grabowski

Taline Mitten 

Stacia Sydoriak

Jennifer Tobin-Gurley

PERFORMANCE PRODUCTS 

CONSULTANTS

Shreyash Chokshi 

Travis Chrupalo 

Erica Hays 

Nirmal Kumawat

Abe Lynn 

Daniel Saldana 

Vinit M. Shah 

Udit S. Tambe 

Duy Vu To 

Peny Villanueva

PRODUCTS UPDATE 

CONSULTANTS

Robert Bachman

Jack Baker

Dustin Cook

Scott Hagie

Angie Harris 

Curt Haselton 

Wyatt Henderson

Monica Huang

Gilberto Mosqueda 

Farzad Naeim 

Barbara Rodriguez 

Kathrina Simonen

Siavash Sorooshian 

Katie Wade

Farzin Zareian

Notice

Any opinions, findings, conclusions, or recommendations expressed in this publication do not 

necessarily reflect the views of the Applied Technology Council (ATC), the Department of 

Homeland Security (DHS), or the Federal Emergency Management Agency (FEMA). 

Additionally, neither ATC, DHS, FEMA, nor any of their employees, makes any warranty, 

expressed or implied, nor assumes any legal liability or responsibility for the accuracy, 

completeness, or usefulness of any information, product, or process included in this publication. 

Users of information from this publication assume all liability arising from such use.

Cover photograph – Rendering of a building designed using FEMA P-58 performance-based design 

concepts © Skidmore, Owings & Merrill LLP | Nephew LA, 2018. All rights reserved.
FEMA P-58-6 Foreword iii

Foreword

The Federal Emergency Management Agency (FEMA) is committed to 

reducing the ever-increasing cost that disasters inflict on our country. 

Preventing losses before they happen, by building to withstand anticipated 

forces, is one of the key components of mitigation, and is the only truly 

effective way of reducing the impact of disasters on our country. One of the 

most promising tools that can be used to reduce damage from an earthquake, 

or other similar disasters, is Performance-Based Seismic Design (PBSD).

PBSD is a concept that permits the design and construction of buildings with 

a realistic and reliable understanding of the risk to life, occupancy, and 

economic loss that may occur as a result of future earthquakes. PBSD is 

based on an assessment of a building’s design to determine the probability of 

experiencing different types of losses, considering the range of potential 

earthquakes that may affect the structure. This allows a building owner or 

regulator to select the desired performance goal for their building.

Current building codes are prescriptive in nature and are principally intended 

to provide a life-safety level of protection when a design-level event, such as 

an earthquake, occurs. While building codes are intended to produce 

structures that meet a life-safety performance level for a specified level of 

ground shaking, they do not provide designers with a means to determine if 

other performance levels would be achieved. During a design level 

earthquake, a code-designed building could achieve the goal of preventing 

loss of life or life-threatening injury to building occupants, but could still 

sustain extensive structural and nonstructural damage and be out of service 

for an extended period of time. In some cases, the damage may be too costly 

to repair, leaving demolition as the only option.

Phase 1 of this project, completed in 2012, resulted in the publication of 

FEMA P-58, Seismic Performance Assessment of Buildings, Volume 1 –

Methodology, Volume 2 – Implementation Guide, and a series of supporting 

electronic materials and background technical information. For practical 

implementation of the methodology, this included the development of an 

electronic tool, referred to as the Performance Assessment Calculation Tool, 

or PACT, to help capture building inventory data, input a given earthquake 

shaking probability or intensity, apply specific fragilities and consequences 
iv Foreword FEMA P-58-6

to each building component, and present the results of a large number of 

runs, or realizations, in a logical format.

The FEMA P-58 methodology utilizes performance measures that can be 

understood by decision makers. These performance measures relate the 

amount of damage to the building and the consequences of that damage 

including: potential casualties; loss of use or occupancy; and repair and 

reconstruction costs.

Phase 2 of this project utilized the FEMA P-58 seismic performance 

assessment methodology to develop performance-based seismic design 

guidelines and stakeholder guidelines. This five-year effort included the 

development of the following products:

• Seismic Performance Assessment of Buildings, Volume 4 – Methodology 

for Assessing Environmental Impacts, which describes a recommended 

methodology for incorporating assessment of environmental impacts, 

along with other consequences, that are associated with the repair of 

damage caused by earthquake shaking.

• Seismic Performance Assessment of Buildings, Volume 5 – Expected 

Seismic Performance of Code-Conforming Buildings, which applies the 

FEMA P-58 seismic performance assessment methodology to a series of 

building archetypes representative of structures conforming to the 

seismic provisions of the current building code to quantify the expected 

seismic performance of code-conforming buildings, identify factors that 

contribute to seismic performance, and provide the technical basis for 

simplified performance-based design guidance. 

• Guidelines for Performance-Based Seismic Design of Buildings, which is 

a design guideline that provides guidance to design professionals on the 

implementation of performance based seismic design of buildings using 

the FEMA P-58 methodology, including: the performance-based seismic 

design process; selection of appropriate performance objectives; 

selection of seismic-force-resisting systems; determining appropriate 

stiffness and strength; and final verification of design adequacy.

• Building the Performance You Need: A Guide to State-of-the-Art Tools 

for Seismic Design and Assessment, which presents information that 

project managers and decision-makers need to know to use a 

performance-based approach for seismic design and assessment.

FEMA wishes to express its sincere gratitude to all who were involved in this 

project and in the development of the FEMA P-58 Phase 2 methodology. It 

is not possible to acknowledge the entire development team here. However, 
FEMA P-58-6 Foreword v

special thanks are extended to: Ronald Hamburger, Project Technical 

Director; John Gillengerten, Performance Products Team Leader; John 

Hooper, Products Update Team Leader; Laura Samant, Stakeholder Products 

Team Leader; William Holmes, Steering Committee Chair; and Jon Heinz 

and Ayse Hortacsu, ATC Project Managers. The hard work and dedication 

of these individuals, and all who were involved in this project, have 

immeasurably helped our nation move towards making performance-based 

seismic design a reality, and towards reducing losses suffered by the citizens 

of our country in future earthquakes.

Federal Emergency Management Agency

FEMA P-58-6 Preface vii

Preface

In 2001, the Applied Technology Council (ATC) was awarded the first in a 

series of contracts with the Federal Emergency Management Agency 

(FEMA) to develop Next-Generation Performance-Based Seismic Design 

Guidelines for New and Existing Buildings. These would become known as 

the ATC-58 series of projects. The overall program was separated into two 

major phases of work: Phase 1 – Developing a Methodology for Assessing 

the Seismic Performance of Buildings; and Phase 2 – Developing 

Performance-Based Seismic Design Procedures and Guidelines.

Development of the Phase 1 assessment methodology was completed in 2012 

with the publication of the series of volumes collectively referred to as

FEMA P-58, Seismic Performance Assessment of Buildings, Methodology 

and Implementation:

• FEMA P-58-1, Seismic Performance Assessment of Buildings, 

Volume 1 – Methodology (FEMA, 2012a)

• FEMA P-58-2, Seismic Performance Assessment of Buildings, 

Volume 2 – Implementation Guide (FEMA, 2012b)

• FEMA P-58-3, Seismic Performance Assessment of Buildings, 

Volume 3 – Supporting Electronic Materials and Background 

Documentation (FEMA, 2012c)

In the FEMA P-58 methodology, performance is measured in terms of the 

probability of incurring casualties, repair and replacement costs, repair time, 

and unsafe placarding. Since its initial development, the methodology has 

been expanded to include the probability of generating environmental 

impacts, including additional embodied energy and carbon.

Upon completion of Phase 1, work began on Phase 2. The purpose of the

five-year Phase 2 work effort was to utilize the FEMA P-58 methodology in

developing guidelines and recommendations for specifying seismic 

performance objectives in terms of FEMA P-58 performance metrics, and for 

selecting appropriate structural and nonstructural systems, configurations, 

and characteristics necessary to achieve the desired performance in varying 

regions of seismicity. As part of this work, the FEMA P-58 methodology

was exercised in assessing the performance of code-conforming buildings. 
viii Preface FEMA P-58-6

Technical improvements and updates to the methodology were developed, as 

necessary, to take advantage of the latest research and to bring results into 

better alignment with expectations based on performance of buildings 

observed in past earthquakes. Phase 2 also included the development of 

products for communicating seismic performance to stakeholders, and 

assisting decision-makers in choosing between seismic design criteria and 

making seismic design decisions. 

This report, Guidelines for Performance-Based Seismic Design of Buildings, 

is one in a series of additional volumes developed under Phase 2 intended to 

expand and complete FEMA P-58 series of products. It describes a 

performance-based seismic design process to enable design of buildings 

capable of meeting user-selected performance objectives, defined in 

accordance with the FEMA P-58 performance measures.

The FEMA P-58 series of products is the result of the collaborative effort of 

more than 200 individuals, across all phases of work, that were involved in 

the development of the underlying methodology and subsequent products and 

reports. ATC is particularly indebted to the Phase 2 leadership of Ron 

Hamburger (Project Technical Director), John Gillengerten (Performance 

Products Team Leader), John Hooper (Products Update Team Leader), Laura 

Samant (Stakeholder Products Team Leader), and the members of the Project 

Management Committee, including Bill Holmes (Steering Committee Chair), 

Steve Mahin, Jack Moehle, Khalid Mosalam, and Steve Winkel. 

ATC would also like to thank the members of the Project Steering 

Committee, the Performance Products Team, the Products Update Team, the 

Stakeholder Products Team, and the many consultants who assisted these 

teams as part of the Phase 2 work effort. The names of individuals who 

served on these groups, along with their affiliations, are provided in the list 

of Project Participants at the end of this report. 

ATC also gratefully acknowledges Michael Mahoney (FEMA Project 

Officer) and Robert Hanson (FEMA Technical Monitor) for their input and 

guidance in the conduct of this work, and Carrie Perna for ATC report 

production services.

Ayse Hortacsu Jon A. Heintz

ATC Director of Projects ATC Executive Director
FEMA P-58-6 Dedication ix

Dedication

This report, one in the collection of reports comprising the FEMA P-58, 

Seismic Performance Assessment of Buildings, Methodology and 

Implementation, is dedicated to the memory of Stephen A. Mahin, longtime 

faculty member at the University of California, Berkeley.

Steve brought a creative approach and limitless enthusiasm to research in 

structural earthquake engineering. With broad expertise in the behavior and 

design of structural steel, reinforced concrete, and timber construction, he 

also had a particular interest in numerical modeling and computer simulation.

Steve was Director of the Pacific Earthquake Engineering Research Center 

(PEER) from 2009 to 2015. It was during his tenure as Director, and with his 

passion for performance-based analysis and design, that he became involved 

in the ATC-58 Project. Steve was a contributor to the development of the 

PEER framework for performance-based earthquake engineering, on which 

the FEMA P-58 methodology is based, and he dedicated much of his 

research to testing the limits of the methodology, and to finding new and 

creative ways to utilize it in seismic performance assessment and design 

optimization.

Following the 1994 Northridge earthquake, Steve, along with Ron 

Hamburger and James Malley, led the FEMA-funded SAC Steel Project, a 

collaborative effort among the Structural Engineers Association of California 

(SEAOC), the Applied Technology Council (ATC), and the Consortium of 

Universities for Research in Earthquake Engineering (CUREE), investigating 

earthquake damage discovered in steel moment frame buildings. This work 

resulted in a series of FEMA publications on innovative solutions for 

evaluating and repairing existing steel moment frame connections, and 

procedures for reliably designing new connections, and was just one of 

Steve’s many significant contributions to the structural engineering 

profession.

Steve contributed to innovation and idea sharing on a global scale. He never 

hesitated to share his time and insight with students, fellow researchers, 

practitioners, and public officials. Countless individuals and organizations 

have benefitted from his support, guidance, and wisdom. His creative spirit 

and generosity will not be forgotten.

Stephen A. Mahin

FEMA P-58-6 Table of Contents xi

Table of Contents

Foreword....................................................................................................... iii

Preface.......................................................................................................... vii

Dedication..................................................................................................... ix

List of Figures............................................................................................. xiii

List of Tables................................................................................................xv

1. Introduction...................................................................................... 1-1

1.1 Designing for Performance ...................................................... 1-1

1.2 FEMA P-58 Methodology........................................................ 1-4

1.3 Basis for Design Guidance ....................................................... 1-7

1.4 Limitations ............................................................................... 1-7

1.5 Organization and Content......................................................... 1-8

2. Implementing Performance-Based Seismic Design....................... 2-1

2.1 Use of Performance-Based Seismic Design............................. 2-1

2.1.1 Voluntary Seismic Upgrade ........................................ 2-1

2.1.2 Mandatory Seismic Upgrade ....................................... 2-2

2.1.3 Enhanced New Building Design ................................. 2-2

2.1.4 Code-Equivalent Design.............................................. 2-3

2.2 Approval................................................................................... 2-3

2.2.1 Voluntary Seismic Upgrades....................................... 2-4

2.2.2 Code-Conforming Designs.......................................... 2-5

2.2.3 Non-Conforming Designs ........................................... 2-5

2.3 Performance-Based Design Process......................................... 2-6

2.3.1 Confirm Approach....................................................... 2-6

2.3.2 Select Performance Objectives.................................... 2-8

2.3.3 Develop Preliminary Design ....................................... 2-9

2.3.4 Assess Performance Capability................................... 2-9

2.3.5 Iteratively Revise Design ............................................ 2-9

3. Selecting Performance Objectives .................................................. 3-1

3.1 Overview .................................................................................. 3-1

3.2 Process for Establishing Performance Objectives.................... 3-2

3.2.1 Assemble Stakeholders................................................ 3-2

3.2.2 Determine Performance Measures of Interest ............. 3-2

3.2.3 Define Earthquake Hazard .......................................... 3-6

3.2.4 State Performance Objectives ..................................... 3-8

3.2.5 Iterate on Performance Objectives.............................. 3-8

3.3 Using Performance Objectives in FEMA P-58 ........................ 3-8

3.3.1 Intensity-based Performance Objectives..................... 3-9

3.3.2 Scenario-based Performance Objectives................... 3-10
xii Table of Contents FEMA P-58-6

3.3.3 Time-based Performance Objectives.........................3-10

3.3.4 Confidence Level.......................................................3-11

3.4 Other Performance Considerations.........................................3-13

3.4.1 Utilities and Back-up Systems...................................3-13

3.4.2 Redundancy ...............................................................3-13

3.4.3 Real Estate Industry Guidelines.................................3-13

3.5 Expected Performance of Code-Conforming Buildings.........3-15

4. Developing Preliminary and Final Designs....................................4-1

4.1. Overview of Preliminary Design ..............................................4-1

4.2 Structural Design Factors Affecting Performance....................4-2

4.2.1 System Selection..........................................................4-2

4.2.2 Stiffness and Strength..................................................4-3

4.2.3 Supplemental Protective Systems................................4-3

4.3 General Procedure for Preliminary Design...............................4-4

4.3.1 Preliminary Building Performance Model...................4-5

4.3.2 Demand Estimation for Conventional Structures......4-10

4.3.3 Demand Estimation for Structures with 

Supplemental Protective Systems..............................4-14

4.4 Direct Design Procedure for Preliminary Design ...................4-15

4.4.1 Performance Estimation Tool....................................4-15

4.4.2 Extrapolation .............................................................4-17

4.5 Other Factors Affecting Performance.....................................4-18

4.5.1 Nonstructural Systems...............................................4-18

4.5.2 Building Configuration..............................................4-20

4.6 Final Design and Performance Verification ...........................4-20

Appendix A: Performance Estimation Tool User Manual ...................A-1

A.1 Design Space ...........................................................................A-1

A.2 Usage Notes.............................................................................A-2

A.3 User Interface Tab ...................................................................A-3

A.4 Detailed Plots Tab....................................................................A-6

References..................................................................................................B-1

Project Participants...................................................................................C-1
FEMA P-58-6 List of Figures xiii

List of Figures

Figure 2-1 Performance-based seismic design process....................... 2-6

Figure 3-1 Example result of an intensity-based assessment .............. 3-9

Figure 3-2 Probability density function for repair cost illustrating 

median, mean, and 90th percentile values........................ 3-12

Figure 3-3 Cumulative probability distribution for repair cost 

illustrating median, mean, and 90th percentile values...... 3-12

Figure 4-1 Plot showing structural and nonstructural component 

contributions to median repair costs, for mid-rise, Risk 

Category II, SDC D, Special RCSW system, healthcare 

occupancy ........................................................................ 4-19

Figure 4-2 Plot showing structural and nonstructural component 

contributions to median repair costs, for mid-rise, Risk 

Category II, SDC D, RC SMRF system, healthcare 

occupancy ........................................................................ 4-19

Figure A-1 Typical design space showing 13 points used to 

characterize the different strength and stiffness 

combinations of each archetype........................................ A-2

Figure A-2 PET User Interface tab...................................................... A-4

Figure A-3 Stiffness and strength input interface and design space 

graphic on the User Interface tab...................................... A-5

Figure A-4 Graph showing mean repair cost as a percentage of 

replacement cost on the User Interface tab....................... A-5

Figure A-5 Detailed plot of mean repair cost versus intensity............ A-6

FEMA P-58-6 List of Tables xv

List of Tables

Table 3-1 U.S. Resiliency Council Rating System Performance 

Goals................................................................................ 3-15

Table 3-2 Generalized Performance Expectations for CodeConforming Buildings ..................................................... 3-17

FEMA P-58-6 1: Introduction 1-1

Chapter 1

Introduction

This report is the sixth in a series of volumes comprising the FEMA P-58, 

Seismic Performance Assessment of Buildings, Methodology and 

Implementation (FEMA, 2012; 2018). The purpose of this volume is to 

provide guidance to structural engineers on implementation of performancebased seismic design of buildings using the FEMA P-58 methodology. 

