Interim Testing Protocols for 

Determining the Seismic 

Performance Characteristics of 

Structural and Nonstructural 

Components 

FEMA 461 / June 2007

FEMA nehrp

FEMA 461 / June 2007 

Interim Testing Protocols for 

Determining the Seismic 

Performance Characteristics of 

Structural and Nonstructural 

Components 

Prepared by the 

APPLIED TECHNOLOGY COUNCIL 

201 Redwood Shores Parkway, Suite 240 

Redwood City, California 94065 

www.ATCouncil.org 

In Cooperation with the 

MID-AMERICA EARTHQUAKE (MAE) CENTER 

Urbana, Illinois 

MULTIDISCIPLINARY CENTER FOR EARTHQUAKE ENGINEERING 

RESEARCH (MCEER) 

Buffalo, New York 

PACIFIC EARTHQUAKE ENGINNERING RESEARCH (PEER) CENTER 

Berkeley, California 

Prepared for 

FEDERAL EMERGENCY MANAGEMENT AGENCY 

Department of Homeland Security (DHS) 

Michael Mahoney, Project Officer 

Washington, D.C. 
Notices 

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

reflect the views of the Department of Homeland Security’s Federal Emergency Management Agency 

(FEMA), the National Science Foundation (NSF), the Applied Technology Council (ATC), the MidAmerica Earthquake (MAE) Center, the Multidisciplinary Center for Earthquake Engineering Research 

(MCEER), or the Pacific Earthquake Engineering Research (PEER) Center. Additionally, neither ATC, 

FEMA, MAE, MCEER, NSF, PEER, 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. 

This work was supported in part by the Earthquake Engineering Research Centers Program of the 

National Science Foundation, under NSF Award Numbers EEC-9701785 (MAE Center), EEC-9701471, 

(MCEER), and EEC-9701568 (PEER Center). 

Cover Photo: Roof-top Air Handling Unit being tested on a shake table in the Structural Engineering and 

Earthquake Simulation Laboratory at the University at Buffalo. Photo courtesy of the American Society for Heating 

Refrigerating and Air-Conditioning Engineers and MCEER. 
FEMA 461 Foreword iii 

Foreword

One of the primary goals of the Department of Homeland Security’s Federal 

Emergency Management Agency (FEMA) is prevention or mitigation of this 

country's losses from hazards that affect the built environment. To achieve 

this goal, we as a nation must determine what level of performance is 

expected from our buildings during a severe event, such as an earthquake. To 

do this, several years ago FEMA contracted with the Applied Technology 

Council (ATC) to develop next-generation performance-based seismic design 

guidelines, which would allow stakeholders and their representatives to 

assess the probable seismic performance of new and existing buildings, and 

to be able to design or improve their structures to meet their performance 

goals. These guidelines could be voluntarily used by engineers and designers 

to: (1) assess and improve the performance of buildings that are currently 

designed to a building code “life safety” level, which would, in all 

likelihood, still suffer significant structural and nonstructural damage in a 

severe event; and (2) more effectively meet the performance targets of 

current building codes by providing verifiable alternatives to current 

prescriptive code requirements. This program is based on a long-term plan 

published as FEMA 445, which was developed with the input of the nation's 

leading seismic professionals. 

One of the key requirements in performance based seismic design is the 

ability to test and evaluate the intended performance of the various structural 

and nonstructural components that make up a building. To develop this 

testing criteria, the project worked closely with the three Earthquake 

Engineering Research Centers (EERC) funded by the National Science 

Foundation. The three EERC’s are: 

• The Mid-America Earthquake Center (MAE) 

• The Multidisiplinary Center for Research in Earthquake Engineering 

Research (MCEER) 

• The Pacific Earthquake Engineering Research Center (PEER) 

The three EERC’s and others involved in the project have done an excellent job 

developing these interim testing protocols for structural and nonstructural 

components. These protocols will go a long way towards bringing consistency 

to the future testing of these components, and will help the various industries by 

providing a clear seismic performance target towards which they can now aim. 
iv Foreword FEMA 461 

It is FEMA’s hope that as performance based seismic design moves into the 

mainstream, these protocols will ultimately become standardized and more 

broadly used. 

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

project and in the development of this publication. The result of their hard work 

and dedication will play an important role in helping the nation move towards 

performance-based seismic design and reducing losses suffered by our citizens 

in future earthquakes. 

—Federal Emergency Management Agency 
FEMA 461 Preface v 

Preface

In October 2001 the Applied Technology Council (ATC), with funding from 

the Federal Emergency Management Agency (FEMA), Department of 

Homeland Security, commenced work on a multi-year project to 

development performance-based seismic design guidelines for eventual 

incorporation in existing standards for the seismic design of new buildings 

and the upgrade of existing buildings (ATC-58 project). The plan for 

development of the guidelines is defined in the companion FEMA 445 

report, Next-Generation Performance-Based Seismic Design Guidelines, 

Program Plan for New and Existing Buildings, which was prepared under the 

ATC-58 project and published by FEMA in 2006. 

As part of the initial work on the ATC-58 project, interim recommended 

protocols (documented herein) were developed for testing of structural and 

nonstructural components and systems found in buildings, for the purpose of 

establishing their seismic performance characteristics. The protocols were 

developed through a cooperative effort of ATC and the three National 

Science Foundation-funded Earthquake Engineering Research Centers 

(EERCs): the Mid-America Earthquake (MAE) Center at the University of 

Illinois, Urbana; the Multidisciplinary Center for Earthquake Engineering 

Research (MCEER), University at Buffalo, The State University of New 

York; and the Pacific Earthquake Engineering Research (PEER) Center at 

the University of California, Berkeley. 

Two interim protocol types are provided in this document: 

• Interim Protocol I – Quasi-Static Cyclic Testing, which should be used 

for the determination of performance characteristics of components 

whose behavior is primarily controlled by the application of seismic 

forces or seismic-induced displacements (e.g., cladding panels, glazing 

panels, drywall partitions, piping and ducting system connections, ducts, 

and various types of anchors and braces); and 

• Interim Protocol II – Shake Table Testing, which should be used to 

assess performance characteristics of components whose behavior is 

affected by the dynamic response of the component itself, or whose 

behavior is velocity sensitive, or sensitive to strain-rate effects (e.g., 

mechanical and electrical equipment). 
vi Preface FEMA 461 

The document also contains an introductory chapter that presents an 

overview of performance-based seismic design (to provide context for the 

recommended interim testing protocols) and discussions on a variety of 

topics and issues germane to these protocols. A Commentary is provided for 

each protocol (in the chapter immediately following the protocol), and an 

appendix is included that describes the process used to develop nonstructural 

component fragility functions based on laboratory testing. 

Christopher Rojahn 

ATC Executive Director 
FEMA 461 Acknowledgements vii 

Acknowledgements

Numerous individuals and institutions deserve credit for the development of 

the interim protocols provided in this document. The need for the protocols 

was first recognized by the FEMA Performance-Based Seismic Design 

Project (ATC-58) Nonstructural Performance Products Team, consisting of 

Robert Bachman (Team Leader), David Bonowitz, Philip Caldwell, Andre 

Filiatrault, Robert Kennedy, Gary McGavin, Eduardo Miranda, and Keith 

Porter. The protocol development effort was carried out by three protocol 

teams: (1) the Shaking Table Testing Protocol Team, consisting of Andre 

Filiatrault (Team Leader), Philip Caldwell, Peter Dusicka, Tara Hutchinson, 

Ahmad Itani, Eduardo Miranda, Gokhan Pekcan, Andrei Reinhorn, Jose 

Restrepo, and James Wilcoski; (2) The Racking Testing Protocol Team, 

consisting of Helmut Krawinkler (Team Leader), David Bonowitz, Barry 

Goodno, Steven Kuan, Joseph Maffei, Ali Memari, Jose Restrepo, and ChiaMing Uang; and (3) the Component Cyclic Testing Protocol Team, 

consisting of Manos Maragakis (Team Leader), George Antaki, Scott 

Campbell, and Robert Kennedy. 

Additional guidance and input was provided by participants in the 

FEMA/ATC-58 Workshop on Interim Protocols for Seismic Performance 

Assessment Testing of Nonstructural Component , held on November 4-5, 

2004 in the San Francisco Bay area. Participants included the individuals 

cited above as well as members of the Project Team, FEMA representatives, 

and invited participants: Dennis Alvarez, John Caffrey, James Carlson, Mary 

Comerio, Craig Comartin (Risk Management Products Team Leader), 

William Gates, Jeff Gatscher, Nathan Gould, Ronald Hamburger (Project 

Technical Director), Robert Hanson (FEMA Technical Monitor), Brian 

Kehoe, Charles Kircher (Risk Management Products Team Member), 

Richard Lloyd, Mike Mahoney (FEMA Project Officer), Sami Masri, Kelly 

Merz, Christopher Rojahn (Project Executive Director), Anshel Schiff, John 

Silva, Donald Smith, Greg Soules, William Staehlin, and Chris Tokas. 

Project and Workshop coordination was provided by Bernadette Hadnagy, 

and editorial and publication services were provided by Gerald Brady and 

Peter Mork. The affiliations of these individuals and those cited above are 

provided in the list of Project Participants and the list of Workshop 

Participants at the end of this document. 
viii Acknowledgements FEMA 461 

This work was also supported in part by the Earthquake Engineering 

Research Centers Program of the National Science Foundation, under NSF 

Award Numbers EEC-9701785 (MAE Center), EEC-9701471, (MCEER), 

and EEC-9701568 (PEER Center). 

Funding for the development of this report under the ATC-58 PerformanceBased Seismic Design Project was provided by the Federal Emergency 

Management Agency through Contract EMW-2001-CO-0378. The 

leadership, insight, and support provided by Michael Mahoney (FEMA 

Project Officer) and the review comments by Robert Hanson (FEMA 

Technical Monitor) are gratefully acknowledged. 
FEMA 461 Contents ix 

Contents

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

Preface..............................................................................................................v 

Acknowledgements....................................................................................... vii 

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

List of Tables .............................................................................................. xvii 

Executive Summary ..................................................................................... xix 

1. Introduction and General Considerations ...........................................1 

 1.1 Purpose and Background .......................................................1 

 1.2 Performance Based Design ....................................................1 

 1.3 Fragility Functions.................................................................4 

 1.4 Relevant Damage States and Performance Levels.................8 

 1.5 Uncertainty Issues..................................................................9 

 1.6 Damage and Repair Costs....................................................10 

1.7 Nonstructural Component Qualification..............................11 

1.8 Protocol Types .....................................................................12 

2. Interim Protocol I – Quasi-Static Cyclic Testing..............................13 

 2.1 Scope ................................................................................13 

 2.2 Applicability ........................................................................14 

 2.3 Component Documentation .................................................15 

 2.3.1 Structural Components ...........................................15 

 2.3.2 Nonstructural Components .....................................15 

 2.4 Procurement, Fabrication and Inspection of Test 

Specimens ............................................................................16 

 2.5 Extrapolation and Interpolation to Similar Components .....16 

 2.6 Test Facility Standards.........................................................17 

 2.6.1 Laboratory...............................................................17 

 2.6.2 Equipment...............................................................17 

 2.7 Test Plan and Procedures.....................................................18 

 2.8 Loading and Load Control...................................................20 

 2.8.1 Deformation-Controlled Testing.............................20 

 2.8.2 Force-Controlled Testing........................................21 

 2.8.3 Directions of Loading .............................................21 

 2.9 Loading Histories.................................................................21 

 2.9.1 Unidirectional Testing ............................................21 

 2.9.2 Bidirectional Testing...............................................24 

 2.9.3 Force-Controlled Loading.......................................24 
x Contents FEMA 461 

 2.10 Reporting............................................................................. 26 

C2. Commentary on Interim Protocol I – Quasi-Static Cyclic 

Testing.............................................................................................. 29 

 C2.6 Test Facility Standards 

 C2.6.2 Equipment .............................................................. 29 

 C2.7 Test Plan and Procedures .................................................... 29 

 C2.8 Loading and Load Control .................................................. 32 

 C2.9 Loading Histories................................................................ 39 

3. Interim Protocol II – Shake Table Testing ....................................... 53 

 3.1 General ................................................................................ 53 

 3.1.1 Scope...................................................................... 53 

 3.1.2 Definitions.............................................................. 53 

 3.2 Test Procedures ................................................................... 54 

 3.2.1 Types of Testing and Sequence.............................. 54 

 3.2.2 Pretest Inspection and Functional Verification ...... 54 

 3.2.3 Definition and Documentation of Functional 

Performance and Anticipated Damage States ........ 55 

 3.2.4 System Identification Tests .................................... 55 

 3.2.5 Performance Evaluation Tests................................ 57 

 3.2.6 Failure Tests........................................................... 57 

 3.3 Intensities of Test Shaking .................................................. 58 

 3.4 Directions of Shaking.......................................................... 58 

 3.5 Data Acquisition System..................................................... 59 

 3.6 Test Plan.............................................................................. 59 

 3.7 Input Motions...................................................................... 59 

 3.8 Time Stamping and Damage State Documentation............. 61 

 3.9 Notch Filtering of Input Motions ........................................ 62 

 3.10 Testing Equipment .............................................................. 63 

 3.10.1 Shake Tables .......................................................... 63 

 3.10.2 Instrumentation and Monitoring ............................ 64 

 3.10.3 Data Acquisition..................................................... 66 

 3.10.4 Safety Procedures................................................... 66 

 3.11 Test Report.......................................................................... 67 

 3.11.1 Test Specimen Description..................................... 67 

 3.11.2 List of Specimens Tested ....................................... 67 

 3.11.3 Preliminary System Identification Tests and 

Report Requirements.............................................. 68 

 3.11.4 Measured Fidelity Data.......................................... 68 

 3.11.5 Performance and Failure Test Evaluations............. 68 

 3.11.6 Photographs and Video Recordings ....................... 69 

C3. Commentary on Interim Protocol II – Shake Table Testing ............ 71 

 C3.1 General 

 C3.1.1 Scope...................................................................... 71 

