Item d. is intended to serve as a generalized “grandfather” clause. It is not the intent of the
Standards to rewrite agency procedures but to set common minimum standards for use by all
Federal agencies. Once the Standards are formally adopted for Federal use, each agency should
be able to demonstrate that its existing programs meet or exceed the Standards, which should be
considered a minimum acceptable level of seismic safety for Federal buildings.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards -13- January 18, 2002


Item a. is based upon the recommendation by the ICSSC to exempt Federal buildings in regions
of low seismicity. Agencies may, at their discretion, choose to apply higher performance levels
to buildings located in areas where Sps<0.167 g and Sp;<0.067 g to meet mission requirements.
Item b, c, and d are based directly on the extent of application of FEMA 310. FEMA 310 does
not automatically exempt any class of buildings, however, based on the exemptions contained in
codes for new buildings, agencies may elect to exempt these classes of construction. Items e, g,
h, and i have been retained from RP 4.

1.3.1 Benchmark Buildings

A benchmark building is one that was designed and built in accordance with adequate seismic
provisions, which are considered to provide acceptable life-safety protection. The determination
of benchmark years is complex and varies with building location, age, structural system, and
governing building code. A table of benchmark years is provided in Table 1-1. Note that if the
seismicity of a region has changed since the benchmark dates listed in Table 1-1, a building must
have been designed and constructed or evaluated in accordance with the current seismicity of the
region to be compliant with the Standards. Only buildings designed and constructed in
accordance with the documents listed in Table 1-1 and being evaluated to the Life-Safety
Performance Level may be considered Benchmark Buildings.

Table 1-1: Benchmark Buildings

Model Building Seismic Design

Provisions

Building TypeTM BOCA | SBCCI_[ UBC | NEHRP
Wood Frame, Wood Shear Panels (Type W1 & W2) 1993 1994 1976 1985
Wood Frame, Wood Shear Panels (Type W1A) 1993 1994 1976 1985
Steel Moment Resisting Frame (Type S1 & S1A) * * 1994 |
Steel Braced Frame (Type S2 & S2A) 1993 1994 1988° | 1991
Light Metal Frame (Type S3) * * * *
Steel Frame w/ Concrete Shear Walls (Type S4) 1993 1994 1976 1985
aes Concrete Moment Resisting Frame (Type 1993 1904 1976 | 1985
Reinforced Concrete Shear Walls (Type C2 & C2A) | 1993 1994 1976 | 1985
Steel Frame with URM Infill (Type $5, S5A) * il * *
Concrete Frame with URM Infill (Type C3 & C3A) * * *
Tilt-up Concrete (Type PC] & PC1A) * * *
Precast Concrete Frame (Type PC2 & PC2A) * * *
Reinforced Masonry (Type RM 1) * 1997 *
Reinforced Masonry (Type RM 2) 1994 1976 1985
Unreinforced Masonry (Type URM)* * 1991" | *

* * *

Unreinforced Masonry (Type URMA) *

‘Building Type refers to one of the Common Building Types defined in FEMA 310, Table 2-2
(p. 2-6 through 2-10).

“Buildings on hillside sites shall not be considered Benchmark Buildings.

3Flat Slab Moment Resisting Frame Buildings shall not be considered Benchmark Buildings.
“Steel Moment-Resisting Frame Connections shall comply with the 1994 UBC Emergency
Provisions, the 1997 UBC, the 1997 AISC Seismic Provisions, the 2000 IBC or FEMA 350; or
the analytical evaluation provisions of FEMA 351.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards -7- January 18, 2002


b. The rehabilitation measures shall not create a new structural irregularity or make an
existing structural irregularity more severe; and

c. All new or rehabilitated structural components and elements shall be detailed and
connected to the existing structure in compliance with the requirements of FEMA
356.

C4.3__Incremental/Partial Rehabilitation

For a variety of reasons, it may be necessary to complete a rehabilitation project in several
phases. This practice is acceptable as long as rehabilitation measures do not reduce the
performance level of the existing structure at any time, except during actual rehabilitation
construction. The requirement demands careful consideration of the performance of the structure
after each increment of rehabilitation in accordance with FEMA 356.

4.4 Local Modification of Components

Local modification of deficient components shall be permitted as an applicable rehabilitation
measure as long as the resultant rehabilitation conforms to FEMA 356.

C4.4 Local Modification of Components

Some existing buildings have substantial strength and stiffness, but some of their components
may not have adequate strength, toughness, or deformation capacity to satisfy the rehabilitation
objectives. An appropriate rehabilitation measure for such structures may be to perform local
modifications of components that are inadequate while retaining the basic configuration of the
building’s lateral-force resisting-system provided that the rehabilitation measures conform to
FEMA 356.

4.5 Removal or Lessening of Existing Irregularities

Removal or lessening of existing irregularities shall be permitted as an applicable rehabilitation
measure, provided the completed rehabilitation conforms to FEMA 356.

C4.5 Removal or Lessening of Existing Irregularities

Removal or lessening of existing irregularities may be an effective rehabilitation measure if a
seismic evaluation shows that the irregularities result in the inability of the building to meet the
performance objective but that their removal would achieve it.

4.6 Innovative Mitigation Methods

Innovative mitigation methods that are beyond the scope of the requirements of FEMA 356 shall
be permitted, provided an analytical procedure acceptable to the agency shows that the required
performance level is attained. When new and innovative rehabilitation techniques are proposed
for a specific building, a peer review panel, acceptable to the agency, shall determine the
adequacy of the mitigation techniques proposed by the engineer (see Section 2.3).

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -17- January 18, 2002



PREFACE

In response to Public Law 101-614, the Standards of Seismic Safety for Existing Federally
Owned or Leased Buildings and Commentary (RP 4) was issued by the Interagency Committee
on Seismic Safety in Construction (ICSSC) in 1994. Pursuant to Executive Order 12941, the
Standards are periodically updated to incorporate advanced knowledge in earthquake
engineering gained from research and from observed performance of structures in recent
earthquakes. This document, Standards of Seismic Safety for Federally Owned and Leased
Buildings (RP 6), is the revision to the Standards of Seismic Safety for Owned or Leased
Buildings and Commentary (RP 4).