Guidance is provided in the following areas of performance-based design:

• Assisting decision-makers in selecting appropriate performance 

objectives for buildings of different occupancies.

• Identifying appropriate structural and nonstructural design strategies to 

achieve specific performance objectives.

• Developing preliminary designs to achieve selected performance 

objectives with minimal iteration during the design process.

1.1 Designing for Performance

The first building codes in the United States were developed and adopted in 

the late 1800s and early 1900s in reaction to the frequent urban 

conflagrations experienced in larger cities. These conflagrations resulted 

from the common use of open flames for cooking, heating, and lighting, the 

predominance of wood frame construction, and the dense construction in 

urban areas. Accordingly, early building codes were written to protect public 

safety and welfare by reducing the risk of urban conflagrations through

limitations on the use of exposed wood frame construction, requirements for 

parapets to minimize the spread of flames from one roof to another, and other 

measures.

Later versions of codes included consideration of other building safety issues 

such as collapse due to structural overload. For most structural loading, 

other than earthquake, building codes address two performance levels: (1) a 

service level, which is a state such that deflections do not exceed levels 

detrimental to normal intended use and damage does not occur; and (2) an 

ultimate level, which is a state of failure. These performance levels are used 

to ensure that structures remain at the service level for routine loading given 

normal occupancy and likely environmental effects, and to ensure a low 
1-2 1: Introduction FEMA P-58-6

probability that the ultimate level will ever be experienced, so that structural 

failure resulting in injury or loss of life is unlikely to occur.

In the early twentieth century, following damaging earthquake events in 

California, Japan, and Italy, development of building code requirements for 

seismic resistance began. Initial seismic requirements were developed as a

series of rules intended to avoid further construction of building features that 

were observed to lead to life-threatening damage, such as requirements to 

positively attach exterior masonry walls to floors and roofs to avoid out-ofplane failure of brick walls. 

Over time, it was observed that, even in the most seismically active regions 

of the United States, some buildings were able to experience overstress and 

damage without life-threatening failure. Because damaging earthquakes are 

rare events that may not occur during expected life of a building, and for 

reasons of economy, building codes adopted a philosophy of permitting 

structural and nonstructural damage that does not result in a significant 

potential for life safety endangerment. This remains the underlying objective 

of building code requirements for most building occupancies in the present 

day.

In the 1971 San Fernando earthquake, the electrical power, water, and 

telephone utility systems of several hospitals were damaged, rendering the

facilities unusable. Following this event, the building code community 

realized that ensuring life safety protection through the avoidance of 

structural collapse alone did not meet the public’s needs for important 

facilities, such as hospitals, and that important facilities should be designed 

for enhanced criteria that would allow them to remain functional following 

most earthquakes. Design criteria for normal occupancy buildings remained

unchanged.

Following a chain of moderate magnitude, but damaging earthquakes that 

struck California during the 1980s and 1990s, building owners and tenants 

sought information on the adequacy of their buildings to survive without 

collapse or support continued operation in the event of future earthquakes. 

Engineers were asked to evaluate earthquake risk, to predict how the

buildings would perform in terms of potential risk to life, and to design 

building retrofits, if necessary, to improve expected performance. In 

response to this need, the Federal Emergency Management Agency 

supported development of a series of tools to assist in identifying and 

mitigating earthquake risk, including FEMA 273/274, NEHRP Guidelines for 

Seismic Rehabilitation of Buildings (and Commentary) (FEMA, 1997a; 

1997b).

The underlying philosophy of 

current building codes is 

minimizing hazard to life. 

Important facilities are 

designed to enhanced criteria.
FEMA P-58-6 1: Introduction 1-3

The FEMA 273/274 Guidelines and Commentary introduced a new seismic 

design process, now known as performance-based seismic design, that is 

substantially different from prescriptive design to building code provisions. 

In prescriptive design, the engineer must ensure that the building design 

conforms to a series of code requirements that regulate building 

configuration, structural system and detailing, and minimum lateral strength 

and stiffness. Buildings designed in conformance with these rules are 

presumed capable of meeting the performance expectations of the building 

code. Building owners and engineers, however, often to not have a good 

understanding of code performance expectations, and, typically, the 

performance capability of the design is neither evaluated, nor communicated,

as part of the design process. In contrast, performance-based design initiates 

with an explicit definition of the desired performance, and the design is

explicitly evaluated to demonstrate that the desired performance can be 

achieved. The resulting design may or may not conform to the prescriptive 

requirements of the building code, but it is expected to reliably meet the 

stated performance objectives. 

The FEMA 273/274 Guidelines and Commentary were subsequently updated 

and accepted as a standard by the American Society of Civil Engineers as 

ASCE/SEI 41-06, Seismic Rehabilitation of Existing Buildings (ASCE, 

2007). More recently, performance-based seismic design is frequently used

in the design of important buildings, including many tall buildings in the 

western United States. Design of such buildings generally follows the

approach outlined in Guidelines for Performance-Based Seismic Design of 

Tall Buildings (PEER, 2017), or An Alternative Procedure for Seismic 

Analysis and Design of Tall Buildings Located in the Los Angeles Region

(LATBSDC, 2017). In this report, performance-based design procedures 

embodied in these, and earlier documents, are referred to as first-generation 

procedures.

First-generation procedures focus primarily on structural performance, and 

nonstructural components are only evaluated for adequacy of attachment to 

the structure, without concern as to whether the components become

damaged or remain functional. First-generation procedures characterize 

performance as discrete levels (Immediate Occupancy, Life Safety, and 

Collapse Prevention) coupled with specific earthquake intensity levels. 

These performance levels qualitatively describe the severity of damage that a 

building might sustain, but they are not quantitatively defined in terms that 

are important to stakeholders. 

Performance-based design 

initiates with the definition of 

the desired performance, and 

then the design is developed to 

achieve this performance.
1-4 1: Introduction FEMA P-58-6

The FEMA P-58 methodology described in this report represents a nextgeneration performance-based seismic design procedure with the following 

advances from first-generation procedures:

• Performance is communicated using metrics that are more directly usable 

and important to stakeholders, including repair cost, repair time, 

environmental impacts, unsafe placarding, and casualties. This 

information enables stakeholders to make better decisions regarding

appropriate performance objectives for their buildings.

• Performance is expressed in probabilistic terms, acknowledging the 

considerable uncertainties that are inherent in prediction of earthquake 

performance, affording designers some protection if actual building 

performance in an earthquake is less than specified.

• The performance of nonstructural components and systems is explicitly

evaluated, resulting in a more complete characterization of actual 

earthquake risk.

Performance-based design is not unique to seismic design, and has been in 

use for many years to design resistance to terrorist attacks. It has also been 

used in the design of structural fire resistance and safety. In addition, the 

wind engineering community is in the early stages of developing 

performance-based design procedures for wind effects.

1.2 FEMA P-58 Methodology

The FEMA P-58 methodology enables assessment of the probable seismic 

performance of new or existing buildings based on their unique site, 

structural, nonstructural, and occupancy characteristics. This section 

provides a brief overview of the methodology. 

First published in 2012, the FEMA P-58 Seismic Performance of Buildings, 

Methodology and Implementation has been updated and expanded in 2018 to 

include the following:

• FEMA P-58-1, Seismic Performance Assessment of Buildings, 

Volume 1 – Methodology, Second Edition (FEMA, 2018a)

• FEMA P-58-2, Seismic Performance Assessment of Buildings, 

Volume 2 – Implementation Guide, Second Edition (FEMA, 2018b)

• FEMA P-58-3, Seismic Performance Assessment of Buildings, 

Volume 3 – Supporting Electronic Materials and Background 

Documentation, Third Edition (FEMA, 2018c)
FEMA P-58-6 1: Introduction 1-5

• FEMA P-58-4, Seismic Performance Assessment of Buildings, 

Volume 4 – Methodology for Assessing Environmental Impacts

(FEMA, 2018d)

• FEMA P-58-5, Seismic Performance Assessment of Buildings, 

Volume 5 – Expected Seismic Performance of Code-Conforming 

Buildings (FEMA, 2018e)

• FEMA P-58-6, Guidelines for Performance-Based Seismic Design of 

Buildings (FEMA, 2018f)

• FEMA P-58-7, Building the Performance You Need, A Guide to State-ofthe-Art Tools for Seismic Design and Assessment (FEMA, 2018g)

Volume 1 provides a complete description of the methodology and Volume 2 

illustrates its implementation. Volume 3 provides a series of tools and 

supporting electronic materials to facilitate its use. This report (Volume 6) 

describes a performance-based seismic design process to enable the efficient 

design of buildings that are capable of meeting user-selected performance 

objectives defined in accordance with FEMA P-58 performance metrics.

As outlined in Volume 1, the primary steps in the FEMA P-58 methodology 

are to:

• Assemble Building Performance Model: A building performance model 

is an organized collection of data used to define the building assets at 

risk and their exposure to seismic hazards. Volume 3 provides two 

electronic tools to help define the building performance model: (1) the 

Normative Quantity Estimation Tool provides approximate quantities 

based on building occupancy and square footage; and (2) the Fragility 

Database includes specifications for many architectural components, 

common contents found in residential and office occupancies, and 

structural systems, both code conforming, and non-conforming. Fragility 

specification associated with the building’s Seismic Design Category 

should be selected.

• Define Earthquake Hazards: Earthquake hazard is a quantification of the 

intensity of ground shaking and the site-specific probability that effects 

of a given intensity will be experienced. Ground shaking hazards are 

specified in different ways, depending on the type of assessment and the 

type of structural analysis used to quantify earthquake response.

• Analyze Building Response: Structural analysis is used to predict the 

response of a building to earthquake shaking in the form of response 

quantities (i.e., demands) that can be associated with structural and 

nonstructural damage. Analysis is conducted using nonlinear response 
1-6 1: Introduction FEMA P-58-6

history analysis for suites of ground motions, or simplified linear 

analysis, to predict median values of key response quantities including 

peak transient and residual story drift, peak floor velocity, and peak floor 

acceleration at each building level in each of two orthogonal directions.

• Calculate Performance: To account for the many uncertainties in factors 

affecting seismic performance, the FEMA P-58 methodology uses a 

Monte Carlo procedure to perform loss calculations. The process 

involves forming hundreds to thousands of realizations for each ground 

motion intensity. Each realization represents one possible outcome of 

the building’s response to ground shaking, and is generated by randomly 

varying the demands, component damage, and consequences, consistent 

with the median values and dispersions defined in the building 

performance model and building response simulation. Volume 1 

describes this process in detail. Volume 3 provides a Performance 

Assessment Calculation Tool (PACT) that is capable of generating 

realizations and performing loss calculations. Proprietary software is 

also available through a licensing agreement with individual developers.

Regardless of the method of calculation, the output of a FEMA P-58 

assessment includes probabilistic estimates of:

• Median repair cost and dispersion

• Median repair time and dispersion

• Median global warming potential and dispersion

• Median embodied energy and dispersion

• Probability of incurring serious injuries or fatalities

• Probability that the building will be posted with an unsafe placard

From probabilistic distributions of repair cost, repair time and other 

performance measures, it is possible to generate best estimate values (means) 

and estimates at any desired confidence level, for example, 90% probability 

of non-exceedance. In addition to providing estimates of probable 

consequences, calculation procedures are designed to provide information on 

components and systems (i.e., fragility groups) that contribute significantly

to these consequences (i.e., losses). Using this information, components that 

are significant contributors to loss can be targeted, and a preliminary design 

can be effectively revised to obtain the desired performance.
FEMA P-58-6 1: Introduction 1-7

1.3 Basis for Design Guidance

The design guidance in this report is based on information contained in 

FEMA P-58, Volume 5, which summarizes a study of the expected seismic 

performance of archetypical buildings designed to the requirements of 

ASCE/SEI 7-10, Minimum Design Loads for Buildings and Other Structures,

(ASCE, 2010). The study assessed a wide range of buildings meeting 

ASCE/SEI 7-10 structural and nonstructural seismic design requirements in 

regions of high seismicity, and included buildings with different structural 

systems, Risk Categories, levels of seismic hazard, building height, and 

occupancies.

The purpose of the study was to quantify the expected seismic performance 

of code-conforming buildings in terms of FEMA P-58 performance metrics, 

identify factors that contribute to seismic performance, and provide a 

technical basis for the development of performance objectives and 

performance-based design guidance using the FEMA P-58 methodology.

It was found that in general, performance varies significantly across the 

range of code-complying systems, and that structural and nonstructural 

design decisions can have a measurable impact on the resulting performance. 

Although traditional code performance expectations focus on safety, current 

design requirements were shown to provide some measure of protection of 

property.

1.4 Limitations

Preliminary design guidance and recommendations presented herein are 

approximate, and appropriate to engineering calculations performed in 

preliminary stages of design. Tools and techniques provided in this report 

should be considered useful in the context of preliminary design, and not 

more. It is expected that building designs will continue to evolve in later 

stages of design, and that the actual performance capability will be verified

against the desired performance objectives using a general application of the 

FEMA P-58 methodology on a final version of the design.

This report presents a number of “short cuts” to the FEMA P-58 

methodology that are appropriate for use in preliminary design. It should be 

noted that these short cuts are not intended for general application of the 

methodology, nor for verification of the performance capability of the final 

design. The complete FEMA P-58 methodology, as presented in FEMA 

P-58, Volumes 1, 2, and 3 should be used for final performance verification.
1-8 1: Introduction FEMA P-58-6

The performance of buildings in earthquakes is highly uncertain and 

dependent on many factors, some of which can be controlled by the engineer 

during the design process (such as structural system selection, configuration, 

proportioning, and detailing) and others which cannot. Factors that cannot be 

controlled include architectural configuration, quality of structural 

construction, quality of nonstructural component installation, building 

maintenance, and character and intensity of the ground motion itself. 

Design guidance presented herein has been based on a study of probable 

seismic performance of buildings with regular configuration, typical quality 

of design and construction, and subjected to typical earthquake ground 

motions of a specified intensity. Even in conditions constrained by these 

assumptions, the actual performance of an individual building in an 

earthquake can vary considerably. Although state-of-the-art techniques were 

used to evaluate the effects of design decisions on probable building 

performance, no warranty is offered that designs conducted in accordance 

with this guidance will perform within the range of expected performance. 

The FEMA P-58 methodology expresses performance in a probabilistic 

manner, acknowledging potential uncertainties and their effects on 

performance. Engineers are cautioned to relate to clients, and others relying 

on this information, that earthquake performance prediction is inherently 

uncertain, and that actual performance may vary from the performance 

predicted using these recommendations.

1.5 Organization and Content

This volume presents guidance for structural engineers on the

implementation of performance-based seismic design of buildings using the 

FEMA P-58 methodology.

Chapter 2 provides an overview of the performance-based seismic design 

process and its uses in seismic design and retrofit of buildings.

Chapter 3 provides guidance in establishing seismic performance objectives 

used as the basis for performance-based seismic design.

Chapter 4 discusses factors affecting performance, presents two procedures 

for developing a preliminary design, and provides guidance on final design 

and performance verification.

Appendix A provides instructions for the use of the Performance Estimation 

Tool (PET), as described in Chapter 4.

References and a list of project participants are provided at the end of this

report.
FEMA P-58-6 2: Implementing Performance-Based Seismic Design 2-1

Chapter 2

Implementing PerformanceBased Seismic Design

Performance-based seismic design is an alternative to code-based 

prescriptive design procedures. In performance-based design, rather than 

demonstrating conformance with applicable building code requirements, 

engineers must explicitly demonstrate that a design will provide a defined 

level of performance. Some buildings designed using performance-based 

procedures will conform to prescriptive requirements of the building code, 

while others may not completely conform to these requirements.

This chapter discusses the use of performance-based seismic design, 

approval of designs, and an overview of the performance-based design 

process. 

2.1 Use of Performance-Based Seismic Design

Performance-based seismic design is applicable to new or existing buildings 

and can be used to: (1) assess the probable seismic performance of a given 

building; (2) design new buildings capable of providing a desired 

performance; or (3) design seismic upgrades for existing buildings to 

improve their performance. 

2.1.1 Voluntary Seismic Upgrade

Because existing buildings were designed to an earlier version of the code (or 

no building code at all), owners of existing buildings are more likely to be 

aware that their building may not perform as well as a new building, and may 

not provide an acceptable level of performance. Often, owners of existing 

buildings will ask an engineer to evaluate their building and assess its likely 

performance. As a result of an evaluation, an owner may decide that the 

assessed performance is unsuitable for the intended use of the building, and 

may voluntarily elect to have the building upgraded to improve its 

performance.

Individual stakeholders can define acceptable performance in different ways. 

Some stakeholders may be primarily interested in the safety of building 

occupants. Other stakeholders may wish to minimize potential disruption of 

occupancy and use following an earthquake. Others may be interested in 
2-2 2: Implementing Performance-Based Seismic Design FEMA P-58-6

maintaining probable repair costs below specific levels, often expressed as a 

percentage of building replacement cost. Acceptable performance in terms 

of repair costs below certain threshold values is a type of performance 

measure that is often used by mortgage lenders, who factor such information 

in lending and financing decisions.

2.1.2 Mandatory Seismic Upgrade

Many communities have adopted ordinances requiring seismic upgrade of 

vulnerable buildings types, characterized by structural system, age, 

configuration, occupancy, or unacceptable performance in past earthquakes. 