 C3.2 Test Procedures 

 C3.2.2 Pretest Inspection and Functional Verification ...... 71 

 C3.2.3 Definition and Documentation of Functional 

Performance and Anticipated Damage States ........ 71 

 C3.7 Input Motions...................................................................... 72 
FEMA 461 Contents xi 

 C3.9 Notch Filtering of Input Motions.........................................89 

 C3.10 Testing Equipment...............................................................91 

 C3.10.1 Shake Tables........................................................92 

 C3.10.2 Instrumentation and Monitoring..........................94 

Appendix A: Determination of Fragility Functions Based on 

Laboratory Data ...................................................................95 

 A.1 Purpose ................................................................................95 

 A.2 Background..........................................................................95 

 A.3 General Procedure................................................................97 

References....................................................................................................101 

Acronyms.....................................................................................................103 

Project Participants ......................................................................................105 

Workshop Participants: Workshop on Interim Protocols for Seismic 

Performance Assessment Testing of Nonstructural Components..........111 

FEMA 461 List of Figures xiii 

List of Figures

Figure 1 Hypothetical cumulative probability fragility curves ..........xx 

Figure 1-1 Hypothetical probability density function fragility 

curves.....................................................................................6 

Figure 1-2 Hypothetical cumulative probability fragility curves ............7 

Figure 2-1 Sketch of deformation-controlled loading history ...............22 

Figure 2-2 Loading history for a1 = 0.048Δm ........................................24 

Figure 2-3 Horizontal plane displacement orbit for drift-controlled 

bidirectional tests .................................................................24 

Figure 2-4 Illustration of conceptual approach for development of 

force-controlled loading history...........................................25 

Figure 2-5 Illustrative force loading history for case illustrated in 

Figure 2-4.............................................................................25 

Figure C2-1 Different sources of story drift: (a) shear drift, and 

(b) rotation drift ...................................................................30 

Figure C2-2 Example of instrumentation and data acquisition 

system ..................................................................................34 

Figure C2-3 Example racking test facility at Penn State University 

with setup for testing curtain walls ......................................35 

Figure C2-4 Example test setup for testing horizontally attached 

cladding panels on the Penn State facility ...........................35 

Figure C2-5 Example test setup for testing vertically attached 

cladding panels on the Penn State Facility ..........................36 

Figure C2-6 Example racking test facility at the University of 

Idaho ....................................................................................36 

Figure C2-7 Example test setup for testing cladding panels on the 

University of Idaho facility..................................................37 

Figure C2-8 ASTM Standards generic test facility and setups for 

racking testing of shear-resisting wall panels ......................38 

Figure C2-9 Ordered relative excursions, pre-peak plus post-peak, 

T = 0.2 sec., SDOF systems .................................................42 
xiv List of Figures FEMA 461 

Figure C2-10 Ordered relative excursions, pre-peak plus post-peak, 

T = 0.3 sec., SDOF and MDOF systems ............................. 43 

Figure C2-11 Ordered relative excursions, pre-peak plus post-peak, 

T = 0.5 and 0.9 sec. ............................................................. 44 

Figure C2-12 Normalized response displacement histories of an 

SDOF system, T = 0.3 sec................................................... 44 

Figure C2-13 Ordered relative excursions, separate for pre-peak 

and post-peak excursions, elastic SDOF system. ................ 47 

Figure C2-14 Monotonic force-deformation test on the component ......... 49 

Figure C2-15 Cyclic test on the component in deformation control: 

(a) applied deformation history; and (b) measured 

force history ........................................................................ 50 

Figure C2-16 (a) Cumulative low-cycle fatigue damage at the end 

of each test stage, and (b) force level at the end of 

each test stage...................................................................... 51 

Figure 3-1 Recommended longitudinal input motion ........................... 60 

Figure 3-2 Recommended transverse input motion .............................. 60 

Figure 3-3 Recommended vertical input motion .................................. 61 

Figure 3-4 5% damped, acceleration response spectra for 

recommended longitudinal, transverse and vertical 

input motions....................................................................... 61 

Figure C3-1 Generated narrow-band random signal, Ran16 record........ 73 

Figure C3-2 Generated narrow-band random signal, Ran18 record........ 74 

Figure C3-3 Generated narrow-band random signal, Ran22 record........ 74 

Figure C3-4 Generated narrow-band random signal, Ran31 record........ 75 

Figure C3-5 Generated narrow-band random signal, Ran34 record........ 75 

Figure C3-6 Response spectra for selected longitudinal records 

(5% of critical damping). .................................................... 76 

Figure C3-7 Spliced longitudinal record ................................................. 77 

Figure C3-8 Scale used for the longitudinal record, plotted in the 

frequency domain................................................................ 77 

Figure C3-9 Scale used for the longitudinal record, plotted in the 

time domain......................................................................... 78 
FEMA 461 Contents xv 

Figure C3-10 Scaled narrow-band random longitudinal record, 

Long_3.................................................................................78 

Figure C3-11 Response spectra for scaled narrow-band random 

records..................................................................................79 

Figure C3-12 Generated narrow-band random signal, Ran7 record ..........81 

Figure C3-13 Generated narrow-band random signal, Ran30 record ........81 

Figure C3-14 Generated narrow-band random signal, Ran55 record ........82 

Figure C3-15 Generated narrow-band random signal, Ran84 record ........82 

Figure C3-16 Response spectra of selected transverse records 

(5% of critical damping). .....................................................83 

Figure C3-17 Spliced transverse record (Spliced_2). ................................83 

Figure C3-18 Scale used for the transverse record, plotted in the 

frequency domain ................................................................84 

Figure C3-19 Scale used for the transverse record, plotted in the 

time domain .........................................................................84 

Figure C3-20 Scaled narrow-band random transverse record....................85 

Figure C3-21 Generated narrow-band random signal, Ran9 record ..........85 

Figure C3-22 Generated narrow-band random signal, Ran20 record ........86 

Figure C3-23 Generated narrow-band random signal, Ran21 record ........86 

Figure C3-24 Generated narrow-band random signal, Ran68 record ........87 

Figure C3-25 Generated narrow-band random signal, Ran90 record ........87 

Figure C3-26 Generated narrow-band random signal, Ran98 record ........88 

Figure C3-27 Response spectra of selected vertical records 

(5% of critical damping). .....................................................88 

Figure C3-28 Spliced vertical record (Spliced_2)......................................89 

Figure C3-29 Scale used for the vertical record, plotted in the 

frequency domain ................................................................90 

Figure C3-30 Scale used for the vertical record, plotted in the 

time domain .........................................................................90 

Figure C3-31 Scaled narrow-band random vertical record ........................91 
xvi List of Figures FEMA 461 

Figure A-1 Hypothetical nonstructural component fragility 

function ............................................................................... 96 
FEMA 461 List of Tables xvii 

List of Tables

Table 2-1 Relative Loading History Deformation Amplitudes............23 

Table 3-1 Time versus Center Frequency for Central Portion 

of Input Motions ..................................................................63 

Table C3-1 Narrow-Band Random Signal Generation Matlab 

Routine Parameters ..............................................................73 

Table C3-2 Narrow-Band Random Records Used for Splicing 

Transverse and Vertical Records .........................................79 

FEMA 461 Executive Summary xix 

Executive Summary

The testing protocols provided in this document have been prepared to 

support the development of seismic performance assessment procedures, 

which when implemented will enable a better understanding of the probable 

performance of a building and its constituent components. The protocols are 

intended to serve as an interim basis for testing of building components and 

systems to establish their performance capability as measured by their 

fragility functions. 

Fragility functions are mathematical relationships used to assess the 

performance of the individual components, of systems incorporating these 

components, and entire buildings containing these components, when 

subjected to loading caused by earthquake ground shaking. A fragility 

function indicates the probability that a component or system will experience 

damage at or in excess of a specific level, given that the component or 

system experiences a specific level of demand. Fragilities are expressed as 

probability distributions, rather than deterministic relationships in order to 

account for the uncertainties inherent in the process of predicting damage as 

a function of demand. These uncertainties include such factors as the 

random nature of ground shaking and the resulting response of structures, 

and the inability of simple engineering demand parameters, such as 

displacement and acceleration, to distinguish between this response variation 

and the damage it causes. 

The testing protocols are interim pending further implementation and 

evaluation by researchers nationwide. They are not intended for seismic 

performance qualification testing of components to satisfy the requirements 

for such qualification testing under relevant building codes. However, these 

loading protocols could be used for that purpose if so determined by the 

Authority Having Jurisdiction as defined by the local building code. 

Two interim protocol types are described in this document: 

• Interim Protocol I – Quasi-Static Cyclic Testing; and 

• Interim Protocol II – Shake Table Testing. 

The introductory section of the document (Chapter 1) provides an overview 

of performance-based seismic design (to provide context for the 

recommended interim testing protocols) and discussions on a variety of 

topics and issues germane to these protocols: fragility functions, relevant 

damage states and performance levels, uncertainty issues, damage and repair 
xx Executive Summary FEMA 461 

costs, and nonstructural component qualification. The document also 

contains commentaries for each protocol, as well as an appendix describing 

the process used to develop nonstructural component fragility functions 

based on laboratory testing. 

Interim Protocol I – Quasi-Static Cyclic Testing 

Protocol I should be used for the determination of performance 

characteristics of components, the behavior of which is primarily controlled 

by the application of seismic forces or seismic-induced displacements. In the 

protocols, these seismic effects are replicated by slow cyclic application of 

loads (or deformations) whose history (in terms of the applied load or in 

terms of the deformation caused by an applied load) follows a predetermined 

pattern. This protocol should not be applied to a component whose behavior 

is significantly affected by its dynamic response, or whose behavior is 

velocity sensitive. This includes components whose behavior is sensitive to 

strain-rate effects. This protocol may be used to determine fragility data for 

many structural and nonstructural components and in addition may be used to 

derive constituent force-deformation properties and hysteretic data for 

structural components needed for structural analysis and assessments. 

Examples of structural components that may be tested in accordance with 

this protocol include shear walls, beam-column assemblies and frame 

assemblies. Examples of nonstructural components for which this protocol is 

suitable include cladding panels, glazing panels, and drywall partitions. This 

protocol may also be used to derive force-deformation properties (of a 

nonstructural component) that can be used in the structural analysis of a 

nonstructural system of which the nonstructural component forms a part. 

Examples of nonstructural system components for which this protocol is 

suitable include piping and ducting system connections, ducts, and various 

types of anchors and braces. 

The interim recommended testing procedures for Protocol I are described in 

Chapter 2. The scope of a testing program using this protocol for the 

development of fragility data is as follows: 

(a) Identification of relevant damage states; 

(b) Identification of a demand parameter, or set of demand parameters, that 

correlates well with the damage states identified in (a); and 

(c) Testing of the component in accordance with a well-defined test plan and 

a loading protocol that permits the establishment of relationships 

between the damage states and the associated demands. 

Ideally the testing procedure involves a sufficiently large number of 

components to permit the quantification of variability, or, with appropriate 
FEMA 461 Executive Summary xxi 

assumptions, identification of the type of probability distribution, the 

quantification of a central value, and a measure of dispersion. 

The protocol provides detailed guidance and information on: (1) procurement, fabrication and inspection of testing specimens; (2) extrapolation and 

interpolation to similar components; (3) laboratory standards, including 

accreditation criterion, actuators, instruments, data acquisition systems, and 

safety procedures; (4) test plan and procedures; (5) loading and load control, 

including deformation-controlled testing, force-controlled testing, and 

directions of loading; (6) loading histories, including unidirectional testing, 

bidirectional testing, and force-controlled loading; and (7) reporting. 

Commentary for selected portions of the protocol is provided in Chapter C2. 

Interim Protocol II – Shake Table Testing 

Protocol II should be used to assess performance characteristics of components 

whose behavior is affected by the dynamic response of the component itself, or 

whose behavior is velocity sensitive, or sensitive to strain-rate effects. This 

protocol should not be used, if in addition to fragility data, hysteretic data on 

force-deformation properties of a component are needed for use in structural 

analysis. Examples of nonstructural components for which this protocol is 

suitable include mechanical and electrical equipment. 

The interim recommended testing procedures for Protocol II are described in 

Chapter 3. The shake table testing protocol is appropriate for use in 

establishing the fragility of components that are sensitive to the dynamic 

effects of motion imparted to the component at a single point of attachment, 

typically at its base. 

The protocol provides detailed guidance and information on: (1) test 

procedures, including types of testing and sequence, pretest inspection and 

functional verification, definition and documentation of functional 

performance and anticipated damage states, system identification tests, 

performance valuation tests, and failure tests; (2) directions of shaking; 

(3) the data acquisition system; (4) test plan; (5) input motions; (6) time 

sampling and damage state documentation; (7) notch filtering of input 

motions; (8) test equipment, including shake tables, instrumentation and 

monitoring, data acquisition, and safety procedures; and (9) the test report, 

including test specimen description, list of specimens tested, preliminary 

system identification tests and report requirements, measured fidelity data, 

performance and failure test evaluations, and photographs and video 

recordings. Commentary for selected portions of the protocol, including 

background on the generation of the recommended acceleration records, is 

provided in Chapter C3. 

FEMA 461 1: Introduction and General Considerations 1 

Chapter 1 

Introduction and General 

Considerations

1.1 Purpose and Background 

The testing protocols provided in this document are intended to serve as an 

interim basis for testing of building components and systems to establish 

their performance capability as measured by their fragility functions. The 

fragility functions are used to assess the performance of the individual 

components, of systems incorporating these components, and entire buildings 

containing these components, when subjected to loading caused by 

earthquake ground shaking. This performance assessment process can be 

implemented independently, to understand the probable performance of a 

building and its constituent components, or as part of a broader performancebased seismic design process. The testing protocols are not intended for 

seismic performance qualification testing of components to satisfy the 

requirements for such qualification testing under relevant building codes. 