The intent of the Standards is to identify common minimum evaluation and mitigation measures
for all Federal departments and agencies, and to ensure that all federal entities have a balanced,
agency-conceived and controlled seismic safety program for their existing owned or leased
buildings.

Since the issuance of RP 4, the Federal Emergency Management Agency (FEMA) has published
a number of documents related to evaluation and rehabilitation of existing buildings. The
Handbook for the Seismic Evaluation of Buildings — A Prestandard (FEMA 310), supersedes the
NEHRP Handbook for the Seismic Evaluation of Existing Buildings (FEMA 178). The
Prestandard and Commentary for the Seismic Rehabilitation of Buildings (FEMA 356) now
provides guidance for seismic rehabilitation of buildings. Under the auspices of FEMA,
standards for seismic evaluation and rehabilitation are being developed by the American Society
of Civil Engineers (ASCE) based on FEMA 310 and FEMA 356. These documents are
referenced and cited throughout the standards (RP 6) and as they become available, they will be
incorporated into RP 6.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards - iii - January 18, 2002


3.0 EVALUATION

The purpose of the evaluation described in this section is to determine whether buildings meet
the Life-Safety or Immediate Occupancy performance levels as required to meet agency mission.
FEMA 310 provides a seismic evaluation process for existing buildings in any region of
seismicity to either the Life-Safety or Immediate Occupancy levels. The flowchart shown in
Figure 3-1 provides an overview of the evaluation process, but does not include further
evaluation steps that may be required based on irregularities or height limits for model building
types. Note also that an agency may determine, through a risk assessment, that the level of risk
is sufficiently low that mitigation is not required.

Understand the Evaluation Process
General Provisions]
¥

1) Collect Data and Visit Site
2) Determine Region of Seismicity
3) Determine Level of Performance

Evaluation Requirements

Benchmark Building? OR
1) Complete the Structural Checklists). QUICK

2) Complete the Foundation Checklist CHECKS
3) Complete the Nonstructural Checklist).

‘Tier 1: Screening Phase|

* Deficiencies? > Further a
Eval?

FULL BUILDING or DEFICIENCY-ONLY EVALUATION
EVALUATE Building using one of the
following procedures:

1) Linear Statie Procedure

2) Linear Dynamic Procedure

3) Special Procedure

‘Tier 2; Evaluation Phase

* Deficiencies? Further a

‘Comprehensive Investigation
(Nonlinear Analysis)
Tier 3:

tailed Evaluation Phase

Deficiencies?

Final Evaluation and Report

Figure 3-1: Schematic of Evaluation Process.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards -14- January 18, 2002


, 2000, Towards Earthquake Resistant Federal Buildings — A Report to the Congress, FEMA-
360, prepared by Degenkolb Engineers and U.S. Army Civil Engineering Research Laboratory
for FEMA, Washington, DC 20472 (under review)

Interagency Committee on Seismic Safety in Construction, Interagency Committee on Seismic
Safety in Construction, 1992. Guidelines and Procedures for Implementation of the Executive
Order on Seismic Safety of New Building Construction, RP-2.1-A, NISTIR 4852, National
Institute of Standards and Technology, Gaithersburg, MD 20899

, 1994. Standards of Seismic Safety for Existing Federally Owned or Leased Buildings and
Commentary, RP-4, NISTIR 5382, National Institute of Standards and Technology,
Gaithersburg, MD 20899
International Code Council, 2000, International Building Code, Falls Church, Virginia

International Conference of Building Officials, 1994, Uniform Code for Building Conservation,
Whittier, California

, 1997, Uniform Building Code, Whittier, California

Southern Building Code Congress International, Standard Building Code, 1999, Birmingham,
Alabama

Building Officials and Code Administrators International, National Building Code, 1999,
Country Club Hills, Mlinois

ABK, 1984, Methodology for Mitigation of Seismic Hazards in Existing Unreinforced Masonry
Buildings, (Topical Report 08), ABK joint venture, El Segundo, California

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards - 20- January 18, 2002


4.0 MITIGATION

4.1 Requirements

Rehabilitation of buildings shall be performed in accordance with FEMA 356 or other methods
that are consistent with and achieve a Performance Level that is equivalent to those prescribed in

the Standards. Alternatives to rehabilitation include, but are not limited to the following:

a. removal of the building from an agency inventory by termination of lease
agreement, sale with full disclosure, or demolition.

b. permanent evacuation of the building, or

c change in occupancy of the building such that it becomes exempt in accordance
with Section 1.3.

C4.1 Requirements

The Standards require reducing the risk to life loss in all federally owned and leased buildings
and in private buildings on Federal land in the largest expected earthquake and acceptable
performance of buildings requiring immediate occupancy as specified by each agency.
Mitigation measures may or may not include rehabilitation of the building itself. In some cases,
the nature or extent of necessary rehabilitation can be so extensive that abandonment and
relocation is a cost effective alternative.

4.2___ Minimum Standards and Scope for Rehabilitation

If shown by evaluation that the desired performance level is not satisfied, the rehabilitation of
any building or site to attain the Life-Safety level and/or the Immediate Occupancy level shall
satisfy substantially the requirements of FEMA 356.

C4.2__ Minimum Standards and Scope for Rehabilitation

Since FEMA 310 is not a design standard, rehabilitation work must comply with FEMA 356 or
agency standards if their requirements are more stringent than FEMA 356.

4.3 Incremental/Partial Rehabilitation

Risk-reduction by incremental or partial rehabilitation of a building is acceptable as an interim
step in a complete seismic mitigation process. It shall be permitted only if the partial
rehabilitation is designed and constructed in accordance with FEMA 356 and takes into account
future completion of the rehabilitation objective. In addition, such partial rehabilitation shall
comply with the following conditions:

a. The rehabilitation measures shall not result in a reduction in the performance level of
the existing building;

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards -16- January 18, 2002


(2) structural system, (3) number of occupants, (4) date of construction, (5) number of stories, (6)
occupancy type, (7) size (area), (8) structural irregularities, (9) unusual building geometry or
characteristics, and (10) importance of building to agency mission.