Building types that are commonly the target of mandatory retrofit ordinances 

include: unreinforced masonry bearing wall structures, older concrete tilt-up 

buildings, nonductile concrete frame buildings, and wood-frame buildings 

having soft first stories or unbraced cripple walls. Many building codes also 

require that buildings undergoing substantial alteration, addition, or repair be 

upgraded to conform to the current code for new buildings, or, depending on 

the extent of work, to some fraction of strength required by the current code.

Most mandatory retrofit ordinances specify prescriptive requirements for 

design of upgrades. Some ordinances specifically allow performance-based 

approaches, such as those in ASCE/SEI 41-13, Seismic Evaluation and 

Retrofit of Existing Buildings, (ASCE, 2013) or other approved design 

criteria documents. Even when mandatory retrofit requirements do not 

specifically allow (or require) performance-based design, it may be possible 

to use such an approach if it can be demonstrated that the resulting 

performance is equivalent, or superior, to prescriptive requirements. 

Upgrades designed using alternative performance-based criteria can be less 

costly and less difficult to construct than upgrades designed using

prescriptive criteria.

2.1.3 Enhanced New Building Design

Most owners or developers of buildings designed and constructed in 

accordance with the applicable building code believe that this provides all the 

protection that they need against potential earthquake damage. Some owners

or developers commissioning new buildings will intentionally specify 

designs that achieve performance that is better than what is expected for 

prescriptively designed buildings. Owners requesting such designs tend to be 

larger institutions, corporations, and government agencies with both the 

understanding of the potential performance of generic code-conforming 

buildings and the perceived need for buildings that perform better.
FEMA P-58-6 2: Implementing Performance-Based Seismic Design 2-3

Enhanced new building designs, however, are not a typical request because 

most owners or developers are unaware that code-conforming buildings are 

designed with the expectation of damage in an earthquake. Depending on the 

use of a building, it may be necessary for an engineer, or architect as the lead 

design professional, to educate owners on the expected performance of codeconforming buildings, the options that are available to enhance performance, 

and the means by which an owner can determine the performance they need. 

Chapter 3 of this report provides guidance on assisting in the selection of

appropriate performance objectives.

2.1.4 Code-Equivalent Design

One of the most common uses of performance-based seismic design is to 

demonstrate performance equivalent to prescriptively designed buildings, 

while not conforming to one or more of the prescriptive requirements in the 

building code. 

Prescriptive code requirements are broad in nature and intended, to the extent 

possible, to address every conceivable building type or design consideration. 

A performance-based approach can allow engineers to omit certain

prescriptive requirements, which is beneficial because it may result in 

designs that are less costly or have positive attributes that are not present in

buildings that fully comply with prescriptive requirements. For example, 

current building codes require the use of special moment-resisting frames as 

part of the seismic force-resisting system for tall structures in regions of high 

seismicity. Placement of special moment-resisting frames around the 

building perimeter is not only costly, but also requires the presence of deep 

spandrel elements at the building facade. In recent years, many project 

development teams have used performance-based design procedures to 

justify the elimination of perimeter special moment-resisting frames in tall 

buildings, resulting in less costly buildings that also provide enhanced views, 

and therefore, greater marketability.

Alternative performance-based approaches also allow the use of innovative 

materials and systems. Because it often takes many code cycles before 

prescriptive building code requirements encompass new engineering and 

construction innovations, use of performance-based design to demonstrate 

equivalence allows the design and construction industry to move forward

with innovative technologies as they become available.

2.2 Approval

Some buildings designed or upgraded using performance-based procedures 

will not meet prescriptive building code requirements. In most jurisdictions, 
2-4 2: Implementing Performance-Based Seismic Design FEMA P-58-6

it will be challenging to obtain a building permit if the design does not 

conform to applicable code requirements. However, building codes include 

provisions specifically intended to allow building permits for such designs to 

be issued. 

2.2.1 Voluntary Seismic Upgrades

Many jurisdictions have adopted the 2015 International Existing Building 

Code (IEBC; ICC, 2015b) as the basis for regulation of existing buildings. 

2015 IEBC Section 403.9 states:

403.9 Voluntary seismic improvements. Alterations to existing 

structural elements or additions of new structural elements that are not 

otherwise required by this chapter and are initiated for the purpose of 

improving the performance of the seismic force-resisting system of an 

existing structure or the performance of seismic bracing or anchorage of 

existing nonstructural elements shall be permitted, provided that an 

engineering analysis is submitted demonstrating the following:

1. The altered structure and the altered nonstructural elements are no 

less conforming to the provisions of the International Building Code 

with respect to earthquake design than they were prior to the 

alteration.

2. New structural elements are detailed as required for new 

construction.

3. New or relocated nonstructural elements are detailed and connected 

to the existing or new structural elements as required for new 

construction.

4. The alterations do not create a structural irregularity as defined in 

ASCE 7 or make an existing structural irregularity more severe.

The intent of this provision is to specifically permit voluntary, non-required 

seismic upgrades of buildings that do not fully conform to the requirements 

of the building code, if the engineer can demonstrate that the alteration work 

does not weaken the structure or make it more susceptible to earthquake 

damage. Although this broadly permits a wide range of voluntary seismic 

improvement programs, it does not specifically permit the use of new 

non-conforming construction as part of retrofit measures.

Some jurisdictions have not adopted the IEBC, and instead, enforce older 

editions of the International Building Code (IBC). Chapter 34 of IBC 

editions prior to 2015 presents language similar to that in IEBC Section 

403.9.
FEMA P-58-6 2: Implementing Performance-Based Seismic Design 2-5

2.2.2 Code-Conforming Designs

In many cases, buildings designed using performance-based seismic design

procedures will conform to all applicable prescriptive requirements and may 

exceed some requirements. In such cases, it is only necessary to demonstrate 

compliance with the building code to obtain a building permit. It is not 

necessary to indicate or demonstrate that enhanced performance is desired or 

provided, nor is it necessary to reveal the procedures that were used to attain 

such performance.

2.2.3 Non-Conforming Designs

2015 International Building Code (ICC, 2015) provides the building official,

and other authorities having jurisdiction, with broad latitude in issuing 

building permits to designs that knowingly do not comply with prescriptive 

code requirements in all respects, provided they determine that the design 

will perform as well as designs of similar buildings conforming to 

prescriptive requirements. 2015 IBC Section 104.11 states:

104.11 Alternative materials, design and methods of construction and 

equipment. The provisions of this code are not intended to prevent the 

installation of any material or to prohibit any design or method of 

construction not specifically prescribed by this code, provided that any 

such alternative has been approved. An alternative material, design or 

method of construction shall be approved where the building official 

finds that the proposed design is satisfactory and complies with the intent 

of the provisions of this code, and that the material, method or work 

offered is, for the purpose intended, not less than the equivalent of that 

prescribed in this code in quality, strength, effectiveness, fire resistance, 

durability and safety. When the alternative material, design or method 

of construction is not approved, the building official shall respond in 

writing, stating the reasons why the alternative was not approved.

A building official has discretion in applying this clause. Even if a building 

official suggests that a performance-based approach may be used, the design 

team must still demonstrate to the satisfaction of the building official, and to 

the satisfaction of any other reviewers commissioned by the building official, 

that the design is equivalent. Historically, many, but not all, building 

officials have been willing to do this. Some have declined on the basis that 

they do not have the competency to determine if an alternative design is 

indeed equivalent, and are concerned that they may permit unsuitable 

construction. In such cases, a peer review process may help gain confidence 

in the use of alternative performance-based procedures.
2-6 2: Implementing Performance-Based Seismic Design FEMA P-58-6

2.3 Performance-Based Design Process

Figure 2-1 presents a flow chart for the performance-based design process. 

The following sections describe the steps in the process, and use of the 

FEMA P-58 methodology and tools for performance-based seismic design.

Figure 2-1 Performance-based seismic design process.

2.3.1 Confirm Approach

Prior to initiating a performance-based seismic design, it is essential to 

confirm that such an approach is acceptable to relevant stakeholders 

including the owner, the prime design professional, and the building official.

2.3.1.1 Owner

The owner or developer (with input from tenants, lenders, and insurers) is an 

integral part of the performance-based design process and needs to make the 

decision to engage in a performance-based design process. To make such a 

decision, the owner needs to understand that this is a choice, that such an 

approach may be beneficial, and that there may be associated risks. Some 

owners will be familiar with this process and may initiate discussion of 

performance-based approaches or specify that they be used. Other owners 

will require education before they are prepared to make such a decision. The 

structural engineer is typically the person most suited to assist an owner in 

becoming familiar with this approach. A companion publication to this 

report, FEMA P-58-7, Building the Performance You Need, A Guide to Stateof-the-Art Tools for Seismic Design and Assessment (FEMA, 2018g) is 

designed to assist in providing such information. In addition, a quiz located 
FEMA P-58-6 2: Implementing Performance-Based Seismic Design 2-7

at http://femap58.atcouncil.org/ can be used to quickly help an owner decide 

if they might be interested in a performance-based approach for their project.

Once an owner has expressed interest in a performance-based approach, they 

will need to select appropriate performance objectives.

2.3.1.2 Prime Design Professional

In cases where the structural engineer is not the prime design professional, it 

will be important to ensure that the prime design professional (e.g., architect)

accepts the approach. This acceptance is important because use of 

performance-based design approaches can increase project risk. There is 

increased uncertainty regarding design measures that will be necessary to 

satisfy the building official and other reviewers to obtain a building permit. 

Even after successful permitting, there is increased risk should the building 

not perform as expected in an earthquake. Although the structural engineer 

would bear the primary responsibility for such risk, additional risk would 

also accrue to the architect. In addition, when performance-based design 

approaches are used, the level of engineering effort may be significantly 

increased, requiring larger fees and extended design schedules.

Once in agreement with the concept, the prime design professional can be a 

valuable partner in helping to educate the owner on the advantages of the 

approach, and assisting the owner in selecting appropriate performance 

objectives. The prime design professional can also help make sure that other 

design professionals contribute the assistance necessary to ensure that the 

resulting design meets the intended performance objectives. In the case of 

architects, it is essential that assistance is provided in designing architectural 

elements, such as ceilings, partitions, and cladding to minimize damage. In 

the case of mechanical or electrical engineers, it is essential that assistance is 

provided in adequately bracing and anchoring mechanical, electrical, and 

plumbing components.

2.3.1.3 Building Official

If the performance objectives selected by the owner are such that the building 

will comply with applicable prescriptive code requirements, possibly with 

some enhancements or informed selection of systems and detailing, the 

building official need not specifically approve the use of such an approach, 

or even be aware of it. In this case, the most expeditious path forward is 

simply to design and detail the structure in conformance with the code, with 

enhancements that may be appropriate to achieve the desired performance,

and submit permit documents demonstrating code compliance. However, if 

the intent is to use performance-based methods to avoid compliance with 
2-8 2: Implementing Performance-Based Seismic Design FEMA P-58-6

certain prescriptive requirements, it is essential to obtain agreement with the 

building official that such an approach will be acceptable.

Before approaching the building official to determine if a performance-based 

design will be acceptable, it is necessary to have a sufficiently developed 

design approach to enable an explanation of the structural system, the 

selected performance objectives, and their equivalence to (or exceedance of)

those prescribed by the building code, and the methods that will be used to 

demonstrate acceptable performance.

2.3.2 Select Performance Objectives

Performance objectives are quantitative statements of the desired building 

performance, for one or more potential earthquake shaking intensities, or 

scenarios, or over a period of time. One example of a performance objective 

is the basic performance goal underlying the design of all Risk Category II

buildings under ASCE/SEI 7-10, Minimum Design Loads for Buildings and 

Other Structures, (ASCE, 2010) and ASCE/SEI 7-16, Minimum Design 

Loads and Associated Criteria for Buildings and Other Structures, (ASCE, 

2017a). In these standards, there is a 10% (or lower) risk that a building will 

experience partial or total collapse, given that it experiences risk-targeted 

maximum considered earthquake (MCER) ground shaking, which is a 

scenario-based objective. In most regions of the country, because of the way 

MCER ground shaking intensity is determined, this equates to a 1% (or 

smaller) risk in 50 years that the building will experience earthquake-induced 

collapse, which is an example of a time-based objective. Performance 

inherent in the building code is both quantitative and expressed in 

probabilistic terms.

Although the building code is intended to achieve certain performance 

objectives, when design is conducted in accordance with the prescriptive 

requirements of the code, the actual performance capability of the design is 

rarely, if ever, explicitly evaluated. Instead, it is presumed that because the 

design complies with the prescriptive requirements, it can provide the

performance expected of code-conforming buildings. Selection of 

performance objectives is fundamental to the performance-based design 

process, and engineers must explicitly demonstrate that the performance 

objectives can be achieved.

The owner is responsible for selecting the performance objectives because 

these objectives have a direct impact on project cost and the building’s 

performance over its life. However, the building owner does not have 

exclusive control over the objectives. Except in the case of voluntary seismic 

The owner is responsible for 

selecting the performance 

objectives. 
FEMA P-58-6 2: Implementing Performance-Based Seismic Design 2-9

upgrade, the building official will typically insist, as a condition of issuing a 

building permit, that the design meets or exceeds the performance objectives 

inherent in the building code.

The owner will often require substantial assistance in selecting appropriate 

performance objectives. Building officials, although typically familiar with 

the life safety performance objectives inherent in the building code, do not 

typically consider performance objectives associated with repair cost, repair

time, and other FEMA P-58 performance metrics. Chapter 3 provides 

additional guidance on assisting in the selection of performance objectives.

2.3.3 Develop Preliminary Design

The performance of a building in future earthquakes depends on many 

factors, including site conditions and seismicity; the structural system used 

for earthquake resistance, and its strength, stiffness, and configuration; and 

the type and location of nonstructural components, and how they are 

installed. Some of these factors can be controlled by the engineer and others 

cannot. Chapter 4 provides guidance on the selection of appropriate 

structural systems, and the strength and stiffness necessary, on average, to 

achieve desired performance for buildings of different occupancies. 

However, based on factors that are outside the control of the engineer, there 

can be considerable variation in the actual performance capability of the 

resulting building.

2.3.4 Assess Performance Capability

Before completing the design process and obtaining a building permit, it is 

necessary to demonstrate that the final building design can meet the selected 

performance objectives. FEMA P-58, Volume 1 (FEMA, 2018a) presents a 

methodology for assessing a building’s performance once a design is 

sufficiently developed to permit meaningful detailed analysis. This 

methodology can be implemented using the Performance Assessment 

Calculation Tool (PACT), provided within FEMA P-58, Volume 3 (FEMA, 

2018c) or other available proprietary software. Assessment of building 

performance using PACT, or other tools, will provide a quantitative measure 

of performance that can be compared to the selected performance objectives.

2.3.5 Iteratively Revise Design

Although the preliminary design procedures and tools provided herein are 

intended to result in designs that will, on average, achieve the desired 

performance, in some cases, when the actual performance capability is 

assessed, the design may not comply with the selected performance 
2-10 2: Implementing Performance-Based Seismic Design FEMA P-58-6

objectives. In such cases, it will be necessary to revise the design, re-assess 

performance, and iterate until the performance objectives are met. PACT 

provides data that can be used to guide the engineer in revising the design, 

including reports that indicate sources of poor performance (e.g., structural 

damage, curtain wall damage, interior partitions, ceilings). Most structural 

and nonstructural damage is directly related to the amount of story drift or 

floor acceleration that occurs at each level and in each direction. Informed 

by sources of poor performance, the engineer can modify the stiffness or 

strength of the structure to reduce the amount of story drift and floor 

acceleration, or specify components (or methods of installing components)

that are less vulnerable to damage than those originally specified.

Once the design is revised, the engineer should reassess the performance 

capability of the building to ensure that the final design meets the selected

performance objectives.
FEMA P-58-6 3: Selecting Performance Objectives 3-1

Chapter 3

Selecting Performance

Objectives

The primary consideration in selecting performance objectives is the desire 

to control or limit the risk associated with one or more earthquake effects. 

This chapter describes the process for establishing and selecting appropriate 

performance objectives.

3.1 Overview

Seismic performance is a function of many factors, all of which are 

uncertain, including: ground shaking intensity, duration, spectral shape, 

building response, building contents, occupancy present during the 

earthquake, as well as post-earthquake actions taken by building officials, 

owners, design professionals and contractors. It is impossible to precisely 

predict the performance of a building in a future earthquake.

Performance objectives are quantitative statements of the acceptable risk of 

incurring consequences of different types, for different characterizations of 

earthquake hazard, and different levels of ground shaking intensity. 

Earthquake hazards can be characterized as a specific ground motion 

intensity, represented by an elastic acceleration response spectrum (used in 

intensity-based objectives), a specific earthquake magnitude on a known 

fault (used in scenario-based objectives), or the probabilistic consideration of

all earthquakes that can occur in a period of time and the probability of 

occurrence of each (used in time-based objectives).

For new buildings and mandated seismic upgrades, performance objectives 

must, as a minimum, be equal to the performance underlying the building 

code or locally adopted retrofit ordinance. It is critically important to obtain 

agreement with the building official that the selected performance objectives 

are acceptable under the requirements of the building code. In voluntary 

seismic upgrades, or cases where better than code-equivalent performance is 

desired, the owner/developer should be the primary decision maker as to 

which performance objectives are adopted, sometimes with input from 

tenants, lenders, and insurers.
3-2 3: Selecting Performance Objectives FEMA P-58-6

Often, the final selection of performance objectives is an iterative process 

that balances the cost associated with designing for a given performance 

against the benefits obtained. At the outset of the project, desired 

performance objectives are selected. As design decisions are made, the 

effects of the decisions are evaluated to verify that the final design is capable 

of achieving the desired performance.