However, these loading protocols could be used for that purpose if so 

determined by the Authority Having Jurisdiction as defined by the local 

building code. 

In the following sections of this introduction, we provide an overview of 

performance-based seismic design (to provide context for the recommended 

interim testing protocols) and discuss a variety of topics and issues germane 

to these protocols: fragility functions, relevant damage states and 

performance levels, uncertainty issues, damage and repair costs, and 

nonstructural component qualification. Chapter 1 concludes with an 

introductory discussion on the applicability of the two interim protocol types 

provided in this document: Interim Protocol I, Quasi-Static Cyclic Testing, 

and Interim Protocol II, Shake Table Testing. Chapters 2 and 3, respectively, 

describe the details of Interim Protocols I and II. Immediately following each 

of these chapters is a commentary (Chapters C2 and C3) providing 

supplemental background and illustrative information for selected sections of 

the protocol. 
2 1: Introduction and General Considerations FEMA 461 

1.2 Performance Based Design 

Performance-based seismic design is a process that permits design of 

buildings with a realistic and reliable understanding of the risk of life, 

occupancy and economic loss that may occur as a result of future 

earthquakes. Basic steps in the performance-based seismic design process 

include: establishment of appropriate performance objectives that define 

expected building performance in future earthquakes; development of a 

preliminary design, believed capable of providing the desired performance; 

assessing whether the design is actually capable of providing this 

performance, through evaluation of the probability of experiencing losses of 

different types; and finally, adjusting the design until the performance 

assessment process indicates a risk of loss that is deemed acceptable. 

This process may be used to achieve the following. 

• Design individual facilities that are more loss-resistant than typical 

buildings designed using prescriptive building code criteria. 

• Design individual facilities with a higher confidence that they will 

actually be able to perform as intended. 

• Design individual facilities that are capable of meeting the performance 

intent of the building codes, but at lower construction cost than would be 

possible using the prescriptive criteria. 

• Design individual facilities that are capable of meeting the performance 

intent of the prescriptive criteria, but which do not comply with all of the 

limitations of the prescriptive criteria with regard to configuration, 

materials and systems. 

• Investigate the performance of typical structures designed using the 

prescriptive provisions of the building codes and develop judgments as 

to the adequacy of this performance. 

• Formulate improvements to the prescriptive provisions contained in the 

building codes so that more consistent and reliable performance is 

attained by buildings designed using these prescriptive provisions. 

A first generation of performance-based seismic design procedures was 

developed in the mid-1990s. The primary focus of the first-generation 

procedures was evaluation and upgrade of existing buildings. These firstgeneration procedures are embodied in such documents as the FEMA-356

Report, Prestandard and Commentary for the Seismic Rehabilitation of 

Buildings (ASCE, 2000) and the ATC-40 Report, Seismic Evaluation and 

Retrofit of Concrete Buildings (ATC, 1996). Since the development of these 
FEMA 461 1: Introduction and General Considerations 3 

first-generation procedures, there has been widespread interest in improving 

performance-based engineering procedures and extending their application to 

the design of new buildings. To this end, recommended programs for 

carrying out the development of performance-based seismic design 

guidelines for new and existing buildings have been prepared for FEMA. 

The first, FEMA 283, was prepared by the Earthquake Engineering Research 

Center, University of California (EERC, 1996) and was subsequently used by 

the Pacific Earthquake Engineering Research (PEER) Center to guide much 

of their work in this area. The second, FEMA 349, was prepared by the 

Earthquake Engineering Research Institute (EERI, 2000), which has guided 

the subsequent work funded by FEMA. Those efforts provided the stimulus 

and basis for the FEMA-funded project to develop next-generation 

performance-based seismic design guidelines for new and existing buildings 

(internally referred to as the ATC-58 project), under which these interim 

protocols were developed. 

Under next-generation performance-based engineering procedures, 

performance is expressed as the probable consequences of earthquake 

damage including potential fatalities and serious injuries (combined as 

casualties), economic costs relating both to repair or replacement of damaged 

buildings, and to the duration of the interruption of occupancy or use. These 

potential losses can be expressed in a variety of formats including: 

• intensity-based performance – the probable losses given that a specific 

intensity of ground shaking is experienced by the building, 

• scenario-based performance – the probable losses given that a specific 

earthquake event occurs, or 

• time-based performance – the probable losses over a period of time 

considering all earthquake events that may occur and the probability of 

each. 

Each of these types of losses can be expressed as a confidence level, 

indicating the likelihood that the loss assessment will either under-predict or 

over-predict the actual losses incurred. 

The basis for these next-generation performance-based design procedures is a 

framework for performance-based engineering developed by PEER. In its 

simplest form, used to calculate losses conditioned upon a single intensity of 

ground shaking, the framework appears mathematically as: 

Expected Loss = > ∑ ∑ ( ) ( = ) ( ) ( ) = ∫

i

i i

systems DS

P Loss DS P D DS DP z P DP z d z (1-1) 
4 1: Introduction and General Considerations FEMA 461 

where: 

P(Loss|DSi) is a mathematical function, termed a loss function, which 

expresses the conditional probability, P, of loss exceeding 

a given amount, given that a component or system is 

damaged to a particular damage state, DSi. 

P(D>DSi|DP=z) is a mathematical function, termed a fragility function, 

which expresses the conditional probability, P, of 

experiencing a given damage state, DSi, as a function of 

demand characterized by the demand parameter, DP, 

P(DP=z)dz is a mathematical function, that expresses the probability, 

P, of a given level of demand, DP, given the particular 

intensity of ground shaking, 

DSi is a unique damage state for the component or system, 

D is the amount of damage sustained by a component or 

system, 

DP is a demand parameter, such as acceleration, force or 

displacement that characterizes the loading on a given 

component or system. 

The protocols presented in this document are intended for use in the 

development of fragility functions (P(D>DSi|DP=z) through testing. 

Guidelines and recommended procedures for the performance-based design 

process are being developed under the Performance-Based Seismic Design 

Project and will be presented separately. 

1.3 Fragility Functions 

A fragility function is a mathematical relationship that indicates the 

probability that a component or system will experience damage at or in 

excess of a specific level, given that the component or system experiences a 

specific level of demand, expressed herein as DP. Mathematically, this may 

be represented in the form: 

( ) i f DP P D DS DP z =≥ = ⎡ ⎤ ⎣ ⎦ (1-2) 

where: 

D is the damage sustained by the component, 
FEMA 461 1: Introduction and General Considerations 5 

DS is a specific damage state, such as initiation of cracking of a partition, a 

piece of electrical equipment developing a short, or a mechanical seal 

losing integrity on a pressure-containing component, 

DP is a parameter used to quantify the demand on the component or system. 

Typical demand parameters include enforced displacement Δ; interstory 

drift ratio, δ; acceleration, a, at point of attachment;, and response 

acceleration, Sa, of the component. 

Fragilities are expressed as probability distributions, rather than deterministic 

relationships in order to account for the uncertainties inherent in the process 

of predicting damage as a function of demand. These uncertainties include 

such factors as the random nature of ground motion records and the response 

they will produce in structures, and the inability of simple engineering 

demand parameters such as displacement and acceleration to distinguish 

between this response variation and the damage it causes. 

As an example, two different ground motions may each produce peak 

interstory drift demands of four inches in a building. However, one of these 

ground motions may cycle the building to this drift level only once and then 

restore it to small oscillations about its original position, while the second 

ground motion may cycle the building to this drift level several times and 

leave the structure displaced nearly to this level. Clearly, the latter motion 

will be more damaging for the structural and nonstructural components than 

the first motion, though the value of the engineering demand parameter 

(interstory drift of four inches) is the same. Such effects are not predictable. 

Additional uncertainty is introduced through such factors as a lack of precise 

definition of material strength, construction quality, and damping. It is 

theoretically possible to reduce these latter uncertainties through further 

study, including component-specific testing, but it is typically not practical to 

do so. Many uncertainties can be reduced through increased quality 

assurance measures. 

Figure 1-1 shows a hypothetical set of fragility functions for a unitized 

building cladding system consisting of glazing panels set in a panelized 

framework of aluminum mullions and cross members. Damage to this 

system is principally caused by in-plane shear distortion, as represented by 

the interstory drift ratio parameter, δ. Feasible damage states of interest 

include loosening of joints in the aluminum framing such that leakage of air 

and moisture can occur, cracking of the glazing, fallout of the glazing from 

the framing panel, and permanent distortion of the aluminum framing. Each 

of these damage states has somewhat different consequences, which may be 

of interest to the performance assessment process. Loosening of the framing 
6 1: Introduction and General Considerations FEMA 461 

joints may require repairs that include application of sealant to the joints, 

with associated repair cost. Cracking of the glazing will require replacement 

of the glazing, resulting both in repair cost and potential short-term 

occupancy interruption while the work is performed. In the performancebased design process, the fragility functions are used to estimate the 

probability that any of these damage states will be experienced, given that 

interstory drift of a given amount is predicted to occur. 

Figure 1-1 Hypothetical probability density function fragility curves 

The fragility curves illustrated in Figure 1-1 are plotted in the form of 

probability density functions. In such plots, at any value of the index 

parameter, in this case interstory drift ratio, the area under a specific curve to 

the left of that value indicates the probability that the given damage state will 

have occurred. Thus, at an interstory drift ratio of 0.01, Figure 1-1 suggests 

that it is highly likely that the frame joints will have loosened, there is 

moderate probability that glazing will have cracked, small probability that 

glazing will have fallen out and negligible probability of permanent 

distortion of the framing. While such qualitative data can conveniently be 

obtained from such plots, the need to calculate these areas makes it difficult 

to obtain quantitative data on these probabilities from such curves. A more 

convenient way to plot this same data that permits quantitative evaluation of 

the probabilities of experiencing the various types of damage is in the form 

of cumulative probability distributions. Figure 1-2 is a plot of this same data 

in the form of cumulative probability distributions. 

When plotted in the form of cumulative probability functions, the vertical 

axis of a fragility plot indicates the probability that the component or system 

will have experienced damage that is equal to or more severe than a given 

damage state. For example, in Figure 1-2, it can be seen that at an interstory 

drift ratio of 0.01, there is a 50% chance that wall damage will include 
FEMA 461 1: Introduction and General Considerations 7 

glazing cracks or more severe damage. When fragilities are plotted in this 

form, the probability that an assembly will be in a specific damage state is 

obtained by reading the difference in cumulative probability for the two 

appropriate curves. For the example illustrated in Figure 1-2, at an interstory 

Figure 1-2 Hypothetical cumulative probability fragility curves 

drift of 0.01, there is a virtual certainty (97%) that the aluminum framing will 

be loosened, or a more severe damage state will occur; a 50% chance that 

glazing will crack, or a more severe state occur; a 12% chance that glazing 

will actually fall out or a more severe state occur and a 2% chance that 

framing will permanently distort. The probability that glazing will crack but 

not fall out is obtained as the difference, at the given demand level, of the 

two cumulative probabilities. Thus, at an interstory drift ratio of 0.01, this 

fragility curve indicates that there is 38% chance (50% – 12%) that glazing 

will crack but not fall out of the wall system. 

Fragility functions are commonly represented as lognormal distributions, 

characterized by a median value of the demand at which the damage state 

will occur, and the standard deviation of the natural logarithm of the values 

of this demand. For fragility functions, the median value is that value of the 

demand parameter at which there is a 50% probability of experiencing the 

particular damage. The standard deviation of the natural logarithm of the 

demand values is typically represented by the parameter, β. Lognormal 

distributions have the property that the mean (average value) of the 

distribution is related to the median value by the relation: 

2 / 2 ˆ β m me Y Y = (1-3) 

where: 

mY is the mean (average) value of demand at which the damage will occur, 
8 1: Introduction and General Considerations FEMA 461 

ˆmY is the median (50%) value of demand at which the damage will occur, and 

β is the standard deviation of the log of the demand values at which the 

damage occurs. 

For small values, β is approximately equal to the coefficient of variation of 

the distribution of values. 

Fragility functions are commonly represented by lognormal distributions for 

several reasons. First, the natural distribution of failure probabilities tend to 

be somewhat skewed. For example, there is zero probability that earthquakeinduced failure of a component will occur at a zero value of demand. 

Lognormal distributions conform to this natural property. Also, lognormal 

distributions are mathematically convenient forms to integrate in the 

framework equation (Equation 1-1) through closed-form solution. 

1.4 Relevant Damage States and Performance Levels 

The basic purpose of the fragility functions developed in accordance with 

this protocol is to permit the estimation of three types of losses: 

• life loss and serious injuries (casualties), 

• direct economic loss resulting from repair or replacement of damaged 

components, and 

• occupancy or service loss, resulting from inoperable components or 

systems (downtime). 

For the purposes of this protocol, a relevant damage state is defined as any 

group of component conditions that: 

• result in similar consequence with regard to potential casualties, direct 

economic loss, or downtime, and 

• are predictable on the basis of a common demand parameter. 

As an example, consider a hypothetical piece of electro-mechanical 

equipment that may incur a variety of types of earthquake damage that render 

it inoperable, and therefore unable to provide service. These could include, 

for example, arcing and burnout of an electrical component, development of 

imbalance in a mechanical component, and loosening of a seal of a pressurecontaining component. Even though these types of damage are technically 

different they may result in similar consequences. For example, they all may 

pose no significant risk to life safety, will all cause loss of use of the 

equipment, and will all require replacement of the equipment with a new 

unit. Thus, in this example, the casualties, direct economic loss and 

downtime consequences of each of these types of damage are identical. If all 
FEMA 461 1: Introduction and General Considerations 9 

of these types of damage can be predicted by the same engineering demand 

parameter, say floor acceleration, then they can all be treated as a single 

damage state, perhaps termed equipment malfunction. 