A building presenting an “exceptionally high risk” may be discovered at any time, either in a
systematic evaluation process, or by review of the building for other purposes. A plan to reduce
such high risks should be developed immediately. One or more of the mitigation measures listed
in Section 4.1 should be considered.

Item e. is intended to prevent unsafe buildings from being permanently added to the Federal
inventory, by triggering a seismic evaluation and if necessary, mitigation, when they are
acquired. It is not intended to apply to buildings temporarily under Federal ownership, such as
those in the assets of failed banks placed under Federal guardianship. Newly leased buildings
are covered in Section 1.3.2.

2.2 Compliance
A building is considered to be in compliance with the Standards if the building is:

a, exempt from the Standards in accordance with Section 1.3,

b. determined by evaluation to be in compliance with the Standards in accordance with Section
3.0, or

c. unacceptable seismic risks have been mitigated in accordance with Section 4.0.

Compliance with the Standards should result in a minimum performance level of Life-Safety.
The Standards also provide for the evaluation of buildings and mitigation of seismic risks to
meet the higher performance level of Immediate Occupancy where this level of performance is
required to meet the agency’s mission.

2.3 Qualifications of Evaluators, Designers, and Reviewers

In general, all evaluation, development of mitigation approaches, and design of rehabilitation
work shall be prepared by a registered professional engineer with experience in the type of work
being considered. For independent peer reviews of alternative or innovative evaluation methods,
analysis techniques or rehabilitation concepts required by the Standards, an individual highly
qualified in the field of earthquake engineering or a panel of such individuals should be selected
by the agency. Tier 2 and Tier 3 evaluations in accordance with FEMA 310 of potential
foundation deficiencies, and geologic site hazards should be conducted by a geotechnical
engineer or engineering geologist qualified to perform the work by registration and/or
experience.

C2.3 Qualifications of Evaluators, Designers, and Reviewers

Registered engineers should be used to evaluate seismic risks for each of the four compliance
categories for a specific building and to plan rehabilitation schemes necessary for mitigation.
The experience and qualifications of the individuals should match the scope and complexity of

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -ll- January 18, 2002



either partial or total structural collapse remains. Injuries may occur, but the level of risk for
life-threatening injury and entrapment is low. People will likely be unable to reoccupy the
building for continuous use until structural repairs are completed.

Immediate Occupancy Level: Building performance that includes very limited damage to both
structural and nonstructural components during the design earthquake. The basic vertical and
lateral-force-resisting systems retain nearly all of their pre-earthquake strength and stiffness.
The level of risk for life-threatening injury as a result of damage is very low. Although some
minor repairs may be necessary, the building can be fully occupied after a design earthquake,
and the needed repairs may be completed while the building is occupied.

In addition to these performance levels, FEMA 356 defines the Damage Control Structural
Performance Range as the continuous range of damage states between the Life Safety Structural
Performance Level and the Immediate Occupancy Structural Performance Level. Design for
performance within the Damage Control Structural Performance Range may be desirable to
minimize repair time and operation interruption, to protect valuable equipment or contents, or to
preserve important historic features when the cost of design for Immediate Occupancy is
excessive.

1.1.2 Additional Objectives

Federal agencies may pursue more stringent standards than Life-Safety for those buildings where
a higher performance level is necessary to control damage or maintain post-earthquake operation
for mission readiness. The Standards provide for evaluation and mitigation of seismic risks in
Federal buildings to a performance level of Immediate Occupancy where this higher level of
performance is needed. Buildings that must remain fully functional during an earthquake and.
afterwards (Operational Level) are beyond the scope of the Standards and must be evaluated
using appropriate, agency specific criteria.

C1.1.2 Additional Objectives

Some Federal agencies own or lease buildings that house facilities that are considered essential
or mission critical and should be evaluated to the Immediate Occupancy performance level. The
definition of what is “essential” or “mission critical” needs to be determined by each individual
agency. As a guide, Section 1.3.1 of the 2000 Edition, NEHRP Recommended Provisions for
Seismic Regulations for New Buildings and Other Structures (FEMA 368) defines the following
buildings as essential facilities:

Fire or rescue and police stations,

Hospitals,

Designated medical facilities having emergency treatment facilities,

Designated emergency preparedness centers

Designated emergency operation centers

Designated emergency shelters

Power generating stations or other utilities required as emergency back-up facilities for
Seismic Use Group III (essential facilities)

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -3- January 18, 2002



TABLE OF CONTENTS

ACKNOWLEDGMENTS.
PREFACE..
ABSTRACT
TABLE OF CONTENTS
STANDARDS.......0....
1.0 INTRODUCTION.
1.1 Objectives...

1.1.1 Seismic Rehabilitation Objective:

1.1.2 Additional Objectives.

1.2 Scope — Compliance Categories

1.2.1 Items Not Included in the Standard.

1.3. Scope — Buildings.

1.3.1 Benchmark Buildings.

1.3.2 Leased Buildings

1.3.3 Privately-Owned Buildings on Federal Land.

2.0 APPLICATION OF THE STANDARDS.....
2.1 Situations Requiring Evaluation and Mitigatio

2.2 Compliance... ccc

2.3 Qualifications of Evaluators, Designers, and Reviewer:

2.4 Additional Requirements.

3.0 EVALUATION
3.1 Evaluation Requirements

4.0 MITIGATION
4.1 Requirement:

4.2. Minimum Standards and Scope for Rehabilitation .

4.3 Incremental/Partial Rehabilitation...

4.4 Local Modification of Components

4.5 Removal or Lessening of Existing Irregularities.

4.6 Innovative Mitigation Methods.

4.7 Historic Buildings
REFERENCES .......scssessesssssessssssssssscsscsscsessesseesessesssssssussussussecsesseeseessssessssussusssssesscsesseeaseessneeasensaes

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -V- January 18, 2002



ABSTRACT

The seismic safety evaluation and mitigation standards, Standards of Seismic Safety for Existing
Federally Owned and Leased Buildings, were developed for use by the Federal Government by
the Interagency Committee on Seismic Safety in Construction (ICSSC) in conjunction with the
National Institute of Standards and Technology (NIST) and with the funding support of several
ICSSC member agencies. The intent of this document is to provide Federal agencies with
minimum (Life-Safety) and extended (Immediate Occupancy) standards for the evaluation and
mitigation of seismic risks in their building inventories. This document responds to Executive
Order 12941 Sec. 4, which directs the ICSSC to “...update the Standards at least every 5 years,”
and to “...update the Standards within 2 years of the publication of the First Edition of FEMA’s
Guidelines for Seismic Rehabilitation of Buildings and Commentary” (FEMA 273).