3.2 Process for Establishing Performance Objectives

This section describes a recommended process for establishing and selecting

performance objectives.

3.2.1 Assemble Stakeholders

Stakeholders who should be involved in the process include owners, 

developers, building officials, and prospective tenants, as well as structural

engineers and other design professionals.

Important responsibilities of the structural engineer are to educate and guide 

the selection of objectives that can be considered for the given project, and to

help ensure that the objectives being considered are reasonable and 

achievable. In almost all cases, this discussion should happen before the 

structural system is selected.

3.2.2 Determine Performance Measures of Interest

The selection of performance measures of interest for a given project will 

depend on the intended building use and specific concerns of a stakeholder, 

who may choose among measures related to safety, function, and cost. In 

many cases, setting a higher performance goal for one performance measure

will lead to a design that provides higher performance in other measures, 

however, this is not always the case. Because losses are associated with both 

structural and nonstructural damage, performance measures must be 

expressed with consideration of the potential for both.

The following sections discuss performance measures considered in the 

FEMA P-58 methodology.

3.2.2.1 Casualties

Casualties include loss of life or serious injury requiring hospitalization, 

occurring within the building envelope. In FEMA P-58, this measure is 

reported as a casualty rate, the probability of any one occupant in a building 

becoming a casualty as a result of an earthquake.
FEMA P-58-6 3: Selecting Performance Objectives 3-3

ASCE/SEI 7-16 Tables 1.3-2 and 1.3-3 set target reliability values for 

structural stability in new structures designed with performance-based 

procedures. The values are dependent on the assigned Risk Category of the 

structure, and indicate the conditional probability of failure caused by 

Maximum Considered Earthquake (MCER) shaking hazard. Studies of the 

seismic performance of code-conforming buildings documented in FEMA 

P-58, Volume 5 confirm that for Risk Categories II and IV, the stated

performance objectives result in a very low risk to life safety, which should 

be acceptable for most stakeholders and projects. Therefore, it is typically 

unnecessary to specify enhanced performance criteria for new buildings 

associated with structural collapse safety or failure of anchorage and bracing

of nonstructural components.

Many existing buildings, however, will not provide the level of life safety 

protection expected of new buildings designed in accordance with ASCE/SEI

7-16. Therefore, protection of life safety is often a primary objective of 

seismic upgrade projects. Many stakeholders find it difficult to consider

non-zero probabilities of injuring building occupants, and even more difficult

to select appropriate levels of life safety as a basis for seismic upgrade. 

Although the FEMA P-58 methodology can indicate the probable number of 

earthquake-related casualties in a building, when life safety is a primary 

earthquake performance goal, it will typically be preferable for stakeholders

to select a life safety goal that is closely related to the safety objectives 

inherent in ASCE/SEI 7-16 for new buildings. 

The choice of an acceptable level of life safety protection will often be 

associated with the cost of achieving the selected goal, unless a locally 

adopted ordinance or building code requires otherwise. Examples of goals 

that may be selected for such projects include:

• Structural collapse, or nonstructural component attachment failure 

probabilities, similar to those specified in ASCE/SEI 7-16 for MCER

shaking

• Structural collapse, or nonstructural component attachment failure 

probabilities, similar to those specified in ASCE/SEI 7-16, but for less 

intense earthquake shaking, such as Design Earthquake shaking or

earthquake shaking with a 500-year recurrence interval

Because it is often very expensive and difficult to retrofit nonstructural 

components and systems, many retrofit projects will only consider the life 

safety effects of structural collapse.
3-4 3: Selecting Performance Objectives FEMA P-58-6

3.2.2.2 Repair Cost

In the FEMA P-58 methodology, repair cost is defined as the cost, in present 

dollars, necessary to restore a building to its pre-earthquake condition, or in 

the case of total loss, to replace the building with a new structure of similar 

construction. In FEMA P-58, this measure is expressed as a percentage of 

the replacement value of the building. Repair costs represent only one aspect 

of potential financial loss due to earthquake damage. Other costs include 

loss of income due to business interruption during repair work, the cost to 

identify, plan, and permit repairs, and the cost of financing repairs.

Performance objectives associated with limiting repair costs represent 

enhanced objectives that are supplemental to those that underlie the basic 

design criteria in the building code. Nevertheless, maintaining expected 

repair costs at target levels can be an important performance objective for 

many buildings. One important driver for adopting performance objectives 

associated with repair cost is that many commercial mortgage lenders in 

regions of high seismicity consider probable repair costs when making 

decisions to offer financing on a property, as well as the terms of such 

financing. Many lenders base decisions on the assessed value of Scenario 

Expected Loss (SEL) for earthquake shaking having a 475-year mean return 

period. SEL represents a mean estimate of the repair cost, expressed as a 

fraction of building replacement value, given such shaking. Many lenders 

require an SEL value of 20% as a condition of making a loan. Some lenders 

also consider Scenario Upper Loss (SUL), which, for a given level of 

shaking, represents a repair cost, expressed as a fraction of replacement 

value, that has only a 10% chance of being exceeded. Acceptable SUL 

values vary considerably among lenders.

Most new buildings constructed in conformance with current building code 

requirements can provide SEL and SUL values typically deemed acceptable 

by lenders. However, many existing buildings will not achieve these values, 

and availability of financing is a frequent reason for selecting a performance 

objective with a lower repair cost when performing seismic upgrades.

3.2.2.3 Repair Time

In FEMA P-58, repair time is reported as the number of days required to 

restore a building to its pre-earthquake condition. Repair time is only a 

portion of the time needed to restore a building to its pre-earthquake 

condition. Additional time is required to identify, plan, and permit the work, 

arrange financing, and hire and mobilize contractors.
FEMA P-58-6 3: Selecting Performance Objectives 3-5

Most stakeholders are not specifically interested in repair time but are 

critically interested downtime, which is the time, following an earthquake, 

until a building can be safely restored to service. Downtime is an important 

design parameter for many building tenants, owners, and occupants. Loss of 

use of a building for an extended period of time following an earthquake can 

have severe impacts, including loss of ability to service customers, loss of 

revenue, and ultimately, loss of the survivability of the organization. Such 

issues are most significant to organizations that have large portions of their 

operations concentrated in a single facility, or multiple facilities in a region 

that could be severely affected by a single earthquake event. The amount of 

downtime that is acceptable to an organization will be highly dependent on 

the importance of the individual facility to overall operations, and the costbenefit ratio associated with designing for reduced downtime.

The relationship between repair time and downtime is highly complex and 

dependent on the actions and capabilities of the building owner, occupant, 

and the community surrounding the building. Some occupancies are tolerant 

of repairs conducted while the building is in use, allowing for reduced 

downtime, relative to repair time, while other occupancies cannot tolerate 

ongoing repairs during building use. Some building operators have the 

financial resources to implement repairs without waiting for insurance 

reimbursement or loans, while others do not, resulting in potentially 

significant time before repairs can even initiate. 

The FEMA P-58 methodology permits design for a target repair time rather 

than downtime because of the many factors affecting downtime that are 

outside of the control of the designer, and outside the influence of the 

individual building design. However, designing for targeted repair time can 

help an organization achieve targets for acceptable downtime.

3.2.2.4 Unsafe Placarding

An unsafe placard, determined in accordance with ATC-20 procedures

(ATC, 2005) and posted on a building, is a post-earthquake safety 

determination that deems a building, or portion of a building, damaged to the 

point that entry, use, or occupancy poses immediate risk to safety. In FEMA 

P-58, this measure is expressed as the probability that a building will incur an 

unsafe placard following an earthquake, based on the occurrence of structural 

or nonstructural damage that is considered significant enough to trigger an 

unsafe posting.

When a building is posted as unsafe (i.e., red tag or placard) following an 

earthquake, this can substantially increase time-related impacts associated 

with the damage. When a building is posted unsafe, it can be difficult for 
3-6 3: Selecting Performance Objectives FEMA P-58-6

design professionals and other to access the building to determine required 

repairs or retrieve contents. Therefore, stakeholders may elect to set 

performance objectives to minimize the risk that a building will incur an

unsafe placard following an earthquake.

3.2.2.5 Building Repairability

The repairability measure is the probability that a building will be considered 

possible to repair following an earthquake. A repairable condition is one in 

which the building does not collapse, the permanent residual drift is less than 

1%, and losses are less than of 50% of the building replacement cost. The 

inverse of this measure represents the risk that an earthquake will result in 

total loss of a building asset. Some stakeholders may wish to formulate 

objectives that maximize repairability, or minimize the inverse risk

associated with irreparability.

3.2.2.6 Environmental Impacts

The FEMA P-58 methodology can quantify environmental impacts, in terms 

of embodied carbon and embodied energy, to restore a building to its preearthquake condition or, in the case of total loss, to replace the building with 

a new structure of similar construction.

Many buildings today are designed with the intent to minimize the carbon 

and energy embodiment, sometimes known as “net-zero” practices. Usually, 

such practices only consider energy and carbon impacts associated with 

building development and normal operations, neglecting repairs that may be 

needed in the event of an earthquake occur during the life of the building. 

When a building is damaged by an earthquake, repair efforts result in 

enlargement of the building’s carbon footprint. By specifying seismic 

performance objectives associated with environmental impacts, stakeholders 

can ensure more comprehensive consideration of the likely impacts of their 

projects on the environment.

3.2.3 Define Earthquake Hazard

Performance objectives are defined by setting acceptable levels of damage 

and consequences based on earthquake ground shaking that may be 

experienced at the site. Other earthquake-related hazards, such as ground 

fault rupture, liquefaction, lateral spreading, land sliding, and tsunami 

inundation, are not measured in the FEMA P-58 methodology but should 

also be considered. 

As part of the formation of performance objectives, stakeholders will need to 

select a hazard level for each performance measure, considering building 
FEMA P-58-6 3: Selecting Performance Objectives 3-7

code requirements and personal risk tolerance. In the selection of 

appropriate earthquake shaking intensities to couple with performance 

measures, a basic concept to note is that for a given site, larger events occur 

less frequently than smaller events. The probable performance of a building 

can be evaluated with different earthquake hazard characterizations based on 

the type of assessment:

• Intensity-Based Assessments. Intensity-based assessments evaluate the 

probable performance of a building conditioned on the occurrence of a 

specific intensity of motion, as represented by an elastic acceleration 

response spectrum. The basic life safety performance objective 

underlying the ASCE/SEI 7 seismic provisions (less than a 10% chance 

of collapse, given the occurrence of MCER shaking) is an example of the 

use of an intensity-based hazard representation in a performance 

objective. Commonly, the response spectrum represents a shaking 

intensity having a specified probability of exceedance in 50 years or may 

be a code-specified spectrum, such as the Design Earthquake or MCER. 

Such objectives are particularly useful for comparison with the 

performance expected of code-conforming buildings. Many stakeholders 

will want to form performance objectives using this type of an approach, 

often referring to the intensity as having a specific return period, e.g., 

100 years, 500 years, or 1,000 years, because they have an intuitive 

understanding of decision making in this context.

• Scenario-Based Assessments. Scenario-based assessments evaluate the 

probable performance of a building assuming it is subjected to an 

earthquake scenario consisting of a specific magnitude earthquake 

occurring at a specific location relative to the building site. This hazard 

characterization will be useful in seismically active regions where 

historic earthquakes have occurred, or, where regional planners have 

forecast the likelihood of a specific magnitude earthquake on a specific 

fault. Examples include the San Francisco Bay Area, where stakeholders 

may wish to formulate objectives around a repeat of the 1906 earthquake, 

or an event on the Hayward fault, or the Seattle area, where stakeholders 

may wish to formulate objectives around occurrence of a large 

magnitude Cascadia subduction event.

• Time-Based Assessments. Time-based assessments evaluate the 

probable performance of a building considering all earthquakes that may 

occur, and the probability and probable consequences of each, to 

determine an average annual loss statistic for each performance measure. 

Time-based assessments can be used to specify limits on probable losses 

over a period of time, considering all earthquake sources that can affect a 
3-8 3: Selecting Performance Objectives FEMA P-58-6

site and the probability of occurrence of each potential event. This type 

of assessment is most useful for institutional investors or property 

owners with large portfolios, as well as for stakeholders using a costbenefit approach to select performance objectives or to determine use of 

additional seismic protection, such as isolation or passive energy 

dissipation devices. 

3.2.4 State Performance Objectives

Stakeholders will ultimately need to make a definitive statement as to the 

desired performance. In addition to indicating the desired limits on one or 

more earthquake consequences, and the earthquake hazard level for which 

consequences will be measured, it will also be necessary to state a level of 

confidence that the result will be achieved. The FEMA P-58 methodology 

forecasts earthquake performance in probabilistic terms, recognizing the 

uncertainties inherent in predicting actual earthquake outcomes. 

Stakeholders will need to determine their willingness to accept performance 

that is worse than specified. Stakeholders should be aware that when higher 

levels of confidence are desired, it may take substantially more protective 

design measures, and increased construction costs, to achieve the specified 

performance at the desired level of confidence.

3.2.5 Iterate on Performance Objectives

In some cases, stakeholders may be able to make a final selection of 

performance objectives based on the steps above, but final selection is 

normally an iterative process. Iteration is largely due to the need to assess 

the feasibility and practicality of selected performance objectives in the 

context of other project considerations, such as cost and schedule, and the 

need to be integrated into architectural, mechanical, and electrical design 

concepts.

3.3 Using Performance Objectives in FEMA P-58

The selection of performance measures combined with the consideration of 

earthquake hazard will lead to a decision regarding how the objective is

framed, which will lead to the choice of a FEMA P-58 assessment type. For 

example, an intensity-based objective for an emergency operations center 

may be stated in terms of the median estimated repair time in the event of an 

earthquake having a 10% probability of occurrence in 50 years. 

Alternatively, consequences may be stated in terms of the repair time 

resulting from the occurrence of a scenario event, or they may be time-based.
FEMA P-58-6 3: Selecting Performance Objectives 3-9 

3.3.1 Intensity-based Performance Objectives

Intensity-based performance objectives are framed as statements of 

acceptable measures resulting from specific intensities of ground shaking. 

Any of the performance measures discussed in Section 3.2 may be addressed 

in an intensity-based objective.

Figure 3-1 shows an example of the variation in median loss in terms of 

percentage of replacement cost for a hypothetical building with a given 

lateral strength and stiffness as a function of increasing earthquake intensity, 

represented as a percentage of MCE shaking. The same figure could have 

been shown with intensity represented in terms of return period. As intensity 

increases, median loss will increase, though not on a linear basis. 

Intensity-based Assessment

Intensity (% MCE)

0% 100%

Median Loss (% Replacement)

67%

15

0

Figure 3-1 Example result of an intensity-based assessment. 

Typical intensity-based objectives are conditioned on a single intensity, 

selected to relate to tangible risk levels for the performance measure of 

interest. For example, “if ground-shaking equivalent to two-thirds of MCE 

ground motion occurs, median repair costs should not exceed 20% of the 

building replacement value, there should be negligible probability of 

casualties, and median repair time should not exceed 30 days.” 

Stakeholders concerned with consequences related to business interruption 

may be interested in performance objectives related to functionality 

associated with multiple levels of probability of occurrence, and may include 

one or more performance measures at one or more intensity levels. For 

example, objectives could consider a frequent event, such as one having a 

50% probability of exceedance in 50 years (72-year return period), and a 

Performance objectives can 

include one or more 

performance measures at one 

or more intensity levels.
3-10 3: Selecting Performance Objectives FEMA P-58-6

larger event having a 10% probability of exceedance in 50 years (475-year 

return period).

Life safety related performance measures are commonly considered at the 

earthquake intensity associated with the building code design earthquake 

level, since the primary purpose of the code is protection of life safety. For 

example, an objective of interest may be the probability of casualties 

occurring at an intensity level corresponding to two-thirds of MCE level 

shaking.

3.3.2 Scenario-based Performance Objectives

Scenario-based performance objectives are framed as statements of 

acceptable risk of casualties, repair costs, and repair time resulting from the 

occurrence of the scenario event. An example of a scenario-based 

performance objective is a statement that if a magnitude-7.0 earthquake 

occurs on the San Andreas Fault, median repair costs should not exceed 15% 

of the building replacement cost, there should be no casualties, and repair 

time should not exceed two months.

Performance objectives may include multiple scenarios, depending on the 

site location relative to known faults in the region. For example, if a site is

located two miles from a fault capable of a magnitude-7.0 earthquake, and 10 

miles from a fault capable of a magnitude-6.5 earthquake, these scenario 

events may be used to describe two performance objectives, one major and 

one moderate. Each scenario could be associated with the same or different 

performance measure, and each would be associated with different 

performance objectives conditioned on the two scenarios. For example, one 

objective could be for the building to achieve no more than a 20% probability 

of incurring an unsafe placard in the major scenario earthquake, and a second 

objective could be for the building to achieve no more than a 10% probability 

of incurring an unsafe placard in the moderate scenario earthquake.

3.3.3 Time-based Performance Objectives

Time-based assessments can be used to specify limits on probable losses over 

a period of time, considering all earthquake sources that can affect a site and 

the probability of occurrence of each event. The impact most commonly 

considered in time-based assessments is loss associated with repair cost, 

which may be considered in terms of the average annual loss, or the loss over 

a specific interval of time, such as 50 or 100 years.