Often, however, different types of damage to a component will result in 

different consequences. For example, if the seal in the piece of equipment 

could be easily replaced requiring a simple service call, while the electrical 

short and mechanical imbalance requires unit replacement, then two separate 

damage states would be defined – repair by service call, and unit 

replacement. Finally, if the electrical short was most closely related to 

imposed velocity of the unit while the mechanical imbalance was related to 

unit acceleration, then three unique damage states would be defined: repair 

by service call, replacement related to excessive velocity, and replacement 

related to excessive acceleration. 

An important step in the characterization of performance of components is 

the selection of appropriate damage states for which fragilities will be 

developed. Typically this will require the cooperative effort of persons 

knowledgeable in the method of operation of the component, the 

consequences of its failure in terms of life loss, and repair procedures. 

1.5 Uncertainty Issues 

Uncertainty introduces dispersion, or scatter, into the predictability of a 

behavior. In the fragility curves illustrated in Figure 1-1, the damage state 

associated with loosening of the aluminum framing is illustrated to have 

relatively low uncertainty, characterized by a tight band of demand values at 

which the damage is likely to occur, while fallout of the glazing and 

permanent distortion of the framing is indicated to have high uncertainty, 

evidenced by the broad range of demands at which the damage may occur. 

Uncertainty of dispersion is accounted for by the parameter β in the fragility 

function. If β has a small value, say on the order of 0.2, this indicates that 

the behavior of the component is relatively predictable and that the damage 

state will initiate within a relatively small range of demands. On the other 

hand, as β becomes larger, this indicates that the onset of the damage state is 

relatively unpredictable and that the damage could initiate over a broad range 

of potential demand values. Typically values of β should not exceed a value 

of about 0.5. In those cases where β does exceed this value this may be an 

indication that the demand parameter being used to predict onset of the 

damage mode is not an appropriate one. 

Uncertainty, represented by the parameter β, occurs from a variety of 

sources. There is natural variation resulting from randomness in material 
10 1: Introduction and General Considerations FEMA 461 

strengths, randomness in ground-motion characteristics, and randomness in 

the adequacy with which a unit is constructed and installed. There is also 

uncertainty related to the way in which the behavior of the unit is predicted 

by modeling. For example, the behavior of a particular component may be 

related to both the acceleration and the displacement to which the component 

is subjected. However, we may decide that it is too difficult to use both 

parameters simultaneously to predict behavior, and that one of these 

parameters, say displacement, tends to be a more dominant predictor of the 

behavior. To the extent that the behavior is actually a function of both 

displacement and acceleration, we will either over-predict or under- predict 

the behavior based on displacement alone. 

Some sources of uncertainty can be reduced by further study or more 

rigorous investigation. For example, by conducting rigorous quality 

assurance measures, uncertainty related to manufacturing and installation 

variability can be reduced. Similarly, by using a more accurate model to 

predict behavior, for example, using both acceleration and displacement in 

the above illustration, modeling uncertainty can be reduced. Other 

uncertainties cannot be reduced, either because it would be impractical to do 

the work necessary to gain the necessary knowledge or because we do not 

have sufficient understanding of the behavior. 

In the development of fragility functions, uncertainty in the form of a β value 

can be derived by two basic means. The first is by testing a sufficient 

number of specimens using varying loading protocols to permit 

characterization of both the natural and modeling uncertainties. The second 

is to apply expert judgment. It is seldom possible to perform sufficient 

testing to allow characterization of the uncertainty by testing alone. 

Therefore, values of β must typically be set on the basis of expert judgment 

or a combination of test data and judgment. 

It is recommended, that as a minimum, three specimens be used to provide 

data on the fragility of each nonstructural component. With three specimens, 

it is possible to determine a median value for fragility, ˆmY , as well as a 

coefficient of variation, which together with expert judgment can be used to 

develop an appropriate value of β. Development of fragility functions from 

laboratory test data is discussed in Appendix A. 

1.6 Damage and Repair Costs 

Component fragility functions are developed to permit the losses associated 

with damage to components and to systems comprised of these components 

to be estimated as part of the performance-based design process. The 
FEMA 461 1: Introduction and General Considerations 11 

consequences of a component damage state, in terms of, for example, loss of 

service, potential casualties, and cost of repair, are determined through 

application of loss functions. Loss functions indicate the conditional 

probability of experiencing a given level of loss, given that a component 

damage state has occurred. Loss functions typically have large associated 

uncertainty because they are inherently dependent on human behavior, which 

is often unpredictable. For example, the time required to repair a window in 

a building depends in large measure on how rapidly the building owner 

actually hires someone to make the repair. In general, a separate series of 

loss functions, indicating the probable casualty impacts, repair or 

replacement cost impacts, and service interruption impacts must be prepared 

for each damage state. The development of loss functions is beyond the 

scope of this protocol document. 

1.7 Nonstructural Component Qualification 

Some building codes and design specifications require that equipment and 

other types of nonstructural components be certified by the supplier as 

qualified to resist certain levels of ground shaking, or other seismic-induced 

loading, without failure. Several guidelines have been developed by 

evaluation services to guide manufacturers and suppliers on approaches to 

equipment qualification. 

The procedures contained in this protocol document are intended to allow 

determination of the median loading at which damage of different types will 

occur in nonstructural components and the dispersion associated with this 

loading. This is not directly compatible with the intent of equipment 

qualification, which is to demonstrate that there is a very low probability that 

failure will occur at a specific level of loading. It should be noted that once a 

fragility curve, characterized by a median value and dispersion, has been 

developed for a nonstructural component and damage state, it should be 

possible to pick that level of loading (at which there is a sufficiently low 

probability of failure) on the fragility function as the loading level for which 

the component is qualified. This is commonly done in the nuclear industry 

for example, where equipment is considered as qualified for adequate 

performance if the fragility for the equipment indicates a 95% confidence 

level of less than a 5% chance of failure at the given loading. 

The protocols presented herein could be used for equipment performance 

qualification, although such use is beyond the intended scope of this 

publication. 
12 1: Introduction and General Considerations FEMA 461 

1.8 Protocol Types 

Two separate protocols for laboratory testing of structural and nonstructural 

components are presented. These are: 

• Protocol I – Quasi-Static Cyclic Testing of Structural and Nonstructural 

Components and Systems, and 

• Protocol II – Shake Table Testing of Structural and Nonstructural 

Components and Systems. 

Protocol I should be used for the determination of performance 

characteristics of components, the behavior of which is primarily controlled 

by the application of seismic forces or seismic-induced displacements. This 

protocol may be used to determine fragility data for many structural and 

nonstructural components and in addition may be used to derive constituent 

force-deformation properties and hysteretic data for structural components 

needed for structural analysis and assessments. Examples of structural 

components that may be tested in accordance with this protocol include shear 

walls, beam-column assemblies and frame assemblies. Examples of 

nonstructural components for which this protocol is suitable include cladding 

panels, glazing panels, and drywall partitions. This protocol may also be used 

to derive force-deformation properties (of a nonstructural component) that 

can be used in the structural analysis of a nonstructural system of which the 

nonstructural component forms a part. Examples of nonstructural system 

components for which this protocol is suitable include piping and ducting 

system connections, ducts, and various types of anchors and braces. 

Protocol II should be used to assess the performance characteristics of 

components whose behavior is affected by the dynamic response of the 

component itself, or whose behavior is velocity sensitive, or sensitive to strainrate effects. This protocol should not be used, if in addition to fragility data, 

hysteretic data on force-deformation properties of a component are needed for 

use in structural analysis. Examples of nonstructural components for which this 

protocol is suitable include mechanical and electrical equipment. 

The protocols are interim pending further implementation and evaluation by 

researchers nationwide. Other protocols are also available for testing of 

structural components, including the ATC-24 Guidelines for Cyclic Seismic 

Testing of Components of Steel Structures (ATC, 1992) and the Consortium 

of Universities for Research in Earthquake Engineering (CUREE) Testing 

Protocol for Wood Frame Structures (Krawinkler et al., 2001). 
FEMA 461 2: Interim Protocol I – Quasi-Static Cyclic Testing 13 

Chapter 2 

Interim Protocol I – Quasi-Static 

Cyclic Testing

2.1 Scope 

This Chapter presents interim recommended testing procedures, loading 

histories, and documentation protocols for performance assessment of the 

characteristics of building components and subsystems using quasi-static 

cyclic testing. The performance characteristics are presented in the form of 

fragility functions that relate the probability that a component will be 

damaged to a defined damage state or more severe state, given that demand 

of specified value is experienced. Demands may be expressed in terms of 

any quantifiable parameter that may be predicted by structural analysis 

including imposed drift, acceleration, velocity, and accumulated energy. The 

scope of a testing program for the development of fragility data is as follows: 

(a) Identification of relevant damage states. The term “relevant” implies 

that the damage states are well defined, clearly discernible, and 

associated with actions whose costs or consequences can be quantified. 

Such an action could be: the application of a specific repair technique, 

for example, epoxy injection of cracks in a concrete wall; the need for 

replacement of the component; the creation of a life-threatening 

condition, for example, rapid depressurization of a pressure-containing 

vessel; or the need to declare the component incapable of fulfilling its 

function. 

(b) Identification of a demand parameter, or set of demand parameters, that 

correlates well with the damage states identified in (a). Typically, the 

demand parameter will be either a deformation quantity such as 

interstory drift ratio, (the relative horizontal displacement between two 

floor levels, normalized by the story height), or the transverse force 

applied to a component. Other demand parameters may be found to be 

more efficient in predicting component behavior. 

(c) Testing of the component in accordance with a well-defined test plan and 

a loading protocol that permits the establishment of relationships 

between the damage states and the associated demands. Ideally, this 

implies the testing of a sufficiently large number of components to 

permit the quantification of variability, or, with appropriate assumptions, 
14 2: Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

identification of the type of distribution, the quantification of a central 

value and a measure of dispersion. 

2.2 Applicability 

This protocol applies to performance testing of building parts or components 

when damage is best predicted by imposed deformation. Examples of 

components that may be tested in accordance with this protocol include 

partitions and their anchorages, cladding, pipes, ducts, and other equipment 

that is connected to floors above and below. Examples of structural 

components that may be tested in accordance with this protocol include shear 

walls, beam-column assemblies, and frame assemblies. 

When non-structural components are tested using this protocol the intent, 

generally, is to obtain fragility data only. When structural components are 

tested using this protocol, in addition to obtaining fragility data, it is also 

important to obtain data on the hysteretic characteristics of the components 

that can be used to form analytical models of the behavior of structures 

incorporating these components. 

The protocol consists of slow cyclic application of load or deformation with 

a predetermined loading pattern. This protocol is not appropriate for use in 

performance testing of components whose behavior is significantly affected 

by the dynamic response of the component, or whose behavior is sensitive to 

strain rate or velocity effects. Components sensitive to these dynamic effects 

should be tested using the Interim Protocol II – Shake Table Testing, as 

described in Chapter 3. 

Two types of testing are covered by this Chapter: 

• Racking Testing. This type of testing is performed for components that 

either are not required to participate in a building’s structural resistance 

or do not provide significant strength or stiffness modification of the 

building structure. These components will not typically be included in 

structural analytical models used to predict building performance. 

• Hysteretic Testing. This type of testing is performed for components 

that either are intended to provide structural resistance or significantly 

alter the strength or stiffness of a building structure. These types of 

components will typically be included in analytical models used to 

predict structural performance. 
FEMA 461 2: Interim Protocol I – Quasi-Static Cyclic Testing 15 

2.3 Component Documentation 

This section specifies the information that should be documented for tested 

components. This information includes component description, functional 

and operational information, installation requirements, and information that 

can be used to extrapolate and interpolate performance characteristics for 

application to similar components. 

2.3.1 Structural Components 

A complete description of the component to be tested shall be provided. 

Information to be supplied, as applicable, includes, but is not limited to: 

• materials of construction including standard ASTM grades as applicable, 

• specimen specific strength tests, including, as applicable, yield strength, 

tensile strength, and compressive strength, 

• assembly drawings showing specimen dimensions and connectivity, and 

• details of fabrication and construction. 

2.3.2 Nonstructural Components 

A complete description of the component to be tested shall be provided. 

Information to be supplied, as applicable, includes, but is not limited to: 

• manufacturer information, 

• Model and Part Number, 

• fabrication information, 

• material type and characteristics, and 

• relevant drawings. 

The functional and operational requirements of components before, during, 

and after testing shall be specified. 

Substitutions for operating requirements shall be described and justified. 

Examples include using air rather than gas for pressurization, or substituting 

water for hazardous liquids. 

Potential safety issues arising from operation during testing must be 

addressed. 
16 2: Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

2.4 Procurement, Fabrication and Inspection of Test 

Specimens 

Test specimens should replicate in-situ conditions so that material properties, 

standard construction techniques, and boundary conditions encountered in 

actual buildings are properly simulated. Full-size specimens should be used 

whenever possible and where not possible, the scale of the specimens should 

be as close to full size as feasible, in order to minimize size effects. 

Whenever feasible, test specimens should be fabricated and installed by 

construction workers who typically construct and install this type of 

component in real buildings so that typical construction quality is exercised. 

In case the specimen is fabricated and installed by lab personnel, all 

applicable fabrication and installation guidelines shall be followed and 

industry standard practice should be adhered to. 

The fabrication and installation of the test specimen shall be fully 

documented, with an itemization of all parts (and their properties) on which 

the damage states depend. Before testing, the specimen shall be inspected by 

an expert who is qualified to attest that the test specimen and its boundary 

conditions represent average in-situ conditions. 

The tested components shall be operational (if applicable) and randomly 

selected from manufacturer’s or retailer’s stock and shall be representative of 

those found in typical installed applications. 

For manufactured components, installation instructions should be provided 

by the manufacturer and adhered to. Any deviation between the tested 

configuration and typical installed conditions shall be described and justified 

as being functionally equivalent. 