Life-Safety is the minimum acceptable performance objective for Federal buildings. This
document further provides for an extended level of performance, Immediate Occupancy, where
required to meet agency mission. FEMA 310, Handbook for the Seismic Evaluation of Buildings
—A Prestandard, and FEMA 356, Prestandard and Commentary for the Seismic Rehabilitation
of Buildings, provide the basis for defining these performance objectives, evaluation, and if
necessary, mitigation criteria.

The Standards and Commentary include: an identification of situations that trigger application

of the Standards, preliminary and detailed evaluation procedures, and mitigation requirements
for the two performance levels, Life-Safety and Immediate Occupancy.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards -iv- January 18, 2002


the assignment. Registration as a Professional Engineer is intended to ensure that an individual
possesses at least a familiarity with design and analysis of buildings for lateral loads. In
addition, training and experience in seismic investigations should be required.

Those with a minimum amount of such background experience may be qualified for relatively
small and simple buildings. Highly qualified individuals may be required for complex buildings
or for peer review. Such persons will likely have academic credentials far beyond the bachelor
level with courses in structural dynamics, inelastic analysis, and other topics in advanced
earthquake engineering. They may have published technical articles on seismic issues of
existing structures or be active in related professional organizations. Their project experience
should relate specifically to seismic investigations of structures. They should be capable of
providing personal references attesting to their successful completion of projects similar to that
contemplated by the agency.

A specialist in geology or geotechnical engineering should be used for evaluation of foundation
deficiencies and geologic site hazards.

2.4 Additional Requirements

As part of each agency’s seismic safety responsibilities for existing buildings, the following
measures shall be implemented as appropriate:

a. development of standards for seismic performance levels higher than Life-Safety and
Immediate Occupancy if necessary to carry out agency mission,

b. development and dissemination of agency-specific policies consistent with all provisions of
the Standards,

c. assurance that consistent measures of quality control are included in such policies and
applied to all phases of evaluation, design, and construction, in a manner consistent with
FEMA 310 and FEMA 356, and

d. assurance that agency-specific standards and procedures for evaluation and mitigation of
hazards are substantially equivalent to or more stringent than FEMA 310 and FEMA 356 or
successor documents adopted by the ICSSC.

C2.4 Additional Requirements

Item c., quality control, cannot be overlooked in a seismic hazard mitigation project. All phases
of a project, including evaluation, design, and construction, must be monitored and evaluated to
be successful. Guidance from documents like the Standards, FEMA 310, and FEMA 356/357 is
needed in order to consistently identify and improve seismically hazardous buildings. However,
earthquake engineering is not an exact science. Codes are constantly developing in an attempt to
incorporate new research results and to balance safety, building performance, and cost.
Considerable engineering judgement is required to properly apply the provision of the Standards
to existing buildings. Reviews of evaluations for consistency, of construction documents for
adequacy, and of construction itself for compliance with drawings and construction standards are
all essential to maximize effectiveness of the project.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards -12- January 18, 2002


Class B (FEMA 302), with a 2 % exceedance probability in 50 years (return period of about
2500 years). Prior to the 1997 NEHRP Recommended Provisions, ground shaking intensity was
characterized by effective peak response acceleration, A,, and effective peak velocity-related
response acceleration, Ay. These values were derived from maps developed by Algermissen and
Perkins for shaking with a 10 % exceedance probability in 50 years (return period of about 500
years) on rock sites.

In 1997, FEMA 273, NEHRP Guidelines for the Seismic Rehabilitation of Buildings and FEMA
274, NEHRP Commentary on the Guidelines for the Seismic Rehabilitation of Buildings were
published. A prestandard based upon these documents was issued in November 2000 as
Prestandard and Commentary for the Seismic Rehabilitation of Buildings (FEMA 356) and is
accompanied by a resource document entitled, Global Topics Report on the Prestandard and
Commentary for the Seismic Rehabilitation of Buildings (FEMA 357). FEMA 310, Handbook for
the Seismic Evaluation of Buildings, A Prestandard, was published in 1998. (It will soon be
published by the American Society of Civil Engineers as the ASCE 31 standard.) While FEMA
178 dealt only with the life-safety risk, FEMA 310 and FEMA 356 include procedures for
evaluation and rehabilitation of buildings for Life-Safety and Immediate Occupancy performance
levels.

1.1 Objectives

The primary objective of the Standards is to reduce the life-safety risk to occupants of Federal
buildings and to the public. Life-Safety is the minimum performance level appropriate for
Federal buildings. In addition, the Standards provide for a higher level of performance,
commonly referred to as Immediate Occupancy, when needed to meet agency mission
requirements. Both levels of performance are defined in Section 1.1.1 below.

Cl.1 Objectives:

RP 4 established Substantial Life-Safety as the minimum performance level for Federally owned
and leased buildings. Executive Order 12941 directed Federal agencies to adopt RP 4 for use in
assessing the seismic safety of their owned and leased buildings and in mitigating seismic risks
in those buildings. Recent earthquakes have clearly identified the importance of immediate use
of critical facilities after an earthquake. Recognizing this need, FEMA 310 provides for
evaluation to a higher level of performance, Immediate Occupancy, in addition to Life-Safety.

The Standards are not intended for use in judging the adequacy of past good-faith agency efforts
at evaluation and mitigation; they are intended to establish appropriate minimums for actions
taken after the Standards are formally adopted by the ICSSC.