Time-based performance objectives are particularly useful when using costbenefit analysis to determine performance. If the average annual repair cost 
FEMA P-58-6 3: Selecting Performance Objectives 3-11

over the building life is known, it is possible, using engineering economics,

to determine the net present value of probable repair costs over the building’s 

useful life, using the formula:

NPV = ( )

( )

1 1

1 N

AAL

i i

    −   +  

(3-1)

where NPV is the net present value of the future losses in dollars, i is the time 

value of money, or interest rate, AAL is the average annual loss in dollars,

and N is the building or investment lifetime in years. Increased investment in 

seismic protection will reduce the size of average annual losses, AAL, 

resulting in a lower net present value, NPV. The optimum investment would 

be a level at which a dollar of additional investment in earthquake protection 

has a probable return of more than one dollar in future losses avoided.

3.3.4 Confidence Level

Confidence level reflects the desired certainty that the actual earthquake 

performance of a building will be at least as good, or possibly better than a 

target level. The following levels are commonly used:

• Median. The median value of a performance measure represents that 

value which will be exceeded half the time. There is a 50% chance that 

actual performance will be better than or equal to the median level.

• Mean. The mean value is the average or expected outcome. Since 

distributions of performance measures tend to be skewed, the mean value 

is usually larger than the median value. Typically, there is a 40% chance 

that a mean value will be exceeded.

• 90th Percentile. The 90th percentile value represents the worst 

performance in 9 out of 10 similar buildings. There is a 10% chance the 

90th percentile value will be exceeded.

Figure 3-2 illustrates the probability density function for repair cost for a 

hypothetical building illustrating the median (10% of replacement value), 

mean (11% of replacement value), and 90th percentile (17% of replacement 

value). Figure 3-3 shows the same distribution in the form of a cumulative 

probability distribution.

The choice of confidence level depends on a stakeholder’s need for certainty 

in results. For example, stakeholders considering the expected performance 

of an emergency operations center or critical manufacturing facility may 

choose the 90th percentile confidence level for post-earthquake repair time or 

avoidance of unsafe placarding. Owners of a large campus of buildings may 
3-12 3: Selecting Performance Objectives FEMA P-58-6

find use of mean repair costs to be an appropriate level of confidence because 

when aggregated over all buildings, this best expresses the probable value of 

the loss.

Figure 3-2 Probability density function for repair cost illustrating median, 

mean, and 90th percentile values.

Figure 3-3 Cumulative probability distribution for repair cost illustrating 

median, mean, and 90th percentile values.
FEMA P-58-6 3: Selecting Performance Objectives 3-13

3.4 Other Performance Considerations

3.4.1 Utilities and Back-up Systems

Most buildings depend on the availability of electrical power, water, and 

other utilities to be useful for their intended occupancy. Earthquakes can

cause disruption of utilities, which affects recovery planning. For buildings 

in which post-earthquake operations are critical, whether for societal or 

financial reasons, owners can consider arranging in advance for back-up 

systems to provide fuel, water, power, and wastewater storage. Replacement 

equipment or parts may be stored on-site, or locally off-site, or arrangements 

can be made in advance for their replacement, if needed. In complex 

laboratory and manufacturing operations, the storage of work-in-process and 

inventory may be appropriate.

3.4.2 Redundancy

Redundancy is an important consideration in establishing performance 

objectives, particularly for buildings supporting operations that are critical,

either to society or a private entity. Setting performance objectives should 

account for the availability of facilities that have redundant or overlapping 

functions. For example, the need for all hospitals in a region to operate 

continuously after an earthquake varies regionally. Stakeholders considering 

performance objectives associated with a substantial initial investment may 

choose to consider the availability of other similar facilities located nearby, 

or outside the region affected by the earthquake.

Redundancy is also a major consideration for laboratory and manufacturing 

facilities. Higher performance objectives, and the associated costs, may be 

appropriate for laboratory buildings that house unique research activities, or 

factories that produce a component that is not easily obtained elsewhere.

3.4.3 Real Estate Industry Guidelines

The real estate industry in regions of high seismicity follow selected 

procedures to determine the financial viability of a project, and these 

considerations may influence the selection of performance objectives.

3.4.3.1 Probable Maximum Loss

Lenders, loan servicers, insurers, and equity investors use a measure of 

seismic risk known as Probable Maximum Loss (PML). Building owners 

and other stakeholders may also use this measure to make decisions related 

to property investment, including the purchase of earthquake insurance. In 

many cases, investment and insurance decisions are based on a PML 

threshold value, such as 20%.
3-14 3: Selecting Performance Objectives FEMA P-58-6

ASTM E-2026, Standard Guide for Seismic Risk Assessment of Buildings,

(ASTM, 2016a) and ASTM E-2557, Standard Practice for Probable 

Maximum Loss (PML) Evaluations for Earthquake Due-Diligence 

Assessments, (ASTM, 2016b) set standard procedures for seismic evaluations 

and the development of PMLs for use in the financial industry. These 

standards define several different measures including:

• Scenario Expected Loss (SEL). This represents the mean repair cost, 

expressed as a percentage of building replacement value, for a selected 

intensity of ground motion.

• Scenario Upper Loss (SUL). This represents the 90th percentile repair 

cost, expressed as a percentage of building replacement value, for a 

particular intensity of ground motion.

• Probable Loss (PL). This represents the loss having a specific 

probability of exceedance over a specified number of years.

The SEL and SUL loss measures commonly reflect damage statistics for 

475-year return period shaking, while PL values correspond to ground 

motions occurring over a specified timeframe, but not a specific scenario 

event. Both SEL and SUL can be determined by performing intensity-based 

assessments for response spectra having a specified return period. The SEL 

is obtained by computing the mean repair cost and the SUL is determined 

directly from the performance curve cost at the 90th percentile. PL can be 

derived from a time-based assessment using an appropriate return period for 

the assessment.

3.4.3.2 U.S. Resiliency Council Rating System

Some stakeholders may elect to design buildings to achieve a specific rating

in accordance with the U.S. Resiliency Council (USRC) rating system. This 

system identifies the expected performance of buildings in earthquakes

across three performance categories: Safety, Damage, and Recovery. USRC 

ratings address structural and nonstructural systems and are applicable to 

both new and existing buildings. The ratings are based on median 

performance in the 475-year return period ground motion and assign one to 

five stars in each of the three categories. Table 3-1 shows the USRC 

performance goals.

Each of the USRC ratings can be assessed using the FEMA P-58 

methodology. On a preliminary basis, Safety can be assessed based on 

casualties, or it may be assessed using the ASCE/SEI 41 methodology. The 

final safety determination should be made based on analysis conducted 

utilizing the Performance Assessment Calculation Tool (PACT), considering

Scenario Expected Loss and 

Scenario Upper Loss can be 

determined by performing 

intensity-based assessments; 

Probable Loss from time-based 

assessments.
FEMA P-58-6 3: Selecting Performance Objectives 3-15

collapse in the 475-year ground motion. The USRC assesses damage based 

on the mean estimated loss, and recovery based on median repair time. It is 

noted that PACT results for loss would be indicated as mean results, not 

median.

Table 3-1 U.S. Resiliency Council Rating System Performance Goals

USRC Rating Range for a New Code-Compliant Building 

(Depends on Structural System)

Safety Damage Recovery

5 Blocking of exit 

paths unlikely

5 Minimal damage 

(<5%)

5 Immediately to 

days

4 Serious injuries 

unlikely

4 Moderate damage 

(<10%)

4 Within days to 

weeks

3 Loss of life unlikely 3 Significant damage 

(<20%)

3 Within weeks to 

months

2 Isolated loss of life 2 Substantial damage 

(<40%)

2 Within months to a 

year

1 Loss of life likely 1 Severe damage 

(40%+)

1 More than one 

year

3.5 Expected Performance of Code-Conforming 

Buildings

The expected performance of buildings designed to the minimum 

prescriptive requirements of the building code can be an important measure 

for selecting performance objectives, or even deciding to adopt a 

performance-based approach. FEMA P-58, Volume 5 presents findings from 

studies conducted to determine the expected performance of codeconforming buildings. Results from these studies can be used to determine if 

code performance is acceptable for a given project, or to inform the selection 

of project-specific performance objectives.

The FEMA P-58 methodology was used to assess a wide range of buildings 

and systems meeting ASCE/SEI 7-10 structural and nonstructural seismic 

design requirements in regions of high seismicity. The following structural 

systems were considered: steel special moment-resisting frames (Steel 

SMRF), reinforced concrete special moment-resisting frames (RC SMRF), 

steel buckling-restrained braced frames (BRBF), steel special concentricallybraced frames (SCBF), and special reinforced concrete shear walls (Special 

RCSW).

Archetypical representations of buildings with a variety of code-conforming 

characteristics were used. Archetypes were defined by lateral system type, 

height, lateral strength, lateral stiffness, occupancy, and design ground 
3-16 3: Selecting Performance Objectives FEMA P-58-6

motion. A total of 1,755 archetypes were designed for five different seismic 

force-resisting systems, two Risk Categories (RC II and RC IV), three levels 

of seismic hazard (Low SDC D, SDC D, and SDC E/F), three height variants 

(low-, mid-, and high-rise), and two occupancies (office and healthcare). 

The concept of a code-conforming design space was developed to bound the 

range of possible archetype designs. The design space is intended to 

represent a reasonable range of lateral strengths and stiffnesses that would be 

expected in typical modern buildings designed in accordance with ASCE/SEI 

7-10. 

The FEMA P-58 assessment of code-conforming buildings showed that

performance varies significantly across the range of code-complying 

systems, and that structural and nonstructural design decisions can have a

measurable impact on the resulting performance. Thus, by selecting an 

appropriate structural system, and proportioning it with sufficient strength 

and stiffness, an engineer can do much to control a building’s probable

seismic performance. Although traditional code performance expectations 

focus on safety, current design requirements were also shown to provide 

some measure of protection of property. 

Table 3-2 presents generalized performance expectations for codeconforming buildings from FEMA P-58, Volume 5, developed based on: 

performance assessment results averaged across all points in the design space 

for each system; experience in post-earthquake damage investigations and 

subsequent repairs; and engineering judgement. Generalized performance 

has been evaluated for two earthquake levels: the design level earthquake and 

the Maximum Considered Earthquake (MCE). The design and MCE 

earthquake levels are based on ASCE/SEI 7-10 ground motion values, with 

design earthquake shaking taken as two-thirds of MCE shaking. 

In the table, repair costs are expressed as a percentage of the replacement 

value of the building. Repair time is expressed in days. Casualty rates are 

expressed as the probability, in percent, of any one occupant in a building 

becoming a casualty as a result of an earthquake. The probability that a 

building will be posted unsafe is shown, as is the probability that the building 

will be considered possible to repair following an earthquake. More detailed 

information is available in FEMA P-58, Volume 5, including the 

performance of individual structural systems, and for other levels of shaking 

intensity.

Generalized performance expectations in FEMA P-58, Volume 5 are 

presented based on median values of loss. If higher levels of confidence are 
FEMA P-58-6 3: Selecting Performance Objectives 3-17

desired, 90th percentile values of these performance measures can be 

approximated by doubling the median values reported in the table. 

Table 3-2 Generalized Performance Expectations for CodeConforming Buildings (FEMA P-58, Volume 5, 

Table 6-1)

Performance Measure

Performance Expectation

Design EQ MCE

Risk Category II – Office

Repair Cost 10% 30%

Repair Time 45 days 150 days

Casualty Rate 1.0% 2.0%

Probability of Unsafe Placard 20% 40%

Repairability 95% 80%

Risk Category II – Healthcare (Medical Office Building or Laboratory)

Repair Cost 20% 40%

Repair Time 60 days 180 days

Casualty Rate 1.0% 2.0%

Probability of Unsafe Placard 20% 40%

Repairability 85% 65%

Risk Category IV – Office (Emergency Operations Center)

Repair Cost 5% 15%

Repair Time 30 days 75 days

Casualty Rate 0.5% 1.5%

Probability of Unsafe Placard 10% 25%

Repairability 98% 90%

Risk Category IV – Healthcare (Hospital)

Repair Cost 10% 20%

Repair Time 45 days 100 days

Casualty Rate 0.5% 1.5%

Probability of Unsafe Placard 10% 25%

Repairability 95% 85%

FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-1

Chapter 4

Developing Preliminary and 

Final Designs

The performance-based seismic design process includes selection of a 

structural system, development of a preliminary design, and assessment of its 

performance capability. Preliminary designs are iteratively revised,

considering factors affecting performance, and a final design that meets the 

performance objectives is ultimately developed. This chapter presents two 

approaches for developing preliminary designs along with considerations for 

developing final designs.

4.1 Overview of Preliminary Design

Preliminary design is initiated with the selection of a candidate structural 

system and consideration of structural design factors. The strength and 

stiffness of the system are determined based on code compliance and 

performance capability. Once the required strength and stiffness are known, 

the structural layout, number, and required size of structural components are

determined. In design iteration, other factors, such as building configuration 

and nonstructural component contributions to loss, are also considered.

This chapter presents the following two approaches for preliminary seismic 

design:

• General procedure. The general procedure is applicable to any 

structure. It requires iterative performance assessments evaluating

performance for varying design assumptions. This approach, along with 

simplifying approximations, is described in Section 4.3.

• Direct design procedure. The direct design procedure is limited to 

buildings with selected systems (e.g., buckling-restrained braced frame, 

steel concentrically braced frame, steel special moment frame, reinforced 

concrete shear wall, and reinforced concrete special moment frame), 

occupancies (office or healthcare), and Risk Categories II or IV. The 

Performance Estimation Tool (PET), provided in FEMA P-58, Volume 

3, is used to directly evaluate the effects of varying assumptions on 

performance, and to directly determine the strength and stiffness required 

to meet selected performance objectives. This approach, along with 
4-2 4: Developing Preliminary and Final Designs FEMA P-58-6

recommendations for extrapolating beyond limitations in available data, 

is described in Section 4.4.

4.2 Structural Design Factors Affecting Performance

Once performance objectives for a project have been selected, and a 

preliminary architectural layout has been determined, structural design 

factors affecting building performance should be considered.

4.2.1 System Selection

All of the structural systems listed in ASCE/SEI 7-16, Table 12.2-1 are 

presumed capable of providing minimum acceptable seismic performance 

when designed in accordance with prescriptive requirements; however, the 

performance capability of these systems in terms of FEMA P-58 

performance metrics will vary considerably. Some systems are flexible, 

permitting large story drifts that can damage architectural and other 

nonstructural components. Other systems are strong, transmitting large floor 

accelerations that can damage contents. Some systems are susceptible to 

developing large permanent drift, rendering them difficult, and potentially 

impossible, to repair. Some structural systems include components that can 

be easily repaired or replaced, while other systems are expected to incur 

damage that may be difficult to repair.

Although seismic performance capability is an important factor to consider in 

the selection of a structural system, it is not the only factor. In addition to 

seismic performance capability, the most appropriate structural system 

should be selected considering:

• Compatibility with the required story height and architectural layout

• Ability to meet the desired performance objectives, project cost, project 

schedule

• Availability of required materials and construction expertise at site 

location

• Inherent fire resistance

• Floor vibration characteristics

Some systems offer advantages for buildings of a certain size and occupancy,

and are, therefore, most commonly selected for certain building types. For

example: wood light-frame or cold-formed steel frame systems are

commonly used in low- to mid-rise residential construction; steel frame 

systems are common in mid- to high-rise office construction; and reinforced 

concrete systems are often used in mid- to high-rise residential construction.
FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-3

4.2.2 Stiffness and Strength

The building code specifies the minimum required strength for new buildings

as a function of site seismicity, soil class, occupancy category, and structural 

system. Indirect requirements are placed on building stiffness through the 

specification of maximum permissible story drift ratio when subjected to 

code-specified minimum seismic design forces. However, there are no 

limitations on design of buildings with additional stiffness and strength. 

Engineers are at liberty to increase the stiffness and strength of buildings 

beyond code-specified minimum values.

Increasing the stiffness of a system reduces the amount of lateral drift that a

building will experience when subjected to earthquake shaking, resulting in 

reduced damage to components that are sensitive to drift, such as cladding 

and partitions. However, increasing building stiffness reduces the 

fundamental period of the structure, resulting in increased acceleration and 

strength demands, which can lead to damage in components that are forcecontrolled or sensitive to acceleration, such as mechanical and electrical 

components and tenant contents.

Increasing the strength of a system reduces the potential for yielding, 

decreases ductility demands, and reduces potential structural damage and 

residual drift. However, increasing strength makes it possible for the 

building to transmit increased accelerations throughout the structure, 

increasing the potential for damage to acceleration-sensitive components.

Achieving targeted performance will require a balance between selected 

values of stiffness and strength. Sections 4.3 and 4.4 provide procedures for 

determining stiffness and strength that will achieve the selected performance 

objectives.

4.2.3 Supplemental Protective Systems

Supplemental protective systems can be considered for enhancing the seismic 

performance capability of a system in order to achieve selected performance 

objectives. The two most common technologies used for this purpose are 

seismic isolation and energy dissipation (i.e., damping) systems. Sometimes, 

it is advantageous to employ both technologies in achieving higher 

performance objectives.

Seismic isolation improves performance by: lengthening the fundamental

period to reduce accelerations experienced by the structure, adding hysteretic 

damping to reduce the response of the structure, and providing a ductile 

interface between the structure and the ground that is capable of resisting 
4-4 4: Developing Preliminary and Final Designs FEMA P-58-6

large displacements with minimal input to the structure. Properly designed 

seismic isolation systems can enable structures to withstand intense ground 

shaking with minimal damage and consequence. Seismic isolation is most 

compatible in buildings with stiff structural systems, such as reinforced 

concrete or masonry shear walls and steel braced frames. To ensure proper 

function of the isolation system, the structure above the isolation plane must 

be designed for essentially elastic behavior under design shaking. 