2.5 Extrapolation and Interpolation to Similar 

Components 

If the fragility function derived from a testing program is to be applied to 

components that vary in configuration, material properties, construction 

details, or boundary conditions, then analytical means could be employed to 

extrapolate from the observed fragility to different conditions (if this can be 

done with adequate confidence). In this case it will be necessary to complete 

supplementary testing programs that will quantify the properties of materials 

and sub-components to the extent needed to permit extrapolation of fragility 

results through analytical means. 
FEMA 461 2: Interim Protocol I – Quasi-Static Cyclic Testing 17 

If it is impossible to test a specimen close to full size, then additional tests 

will be needed to quantify size effects to the extent that will permit reliable 

extrapolation from reduced-scale tests to full-size behavior. 

Test results may be extrapolated or interpolated to functionally similar 

components provided that: 

• the untested components are completely described, with particular 

emphasis on differences with the tested components, and 

• justification for the extrapolation or interpolation is provided, showing 

that the performance envelope of the untested component lies between 

two of the tested components, or is greater (in the sense of “better”) than 

the tested component. 

2.6 Test Facility Standards 

This section describes basic calibration and maintenance criteria for 

laboratories and equipment used for performance testing. The requirements 

of Sections 2.6.1 and 2.6.2 may be relaxed if the sole purpose of testing is the 

development of drift-dependent fragility data as opposed to derivation of 

load-deformation response for analytical modeling. 

2.6.1 Laboratory 

Testing laboratories shall comply with a national or international 

accreditation criterion such as the International Code Council (ICC) 

Evaluation Service (ES) Acceptance Criteria for Laboratory Accreditation

(ICC, 2000) or satisfy the requirements of the Network for Earthquake 

Engineering Simulations (NEES) Consortium. 

2.6.2 Equipment 

2.6.2.1 Actuators 

Actuators should be sized to provide reserve capacity for both force and 

displacement beyond the maximum anticipated as necessary for the test. 

Control of the actuators shall permit stopping immediately in any position 

and holding that position. If a power or computer failure occurs during 

testing, the actuators shall be capable of stopping immediately. Actuator 

mounting shall be designed so as to create loading in the desired direction 

only. During the loading cycle, minimize the off-axis forces and 

displacements created by rotations of the actuator or component under test. 
18 2: Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

2.6.2.2 Instruments 

The model, type, location and orientation of instrumentation shall be 

documented and uniquely identified. Instrumentation calibrations shall 

conform to NIST traceable primary standards or other applicable standards. 

The instruments shall be recalibrated at least once each year. These 

calibrations shall be verified before each test. 

2.6.2.3 Data Acquisition System 

Data acquisition system calibrations shall conform to NIST traceable primary 

standards, or other applicable standards. The data acquisition system shall be 

recalibrated at least once every year. These calibrations shall be verified 

before each test. The sampling rate shall be sufficient to capture all aspects 

of the load-deformation response relevant to the analytical modeling of the 

component. 

2.6.2.4 Safety Procedures 

The testing laboratory shall follow the standard safety procedures 

individually developed at each test site. These procedures shall ensure the 

safety of the occupants and testing systems at all times. The minimum 

requirements and procedures should include but should not be limited to the 

following. 

• Laboratory safety procedures as mandated by the testing facility to 

minimize hazard and danger to persons in the test area shall be followed. 

• Personal safety during all phases of testing (including during post-test 

examination) shall be observed and may include hard-hat, protective 

eyewear, clothing, gloves, and safety shoes as appropriate. 

• The testing could involve the use of hazardous materials, operations, and 

equipment. This document does not address specific safety issues 

associated with these uses. It is the responsibility of the laboratory 

implementing this recommended test protocol to establish appropriate 

safety precautions. 

2.7 Test Plan and Procedures 

A detailed test plan should be developed, documented and approved by 

responsible personnel prior to the execution of a test program. This test plan 

should address the following aspects: 

• identification of test specimen and its relation to the component whose 

performance is to be evaluated, 
FEMA 461 2: Interim Protocol I – Quasi-Static Cyclic Testing 19 

• preliminary identification of damage states for which fragilities are to be 

determined, 

• number of specimens to be tested, 

• loading history, 

• design of a test set-up that permits appropriate load simulation and 

proper simulation of all important boundary conditions, 

• identification of all important response parameters, and an 

instrumentation plan for measurement of these parameters, 

• detailed drawings of test specimens, test setup, boundary condition 

simulation, loading arrangement, and instrumentation, 

• identification of needs for supplementary testing, and 

• identification of a test schedule to ensure that the objectives of the testing 

program will be achieved in a timely and cost-effective manner. 

Recommendations for specimen fabrication, material testing, planning and 

execution of experiments, test control, and specimen instrumentation shall be 

taken from existing standards and guidelines for testing of components and 

materials (see, for example, ASTM). 

The component whose performance is to be evaluated needs to be isolated 

from its in-situ surroundings so that it can be tested in a laboratory 

environment. The lab should faithfully reproduce these in-situ conditions. 

The number of test specimens is to be decided by the entity requesting the 

fragility tests. 

The test plan should contain clear and well-documented procedures for the 

simulation of all boundary and initial conditions that may significantly affect 

any of the damage states of interest. The boundary conditions comprising the 

anchorage details and distribution of forces resulting from the imposed 

deformations shall be equivalent to those encountered in a typical 

application. 

The test plan should contain a clear and well-documented plan for the 

measurement, recording, and documentation of all relevant data to be 

measured or visually observed during the test. For racking testing the 

primary parameter to be measured, with good accuracy, is the demand 

parameter that will be used to define the fragility function (typically an 

imposed deformation). For hysteretic testing all parameters of importance 

for analytical modeling should be identified, including forces, moments, and 
20 2: Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

shears, and axial, shear and flexural deformations. Instrumentation 

appropriate for accurate measurement of these parameters shall be provided. 

2.8 Loading and Load Control 

A test may be carried out under deformation control or force control (or a 

combination of the two when accurate force and deformation data are 

needed) within the elastic as well as the inelastic range. 

2.8.1 Deformation-Controlled Testing 

The deformation control parameter may be a displacement or other suitable 

deformation quantity (e.g., a rotation). However, it is important that this 

parameter can be correlated with a building deformation parameter, for 

example, interstory drift, that can be predicted by conventional structural 

analysis of a building structure. Items to consider include: 

• feedback control of the deformation, 

• appropriate control of the direction and speed, using suitable valving, 

hydraulic fluid control valves, and servo valves, and 

• type of controller, hardware or software, considering the feedback update 

rate and the recording sample rate. 

The deformation increment should be sufficiently small that: 

• dynamic effects are negligible, 

• the value of the deformation parameter, at which onset of the various 

damage states of interest initiate, is clearly identifiable, 

• thermal effects due to work-hardening are not significant, and 

• power requirements are not unreasonable. 

The deformation increment should be sufficiently large that: 

• the duration of the test is not excessive, 

• material creep is not a significant effect (unless creep is considered to be 

part of the damage states of interest), and 

• the number of cycles experienced by the component at the onset of 

significant damage states is of the same order of magnitude as that 

experienced by real components in buildings subjected to strong 

earthquake motion. Particular care should be taken to avoid introduction 

of low-cycle fatigue behavior that is unlikely to be experienced by real 

components in buildings. 
FEMA 461 2: Interim Protocol I – Quasi-Static Cyclic Testing 21 

2.8.2 Force-Controlled Testing 

The force-control quantity shall be a measurable and controllable quantity 

that relates well to a demand quantity that can be predicted by structural 

analysis of a building structure. Considerations include: 

• feedback control of the force, 

• imposed force fluctuations during load reversals due to pressure 

fluctuations or mechanical inertia of the actuator, 

• appropriate control of the direction and speed using suitable valving, 

hydraulic fluid control valves, and servo valves, and 

• type of controller, hardware or software, considering the feedback update 

rate and the recording sample rate. 

The force increment should be sufficiently small that: 

• dynamic effects are negligible, 

• the applied force initiating the various damage states of interest must be 

clearly identifiable, 

• thermal effects due to work hardening are not significant, and 

• power requirements are not unreasonable. 

The force increment should be sufficiently large that: 

• the duration of the test is not excessive, and 

• material creep is not a significant effect (unless creep is considered to be 

part of the damage states of interest). 

2.8.3 Directions of Loading 

Imposed deformation or force will typically be applied in a single degree of 

freedom (unidirectional loading). Bidirectional loading (loading in two 

orthogonal horizontal directions) should be carried out whenever it is 

anticipated that such loading has a significant effect on any of the damage 

states and the associated fragility function. Written justification should be 

provided if it is decided in this case to apply only unidirectional loading. 

2.9 Loading Histories 

2.9.1 Unidirectional Testing 

This section describes a recommended loading history appropriate for 

racking testing or hysteretic testing if a single specimen will be used to 
22 2: Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

quantify all damage states for which fragility functions are to be developed. 

Quantification implies that at least one data point will be obtained for the 

loading at which each damage state (DSi) initiates (several data points can be 

obtained if multiple damage state interpretations are made by several 

experts). It is highly recommended to perform an additional monotonic test 

to provide a baseline for estimating the cumulative damage effect at each 

damage state. 

Figure 2-1 presents a conceptual diagram of the recommended loading 

history. The loading history consists of repeated cycles of step-wise 

increasing deformation amplitudes. Two cycles at each amplitude shall be 

completed. 

Figure 2-1 Sketch of deformation-controlled loading history 

The loading history is defined by the following. 

Δo = the targeted smallest deformation amplitude of the loading history. It 

must be safely smaller than the amplitude at which the lowest 

damage state is first observed. At the lowest damage state at least six 

cycles must have been executed. If no data exists regarding what 

amplitude of deformation is likely to initiate damage, a 

recommended value for Δo (in terms of story drift index, δ/h) is 

around 0.0015. 

Δm = the targeted maximum deformation amplitude of the loading history. 

It is an estimated value of the imposed deformation at which the 

most severe damage level is expected to initiate. This value must be 

estimated prior to the test. (It can be estimated from a monotonic 

test). If the most severe damage initiates at a drift smaller than the 

target value, judgment must be used to assess whether the cumulative 

damage effect at the actual initiation of damage is indeed comparable 

0

-1.2

1.2

Target: Δ m

Δm

Target: Δ0 0

-1.2

1.2

Target:

Target: 
FEMA 461 2: Interim Protocol I – Quasi-Static Cyclic Testing 23 

to that which would have occurred if the specimen had sustained the 

complete loading history. If the most severe damage state has not 

yet occurred at the target value, the loading history should be 

continued by using further increments of amplitude of 0.3Δm. A 

recommended value for this amplitude, lacking other evidence, such 

as the results of a prior monotonic test (in terms of story drift index, 

δ/h), is 0.03. 

n = the number of steps (or increments) in the loading history, generally 

10 or larger. 

ai = the amplitude of the cycles, as they increase in magnitude, i.e., the 

first amplitude, a1, is Δo (or a value close to it), and the last planned 

amplitude, an, is Δm (or a value close to it). Whenever possible, the 

test should be continued beyond Δm even if the most severe damage 

state has been attained. Tests should be terminated only when the 

capabilities of the test setup have been reached, e.g., the available 

stroke of the loading ram has been reached, or the test specimen has 

degraded so severely that no relevant additional information about 

performance can be acquired. 

The amplitude ai+1 of the step i+1 (not of each cycle, since each step has two 

cycles) is given by the following equation: 

a a i i +1 =1.4 (2-1) 

where ai is the amplitude of the preceding step, and an is the amplitude of the 

step close to the target, Δm. 

If the specimen has not reached the final damage state at Δm, the amplitude 

shall be increased further by the constant increment 0.3Δm. If it is desired 

that the largest amplitude, an, be exactly equal to Δm, then the ratios ai/an

shall be as shown in Table 2-1. A loading history with an = Δm and a1 = 

0.048Δm (i.e., n = 10, number of cycles is 10 x 2 = 20 cycles) is shown in 

Figure 2-2. 

Table 2-1 Relative Loading History Deformation Amplitudes 

n 13 12 11 10 9 8 7 6 5 4 3 2 1 

ai/an 0.018 0.025 0.035 0.048 0.068 0.095 0.133 0.186 0.260 0.364 0.510 0.714 1.000

Note: Generally, the number of steps n should be 10 or larger. 
24 2: Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

Figure 2-2 Loading history for a1 = 0.048Δm

2.9.2 Bidirectional Testing 

When bidirectional testing is performed the loading path should follow the 

orbital pattern shown in Figure 2-3. The amplitude of loading, a, in the 

figure should follow the history described in the previous section on 

unidirectional testing. 

Figure 2-3 Horizontal plane displacement orbit for drift-controlled bidirectional tests. Displacements during the first cycle, containing 

seven steps (i through vii), are shown. 

2.9.3 Force-Controlled Loading 

Force-controlled testing should be performed if a force quantity controls 

performance of the component, or if a suitable deformation parameter cannot 

be found. The reference value on which to base the amplitudes of individual 

cycles is the maximum force to which the component or part may be 

subjected in a severe earthquake. Since the force demands will be greatly 

dependent on the type of component or part and on the in-situ conditions, it 
FEMA 461 2: Interim Protocol I – Quasi-Static Cyclic Testing 25 

is impossible to develop a general force-based loading protocol. The 

following guidelines should be employed to develop case-specific protocols. 

The basic premise is that forces are consequences of deformations, and that 

the deformations, in relative magnitude, have the history shown in Figure 2-1 

and are given by Equation 2-1. If the force-deformation characteristics of the 

force-sensitive component (or part) are known (from analytical predictions or 

from a monotonic test of the subsystem of which the force-sensitive 

component is part), then the cyclic loading history shown in Figure 2-1 and 

the load-deformation response of the component can be combined to develop 

a force history to be applied to the component. This is illustrated in Figure 2-

4, where it is assumed that the force-deformation behavior of the component 

is given, and where it is also assumed that the maximum deformation in the 

component can be related to the Δm value of Figure 2-1. With this 

knowledge, the forces corresponding to all other amplitudes of the drift 

loading history can be deduced graphically, and a force history can be 

developed. The loading history for the case illustrated in Figure 2-4 is shown 

in Figure 2-5 for illustrative purposes. 