1.1.1 Seismic Rehabilitation Objectives

FEMA 310 defines the Life-Safety and Immediate Occupancy Performance Levels as follows:

Life-Safety Level: Building performance that includes significant damage to both structural and
nonstructural components during the design earthquake, though at least some margin against

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -2- January 18, 2002



C4.6__Innovative Mitigation Methods

New materials and structural systems, or other non-complying techniques are generally allowed
by building codes subject to some form of review and approval. Generally, the alternative
methods must conform to the intent of the prevailing standard. This allowance is particularly
important for the seismic rehabilitation of existing buildings due to large numbers of special
conditions that inevitably arise. Many private and public institutions have established
procedures for peer review. Some have standing panels; others hire reviewers specifically for
projects when the need arises. Agencies should establish policies to ensure the independence
and qualifications of the reviewers. The policy should also cover the general procedures to be
followed by the engineer and the reviewers.

47 Historic Buildings

Historic buildings shall not be exempted from the Standards, and depending upon their use may
be required to meet the same performance objectives as all other buildings in the Federal
inventory. Many codes covering historic buildings allow some flexibility in required
performance depending on the effect of rehabilitation on important historic features. In some
cases, it may be appropriate to rehabilitate an historic building to the Damage Control Structural
Performance Range per FEMA 356 to ensure that the architectural fabric survives certain
earthquakes.

In preserving the historic fabric of these buildings, publications such as the Secretary of the
Interior’s Standards for Rehabilitation and Guidelines for Rehabilitating Historic Buildings and
Standards for the Treatment of Historic Properties shall be used. Alternative methods of
mitigation of seismic risks for historic buildings shall be permitted subject to the requirements of
Section 4.6.

C4.7__ Historic Buildings

The rehabilitation of historic buildings is a sensitive process. The design professionals must take
care to protect the historical character and fabric of the building as much as possible. This
reduces the flexibility and freedom to make alterations to the structure. In the development of
mitigation strategies, consideration must be given to the architectural and historic value of the
building. Many codes covering historic buildings allow some amount of flexibility in required
performance, depending upon the effect of rehabilitation on important historic features. Modern
building standards, including FEMA 356, do not specifically cover the use of all archaic
materials and systems. The intent of the Standards is to provide essentially the same level of
seismic performance objectives as for others without unreasonable impediment to the historic
preservation process. Consequently, alternative mitigation methods (see Section 4.6) are allowed
and encouraged when they can lessen the impact of the structural strengthening.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -18- January 18, 2002



Standards of Seismic Safety for Existing
Federally Owned and Leased Buildings

Stephen A. Cauffman
H. S. Lew
Editors

U.S. DEPARTMENT OF COMMERCE
Technology Administration
Structures Division
Building & Fire Research Laboratory
National Institute of Standards

and Technology
Gaithersburg, MD 20899

NIST

National Institute of Standards
and Technology

Technology Administration

U.S. Department of Commerce


These maps should be used by agencies along with site-specific studies (where appropriate) to
establish the seismicity of a site.

1.2.1 Items Not Included in the Standards

The Standards do not include means to evaluate or mitigate the effects of:

- flooding,

- fire,

- wind,

- blast, or

- volcanic activity.

The Standards also do not address criteria for:
- repair of damaged or deteriorated buildings, including damage caused by previous
earthquakes,
- preparation of post-earthquake preparedness plans, or
- seismic instrumentation of Federal buildings.

C1.2.1 Items Not Included in the Standards

Although there are obvious interactions between seismic hazards and other natural or manmade
threats to buildings, a multi-hazard approach is beyond the scope of this document. However,
before mitigation measures are taken for seismic deficiencies, it is strongly suggested that other
potential hazards, particularly wind and blast, be considered. It is beyond the scope of these
Standards to address evaluation and mitigation criteria for damaged or deteriorated buildings,
including those buildings damaged by earthquakes. However, any agency conducting an
evaluation of a building damaged by any cause must investigate the condition of both the vertical
and lateral-force-resisting elements to ensure that these elements can perform dependably during
an earthquake.

Seismic instrumentation of Federal buildings is not addressed by the Standards. Agencies should
be encouraged to instrument a sample number of Federal buildings to record their responses
during seismic events in order to validate and/or improve their expected performance.

1.3 Scope — Buildings

Except for buildings that require a seismic performance level beyond Life-Safety or Immediate
Occupancy because of agency mission requirements, the following buildings are exempt from
the Standards:

a. all buildings located in regions of low seismicity where Sps<0.167 g, and
Sp1<0.067 g (unless designated by agency as a critical facility),
b. detached one- and two-family dwellings located where Sps<0.4 g,

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -5- January 18, 2002



Emergency vehicle garages and emergency aircraft hangars
Designated communication centers

Aviation control towers and air traffic control centers

Structures containing sufficient quantities of toxic or explosive substances deemed to be
hazardous to the public

e Water treatment facilities required to maintain water pressure for fire suppression

The Standards provide tools for evaluating buildings to the Immediate Occupancy performance
level. Agencies may, at their discretion, designate buildings other than those listed above to have
a performance level of Immediate Occupancy. Levels of performance higher than Immediate
Occupancy require consideration of all critical building systems and the availability of utilities.
Such consideration is beyond the scope of the Standards.

1.2____ Scope ~ Compliance Categories

The Standards address the potential vulnerability of Federal buildings to all significant seismic
risks, which are grouped into four compliance categories:

- Structural,

- Nonstructural,

- Foundation,

- Geologic Site, and
- Adjacency.

The basis for evaluation of buildings within the United States (the fifty states and territories)
shall be the Maximum Considered Earthquake (MCE) shaking values obtained from the seismic
hazard maps, modified to account for Site Class effects and reduced by a factor of 2/3 as found
in FEMA 310. The MCE maps show values of 5 % damped, spectral response accelerations with
a 2% chance of exceedance in 50 years, except at some sites in highly active seismic regions,
where MCE shaking contours are based on maximum magnitude earthquakes on the known
faults in the region. As an alternative to using mapped values of MCE shaking demands, site-
specific MCE seismic hazards defined using the site-specific procedure described in the 2000
NEHRP Provisions, incorporating detailed information about a particular site’s geology and
seismicity, may also be used.