Seismic isolation systems are most effective when used in a structural system

with a fixed base fundamental period of 1 second or less. ASCE/SEI 7-16 

Chapter 17 provides seismic design requirements for new seismically 

isolated buildings, and ASCE/SEI 41-17 Chapter 14 provides criteria for 

seismic isolation of existing buildings.

Damping systems improve performance by dissipating earthquake energy 

through conversion of kinetic energy to heat energy in components (i.e., 

dampers) that are specifically designed for this purpose. As a result of 

damping, lateral displacement response is reduced, resulting in less damage 

to structural components and drift-sensitive nonstructural components. 

Because the amount of energy dissipated is related to displacement in the 

dampers, damping systems are most effective in relatively flexible structural 

systems, such as moment frames. For damping systems to be effective, it is 

typically necessary that the structure experience only limited inelastic 

behavior. 

Damping systems are most effective when used in a structure with a 

fundamental period of vibration of 1 second or more. ASCE/SEI 7-16

Chapter 18 provides seismic design requirements for new buildings with 

damping systems, and ASCE/SEI 41-17 Chapter 14 provides criteria utilizing

damping systems in existing buildings.

4.3 General Procedure for Preliminary Design

The general procedure is initiated by designing a building to conform to 

applicable building code requirements, potentially with some enhancement or 

modification. The preliminary design is then subjected to a performance 

evaluation using the FEMA P-58 methodology, and the predicted 

performance is compared with targeted performance objectives. If the 

predicted performance fails to meet the targeted performance, the design is

revised through one or more of the following actions: changing the building 

configuration, strengthening the design, stiffening the design, or selecting 

less fragile (i.e., more robust) components. The revised design is then re-
FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-5

assessed to evaluate performance in an iterative process until the design 

satisfies the targeted performance objectives.

The general procedure involves assembling a building performance model to 

a level of detail that is appropriate for the current stage of design, along with 

estimates of stiffness and strength, and approximate estimates of earthquake 

demands for input into the Performance Assessment Calculation Tool

(PACT), or other comparable tool, to estimate building performance. PACT 

results provide estimates of the probable distribution of repair cost, repair 

time, and other earthquake impacts, as well as information on components 

and systems that significantly contribute to losses. With this information, 

preliminary designs can be effectively revised to achieve the targeted

performance.

The following sections describe approximations and shortcuts available for 

use in a preliminary design context in conjunction with detailed procedures 

outlined in FEMA P-58, Volume 1 (Methodology) and illustrated in Volume 

2 (Implementation Guide). Approximations and shortcuts are provided to 

reduce the level of effort associated with analyses of buildings utilizing

conventional structural systems such as shear walls, moment frames, and 

braced frames, as well as structures utilizing protective technologies, such as

seismic isolation and damping systems.

4.3.1 Preliminary Building Performance Model

A building performance model is a quantified description of the building 

including structural and nonstructural components that have susceptibility 

(fragility) to earthquake-induced damage, as well as the population (i.e.,

number of persons) likely to be present in the building at different times. 

Building components and systems can generally be categorized as 

architectural components, structural components, 

mechanical/electrical/plumbing components, and contents.

4.3.1.1 Architectural Components

The following architectural components are considered the most significant

contributors to consequences (i.e., losses) experienced by buildings in 

earthquakes:

• Exterior cladding

• Ceilings

• Partitions

• Stairways

Short Cut for Preliminary 

Design

It is considered adequate to 

include only the following 

architectural components in a 

preliminary building 

performance model: Exterior 

cladding, ceilings, partitions, 

stairways, and elevators.
4-6 4: Developing Preliminary and Final Designs FEMA P-58-6

• Elevators

Accordingly, for purposes of preliminary design, it is considered adequate to

include only these components in the building performance model for 

preliminary design.

To the extent that preliminary architectural drawings define the quantities of 

these components, they should be used directly to define the building 

performance model. Where they are not defined, the Normative Quantity 

Estimation Tool provided in FEMA P-58, Volume 3 can be used to define 

approximate quantities based on number of stories, floor area of each story, 

building occupancy, and square footage. Once the quantity for each of the 

architectural components is defined, it will be necessary to associate a 

fragility specification with each component type.

FEMA P-58, Volume 3 includes a Fragility Database with specifications for 

many architectural components. Fragility specifications associated with the 

building Seismic Design Category should be selected. The following should 

also be considered when specifying architectural components:

• The Fragility Database provides specifications for several different types 

of exterior cladding including glazed storefronts, glazed curtain walls,

and precast panels. Some fragility specifications require that the 

engineer input the median deformation demand at which damage states 

will initiate. For preliminary design, use of fragilities computed from

code-required design earthquake displacement capacity for cladding in 

accordance with the procedures of FEMA P-58, Volume 2, is 

recommended.

• Hard ceilings constructed of plaster or gypsum board on suspended 

framing are considered rugged in the Fragility Database and need not be 

included in the performance model. Fragility specifications for 

suspended lay-in acoustic tile ceilings are provided in the Fragility 

Database.

• Damage to partitions can be a significant contributor to losses in 

buildings with flexible seismic force-resisting systems, even in moderate 

levels of shaking. At modest levels of story drift, damage consists of 

cracking of gypsum board sheathing, concentrated primarily at re-entrant 

corners, above door and window openings, and at wall intersections. At 

larger story drifts, steel stud framing can become permanently deformed 

requiring replacement of the entire wall. Full-height walls, that frame 

between floor levels are more susceptible to damage than partial height 

walls. Full-height walls are typically used as code-required fire barriers 
FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-7

and are typically used to enclose stairwells, elevator and air shafts, and 

corridors required for egress. Full-height walls are also commonly used 

around lavatories to limit sound and odor migration. Most other

partitions are partial height. There are two types of partial-height walls:

(1) those in which the framing and sheathing terminate at the ceiling 

level; and (2) those in which the framing extends to the floor level above, 

but the sheathing stops at the ceiling level. Both types have substantial 

resistance to earthquake-related damage. The Fragility Database

includes fragilities for full-height walls with several types of detailing 

including walls with the framing hard-attached to the floor above and 

walls with compensation channels that allow sliding of the wall relative 

to the floor above. Detailing with compensation channels is 

recommended. The building performance model should include 

selection of fragility specifications representing the detailing that will be 

used in the building.

• Several options for stairway systems are provided in the Fragility 

Database. Unless it is known that an alternate type of stair will be used,

steel stringers with provision for displacement equal to the codespecified drift limit can be assumed for preliminary design.

• Separate fragility specifications are provided for traction and hydraulic 

elevators in the Fragility Database. Most elevators that service three

stories or less will be hydraulic. Traction elevators should be assumed in

applications servicing more than three stories.

4.3.1.2 Mechanical/Electrical/Plumbing Components

If the mechanical/electrical/plumbing (MEP) systems are not design-build, 

the structural engineer should coordinate with mechanical, electrical, and 

plumbing design professionals to identify the size and types of equipment

and systems that will be specified. Important MEP components that are the 

most significant contributors to consequences (i.e., loss) include: 

• Air handlers 

• Chillers

• Generators

• Fire sprinkler drops

• Domestic water piping

• Packaged air conditioning systems

The Normative Quantity Estimation Tool provides recommendations for the 

quantity and size of typical MEP components and systems. The Fragility 
4-8 4: Developing Preliminary and Final Designs FEMA P-58-6

Database presents fragility specifications for these components. The key 

fragility for MEP equipment is the adequacy of anchorage. FEMA P-58, 

Volumes 1 and 2 present procedures for computing fragilities for equipment 

anchorage based on code-specified minimum capacity.

Electrical panels, transformers, motor control centers, and switchgear do not 

typically have a large impact on seismic performance and can be ignored for 

preliminary design.

4.3.1.3 Contents

Damage to contents can dominate the consequences of earthquake shaking 

on buildings, particularly for moderate levels of motion. However, the effect 

of contents on performance is not necessarily of interest to all parties. 

Owners of multi-tenant office buildings and residences may not be concerned 

about content performance because they do not own the contents, nor are 

they responsible for replacement of contents when damaged. However, the 

performance of contents can be a critical concern for operators of certain 

types of buildings, including most structures designated as essential facilities 

(Risk Category IV), laboratory, research, and manufacturing facilities.

The Fragility Database includes fragility specifications for common contents 

found in office and residential occupancies. It does not include fragility 

specifications for Risk Category IV, laboratory, research, and manufacturing 

facilities. Suppliers of critical equipment may have some fragility data 

available. If the performance of contents is critical to achieving the targeted

performance objectives, consideration should be given to specifying shake 

table qualification testing as part of purchase specifications for the 

equipment. 

Most vulnerable equipment and contents in laboratory, healthcare, and 

manufacturing facilities include unanchored countertop items or cartmounted items. FEMA P-58, Volumes 1 and 2 provide procedures for 

estimating the fragility of these items for sliding or overturning, including 

examples illustrating implementation of these procedures.

When properly anchored or secured, many contents are relatively rugged. 

FEMA P-58, Volumes 1 and 2 provide guidance for developing fragilities for 

equipment anchorage. The consequences of anchor failure will be largely 

dependent on the type of equipment and the types of connections (e.g., 

electrical and gas) to the surrounding facility. Engineers developing 

fragilities for such items will need to work with equipment suppliers, or 

persons knowledgeable in the use of the equipment, to develop an 

Short Cut for Preliminary 

Design

The key fragility for MEP 

equipment is anchorage. 

Short Cut for Preliminary 

Design

FEMA P-58, Volume 3 provides 

fragility specifications for 

common contents in office and 

residential occupancies. 
FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-9

understanding of the likely consequences of failure in terms of repair cost, 

repair time, and other impacts.

4.3.1.4 Structural Components

The Fragility Database provide a large number structural fragility 

specifications covering most structural systems, including structural 

components that conform to current code detailing provisions, and those that 

do not. Structural information necessary to develop a building performance 

model for preliminary design is similar to the level of information presented

in typical conceptual and schematic structural documents, including:

• Identification of the structural system (e.g., steel concentric braced 

frame, masonry wall, light framed wall)

• Identification of the number and dimensions of bays of walls, moment 

frames, or braces to be used in the structure 

• Identification of approximate framing sizing, including approximate wall 

thickness, approximate member depth, and weight

• Level of seismic detailing (e.g., special, intermediate, ordinary, nonconforming) to be used

With this information, the engineer can enter structural components into the 

building performance model using the standard fragility specifications 

available in PACT, and choose fragility specifications appropriate to the 

design concept in accordance with the instructions in FEMA P-58, Volumes

1 and 2.

4.3.1.5 Collapse Fragility 

PACT also requires input of a building-specific collapse fragility. For new,

code-conforming structures, the simplified method contained in FEMA P-58, 

Volume 1 should be used to estimate collapse fragility based on the response 

modification factor, R, and overstrength, Ω0, values appropriate to the 

selected structural system. For existing buildings, the results of an 

approximate pushover analysis can be used together with the SPO2IDA tool

provided in FEMA P-58, Volume 3 to develop a collapse fragility. For 

preliminary design, it is typically sufficient to assume that only a single 

collapse mode occurs, encompassing complete collapse of the structure. 

More refined collapse modes can be considered, if desired.

Short Cut for Preliminary 

Design

The collapse fragility of new 

structures can be determined 

with the simplified method of 

FEMA P-58, Volume 1.
4-10 4: Developing Preliminary and Final Designs FEMA P-58-6

4.3.1.6 Population Model

As described in FEMA P-58, Volume 1, PACT has built-in population 

models for commercial office, education, healthcare, hospitality, multi-unit 

residential, research laboratory, retail, and warehouse occupancies. For 

preliminary design, it is typically acceptable to use an equivalent continuous 

occupancy (ECO) model, which is a time-weighted average of the population 

theoretically occupying the building on a continual basis.

4.3.2 Demand Estimation for Conventional Structures

The FEMA P-58 methodology allows both nonlinear dynamic analysis and 

simplified analysis procedures. For preliminary design, the level of rigor and 

effort associated with nonlinear response history analysis is not practical, and 

the simplified analysis procedure as described in FEMA P-58, Volume 1 

should be used for preliminary performance assessments.

This section describes several shortcuts that can be used in conducting 

preliminary analyses to reduce the effort to a level commensurate with 

preliminary design. Engineers are cautioned that these shortcuts may 

introduce additional bias, either conservative or unconservative, and 

substantial additional uncertainty, into the performance assessment. Because

these shortcuts are not recommended for use in verification of performance 

capability of final designs, it is not necessary to account for this additional 

bias and uncertainty. However, knowing that additional bias and uncertainty 

could potentially exist reinforces the need to conduct a final design 

verification using a complete FEMA P-58 performance assessment.

The FEMA P-58 methodology typically requires determination of the 

following demand parameters for each level of ground shaking for which 

performance is being assessed:

• Peak transient story drift in each of two orthogonal directions

• Residual story drift in each of two orthogonal directions

• Peak floor acceleration in each of two orthogonal directions

In addition to the above parameters, it is also necessary to estimate peak floor

velocity if the performance model includes fragilities for unanchored 

equipment or contents.

The most direct way to obtain demand parameters for assessment of a 

preliminary design is to construct a simple elastic analytical model of the 

seismic force-resisting system, in each primary direction of the building,

using the simplified analysis procedures of FEMA P-58, Volume 1.

Short Cut for Preliminary 

Design

An equivalent continuous 

occupancy (ECO) model can be 

used to estimate population.

Short Cut for Preliminary 

Design

Preliminary performance 

assessment should be 

conducted with the simplified 

analysis procedure of FEMA 

P-58, Volume 1 in each 

primary direction of building 

response. 
FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-11

4.3.2.1 Structural Period

The first mode period of vibration, T, of the structure in each primary 

direction of response is a key parameter used to estimate structural demands. 

For preliminary performance assessment, the approximate fundamental 

period can be calculated using ASCE/SEI 7-16 Section 12.8.2.1 Equation 

12.8-7:

Ta = Cthn

x (4-1)

where hn is the structural height as defined in ASCE/SEI 7-16, and Ct and x

are determined per ASCE/SEI 7-16 Table 12.8-2.

Use of this approximate period formula affords several advantages. First, it

allows rapid calculation of the structural period based on building height and 

the type of seismic force-resisting system. Second, approximate periods are 

calibrated to the measured response of real buildings, and inherently account 

for the stiffening (period shortening) effects of gravity framing and 

nonstructural systems. Periods obtained by analysis will not include these 

effects, unless the engineer has deliberately included representation of 

additional stiffening elements in the analytical model, which is not typically 

done. For flexible structural systems, such as steel moment-resisting frames, 

analytical period determination using models that include only the seismic

force-resisting system can over-estimate periods by 40%, or more. This

typically results in over-prediction of consequences (i.e., poorer 

performance). Use of the code-specified approximate period formula avoids 

this potential inaccuracy.

4.3.2.2 Yield Strength

The yield strength, Vy, under lateral forces, is a key parameter used to 

estimate demands in the simplified analysis procedure. FEMA P-58,

Volume 1, Section 5.2.1 suggests that for preliminary design, an approximate 

approach to estimating building yield strength can be based on building 

design parameters. This approach is modified for preliminary design using a 

bias factor, B.

Accordingly, the following modified approach for estimating yield strength, 

Vy, may be used in assessing the performance of preliminary designs:

Vy = 

2 ( )

/

BS T Da 1 W

R I (4-2)

where:

Vy = yield strength

B = bias factor

Short Cut for Preliminary 

Design

The approximate fundamental 

period can be calculated using

ASCE/SEI 7-16 Equation 

12.8-7. 

Short Cut for Preliminary 

Design

Building yield strength is 

determined based on design 

parameters and a bias factor.
4-12 4: Developing Preliminary and Final Designs FEMA P-58-6

SDa(T1) = design spectral acceleration at the fundamental period of the 

building, as determined from ASCE/SEI 7-16

R = response modification coefficient for the structural system 

under consideration, as specified in ASCE/SEI 7-16

I = Importance Factor for the building used in design

W = effective seismic weight of building, as defined in ASCE/SEI

7-16

The bias factor, B, is used to adjust the estimated yield strength of the 

building to account for deliberate design decisions that strengthen the 

building beyond what is required in the building code. For example, if the

engineer elects to design the structure twice as strong as the minimum codespecified base shear strength as a means of improving its performance

capability, the value of B should be taken as 2. This is a convenient way to 

rapidly explore the effects of alternative building strength levels on 

performance. The bias factor, B, can also be used to account for the strength 

of an existing building, which may be less than what is currently specified in

the building code. As an example, if a building was designed in accordance 

with an earlier edition of the code that utilized 75% of the strength specified 

in the current code, the value of B should be taken as 0.75.

In the case of existing buildings, an estimate of the yield strength may be 

available as a result of a completed ASCE/SEI 41 Tier 3 evaluation. Where 

available, results of prior detailed analyses should be used as appropriate.

4.3.2.3 Strength Ratio

The strength ratio, S, is used to determine demands in the FEMA P-58 

simplified analysis procedure. In accordance with FEMA P-58, Volume 1 

the strength ratio is taken as:

S = ( ) a 1

y

S T W

V (4-3)

where Sa(T1) is the spectral acceleration at the fundamental period, T1, for the 

intensity of shaking at which performance is being evaluated. All other 

terms are as previously defined.

4.3.2.4 Uncorrected Story Drift Ratio

The uncorrected story drift ratio, Δi, at each story “i” can be computed using 

an analytical model and the formula contained in FEMA P-58, Volume 1, 

Section 5.3.2. Alternatively, the story drift at each level can be taken as:

Δi = 

( )

( )

a1 a

d Da 1

DS T

CS T

∆ (4-4)
FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-13

where:

D = fraction of the allowable story drift ratio for the structural system,

per ASCE/SEI 7-16 Section 12.12, that the engineer elects to target 

in the design

Δa = allowable story drift ratio, per ASCE/SEI 7-16 Section 12.12

Cd = deflection modification coefficient for the specified structural 

system, per ASCE/SEI 7-16 Section 12.2

and other terms are as previously defined. Note that for existing buildings it 

will be necessary to perform analysis to determine the values of Δi or select a 

target value that the retrofit is intended to achieve.