Figure 2-4 Illustration of conceptual approach for development of forcecontrolled loading history 

Figure 2-5 Illustrative force loading history for case illustrated in Figure 2-4 
26 2: Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

It is important to incorporate cyclic hardening in the subsystem of which the 

force-sensitive component is part when developing criteria for the maximum 

absolute force the force-sensitive component must sustain. 

2.10 Reporting 

Each test should be documented in a comprehensive test report. The test 

report should include information about the testing agency/laboratory and 

sponsoring agency, including location of the test site and contact 

information, test date, date of report, a statement that the test has been 

conducted based on this protocol (including identification of deviations from 

this protocol, as appropriate), and the name of the organization reporting the 

tests with names and signatures of members of the experimental team 

responsible for carrying out the tests. The report should also include any 

witnessing requirements such as a list of independent observers and any 

required verification/certifications of all test phases. Specific information to 

be contained in the report also includes: 

• a detailed description of the test specimens, including, for example, 

manufacturer (if any component is supplied), type, material used, and 

dimensions, and, furthermore, details needed for the understanding of the 

design and manufacture of the specimen, 

• if an equipment/instrument component is being tested, a description of 

the component under investigation including type, 

manufacturer/fabricator, model number, specification, calibration 

procedure, any available/required calibration certificates, material 

information and characteristics, manufacturing information, any specific 

handling requirements, functional requirements, and sketches and 

pictures of the component, 

• a description of the physical and engineering characteristics of the 

material(s) (type, grade, size, yield point, tensile and compressive 

strength, density, moisture content, as applicable) of structural elements 

and details (dimensions, spacing, property) of anchoring elements and 

fasteners for nonstructural components, 

• a summary table that describes all specimen configurations and their 

corresponding tests (i.e., the complete test matrix), 

• a conceptual plan of the test facility and a sketch of the test setup. This 

sketch should include details of the attachment of the specimen to the 

testing frame with an indication of the location of the measuring devices 

(load cells, strain gages, deflection gages (LVDT), and any other 

applicable items), 
FEMA 461 2: Interim Protocol I – Quasi-Static Cyclic Testing 27 

• a description of the conditions under which the tests were carried out, 

including ambient conditions (e.g., temperature, relative humidity, and 

moisture content, as applicable), 

• a complete description of measurement methods and devices, including 

direction of measurement, and technical specification of instruments used 

for load and displacement/deformation/strain measurement, and 

furthermore, a description of the conditions of the measurement 

instruments, tolerances, and accuracy, 

• the following information for the data acquisition system: type, 

manufacturer name and model number, system identifications, all 

calibration procedures, any available/required calibration certificates, and 

schematic information flow, 

• a description of the test specimen before the beginning of the test 

(including any unusual characteristics or defects) and after each test 

interval, including any modifications to the specimens during the test, 

[The description should include the observed performance of the 

specimen in relation to all damage states of interest and clear sketches 

and written descriptions of the visible characteristics of damage patterns 

and failure modes (e.g., cracking, fallout, brittle or ductile fracture, 

yielding, excessive deflection or distortion). The report should include 

photographs of specimens taken before, during, and after each test. 

Alternatively, video taping of the testing shall be performed and included 

as part of the test report. Links to download video clips of the test 

should be made available.] 

• as applicable, the load versus time, displacement versus time and loaddisplacement relationships (i.e., a complete record in the form of tables, 

plots, hysteresis curves, and envelope curves) at all measurement 

locations. [The report should include a summary table of load and 

deformation values at all damage states of interest.] 

Electronic dissemination of test procedures and results is strongly 

encouraged. If the information is available for public use, a link from which 

all the data as well as the test report can be downloaded shall be provided. 

As much as feasible, the data format should correspond to that developed by 

NEES for its data repository. 

FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 29 

Chapter C2 

Commentary on Interim Protocol I 

– Quasi-Static Cyclic Testing

Chapter C2 contains commentary for Sections 2.6, 2.7, 2.8 and 2.9 of Interim 

Protocol I – Quasi-Static Cyclic Testing. Commentary is not provided for 

the other sections. 

C2.6 Test Facility Standards 

C2.6.2 Equipment

The purpose of testing goes beyond the establishment of an empirical 

fragility curve. A test serves to improve understanding of behavior and, if 

appropriate, to provide the basis for analytical prediction of the behavior of 

the component and of the factors that contribute to damage. Since the action 

on the test specimen is the load causing a predetermined deformation, it is 

necessary to record the load (or loads) causing the resulting deformation(s). 

Additional instrumentation should be provided as is deemed necessary to 

improve understanding of behavior and to quantify parameters on which the 

behavior depends. Since most components can be used in a variety of 

configurations, an attempt should be made to measure all relevant parameters 

on which behavior (or, specifically, damage states) depends. This may 

include geometry, thickness, and method of attachment. In this manner it 

should be possible to extrapolate fragility curves to different component 

configurations, if the measurements provide sufficient quantitative data to 

assess the effects of important parameters analytically. 

Damage states, which are described in Section 1.4, can sometimes be 

quantified through direct measurements, and sometimes they have to be 

assessed through visual observations. A comprehensive log should be kept 

of all important visual observations and should be supplemented by 

frequently taken photos and other means of instantaneous or continuous 

visual documentation (e.g., sketches and videos). 

C2.7 Test Plan and Procedures 

Reproduction of in-situ conditions is perhaps the most critical aspect of a 

component testing program, as it requires isolation of a component, careful 
30 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

simulation of boundary conditions, and realistic simulation of seismic 

effects. 

In the context of a general testing protocol it is possible to provide broad 

guidelines on issues that should be considered, such as those discussed in the 

following. 

• The isolated component must be representative of the actual in-service 

conditions the component will experience in a real building. In addition 

to the requirement that the condition of manufacture/construction and 

installation replicate the in-situ conditions as closely as possible, it is also 

important that the relationship between the loading parameter used in the 

tests and the damage states obtained from the testing program is 

representative of the conditions that will exist in buildings for the range 

of components for which the fragility function is to be applied. 

• For many components, it is anticipated that the loading parameter used in 

the test will be intended to represent deformation induced in the 

component due to the interstory shear drift in a real building. The term 

“shear“ implies a story distortion as shown in Figure C2-1(a), and not a 

story drift caused by cumulative rotation as the one shown in Figure C2-

1(b). A component mounted on a floor of a building in a story that 

undergoes rotation drift, as illustrated in Figure C2-1(b) may not 

experience any real deformation demand. It is important that test 

boundary conditions replicate or can be converted to the mode of 

deformations that will actually occur in the building. 

δi δi

(a) (b)

δi δi

(a) (b)

Figure C2-1 Different sources of story drift: (a) shear drift, and 

(b) rotation drift. 

• Any deformation can be used as a loading parameter in a test. However, 

it is important that the deformation used in the test can be used to predict 

damage of components in a real building based on typical response 

quantities obtained from structural analysis of a building structure. The 

most convenient such deformation parameter is interstory drift. If the 

test specimen loading is controlled by a loading parameter other than the 

story shear drift, the relationship between this loading parameter and 

story shear drift should be clearly established so that the resulting 
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 31 

fragility functions can be transformed to a domain that is useful in 

predicting building damage. 

• The way in which loading will be transferred between the real 

component in a building and the building’s structural system must be 

properly simulated in the test. For instance, a nonstructural wall tied 

continuously to a framing system will behave differently from a 

nonstructural wall pushed at diagonally opposite corners. Thus, 

anchorage and boundary conditions must be well simulated, and the 

loading applied to a test specimen must be transferred to the test 

specimen as closely as possible to the way in which loading will be 

applied in a real building. 

Fragility functions of the type discussed in Section 1.3 define the probability 

of being in or exceeding a specified damage state as a function of a relevant 

demand parameter that correlates well with the observed damage and can be 

predicted by structural analysis. The correlation with observed damage will 

never be perfect, which necessitates the development of probabilistic fragility 

functions. There are many sources of uncertainty that should be considered, 

including uncertainties caused by: 

1. testing a component isolated from its in-situ conditions such as electrical 

conduits, piping, or supported floor slabs, 

2. imperfect simulation of boundary conditions, 

3. extrapolation to in-situ conditions not fully simulated in the test, 

4. variability in configuration, 

5. employment of a loading history that cannot precisely replicate the 

loading experienced by components in a real building responding to 

earthquake shaking, 

6. uncertainty in the definition of the several damage states, and the input 

loading at which they initiate, and 

7. variability in material properties and fabrication/construction methods 

and details. 

The first four of the above can be reduced by careful planning of the testing 

program. The fifth one is believed to be small compared to some of the 

others. The last two can be considered explicitly in the testing program. 

Criteria for damage states are not uniquely defined in most cases and the 

decision as to what loading initiates a specific damage state requires 

judgment, based mostly on experience. This uncertainty can be reduced by 

the development of well-defined criteria for damage states and by the 
32 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

employment of experts capable of exercising good judgment. For a single 

specimen test, this uncertainty can be estimated by using a sufficiently large 

number of experts performing an independent assessment. Experts making 

the decision on damage states may not have to be present during the test if 

thorough and complete documentation is provided through measurements, 

sketches, photos, videos, and other means of observation. This encourages 

the employment of an instrumentation system that permits the measurement 

of physical parameters on which the damage states depend (e.g., crack width 

in a partition). 

Uncertainties associated with the variability in material properties and 

construction methods and details can be evaluated only by testing of multiple 

specimens (unless analytical means can be employed to estimate the 

uncertainties from material and sub-component tests). 

Thus, a testing program can range from a single-specimen, single-evaluator 

program to a multi-specimen, multi-evaluator program. A thorough pilot test 

on the latter is most desirable in order to gain insight into the various sources 

of dispersion that define the shape of fragility functions. A single-specimen, 

multi-evaluator program is desirable if the interpretation of damage states 

requires much expert judgment. A single-specimen, single-evaluator 

program is only recommended if the damage states can be clearly identified 

and if the material/construction uncertainties are known to be small 

compared with the other uncertainties enumerated above. 

C2.8 Loading and Load Control 

The boundary and initial conditions prior to testing a nonstructural 

component or system should be equivalent to those found in a typical 

application. Restraint forces due to temperature or shrinkage or other type of 

volumetric change should be emulated when such conditions are found and 

are significant in the application considered. Similarly, the effects of 

interstory shortening or elongation, beam shortening or elongation, and 

concentrated rotations should be emulated if the application considered is 

significantly affected by one or several of these conditions. 

Gravity loading present in the element tested should be representative of the 

conditions found in the application. When testing a reduced-size component, 

additional gravity loading may have to be distributed throughout the test 

specimen. The arrangement of the additional loading should be reported, as 

specified in Section 2.10. It should be ensured that the mechanisms required 

to simulate the additional gravity loading will not cause spurious changes in 

stiffness or strength. 
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 33 

In-situ boundary conditions that contribute to the initiation and propagation 

of damage should be properly simulated. This should include anchorages to 

structural or nonstructural components other than that under test, as well as 

imposed force or deformation patterns that are caused by deformations in the 

elements surrounding the component to be tested (e.g., deformation pattern 

of structural framing elements to which a piece of cladding is anchored). 

Simulation of boundary conditions also includes all relevant threedimensional features that may have a significant effect on damage initiation 

and propagation. In particular, the effects of story deformations in two 

orthogonal horizontal directions and in the vertical direction should be 

considered when significant. If it is found that story deformations orthogonal 

to the primary loading direction have a clear effect on damage, the 

bidirectional loading option discussed in Sections 2.8.3 and 2.9.2 should be 

utilized. 

Some component types can span upwards over more than one story. In such 

cases, the testing program should either contain tests of multi-story high 

specimens, or proper boundary conditions should be created to simulate 

attachment to more than one story. The boundary condition that are critical 

include panel-to-panel joints (adjacent panels, horizontally and vertically), 

guides (with minimum friction) to restrain panels in-plane throughout 

racking tests, prevention of uplift in wall systems that may otherwise uplift 

when subjected to transverse load at the top, application of horizontally 

distributed load at the top (this is accomplished by proper attachments to the 

moving beams of the test facility), and connectors that attach the component 

to the moving beams. 

Examples of test setups suitable for either racking or hysteretic testing of 

wall and cladding panel assemblies are provided in this commentary section. 

A test facility can consist of a structural support (reaction) frame that is very 

strong and stiff (compared with the test frame and specimens) and is fixed to 

a strong floor, a frame that simulates the building structural system to which 

the wall specimen will be attached, hydraulic actuators, load cells, LVDTs, 

sliding or gliding steel members (e.g., structural tubing) to which specimens 

will be attached directly or indirectly, and various linkages.

A schematic diagram of a typical stroke control and data acquisition system 

for a test facility is shown in Figure C2-2. The system can consist of 

computer and interface instrument, controller console, function generator, 

digital oscilloscope, load cell signal conditioning, LVDT signal 
34 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

Figure C2-2. Example of instrumentation and data acquisition system 

conditioning, and servovalve units. The test apparatus should include a 

means of recording all the necessary data.

For the example test facility shown in Figures C2-3 to C2-5, each specimen 

(e.g., curtain wall or cladding panel) should be centered between the sliding 

steel tubes of the test facility, and the wall specimen attached at all four 

corners to the facility’s sliding members (e.g., steel tubes). The sliding 

members shown in these three figures are steel tubes that slide on roller 

assemblies in opposite directions by means of a fulcrum and pivot arm 

mechanism. The bottom sliding steel tube is displaced by a computercontrolled electrohydraulic servoactuator having a dynamic stroke capacity 

of ± 76 mm (± 3 in.). The fulcrum and pivot arm mechanism attached to the 

top and bottom sliding steel tubes doubles the effective servoactuator stroke 

capacity to ± 152 mm (± 6 in.). 