C1.2__ Scope — Compliance Categories

The compliance categories identified — structural, nonstructural, foundation, geologic

site, and adjacency — are convenient groupings of sources of potential life-safety risks. Elements
of all are included within the scope of FEMA 310. The adjacency category often will directly
involve property not owned by the government and may therefore require legal or administrative
intervention, rather than engineering solutions.

The seismic maps accompanying the 2000 NEHRP Recommended Provisions and referenced in
the Standards represent the varying levels of seismic hazard for all areas in the United States.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -4- January 18, 2002



STANDARDS
1.0 INTRODUCTION

The intent of the Standards of Seismic Safety for Federally Owned and Leased Buildings
(hereinafter referred to as the Standards) is to provide Federal agencies with common minimum
and higher standards for the evaluation and mitigation of seismic risks in their owned or leased
buildings, and privately owned buildings on Federal land to ensure that all agencies have a
balanced, agency-conceived and controlled seismic safety program. The Standards allow for
two levels of seismic performance: a minimum Life-Safety level intended to provide a low risk
of earthquake induced life safety endangerment and a higher Immediate Occupancy level,
intended to minimize the risk of earthquake-induced impairment of mission, recommended for
critical facilities. The Standards build upon previous efforts by the Interagency Committee on
Seismic Safety in Construction (ICSSC) in support of the National Earthquake Hazards
Reduction Program (NEHRP). This document supersedes the Interagency Committee on Seismic
Safety in Construction’s Standards of Seismic Safety for Existing Federally Owned or Leased
Buildings and Commentary (RP 4).

The Standards consist of this Introduction and three additional sections as follows:

The Application of the Standards section identifies situations that trigger the application of the
Standards, defines compliance with the Standards, and identifies additional measures that must
be included in each agency’s seismic safety responsibilities for existing buildings.

The Evaluation Requirements of the Standards identifies building data required before
conducting a building evaluation and provides guidance on the application of FEMA 310 and
FEMA 356 based on building type and other factors.

The Mitigation Requirements section of the Standards includes the requirements for mitigation
of seismic risks; standards for rehabilitation of structural, non-structural,
foundation/geologic/site, and adjacency hazards; guidance on incremental or partial
rehabilitation; alternative mitigation methods; and rehabilitation of historic buildings based on
FEMA 356.

C1 INTRODUCTION:

RP 4, published in 1994, was based upon FEMA 178, NEHRP Handbook for the Seismic
Evaluation of Existing Buildings, which established the criteria for evaluating buildings to a
performance level of Substantial Life-Safety. Since the publication of RP 4, several new
documents have been published that have made RP 4 obsolete. The 1997 NEHRP Recommended
Provisions for Seismic Regulations for New Buildings and Other Structures Parts 1 and 2
(FEMA 302 and 303) introduced new seismic hazard maps that better defined the risk of
damaging ground shaking across the United States. These design maps were based on
probabilistic seismic hazard maps produced by the U.S. Geological Survey. The maps provide
median values of 5 % damped spectral accelerations at two periods (0.2 sec and 1.0 sec) for Site

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -l- January 18, 2002



3.1 Evaluation Requirements

Seismic evaluation of a building for a specific performance level shall be carried out to satisfy
the objectives of the Standards (Section 1.1). The level of performance shall be established by
the agency having the jurisdiction over the building.

All buildings that do not meet the exemption criteria defined in Section 1.3 shall be evaluated
using the procedures set forth in FEMA 310 or successor document. Buildings complying with
the intent of all the requirements of FEMA 310 (or successor document) shall be deemed to meet
the specified performance level, either Life-Safety or Immediate Occupancy.

Buildings may be evaluated for higher levels of performance than Life-Safety and Immediate
Occupancy by other well-established procedures based on rational methods of analysis.

C3.1__ Evaluation Requirements

FEMA 310 provides a three-tier process for seismic evaluation of existing buildings. The
procedures allow buildings to be evaluated to either the Life-Safety or Immediate Occupancy
level. A Tier 1 evaluation shall be conducted for all non-exempt buildings in accordance with
the requirements of Chapter 3 of FEMA 310. The Tier 2 evaluation is intended to be a detailed
follow-up on the potential deficiencies that are identified by the Tier | evaluation. For relatively
short, regularly configured buildings with a predictable earthquake performance record, the Tier
2 evaluation need only address the identified deficiencies as outlined in FEMA 310. A full
building evaluation is not needed since it will likely not identify any other deficiencies that need
attention. For all other buildings, a full building evaluation is needed along with the detailed
consideration of the identified deficiencies to assure that the performance objective is properly
addressed. Full building Tier 2 or Tier 3 evaluations are required for Immediate Occupancy
performance level, taller buildings, and buildings that resist earthquakes in a complex manner.
The evaluation process may be terminated and the building deemed to be compliant with the
Standards, if the results of analysis demonstrate that the building or its elements satisfy
performance requirements.

Special and historic buildings, because of their importance and value to the society, may be
evaluated to an appropriate level of performance using rational methods of analysis based on
principles of mechanics. The performance level may be better than or less than required for life-
safety, depending on the building and whether the historic fabric is to be protected adequately. It
is important to note that FEMA 310 is intended to serve as a guideline reference for evaluation of
buildings, but strict adherence to the letter of the document may not be appropriate at all times.
Engineering judgement must be applied in situations where FEMA 310 is silent or not
applicable. What is important is that agencies meet the intent of FEMA 310, i.e. meet the
performance goal desired, when evaluating their buildings.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -15- January 18, 2002



ICSSC Technical Secretariat

Stephen Cauffman

Degenkolb Engineers

John Dal Pino
Chris Poland

ICSSC RP 6

Standards of Seismic Safety for Existing Federal Buildings

Standards

-ii-

January 18, 2002


Buildings with thin-walled steel tubes in braced frames shall not be considered Benchmark
Buildings.

°URM buildings evaluated using the ABK Methodology (ABK, 1984) may be considered
benchmark buildings.

"Refers to the UCBC.

*No benchmark year; buildings shall be evaluated using the Standards.
**7 ocal provisions shall be compared with the UBC.

BOCA - Building Officials and Code Administrators, National Building Code.

SBCCI — Southern Building Code Congress International, Standard Building Code.