4.3.2.5 Median Story Drift Ratio

If the strength ratio, S, at the ground motion intensity level of interest has a 

value of 1 or less, the median story drift ratio, * ∆i , can be taken as the 

uncorrected value, Δi, computed in accordance with Equation 4-4. If the 

strength ratio, S, has a value exceeding 1, the values of Sa(T), S, T, and Δi

computed in accordance with the procedures above should be used in “Step 

3” of FEMA P-58, Volume 1, Section 5.3.2 to correct story drift ratios to 

account for inelastic behavior and higher mode effects.

4.3.2.6 Median Floor Acceleration

The median floor acceleration, *

i a , at each story “i” is calculated following 

the procedures of “Step 4” of FEMA P-58, Volume 1, Section 5.3.3 to 

estimate peak floor acceleration from peak ground acceleration. The strength 

ratio, S, is taken as previously computed in Section 4.3.2.3.

The value of peak ground acceleration (PGA) at the site can be calculated for 

the ground motion of interest from the equation:

PGA = ( )

2.5 ( )

DS a

Da

S ST

S T (4-5)

where SDS is the value of the short period design spectral acceleration for the 

building and Sa(T) and SDa(T) are as defined previously. Alternatively, PGA 

may be obtained directly from a site-specific seismic hazard report, if 

available.

4.3.2.7 Median Peak Ground Velocity

If the building performance model includes fragilities that depend on peak 

floor velocity, the median peak floor velocity, *

i v , is computed at each story 

“i” following the procedures of “Step 5” of FEMA P-58, Volume 1, Section 

5.3.2 to estimate peak floor velocity from peak ground velocity.

Short Cut for Preliminary 

Design

A simplified approach to 

calculating uncorrected story 

drift ratio is provided.
4-14 4: Developing Preliminary and Final Designs FEMA P-58-6

4.3.2.8 Dispersions

Demand dispersions are computed in accordance with the recommendations 

of FEMA P-58, Volume 1, Section 5.3.2.

4.3.3 Demand Estimation for Structures with Supplemental 

Protective Systems

This section describes modification to the approximate procedures in Section 

4.3.2 for structures that incorporate supplemental protective technologies.

4.3.3.1 Seismic Isolation

As a general rule of thumb, the response of an isolated structure can be 

reduced to approximately 20% of the response of fixed base structures

through the combined effects of period lengthening and supplemental 

damping. To explore the potential benefits of seismic isolation in

preliminary design, demand calculations in Section 4.3.2 can be modified 

using the following approximations:

• The period of the structure can be taken as that produced by the isolation 

system, which is typically in the range of 2 < T < 3 seconds.

• Effective viscous damping of 30% can be assumed. This has the effect 

of reducing spectral amplitudes by about 50%.

• Effective response can be reduced by 1/T plus the added effect of 

damping.

• To approximately evaluate the effect of the system, 1/4 of the intensity of 

motion can be used to check performance.

These approximations can be implemented by halving the values of Sa(T), 

PGA, and PGV computed for a fixed-base structure on the site. Demand 

dispersions should be computed as for a fixed-base structure.

4.3.3.2 Damping Systems

As a general rule of thumb, properly designed passive energy dissipation 

systems can reduce the effective response by 50% compared to an undamped

structure. To explore potential benefits of a damping system in preliminary 

design, demand calculations in Section 4.3.2 can be modified using the 

following approximations:

• Effective viscous damping on the order of 30% to 40% can be assumed.

• To approximately evaluate the effect of the system, 1/2 of the intensity of 

motion can be used to check performance.

Short Cut for Preliminary 

Design

Demand estimates for an 

isolated structure are half of 

those for a fixed base 

structure. 

Short Cut for Preliminary 

Design

Demand estimates for a 

damped structure are half of 

those for a fixed base 

structure. 
FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-15

These approximations can be implemented by halving the values of Sa(T), 

PGA, and PGV computed for an undamped structure. Demand dispersions 

should be computed as for an undamped structure.

4.4 Direct Design Procedure for Preliminary Design

The direct design procedure is based on the use of an interactive spreadsheet 

tool, the Performance Estimation Tool (PET), which allows direct 

determination of required stiffness and strength of a structural system that 

will achieve specific performance objectives, for the systems and 

occupancies addressed within the available performance data. Once the 

necessary design strength and story drift are known, the engineer can proceed 

to select structural member sizes that will provide the required level of 

strength and stiffness. The direct design procedure is applicable if the 

building under consideration is:

• One of the following structural systems: Special reinforced concrete 

shear wall (Special RCSW), reinforced concrete special momentresisting frame (RC SMRF), steel special moment-resisting frame (Steel 

SMRF), special steel concentrically-braced frame (Steel SCBF), or steel 

buckling-restrained braced frame (Steel BRBF)

• Office or healthcare occupancy

• Risk Category II or IV

Reasonable approximations can be made to extrapolate results beyond the 

data available within the tool. For example, the performance of masonry 

shear wall structures could be considered similar to the performance of 

concrete shear wall structures for preliminary design purposes. Extrapolation

is discussed in Section 4.4.2.

If the building under consideration is not one of these systems or 

occupancies, and cannot reasonably be extrapolated from similar results 

available within the tool, then the structural system should be selected and 

designed using the general procedure described in Section 4.3.

4.4.1 Performance Estimation Tool

The Performance Estimation Tool (PET) is provided in electronic format in 

FEMA P-58, Volume 3. The tool was developed based on an application of 

the FEMA P-58 methodology to a wide range of archetypical buildings 

conforming to the seismic design requirements of ASCE/SEI 7-10. The tool

returns the performance of simple buildings (with no irregularities in

stiffness, mass, and configuration) based on selected combination of seismic

force-resisting system, occupancy type, Risk Category, building height, and 

Short Cut for Preliminary 

Design

Performance Estimation Tool

(PET) allows direct 

determination of the required 

strength and stiffness of a 

structural system to achieve 

specified performance 

objectives. 
4-16 4: Developing Preliminary and Final Designs FEMA P-58-6

seismic hazard from the available options contained within the database of 

performance assessment results. Results are presented in terms of FEMA 

P-58 performance metrics, including repair cost, repair time, casualties, 

unsafe placard, probability of collapse, probability of reparability, and 

probability of unrepairable permanent drifts for a range of ground motion 

intensities. The tool does not address environmental impacts. If 

environmental impacts are critical to achieving the targeted performance 

objectives, preliminary design should be conducted using the general 

procedure described in Section 4.3.

The Performance Estimation Tool explicitly covers the following five 

structural systems, considering low-, mid- and high-rise buildings in office 

occupancies, and low- and mid-rise buildings in healthcare occupancies:

• Special RCSW

• RC SMRF

• Steel SMRF

• Steel SCBF

• Steel BRBF

The tool addresses the following three seismic hazard levels:

• SDC E and F (SDS = 1.33g, SD1 = 0.75g) 

• SDC D (SDS = 1.00g, SD1 = 0.60g) 

• Low SDC D (SDS = 0.50g, SD1 = 0.35g) 

and provides performance estimates at five levels of shaking intensity, as a 

fraction of Maximum Considered Earthquake (MCE) intensity:

• 20% MCE 

• 40% MCE

• 67% MCE

• 80% MCE

• 100% MCE

Appendix A provides instructions on how to use the Performance Estimation 

Tool (PET) to select from the range of available options, adjust design 

strength and stiffness, and review the resulting performance assessment 

results.
FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-17

4.4.2 Extrapolation

The Performance Estimation Tool directly addresses only the seismic forceresisting systems and occupancies noted above. Although these represent 

only a fraction of all permissible seismic force-resisting systems included in 

ASCE/SEI 7, they cover a wide range of system strengths, stiffnesses, and 

ductilities, and allow for reasonable extrapolations to be made for systems

with similar characteristics.

4.4.2.1 Extrapolation to Other Systems

For preliminary design, it is reasonable to extrapolate results obtained for 

Special RCSW systems to Special Masonry Shear Wall systems and 

Ordinary Reinforced Concrete Shear Wall systems, where the building code 

permits the use of such systems. Similar extrapolation of results for Steel 

SCBF systems to Ordinary Concentrically Braced Frame systems, and for 

Steel SMRF and RC SMRF systems to Intermediate Moment-Resisting

Frame systems are also possible.

4.4.2.2 Extrapolation to Other Occupancies and Uses

The Performance Estimation Tool addresses two occupancies classified as 

Risk Category II, and two occupancies classified as Risk Category IV. Risk 

Category II occupancies include commercial office and medical office 

buildings, and Risk Category IV occupancies include emergency operations

centers and acute-care hospital buildings. In each Risk Category, one 

occupancy represents relatively low building value (i.e., office occupancies),

and one represents relatively high building value (i.e., healthcare 

occupancies). 

For preliminary design, the expected performance of other occupancies can 

be approximated using a building fitting the same combination of Risk 

Category and building value. For example, a laboratory building having a 

high building value, but not containing significant hazardous materials, could 

be classified as Risk Category II, and the measured performance of the

medical office building could be used as a starting point for preliminary 

design of the laboratory building.

4.4.2.3 Extrapolation to Supplemental Protective Systems

As discussed in Section 4.3.3, use of supplemental protective systems, such 

as base isolation or energy dissipation (damping) can reduce the demands on 

the structure by one-half. When base isolation and energy dissipation are 

used together, total demands can be reduced to as little as one-third of 

demands for a fixed-base structure. 
4-18 4: Developing Preliminary and Final Designs FEMA P-58-6

Similarly, results in the Performance Estimation Tool can be extrapolated to 

supplemental protective systems by considering demand intensities that are 

adjusted based on the amount of demand reduction expected to be provided 

by the supplemental protective system that is used.

4.5 Other Factors Affecting Performance

4.5.1 Nonstructural Systems

The engineer generally has limited involvement in the specification of 

nonstructural components and systems during preliminary design. 

Unfortunately, in many projects, the engineer can have limited or no 

involvement in the specification of nonstructural components at any stage of 

design. Damage to nonstructural components and systems, however, can 

dominate measured performance, particularly in moderate levels of shaking. 

The following observations related to specification of nonstructural systems 

were developed based on FEMA P-58, Volume 5 studies:

• Exterior cladding and glazing systems are a major contributor to losses, 

especially in frame systems.

• Flooding due to piping failures is a significant contributor to repair costs

and repair time.

• Ceiling damage is a significant contributor to repair costs, and, to a 

smaller degree, casualties.

• In healthcare occupancies, unanchored medical equipment is a major 

contributor to losses.

• Partitions are a significant contributor to losses.

Explicit coordination between the structural design and specification of 

nonstructural components is necessary to achieve targeted performance 

objectives. For example, in the design and installation of exterior enclosures, 

a specialty engineer is generally responsible to design the cladding system 

based on story drift ratios provided by the building engineer. Often, when 

the building engineer develops a structural design with reduced levels of 

story drift, this is used to allow the design of cladding, stairways, and other 

drift-sensitive components to reduced drift levels, which leaves these 

components vulnerable to damage. Alternatively, consideration should be 

given to selecting enhanced criteria that require minimal earthquake damage 

to cladding and other components, leading to the specification of design drift

capacities for nonstructural components that substantially exceed story drifts

that are expected to occur in the structural system.
FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-19

Use of PACT provides the engineer with deaggregation plots identifying 

component contributions to loss, which assist the engineer in targeting major 

contributors to loss, and adjusting the design to minimize contributions to 

loss. Figures 4-1 and 4-2 show repair cost deaggregation plots associated 

with two reinforced concrete systems: Special RCSW and RC SMRF. 

Figure 4-1 Plot showing structural and nonstructural component 

contributions to median repair costs, for mid-rise, Risk Category 

II, SDC D, Special RCSW system, healthcare occupancy.

Figure 4-2 Plot showing structural and nonstructural component 

contributions to median repair costs, for mid-rise, Risk Category 

II, SDC D, RC SMRF system, healthcare occupancy.
4-20 4: Developing Preliminary and Final Designs FEMA P-58-6

A comparison between the plots at higher intensities shows that:

• In the stiffer shear wall system, losses associated with damage to 

acceleration-sensitive components, including MEP equipment, medical 

equipment, ceilings, and flooding, are proportionally larger.

• In the more flexible moment-resisting frame system, losses associated 

with damage to drift-sensitive components, including the structural frame 

and exterior window systems, are proportionally larger. 

Deaggregation information is also useful for establishing seismic design 

criteria for components that are critical due to high cost of initial investment,

or long lead time for replacement.

4.5.2 Building Configuration

Observations of building performance in past earthquakes have consistently 

shown that building configuration has a significant impact on seismic 

performance. Buildings without significant irregularities in stiffness, mass,

and configuration have exhibited better performance than buildings with 

irregularities. The building code includes provisions that are intended to 

address irregularities, including requirements related to modeling, selection 

of analysis procedures, and required redundancy. The building code

prohibits certain irregularities that are judged to be unacceptable in areas of 

higher seismicity.

Experience strongly suggests that eliminating, or at least minimizing,

irregularities is a more effective solution for buildings with higher 

performance targets. To the extent the building under consideration is 

irregular, performance predicted using the direct design procedure in Section 

4.4 would overestimate the actual performance capability. Evaluation of 

irregularity effects would require a full FEMA P-58 assessment based on 

detailed structural analysis of the building considering the presence of 

irregularities, using the general design procedure in Section 4.3.

4.6 Final Design and Performance Verification

The last step of the performance-based design process involves assessment of 

the performance capability of the final design, using detailed and specific 

information, to ensure that the resulting design meets the targeted

performance objectives.

Final performance verification should be conducted using the performance 

assessment procedures in FEMA P-58, Volume 1. Typically, it will be

necessary to advance the design to at least a Design Development level of 
FEMA P-58-6 4: Developing Preliminary Design and Final Designs 4-21

completion before sufficient information is available to allow a meaningful 

detailed performance evaluation to be conducted. Final performance 

verification should use a building-specific performance model and an 

appropriately detailed structural analysis of the building, as depicted in the 

construction documents.

Building performance can be dominated by the performance of nonstructural 

components and systems. Thus, it is imperative that the engineer work with 

the other design disciplines to ensure that the fragilities used in the building 

performance model are appropriate to the actual nonstructural components 

specified for installation.

It is also essential to confirm that structural and nonstructural components are 

constructed as assumed in the design, and with appropriate levels of quality 

assurance. The engineer should consider extending structural observation 

activities, normally performed on structural components, to the installation of 

nonstructural components and systems that are critical to meeting the 

targeted performance objectives.

FEMA P-58-6 A: Performance Estimation Tool User Manual A-1

Appendix A

Performance Estimation Tool

User Manual

The Performance Estimation Tool (PET) is an interactive spreadsheet 

provided in FEMA P-58, Volume 3, Supporting Electronic Materials and 

Background Documentation. The tool was developed from an application of 

the FEMA P-58 methodology to 1,755 archetypical buildings conforming to 

the seismic design requirements of ASCE/SEI 7-10, Minimum Design Loads 

for Buildings and Other Structures, (ASCE, 2010) for different structure 

types and different occupancies. The tool was originally developed to view 

and analyze data from these assessments, and overall results and conclusions 

from these data are summarized in FEMA P-58, Volume 5.

The Performance Estimation Tool can also be used as a design aid to quickly

determine the level of strength and story drift necessary to achieve specific 

performance objectives for the systems and occupancies represented within 

the database. Once the required shear strength and design story drift are 

known, designers can proceed in selecting member sizes that result in a 

structural system with the necessary strength and stiffness.

A.1 Design Space

The Performance Estimation Tool incorporates the concept of a codeconforming design space that bounds the possible archetype designs and 

represents a reasonable range of lateral strengths and stiffnesses that would 

be expected in typical modern buildings designed in accordance with 

ASCE/SEI 7-10 seismic design requirements. The design space is intended 

to capture the range of structural design choices, from buildings designed to 

code-specified minimum base shear and maximum allowable story drift to 

those designed more conservatively in whole or in part.

Figure A-1 shows a typical design space with 13 points used to characterize 

archetypes with different strength and stiffness combinations. Lateral 

stiffness, in terms of story drift ratio, is presented on the horizontal axis, and 

lateral strength, as a multiple of the minimum design base shear strength, is 

presented on the vertical axis. The four corners of the design space represent 

the limits of the combinations of lateral strength and stiffness considered in 

the study. Point 1 represents a structure with a low design story drift ratio 
A-2 A: Performance Estimation Tool User Manual FEMA P-58-6

and minimum permitted lateral strength. Point 2 represents theoretical codeminimum design, which is a structure having the maximum practical design 

story drift ratio and code-minimum lateral strength. Point 3 represents the 

stiffest, strongest structure considered in the study. Point 4 represents a 

flexible structure having the maximum practical design story drift ratio and a 

high level of lateral strength.

Figure A-1 Typical design space showing 13 points used to characterize the 

different strength and stiffness combinations of each archetype.

Seismic requirements only specify the minimum strength and maximum 

allowable drift boundaries of the design space. The design space boundaries 

vary for each seismic force-resisting system based on the strength and 

stiffness characteristics of typical buildings utilizing these systems. Design 

space boundaries and parameters for representative designs are presented in 

FEMA P-58, Volume 5.