For the example test facility shown in Figures C2-6 and C2-7, the test 

specimen (e.g., precast concrete cladding panels) is attached to the 

supporting frame with four connections, which can be of different types, e.g., 

flexible, bearing, or slotted. The test facility includes a support (test) frame 

that is used to represent a single bay of the building and in the figure
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 35 

Figure C2-3 Example racking test facility at Penn State University with setup 

for testing curtain walls 

Figure C2-4 Example test setup for testing horizontally attached cladding 

panels on the Penn State facility. 
36 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

Figure C2-5 Example test setup for testing vertically attached cladding panels 

on the Penn State facility 

Figure C2-6 Example racking test facility at the University of Idaho 
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 37 

Figure C2-7 Example test setup for testing cladding panels on the University 

of Idaho facility 

is shown as four W8x35 steel sections with moment-resisting joints. At the 

bottom of the support frame, there are four transverse guides (ball bearing) 

that prevent the specimen panel from moving out-of-plane during the racking 

movements. The guides may slightly add to the in-plane resistance due to 

friction. In the test facility shown in Figures C2-6 and C2-7, steel tubes (8 in. 

x 4 in. x 3/8 in.) connect the top of the support frame to the displacementcontrolled system with moment connections at the test frame and pin 

connections at the displacement control system. The displacement control 

system, which is used to apply racking movements to the specimen panel, 

consists of a hydraulic actuator connected to a W6x20 steel beam suspended 

from a lubricated glide system. An external reaction frame is used to support 

the support frame, the specimen and racking loading equipment. The reaction 

frame is very stiff relative to the internal frame to act as a stationary support 

for the support frame. 

The three schematic facilities shown in Figure C2-8 are generic ASTM 

Standard racking test facilities that are primarily for testing panels that are 

supported directly by the floor (e.g., a partition wall or an infill wall) and not 

attached to the building frame as a curtain wall or a cladding panel. The 

specimen in this case can be supported by a timber or steel member, which is 

in turn attached rigidly to the base of the loading frame or strong floor. The 
38 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

Figure C2-8 ASTM Standards generic test facility and setups for racking testing of shear-resisting wall panels. 

TEST WALL 
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 39 

sole plate of the specimen panel should be firmly attached (e.g., bolted or 

welded) to the base support member. Since the wall panel in this case will 

show large shear resistance, a hold-down mechanism such as rods or gravity 

loads should be provided to prevent the uplift tendency (rigid body rotation) 

as the racking loads are applied to the top of the wall. Mechanisms (e.g., 

rollers, sliding plates) should be provided to allow horizontal movement of 

the top of the wall panel with respect to the bottom without interference with 

the hold-down mechanism. In the facilities shown in Figure C2-8, the load is 

applied to the specimen top through a timber beam firmly bolted to the upper 

plate or part of the panel (to simulate connection of the wall top to floor 

above). Transverse guides (with minimum friction resistance) are also needed 

to prevent out-of-plane movement of the panel during the racking 

movements. For the tests on this type of facility, displacements should be 

measured to the nearest 0.25 mm (0.01 in.). The location of the dials shall be 

at all points where the data can be used to characterize properly the 

performance of the wall system, including the lower left, lower right, and 

upper right corners of the test assembly (assuming that the hold-down rods 

are on the left side). For the test setups shown in Figure C2-8, the lower left 

dial measures the rigid body rotation of the panel (because the hold-down 

rods could elongate and allow some rotation), the lower right dial measures 

the slippage (if any), and the upper right dial measures total deformation 

(including the effect of panel rigid body rotation and sliding). 

C2.9 Loading Histories 

Important Considerations 

The following are important considerations that enter in the decision process 

for developing or selecting a loading history for slow cyclic testing of 

nonstructural components. 

In general, there are several damage states to consider for each type of 

component. The options are to quantify all of them with a single specimen or 

to use separate specimens for each damage state. The usual preference is to 

use a single specimen, which appears justified unless cumulative damage 

becomes a dominant issue for low-damage states. 

The use of a single specimen necessitates a step-wise increasing loading 

history in which the loading sweeps through the full range of realistic values 

that may trigger one of the damage states. 

It is assumed that the fragility function is not conditioned on the structural 

system in which the component is mounted or on the ground motion 

experienced by the structure (i.e., the probability is assumed to be the same 
40 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

regardless of the source and the history of the loading on the component). It 

is well known that this assumption is incorrect but nonetheless, this 

assumption has to be made in order make the problem tractable. 

The only reason why a cyclic loading protocol is needed is that damage is a 

cumulative process and is affected by the history of excursions (an excursion 

is the path from one peak loading value to the next loading peak value) that 

precede the initiating loading for a damage state that is represented by the 

fragility function. 

Cumulative damage depends on the number and relative amplitudes of the 

excursions preceding the one at which the damage state is first observed, as 

well as on the sequence in which the excursions occur, the mean effect (since 

excursions are not symmetric with respect to the origin), and possibly on the 

“loading” rate at which the cyclic loading history is applied to the specimen. 

Mean effects and loading rate effects cannot be considered systematically in 

a slow static testing program. Mean effects (the fact that individual 

excursions are not symmetric with respect to the origin) are customarily 

neglected, i.e., each excursion is centered with respect to the undeformed 

configuration, resulting in a “symmetric” loading history. Load rate effects 

are neglected in favor of a testing process in which the load application is 

slow enough to permit visual observations of damage. 

Sequence effects can be incorporated conservatively by assuming that all 

excursions in a response history occur before the maximum one (this clearly 

is not the case and leads to a severe over-estimation of cumulative damage). 

An alternative is to consider only so-called “pre-peak” excursions as 

described below. Both options are pursued here. 

The task at hand is to develop a single loading history, which, in part by 

statistical evaluation of seismic response data and in part by judgment, 

represents all the cumulative damage effects at all the damage states that are 

to be quantified in a test. 

The alternative is to use different test specimens for each damage state and 

apply to each specimen a statistically representative deformation history in 

which the maximum excursion is deemed to be the excursion at which the 

damage state is attained for the first time. In order to assist in estimating this 

target maximum excursion for each damage state, it is most helpful to 

perform first a monotonic test on a separate specimen in which the loadings 

associated with the initiation of the various damage states are estimated. (The 

expectation is that each loading initiating a damage state in a monotonic test 

will be somewhat larger than the corresponding initiating loading from the 

cyclic test. However, it also has to be considered that a monotonic test may 

mask damage states occurring in a cyclically loaded specimen). Thus, if m

damage states are to be evaluated, this testing program would require m+1 
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 41 

test specimens to provide one data point for each damage state. This option 

is not pursued further. 

Basis for the Recommended Loading History 

The recommended loading history is based on the following assumptions, 

processes, reasoning, and observations. 

The number and relative amplitude of individual excursions are based on the 

response of structures to a set of 20 “ordinary” (no near-fault effect) ground 

motion records. The set of records is the one used to develop the CUREECalTech Woodframe Project loading protocol (Krawinkler et al., 2001). 

Near-fault ground motions may cause larger demands on components but 

will generate fewer response cycles, i.e., they will not control the number and 

relative amplitudes of the excursions in a loading history. 

This set of ground motions is used to perform response history analysis of 

elastic and inelastic (with a target ductility of 3) single-degree-of-freedom 

(SDOF) systems and multi-degree-of-freedom (MDOF) frame structures. 

Systems with periods of 0.2, 0.3, 0.5, 0.9 and 3.6 sec are evaluated. The 

hysteretic properties of the SDOF systems and the plastic hinge momentrotation relationships of MDOF systems are assumed to be peak-oriented. 

For each system the deformation response (displacement for SDOF systems 

and story drift for MDOF systems) for each ground motion is rearranged in 

excursions using the rainflow cycle counting method (ASTM, 2003). The 

deformation range (peak-to-peak value) of each excursion is centered with 

respect to the origin (i.e., the deformation amplitude is assumed to be half of 

the range, which implies that mean effects are ignored) and is normalized 

with respect to the amplitude of the largest excursion of the response. When 

ordered in magnitude, this results in a string of numbers from 2.0 on 

downwards, identifying the relative magnitudes of all excursions of the 

response. 

For the set of 20 records, statistical measures (median and 84th percentile) of 

each normalized range (the largest one, the second largest one, the third 

largest one, and so on) are computed, providing statistical values of the 

ranges relative to the largest one. Examples of such statistical values are 

shown graphically for elastic and inelastic SDOF and MDOF systems in 

Figures C2-9 to C2-12. The figures show relative ranges ranging from the 

maximum to 6.67% of the maximum excursion, considering all excursions of 

response histories, regardless of whether they occur before the peak response 

(pre-peak excursions) or after the peak response (post-peak excursions). 
42 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Elastic, SDOF, T=0.2 sec, 2% Damping, Median

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Elastic, SDOF, T=0.2 sec, 2% Damping, Median

(a) Elastic, 2% damping, 84th percentiles (b) Elastic, 2% damping, median values 

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Elastic, SDOF, T=0.2 sec, 5% Damping, 84%

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Elastic, SDOF, T=0.2 sec, 5% Damping, Median

(c) Elastic, 5% damping, 84th percentiles (d) Elastic, 5% damping, median values 

Figure C2-9 Ordered relative excursions, pre-peak plus post-peak, T = 0.2 sec., SDOF systems 

The following are relevant observations from these figures (C2-9 through 

C2-12): 

• For short-period structures the number of excursions between maximum 

and 6.67% of maximum is very large. The reason is that in the process 

followed here all excursions are counted, regardless of their sequence of 

occurrence. Depending on the ground motion, a large or very large 

portion of these excursions will occur after the peak response (see Figure 

C2-12 (a) and (b)). 

• All elastic histories show similar tapered decays in deformation ranges. 

• Inelastic histories show a more rapid decay and fewer excursions. 

• The 84th percentile graphs result in a very large number of excursions. 

The number of excursions for the median values are about 10 to 20% 

smaller. 

84%
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 43 

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Elastic, SDOF, T=0.3 sec, 5% Damping, 84%

 

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Elastic, SDOF, T=0.3 sec, 5% Damping, Median

(a) Elastic SDOF, 5% damping, 84th percentiles (b) Elastic SDOF, 5% damping, medians 

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Elastic, MDOF, 3 Story, T=0.3 sec, BOT

 5% Damping, Median

 

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Elastic, MDOF, 3 Story, T=0.3 sec, TOP

 5% Damping, Median

(c) Elastic MDOF, 5% damping, bottom story, (d) Elastic MDOF, 5% damping, top story, 

 median values median values 

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Inelastic, SDOF, T=0.3 sec, 5% Damping, μ≈3.0, Median

 

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Inelastic, MDOF, 3 Story, T=0.3 sec, TOP

 5% Damping, μ≈3.0, Median 

(e) Inelastic SDOF (μ ≈ 3), 5% damping, (f) Inelastic MDOF, 5% damping, top story, 

 median values median values 

Figure C2-10 Ordered relative excursions, pre-peak plus post-peak, T = 0.3 sec., SDOF and MDOF systems 
44 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Elastic, SDOF, T=0.5 sec, 5% Damping, Median

 

Ordered Excursions

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

Inelastic, MDOF, 9 Story, T=0.9 sec, TOP

 5% Damping, μ≈3.0, Median 

(a) Elastic SDOF, T = 0.5 sec., 5% damping, (b) Inelastic 9-story MDOF, 5% damping, 

 median values top story, median values

Figure C2-11 Ordered relative excursions, pre-peak plus post-peak, T = 0.5 and 0.9 sec. 

Elastic Response History, SDOF, T=0.3 sec., ξ=5%, cm92for 

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 10 20 30 40 50

Time (sec.)

δ/δmax

Elastic Response History, SDOF, T=0.3 sec., ξ=5%, ld92dsp 

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 10 20 30 40 50

Time (sec.)

δ/δmax

 (a) Peak displacement response (b) Peak displacement response 

 occurs relatively late occurs relatively early 

Figure C2-12 Normalized response displacement histories of an SDOF system, T = 0.3 sec. 

• The responses of 5% damped systems have about 15% fewer excursions 

than the responses of 2% damped systems. 

• For short-period MDOF systems the story drift responses are well 

correlated with the responses of the one-mode SDOF system. In general, 

the bottom story MDOF drifts decay slightly faster than the SDOF 

response, and the top story drifts decay slightly slower than the SDOF 

response. In the frame structures used in this study the top stories are 

flexible and weak, which in part explains the relatively slow decay. 

Considering all other uncertainties and judgmental decisions, it can be 

stated that the SDOF responses are adequate surrogates for the MDOF 

responses (at least for structures with not very important higher mode 

effects). 
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 45 

• For long-period MDOF systems the higher mode effects become more 

important and the top story shows a considerably larger number of 

excursions than the SDOF system with the same first-mode period. 

However, this number is smaller than that for short-period MDOF 

systems, which leads to the conclusion that short-period structures 

govern the response values (in terms of the number and relative 

amplitude of excursions) rather than longer-period structures. 

• The number of excursions decreases consistently with an increase in the 

period of the system, which makes the T = 0.2 system the most critical 

one in terms of the number and relative amplitude of excursions. 

The use of median values is appropriate because the objective of testing is to 

obtain fragility curves in which the effect of record-to-record variability 

should be represented as an average. (The use of the 84th percentile would 

provide high values of fragilities). 

The use of structures with very short periods for the development of a 

generally applicable loading protocol is inappropriate. They overestimate the 

number and relative amplitude of excursions for most cases, and they are not 

representative for the full range of drift demands for which the performance 

of most nonstructural components has to be evaluated. The following 

argument supports this observation: 

For SDOF systems the period T is given by 

2 0.32 0.32

/

y

y

y y

W W T

gK F F W

δ == = π δ (C2-1) 

or 

2

2

y 0.32

y

F

W T = δ

Using an interstory drift ratio at yield (IDRy) = 0.01 and h = 144 in., 

gives δy = 1.44 in., and we obtain: 

For T = 0.2 sec → Fy/W = 3.69 

T = 0.3 sec → Fy/W = 1.64 

This means that for short-period structures large demands on story drifts are 

possible only for very flexible and very strong structures, which will respond 

elastically even in a very large earthquake (probably not many of these 

structures exist). For inelastic story drifts to occur, the structure would have 

to be very stiff, in which case the drift demands will be very small, i.e., little 

(if any) drift-sensitive damage is to be expected. 