UBC - International Conference of Building Code Officials, Uniform Building Code.

NEHRP - Federal Emergency Management Agency, NEHRP Recommended Provisions for the
Development of Seismic Regulations for New Buildings and Other Structures.

UCBC - Uniform Code for Building Conservation

Note: Table adapted from fourth ballot version of ASCE Draft Standard for Seismic Evaluation
of Existing Buildings.

C1.3.1 Benchmark Buildings

The establishment of benchmark years that will automatically qualify buildings as being
structurally adequate is complex. The designation of benchmark years changes to reflect new
knowledge gained from studying the performance of buildings in seismic events, from new
research results, and other relevant information. Table 1-1 reflects the benchmark years adopted
by the ICSSC for Federal Buildings. Benchmark years for any previously used seismic
provisions can be established by comparing resulting designs by building types with the
acceptance standards. Care must be taken in such comparisons to consider all possible variations
of the building type studied.

1.3.2 Leased Buildings

The Standards shall apply to all or portions of non-Federally owned buildings leased by the
Federal Government, unless exempt under the provisions of Section 1.3

The following provisions shall also apply:

a. No new leases or lease renewals/extensions shall be made in buildings that do not comply
with the Standards.

Exception: If no seismically conforming space is available, otherwise acceptable space with the
best seismic resistance shall be pursued.

b. The building owner shall obtain certification by a registered professional engineer that the
building conforms to the Standards.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
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2.0 APPLICATION OF THE STANDARDS

This section defines those situations that trigger a seismic evaluation and rehabilitation of a
Federal building.

2.1 Situations Requiring Evaluation and Mitigation

At a minimum, a building shall be evaluated and unacceptable risks mitigated when any of the

following occur:

a. achange in the building’s function which results in a significant increase in the building’s
level of use, importance, or occupancy, as determined by the agency,

b. a project is planned which significantly extends the building’s useful life through alterations
or repairs which total more than 30 % of the replacement value of the facility.

c. the building or part of the building has been damaged by fire, wind, earthquake, or other
cause to the extent that, in the judgement of the agency, significant structural degradation of
the building’s vertical or lateral load carrying systems has occurred,

d. the building is deemed by the agency to be an exceptionally high risk to occupants or the
public at large, or

e. the building is added to the Federal inventory through purchase or donation after adoption of
the Standards.

C2.1 Situations Requiring Evaluation and Mitigation

Seismic risk mitigation programs consist of both “active” and “passive” components. “Active”
components of a seismic risk mitigation program specifically require some action to be taken,
such as inventory, evaluation, planning for rehabilitation, and rehabilitation of buildings.

The focus of the “passive’’ components or “triggers” is on changes to the building which increase
its life or value or will increase the risk level of the building, such as a change in occupancy.

The philosophy of the use of triggers is to achieve safety similar to a new building when
renovating an old building. Such triggers also serve to gradually reduce the overall seismic risk
presented by the existing building stock. Since such triggered improvements will be done
concurrently with significant non-seismic work, the cost and disruption attributable to the
seismic rehabilitation is minimized.

In the private sector, strict enforcement of such triggers has also served to effectively limit
improvements to the existing building stock and at times has encouraged careful planning to
avoid the triggers.

The basic triggers listed in this section encourage consistent application of the “renovation”
philosophy discussed above. Because of the efficiency of combining seismic rehabilitation with
other work, additional triggers may be advantageous for each agency considering characteristics
of its own program.

The definition of the term “exceptionally high risk” varies from agency to agency but is based
upon consideration of one or more of the following factors: (1) seismicity of the building site,

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards -10- January 18, 2002


ACKNOWLEDGMENTS

The Interagency Committee on Seismic Safety in Construction (ICSSC) developed the Standards
as part of the continuing effort toward seismic safety for existing Federal buildings. The report
was drafted by the National Institute of Standards and Technology (NIST) on behalf of ICSSC
Subcommittee | and reviewed with the members of Subcommittee 1, who provided valuable
input from their agency’s perspective. Degenkolb Engineers made a critical review of the draft
document. The following persons contributed to this project:

ICSSC Subcommittee 1 Members and Standards Project Participants:

H.S. Lew, Chair National Institute of Standards and Technology
John Baals Department of Interior

James Binkley U.S. Postal Service

Larry Black Department of the Army Headquarters

Hao Bui Department of State

James Caulder Air Force Civil Engineer Support Agency
Harish Chander Department of Energy

Joseph Corliss Health and Human Services/Indian Health Service
Mike Davister Department of Energy

Freda Gerard International Broadcasting Bureau

Joseph Hartman U.S. Army Corps of Engineers

Jack Hayes U.S. Army Corps of Engineers

Donald Heald USDA Rural Utilities Service

Larry Hultengren Department of State

Howard Kass National Aeronautics and Space Administration
Leon Kempner, Jr. Bonneville Power Administration

Catherine Lee General Services Administration

Rita Martin Department of Transportation

Ugo Morelli Federal Emergency Management Agency
Thomas Nelson Lawrence Livermore National Laboratory
Howard Nickerson Naval Facilities Engineering Command

Bela Palfalvi General Services Administration

Bryan Partin Tennessee Valley Authority

Eufracio Sabay Bureau of Indian Affairs

Subir Sen Department of Energy

Tim Sheckler Federal Emergency Management Agency
Robert Stein Department of Transportation

C. A. Stillions Architect of the Capitol

Lance Swanhorst Environmental Protection Agency

Steven Sweeney U.S. Army Corps of Engineers

Doris Turner Federal Aviation Administration

Mahlon White Department of Defense

James Woods Department of Commerce

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards -i- January 18, 2002


REFERENCES

Federal Emergency Management Agency, 1992. NEHRP Handbook for the Seismic Evaluation
of Existing Buildings, FEMA-178, Prepared by the Building Seismic Safety Council for FEMA,
Washington, D.C. 20472

,1997. NEHRP Recommended Provisions for Seismic Regulations for New Buildings and
Other Structures, Part I and 2, FEMA-302 and 303, Prepared by the Building Seismic Safety
Council for FEMA, Washington, D.C. 20472

,1997. NEHRP Guidelines for the Seismic Rehabilitation of Buildings, FEMA-273, Prepared
by the Applied Technology Council and the Building Seismic Safety Council for FEMA,
Washington, D.C. 20472

, 1997. NEHRP Commentary on the Guidelines for the Seismic Rehabilitation of Buildings,
FEMA-274, Prepared by the Applied Technology Council and the Building Seismic Safety
Council for FEMA, Washington, D.C. 20472

, 1998. Handbook for the Seismic Evaluation of Buildings—A Prestandard, FEMA-310,
Prepared by the American Society of Civil Engineers for FEMA, Washington, D.C. 20472

, 2000. Prestandard and Commentary for the Seismic Rehabilitation of Buildings, FEMA-356,
Prepared by the American Society of Civil Engineers for FEMA, Washington, D.C.