A.2 Usage Notes

The Performance Estimation Tool was created in Microsoft Office 2013 as a 

macro enabled Excel file (.xlsm). The tool uses Excel macros, and macros 

must be enabled for the tool to run. It contains several worksheets, accessed 

as tabs, and labeled as follows:

• Instructions. The Instructions tab summarizes important information 

about the use of the tool.

• User Interface. The User Interface tab is used for selecting input 

parameters and obtaining the results.
FEMA P-58-6 A: Performance Estimation Tool User Manual A-3

• Detailed Plots. The Detailed Plots tab presents additional, more detailed 

information in graphical format for each loss metric shown on the User 

Interface tab.

In each tab, users access all options through of grey-shaded buttons, dropdown menus, and sliders located on the bottom and right side of the design 

space. Information should not be typed into any of the cells, especially the 

selection cells identified with heavy black borders.

A.3 User Interface Tab

Figure A-2 shows the PET User Interface tab. The left side of the tab is the 

user input interface. The user may select any combination of seismic forceresisting system, occupancy type, Risk Category, building height, and 

seismic hazard from the available options. Risk Category II office 

occupancies will allow selection of low-, mid-, and high-rise buildings, but 

healthcare occupancies and Risk Category IV office occupancies are limited 

to low- and mid-rise selections. The available gradient in seismic hazard 

level (i.e., Low SDC D, SDC D and SDC E/F) is representative of the 

Seismic Design Category D-E transition. The figure shows the tool with the 

following selections: special steel moment-resisting frame (“Steel SMRF”), 

“office” occupancy, Risk Category “II”, “mid-rise” building height, and 

“SDC D” hazard level.

Figure A-3 shows the stiffness and strength input interface, including the 

design space graphic, which shows the boundaries of the design space for the 

selected seismic force-resisting system. Each point within the design space 

is characterized by a design story drift ratio and design strength expressed as 

a multiple of minimum base shear. The green dot indicates the location of 

the representative design within the design space. The red dot reflects the 

current selection of stiffness and strength within the design space. The red 

dot can be moved using the sliders located along the bottom and right side of 

the design space, or through selections from dropdown menus associated 

with the buttons for multiple of minimum base shear and design story drift. 

In the figure, input fields indicate the selection of a design story drift ratio of 

0.015 and base shear ratio of 2.5.

Once data have been entered, the User Interface tab provides graphs showing 

estimates of building performance in terms of median, mean, and 90th

percentile repair costs and repair times; probability of collapse; probability of 

reparability; and probability of unrepairable permanent drifts for different 

intensities of ground motion expressed as a percentage of the MCE shaking 

intensity at the building site. A change in any of the input parameters

automatically updates all of the graphs.
FEMA P-58-6 A: Performance Estimation Tool User Manual 

Figure A-2 PET User Interface tab.
FEMA P-58-6 A: Performance Estimation Tool User Manual A-5

Figure A-3 Stiffness and strength input interface and design space graphic 

on the User Interface tab.

Figure A-4 provides an example of one graph showing mean repair cost 

expressed as percentage of replacement cost. In all graphs, a blue shaded 

area indicates the range of performance (ROP) for all buildings within the 

design space. A green line indicates the performance of the representative 

design (RD) for the selected system, and a red line indicates the performance 

of the current search (CS) parameters including the selected values of story 

drift ratio and base shear multiple. Performance values for current search 

(CS) parameters are also tabulated below the graph at each intensity level.

Figure A-4 Graph showing mean repair cost as a percentage of 

replacement cost on the User Interface tab.
A-6 A: Performance Estimation Tool User Manual FEMA P-58-6

A.4 Detailed Plots Tab

The Detailed Plots tab provides all data for the parameters currently selected 

in the User Interface tab in larger scale and with additional detail. The tab 

displays one detailed plot at a time for the selected performance metric. 

Results for different performance metrics can be accessed through grayshaded buttons on the left side of the tab. Figure A-5 provides a detailed plot 

of mean repair cost versus intensity, which is a more detailed version of the 

information shown in Figure A-4. Similar to Figure A-4, the red line shows 

the performance of the current search parameters, and the green line shows 

the performance of a representative building design for the selected system. 

The two blue lines indicate an upper and lower bound characterizing the 

range of performance considering all buildings within the design space. The 

performance of the current search, representative design, and bounds for the 

performance range are also tabulated below the plot.

Figure A-5 Detailed plot of mean repair cost versus intensity.
FEMA P-58-6 References B-1

References

ASCE, 2007, Seismic Rehabilitation of Existing Buildings, ASCE/SEI 41-06, 

Structural Engineering Institute of American Society of Civil Engineers, 

Reston, Virginia.

ASCE, 2010, Minimum Design Loads for Buildings and Other Structures, 

ASCE/SEI 7-10, American Society of Civil Engineers, Reston, Virginia.

ASCE, 2013, Seismic Evaluation and Retrofit of Existing Buildings, 

ASCE/SEI 41-13, Structural Engineering Institute of American Society 

of Civil Engineers, Reston, Virginia.

ASCE, 2017a, Minimum Design Loads and Associated Criteria for Buildings 

and Other Structures, Provisions, ASCE/SEI 7-16, American Society of 

Civil Engineers, Reston, Virginia.

ASCE, 2017b, Seismic Evaluation and Retrofit of Existing Buildings, 

ASCE/SEI 41-17, Structural Engineering Institute of American Society 

of Civil Engineers, Reston, Virginia.

ASTM, 2016a, Standard Guide for Seismic Risk Assessment of Buildings,

ASTM E-2026, ASTM International, West Conshohocken, Pennsylvania.

ASTM, 2016b, Standard Practice for Probable Maximum Loss (PML) 

Evaluations for Earthquake Due-Diligence Assessments, ASTM E-2557, 

ASTM International, West Conshohocken, Pennsylvania.

ATC, 2005, Field Manual: Postearthquake Safety Evaluation of Buildings, 

Second Edition, ATC-20-1, Applied Technology Council, Redwood 

City, California.

FEMA, 1997a, NEHRP Guidelines for the Seismic Rehabilitation of 

Buildings, FEMA 273, prepared by the Applied Technology Council for 

the Building Seismic Safety Council and the Federal Emergency 

Management Agency, Washington, D.C.

FEMA, 1997b, NEHRP Commentary on the Guidelines for the Seismic 

Rehabilitation of Buildings, FEMA 274, prepared by the Applied 

Technology Council for the Building Seismic Safety Council and the 

Federal Emergency Management Agency, Washington, D.C.
B-2 References FEMA P-58-6

FEMA, 2012a, Seismic Performance Assessment of Buildings, Volume 1 –

Methodology, FEMA P-58-1, prepared by the Applied Technology 

Council for the Federal Emergency Management Agency, Washington, 

D.C.

FEMA, 2012b, Seismic Performance Assessment of Buildings, Volume 2 –

Implementation Guide, FEMA P-58-2, prepared by the Applied 

Technology Council for the Federal Emergency Management Agency, 

Washington, D.C.

FEMA, 2012c, Seismic Performance Assessment of Buildings, Volume 3 –

Supporting Electronic Materials and Background Documentation,

FEMA P-58-3, prepared by the Applied Technology Council for the 

Federal Emergency Management Agency, Washington, D.C.

FEMA, 2018a, Seismic Performance Assessment of Buildings, Volume 1 –

Methodology, Second Edition, FEMA P-58-1, prepared by the Applied 

Technology Council for the Federal Emergency Management Agency, 

Washington, D.C.

FEMA, 2018b, Seismic Performance Assessment of Buildings, Volume 2 –

Implementation Guide, Second Edition, FEMA P-58-2, prepared by the 

Applied Technology Council for the Federal Emergency Management 

Agency, Washington, D.C.

FEMA, 2018c, Seismic Performance Assessment of Buildings, Volume 3 –

Supporting Electronic Materials and Background Documentation, Third

Edition, FEMA P-58-3, prepared by the Applied Technology Council for 

the Federal Emergency Management Agency, Washington, D.C.

FEMA, 2018d, Seismic Performance Assessment of Buildings, Volume 4 –

Methodology for Assessing Environmental Impacts, FEMA P-58-4 

prepared by the Applied Technology Council for the Federal Emergency 

Management Agency, Washington, D.C.

FEMA, 2018e, Seismic Performance Assessment of Buildings, Volume 5 –

Expected Seismic Performance of Code-Conforming Buildings, FEMA 

P-58-5, prepared by the Applied Technology Council for the Federal 

Emergency Management Agency, Washington, D.C.

FEMA, 2018f, Guidelines for Performance-Based Seismic Design of 

Buildings, FEMA P-58-6, prepared by the Applied Technology Council 

for the Federal Emergency Management Agency, Washington, D.C.
FEMA P-58-6 References B-3

FEMA, 2018g, Building the Performance You Need, A Guide to State-of-theArt Tools for Seismic Design and Assessment, FEMA P-58-7, prepared 

by the Applied Technology Council for the Federal Emergency 

Management Agency, Washington, D.C.

ICC, 2015a, 2015 International Building Code, International Code Council, 

Whittier, California.

ICC, 2015b, 2015 International Existing Building Code, International Code 

Council, Whittier, California.

LATBSDC, 2017, An Alternative Procedure for Seismic Analysis and Design 

of Tall Buildings Located in the Los Angeles Region, Los Angeles Tall 

Buildings Structural Design Council, June.

PEER, 2017, Tall Buildings Initiative, Guidelines for Performance-Based 

Seismic Design of Tall Buildings, developed by Pacific Earthquake 

Engineering Center, Report No. 2017/06, Version 2.03.l.

FEMA P-58-6 Project Participants C-1 

Project Participants

Federal Emergency Management Agency

Mike Mahoney (Project Officer)

Federal Emergency Management Agency

400 C Street, SW 

Washington, D.C. 20472

Robert D. Hanson (Technical Monitor) 

Federal Emergency Management Agency

5885 Dunabbey Loop 

Dublin, Ohio 43017

Applied Technology Council

Christopher Rojahn 

Applied Technology Council

201 Redwood Shores Parkway, Suite 240 

Redwood City, California 94065 

Jon A. Heintz (Project Executive)

Applied Technology Council

201 Redwood Shores Parkway, Suite 240 

Redwood City, California 94065

Ayse Hortacsu (Project Manager)

Applied Technology Council

201 Redwood Shores Parkway, Suite 240 

Redwood City, California 94065

Project Management Committee

Ronald O. Hamburger (Project Technical Director)

Simpson Gumpertz & Heger, Inc. 

100 Pine Street, Suite 1600 

San Francisco, California 94111 

John Gillengerten

1055 Rivermeade Dr. 

Hebron, Kentucky 41048 

William T. Holmes

Rutherford + Chekene 

375 Beale Street, Suite 310 

San Francisco, California 94105 

John D. Hooper 

Magnusson Klemencic Associates

1301 Fifth Avenue, Suite 3200 

Seattle, Washington 98101 

Stephen A. Mahin (deceased)

University of California, Berkeley

777 Davis Hall 

Berkeley, California 94720 

Jack P. Moehle

University of California, Berkeley

3444 Echo Springs Road 

Lafayette, California 94549 

Khalid Mosalam

University of California, Berkeley

Structural Engineering, Mechanics, and Materials 

Civil and Environmental Engineering 

723 Davis Hall 

Berkeley, California 94720 

Laura Samant

2547 Diamond Street 

San Francisco, California 94131 

Steven R. Winkel 

The Preview Group, Inc. 

2765 Price Street 

Berkeley, California 94705 
C-2 Project Participants FEMA P-58-6

Steering Committee

William T. Holmes (Chair)

Rutherford + Chekene

375 Beale Street, Suite 310

San Francisco, California 94105

Lucy Arendt

St. Norbert College

100 Grant Street, Cofrin Hall, 310

De Pere, Wisconsin 54115

Deborah Beck

Beck Creative Strategies LLC

531 Main Street, Suite 313

New York, New York 10044

Christopher Deneff

FM Global

270 Central Avenue

Johnston, Rhode Island 02919

H. John Price

9839 Caminito Rogelio

San Diego, California 92131

Jonathan C. Siu

City of Seattle, Dept. of Planning and 

Development

P.O. Box 34019

Seattle, Washington 98124

Jeffrey Soulages

Intel Corporation

2501 NW 229th Street, MS: RA1-220

Hillsboro, Oregon 97124

Eric von Berg

Newmark Realty Capital, Inc.

595 Market Street, Suite 2550

San Francisco, California 94105

Williston Warren (ATC Board Contact)

SESOL Inc. 

1918 Santiago Drive, Suite A

Newport Beach, California 92660

Stakeholder Products Team

Laura Samant (Team Leader)

2547 Diamond Street

San Francisco, California 94131

David Mar

Mar Structural Design

2629 Seventh Street, Suite C

Berkeley, California 94710

Lori Peek

University of Colorado 

Natural Hazards Center

Institute of Behavioral Sciences Building

1440 15th Street

Boulder, Colorado 80302

Maryann T. Phipps

Estructure

1144 65th Street

Oakland, California 94608

Sharyl Rabinovici

1702 Le Roy Avenue

Berkeley, California 94709

L. Thomas Tobin

Tobin & Associates

444 Miller Avenue

Mill Valley, California 94941

Performance Products Team

John Gillengerten (Team Leader)

1055 Rivermeade Drive

Hebron, Kentucky 41048

David R. Bonneville

Degenkolb Engineers

375 Beale St., Suite 500

San Francisco, California 94105
FEMA P-58-6 Project Participants C-3

Dominic Campi

Rutherford + Chekene

375 Beale Street, Suite 310

San Francisco, California 94105

Vesna Terzic

California State University, Long Beach

Department of Civil Engineering & Construction 

Engineering Management

Long Beach, California 90815

Products Update Team

John D. Hooper (Team Leader)

Magnusson Klemencic Associates

1301 Fifth Avenue, Suite 3200

Seattle, Washington 98101

Russell Larsen

Magnusson Klemencic Associates

1301 Fifth Avenue, Suite 3200

Seattle, Washington 98101

Peter Morris

AECOM

2020 L Street

Sacramento, California 95811

Stakeholder Products Consultants

Sandra L. Grabowski

Adler Enterprises LLC

4600 Miller Street

Wheat Ridge, Colorado 80033

Taline Mitten 

Mar Structural Design

2629 Seventh Street Suite C

Berkeley, California 94710

Stacia Sydoriak

2049 Bronson St

Fort Collins, Colorado 80526

Jennifer Tobin-Gurley

University of Colorado 

Natural Hazards Center

Institute of Behavioral Sciences Building

1440 15th Street

Boulder, Colorado 80302

Performance Products Consultants

Shreyash Chokshi

California State University, Long Beach

1250 Bellflower Blvd, VEC-129

Long Beach, California 90840

Travis Chrupalo

Degenkolb Engineers

375 Beale St., Suite 500

San Francisco, California 94105

Erica Hays

Degenkolb Engineers

375 Beale St., Suite 500

San Francisco, California 94105

Nirmal Kumawat

California State University, Long Beach

1250 Bellflower Blvd, VEC-129

Long Beach, California 90840

Abe Lynn

Degenkolb Engineers

375 Beale St., Suite 500

San Francisco, California 94105

Daniel Saldana

California State University, Long Beach

1250 Bellflower Blvd, VEC-129

Long Beach, California 90840

Vinit M. Shah

California State University, Long Beach

1250 Bellflower Blvd, VEC-129

Long Beach, California 90840

Udit S. Tambe

California State University, Long Beach

1250 Bellflower Blvd, VEC-129

Long Beach, California 90840
C-4 Project Participants FEMA P-58-6

Duy Vu To

15662 Jefferson Street

Midway City, California 92655

Peny Villanueva

California State University, Long Beach

1250 Bellflower Blvd, VEC-129

Long Beach, California 90840

Products Update Consultants

Robert Bachman

R.E. Bachman Consulting Structural Engineers

25152 La Estrada Dr. 

Laguna Niguel, California 92677

Jack Baker

Haselton Baker Risk Group, LLC

728 Cherry Street, Suite C

Chico, California 95928

Dustin Cook

Haselton Baker Risk Group, LLC

728 Cherry Street, Suite C

Chico, California 95928

Scott Hagie

John A. Martin and Associates, Inc.

950 S. Grand Ave. 4th Floor

Los Angeles, California 90015

Angie Harris

19413 Broadacres Ave.

Carson, California 90746

Curt Haselton

Haselton Baker Risk Group, LLC

728 Cherry Street, Suite C

Chico, California 95928

Wyatt Henderson

Magnusson Klemencic Associates

1301 Fifth Avenue, Suite 3200

Seattle, Washington 98101

Monica Huang

Carbon Leadership Forum

Center for Integrated Design

1501 East Madison St. Suite 200

Seattle, Washington 98122

Gilberto Mosqueda

University of California, San Diego

Department of Structural Engineering

9500 Gilman Dr. #8085

La Jolla, California 92093

Farzad Naeim

Farzad Naeim, Inc.

100 Spectrum Center Drive, Suite 900

Irvine, California 92618

Barbara Rodriguez

Carbon Leadership Forum

Center for Integrated Design

1501 East Madison St. Suite 200

Seattle, Washington 98122

Kathrina Simonen

Carbon Leadership Forum

Center for Integrated Design

1501 East Madison St. Suite 200

Seattle, Washington 98122

Siavash Soroushian 

K.N. Toosi University of Technology

Department of Civil and Environmental 

Engineering

Tehran, Iran

Katie Wade

Haselton Baker Risk Group, LLC

728 Cherry Street, Suite C

Chico, California 95928

Farzin Zareian

University of California, Irvine

Department of Civil and Environmental 

Engineering

Irvine, California 92697

FEMA P-58-6 

Catalog No. 1894-9