, 2000. Global Topics Report on the Prestandard and Commentary for the Seismic
Rehabilitation of Buildings, FEMA-357, prepared by the American Society of Civil Engineers for
FEMA, Washington, D.C.

, 2000, NEHRP Recommended Provisions for New Buildings and Other Structures, FEMA-
368, prepared by the Building and Seismic Safety Council for FEMA, Washington, DC 20472

, 2000, NEHRP Recommended Provisions for New Buildings and Other Structures Part 2:
Commentary, FEMA-369, prepared by the Building and Seismic Safety Council for FEMA,
Washington, DC 20472

, 2000, Recommended Seismic Design Criteria for New Steel Moment Frame Buildings,
FEMA-350, prepared by the SEAOC, ATC, and CUREE Joint Venture for FEMA, Washington,
DC 20472

, 2000, Recommended Seismic Evaluation and Upgrade Criteria for Existing Welded Steel
Moment Frame Structures, FEMA 351, prepared by the SEAOC, ATC, and CUREE Joint
Venture for FEMA, Washington, DC 20472

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -19- January 18, 2002



Standards of Seismic Safety for Existing
Federally Owned and Leased Buildings

Stephen A. Cauffman
H. S. Lew
Editors

U.S. DEPARTMENT OF COMMERCE
Technology Administration
Structures Division
Building & Fire Research Laboratory
National Institute of Standards

and Technology
Gaithersburg, MD 20899

January 2002

U.S. DEPARTMENT OF COMMERCE
Donald L. Evans, Secretary

TECHNOLOGY ADMINISTRATION
Phillip J. Bond, Under Secretary for Technology

NATIONAL INSTITUTE OF STANDARDS
AND TECHNOLOGY
Arden L. Bement, Jr., Director


c. detached one- and two-family wood frame dwellings located where Sps =0.4 g that
satisfy the light-frame construction requirements of the 2000 NEHRP Recommended
Provisions for Seismic Regulations for New Buildings and Other Structures,

d. agricultural and storage structures that are intended only for incidental human
occupancy or that are occupied by persons for a total of less than 2 hours a day,

e. one story buildings of steel light frame or wood construction with areas less than
280 m? (3000 ft”),

f. special structures including, but not limited to: bridges, transmission towers,
industrial towers and equipment, piers and wharves, and hydraulic structures,

g. fully rehabilitated buildings that comply with these Standards, to the satisfaction of
the owning agency, in all compliance categories (structural, nonstructural, foundation,
geologic site hazards, and adjacency),

h. post-benchmark buildings as defined in Table 1-1 which also comply with the
structural, nonstructural, foundation, geologic site hazards, and adjacency compliance
categories and are being evaluated to the Life-Safety Performance Level,

i. pre-benchmark buildings which have been shown by evaluation to the satisfaction of
the owning agency to be life-safe in all four compliance categories,

j. buildings constructed for the Federal Government whose detailed design was done
after the date of adoption of Executive Order 12699 (January 5, 1990) and that were
designed and constructed in accordance with the ICSSC Guidelines and Procedures
for Implementation of the Executive Order on Seismic Safety of New Building
Construction, RP 2.1-A,

k. buildings scheduled for demolition; temporary short-term leases; and foreclosure
buildings,

1. the remaining useful life of the building or the agency’s requirement for the building
has been identified as being less than five years,

m. rehabilitated buildings that substantially comply with RP 4, or other agency specific
standards and criteria to the satisfaction of the owning agency, in all four compliance
categories (structural, nonstructural, foundation, geologic site hazards, and
adjacency).

C1.3__ Scope - Buildings

Buildings that require higher performance than Life-Safety should be identified as such prior to
their elimination as exempted buildings to assure that they are given adequate consideration.
Also, performance expectations for recently constructed buildings should be compared with their
required objectives. Benchmark years, suggested in Table 1-1 of the Standards (Section 1.3.1),
may not be applicable to the higher performance objectives.

The list of buildings that need not meet the Standards — either because they are unlikely to
present a significant life-safety risk or because they do not fit within the boundaries commonly
placed on building standards and technology — was developed considering the extent of
application of FEMA 310, and previous exemptions listed in the Standards of Seismic Safety for
Existing Federally Owned or Leased Buildings and Commentary, RP 4, that are still valid.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings
Standards -6- January 18, 2002



C1.3.2 Leased Buildings

Non-federally owned buildings in which the Federal Government leases space are subject to the
Standards, unless exempt per Section 1.3. RP 4 provided an exception that allowed agencies to
continue leasing space in non-conforming buildings if no other conforming space was available.

1.3.3 Privately-Owned Buildings on Federal Land

The Standards shall be applied to all privately owned buildings located on Federal land.
Application of the Standards to evaluation and rehabilitation of seismic risks shall be the
responsibility of the building owner.

C1.3.3 Privately-Owned Buildings on Federal Land

Privately-owned buildings on Federal land, such as concessionaire buildings in National Parks,
schools on military bases, and buildings constructed and owned by private contractors with long-
term exclusive relationships with Federal agencies, were exempted by RP 4. However, the
ICSSC has recommended that these buildings be evaluated and that unacceptable seismic risks
be mitigated. As a result, the Standards shall apply to all privately owned buildings located on
Federal land.

ICSSC RP 6 Standards of Seismic Safety for Existing Federal Buildings

Standards -9- January 18, 2002