This argument can be used to “disregard” the response characteristics of very 

short period structures (i.e., T = 0.2 sec). 
46 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

The results from the analytical study show that, given an initiating value of 

loading for a damage state, the prior history will have more and relatively 

larger excursions if the response of the structure is elastic rather than inelastic 

(in general, the number and relative amplitude decrease with the degree of 

inelasticity). Thus, elastic response histories provide a conservative (high) 

estimate of the number and relative amplitude of excursions. 

The number and relative amplitudes of the excursions should represent, on 

average, the history of the loading at each damage state that is to be 

quantified. This is not possible because lower damage states are associated 

with smaller earthquake intensities and higher damage states are associated 

with larger earthquake intensities. The use of a single loading history for all 

damage states is a compromise made necessary by the desire to catch all 

damage states with a single specimen. The consequence of using a single 

loading history for the evaluation of multiple damage states implies that for 

low-level damage states (a small amount of damage) the number and 

amplitude of excursions are “too small”, and for high levels of damage the 

number and amplitude of excursions are “too large”. 

Experimental pilot studies with a loading history that was based on pre-peak 

plus post-peak excursions disclosed that the large cumulative damage caused 

by the many excursions may severely distort the behavior at high-level 

damage states (large damage). Since these are the damage states of greater 

interest, and since low-level damage states are less affected by cumulative 

damage, it was decided to develop a loading history that is based only on 

pre-peak excursions and that represents, statistically, the number and 

amplitude of damaging excursions associated with earthquakes causing the 

highest-level damage state. 

Pre-peak excursions are those excursions that occur before both the 

maximum positive and maximum negative peaks in the response have been 

reached. As discussed in Krawinkler et al. (2001), it is the pre-peak 

excursions that cause most of the damage at high-level damage states. It is 

seen from Figure C2-12 that typically the peaks occur relatively early in the 

response history. Statistical data (median values) for the number and 

deformation ranges of pre-peak excursions (increasing from small to large 

values) and post-peak excursions (decreasing from large to small values) are 

shown in Figure C2-13 for elastic SDOF systems with T = 0.3 and 0.5 sec. It 

is seen that fewer than half of the total number of excursions are pre-peak 

excursions. 
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 47 

Ordered Excursions

Elastic, SDOF, T=0.3 sec, 5% Damping, Median

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

 

Ordered Excursions

Elastic, SDOF, T=0.5 sec, 5% Damping, Median

-1

-0.5

0

0.5

1

0 30 60 90 120 150 180 210 240

Number of Excursions

Amplitude (/Δ)

(a) T = 0.3 sec. (b) T = 0.5 sec. 

Figure C2-13 Ordered relative excursions, separate for pre-peak and post-peak excursions, elastic SDOF system. 

Using an equation of the form given by Equation C2-1, a close match for prepeak excursions was obtained by using a coefficient of 1.3 and 1.6 for 

T = 0.3 sec and 0.5 sec, respectively. The value of 1.4, as provided in 

Equation C2-1, is a compromise between these two coefficients. 

Every loading history needs reference values for the loading. For 

nonstructural components with several damage states such reference values 

are case specific. Any reference story drift depends on the intensity of the 

ground motion and on the stiffness and strength of the structure. The drift is 

expected to be relatively small for lower stories in wall structures and 

relatively large for moment-resisting frames. Thus, rather than committing to 

fixed values of reference drifts, it is decided to use generic reference values 

Δ, and define all cycle amplitudes in terms of a target value of Δ associated 

with the largest damage level. The advantage is that the user has the freedom 

to choose appropriate values for Δ. 

Low-Cycle Fatigue Considerations 

The existence of cumulative damage is the primary reason for cyclic load 

testing. Low-cycle fatigue is one type of cumulative damage, which is 

usually associated with cracking or fracture in metals. Many low-cycle 

fatigue models exist, the simplest one being that based on the two hypotheses 

of a Manson-Coffin relationship and Miner’s rule (Krawinkler et al., 1983). 

The first hypothesis postulates that for constant amplitude cycling the 

number of excursions to failure, Nf, and the plastic deformation range, Δδp, 

are related by the following equation: 

 Nf = C-1(Δδp)-c (C2-2) 

In this equation C and c are structural performance parameters that have to be 

determined experimentally. The equation implies that on a log-log plot the 
48 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

relationship between Nf and Δδp is linear. The second hypothesis is Miner's 

rule of linear damage accumulation, which postulates that the damage per 

excursion is 1/Nf, and that the damage from excursions with different plastic 

deformation ranges, Δδpi, can be combined linearly. Thus the total damage 

D is given by the equation 

=

= ∑

N c pi i 1

DC ( ) Δδ (C2-3) 

If this hypothesis were accurate, a total damage of D = 1.0 would constitute 

failure. Because of the known shortcomings of Miner's rule (neglect of mean 

deformation and sequence effects) and the scatter in the structural 

performance parameters C and c, the limit value of damage that constitutes 

failure cannot be expected to be exactly 1.0. Krawinkler et al. (1983) 

provide an extensive discussion of many issues associated with this damage 

model. 

If this simple damage model is acceptable, if D = 1.0 indeed constitutes 

failure, and if the scatter in the model parameters C and c can be neglected, 

then tests with at least two specimens are needed to determine C and c. Most 

commonly, two constant amplitude tests (with very different amplitudes) are 

performed for this purpose. In the ATC-24 Report, Guidelines for Cyclic 

Seismic Testing of Components of Steel Structures (ATC, 1992), it is 

recommended to perform at least three tests. In the most simple case it may 

be adequate to make a reasonable assumption on the value of the exponent c, 

with 2.0 being an often-used value. If this can be done, the coefficient C can 

be estimated from a single specimen. 

The determination of low-cycle fatigue parameters is essential if analytical 

means are employed to predict performance of a component or system 

affected by low-cycle fatigue. If the main objective is to estimate only the 

deformation amplitude at which failure is likely to occur, then a single test 

with the previously discussed loading protocol should be adequate. This can 

be justified by the observation that the exponent c usually is significantly 

larger than 1.0, which implies that low-cycle fatigue damage is dominated by 

the largest cycles, i.e., the damage due to the many smaller cycles is not 

relevant. 

Suggested Loading Protocol 

Alternatively, the following loading protocol is suggested to evaluate failure 

modes for items of systems that are deemed to be susceptible to low-cycle 

fatigue failures. These items are likely to include but are not be limited to 

piping and duct system connections. The following steps could be used to 

obtain the fragility curve for these items:
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 49 

1. Conduct a monotonic force-deformation test on the component (Figure 

C2-14). Estimate the deformation at which the component undergoes 

complete damage (breaks, leaks or experiences unacceptable 

deformation). Call this ultimate deformation, Δult. The cyclic test is 

started at 1/10th of the ultimate deformation, Δ1 = Δult/10. 

Figure C2-14 Monotonic force-deformation test on the component 

2. In the 1st stage of the cyclic test, apply 10 cycles of deformation 

amplitude Δ1 (Figure C2-15a). Measure the force throughout the test 

(Figure C2-15b). The force level will generally reduce from one cycle to 

the next due to stiffness degradation. The minimum force amplitude 

during the 1st stage is called F1. 

3. For the 2nd stage of the cyclic test, increase the deformation amplitude by 

20%, i.e., Δ2 = 1.2Δ1. Subject the component to three cycles of 

deformation amplitude, Δ2. Measure the force. The minimum force level 

during the 2nd stage is called F2. 

4. For each subsequent stage, increase the deformation amplitude by 20% 

and subject the component to three deformation cycles. Record the 

minimum force amplitude during each stage: F3, F4, F5, and so on. 

Continue the cyclic test in this manner until the component suffers 

complete damage (breaks, leaks or undergoes unacceptable deformation). 

The last stage during which the component does not suffer complete 

damage is the n

th stage. The force amplitude in the nth stage Fn

corresponds to the 100% (complete) damage state. The force levels for 

the other damage states are established as follows. 
50 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing FEMA 461 

Figure C2-15 Cyclic test on the component in deformation control: (a) 

applied deformation history; and (b) measured force history. 

5. Obtain the normalized fatigue damage at the end of each test stage. (The 

normalized fatigue damage at the end of the n

th test stage is 100%.) The 

normalized fatigue damage at the end of the i

th test stage is: 

100

1

2

1

2

×

Δ⋅

Δ⋅

=

∑

∑

=

=

n

j

jj

i

j

jj

i

N

N

D (C2-4) 

where Nj is the number of cycles in different test stages; N1 = 10; N2 = N3

= ... = Nn = 3. 

6. Plot Di at the end of each test stage (See Figure C2-16). Identify the 

exact cycle during which the component reaches different damage states. 

7. Plot the force level at the end of each test stage (Figure C2-15b). Read 

the force corresponding to each damage state. 
FEMA 461 C2: Commentary on Interim Protocol I – Quasi-Static Cyclic Testing 51 

Figure C2-16 (a) Cumulative low-cycle fatigue damage at the end of each test 

stage, and (b) force level at the end of each test stage. 

FEMA 461 3: Interim Protocol II – Shake Table Testing 53 

Chapter 3 

Interim Protocol II – Shake Table 

Testing

3.1 General 

3.1.1 Scope 

This Chapter establishes a recommended protocol for shake table testing of 

structural and nonstructural building components for the purpose of 

determining fragilities for use in the seismic performance assessment 

process. This shake table testing protocol is appropriate for use in 

establishing the fragility of components that are sensitive to the dynamic 

effects of motion imparted to the component at a single point of attachment, 

typically its base. 

Specimens sensitive to the relative motion of several connection levels, such 

as floor-to-ceiling partitions or vertical risers of piping systems should be 

tested using the protocol for quasi-static cyclic testing of structural and 

nonstructural components presented in Chapter 2 of this document. 

3.1.2 Definitions 

The following terms have the noted meanings in this interim shake table test 

protocol: 

Damping: An energy dissipation mechanism that reduces the amplification 

and broadens the vibratory response in the region of resonance. Damping is 

expressed as a percentage of critical damping, that minimum damping level 

permitting a system to return to its rest position, after displacement from this 

position, without overshooting.

Input Motion Response Spectrum (IMRS): The response spectrum 

generated using one of the input motions detailed in Section 3.7.

Octave: The interval between two frequencies that have a frequency ratio of 

two. 

One-Third Octave: The interval between two frequencies that have a 

frequency ratio of 2/3. 
54 3: Interim Protocol II – Shake Table Testing FEMA 461 

Test Response Spectrum: An acceleration response spectrum that is 

developed from the actual acceleration time-history of the motion of the 

shake table. 

Triaxial Test: A dynamic test in which the test specimen is subjected to 

acceleration in two principal horizontal axes and the vertical axis 

simultaneously. The two horizontal components and the vertical acceleration 

component are derived from three different input signals that are phaseincoherent. 

Uniaxial Test: A dynamic test in which the test specimen is subjected to 

acceleration in one principal axis. The acceleration components are derived 

from a single input signal. 

3.2 Test Procedures 

3.2.1 Types of Testing and Sequence 

The test specimen should be subjected to a seismic fragility test program, 

consisting of the following sequential test elements: 

(a) Pretest elements 

• Pretest inspection and functional verification. 

• Definition and documentation of functional performance and 

anticipated damage states. 

(b) Testing elements 

• System identification tests. 

• Seismic performance evaluation tests. 

• Failure tests. 

All of the elements of the test program should be described in a test plan as 

described in Section 3.6. The test plan should be a complete document. 

3.2.2 Pretest Inspection and Functional Verification 

Upon arrival at the test facility, the test specimen should be visually 

examined by the testing laboratory personnel, to verify that no damage has 

occurred during shipping and handling. The facility should make adequate 

arrangements in order to reproduce the operating condition of the test 

specimen. Functional tests, operability tests, or both, should be performed by 

the testing laboratory to verify pretest functional performance. Alternatively, 

functional and operability testing could be performed at the manufacturing 
FEMA 461 3: Interim Protocol II – Shake Table Testing 55 

facility before shipping if the laboratory is unable to reproduce the operating 

conditions of the test specimen. Test description and results should be 

documented. 

3.2.3 Definition and Documentation of Functional Performance 

and Anticipated Damage States 

Prior to testing, appropriate damage states should be defined for the 

component or system. Section 1.4 provides discussion of considerations 

relevant to selection of appropriate damage states. A preliminary estimate 

should be made of the excitation frequency and intensity expressed in peak 

spectral acceleration at the particular frequency, at which each damage state 

is expected to occur. Once damage states are defined, they should be 

documented as they occur in the test specimen during the testing program. 

3.2.4 System Identification Tests 

System identification tests should be conducted in order to identify, as much 

as possible, the dynamic characteristics of the test specimen and also the 

evolution of these dynamic characteristics throughout the test program. 

Single-axis system identification tests should be conducted in each principal 

direction of the test specimen before and after each of the performance 

evaluation tests and failure tests described in Sections 3.2.5 and 3.2.6, 

respectively. 

For the purpose of identifying natural frequencies of the test specimen, at 

least one of the methods of Section 3.2.4.1, 3.2.4.2 or 3.2.4.4 should be used 

for each principal direction. The equivalent fundamental modal viscous 

damping of the test specimen should be determined based on one of the 

methods of Section 3.2.4.3 or 3.2.4.4 for each principal direction. If mode 

shapes of the test specimen are to be determined, they should be established 

in each principal direction by the relative intensities and phases between the 

resonant peaks of the power spectral density or transmissibility plots 

measured by the in-line test response monitoring sensors during the natural 

frequency evaluation tests. Equivalent modal viscous damping values for 

higher modes of the test specimen may be established, if needed, based on 

the half-bandwidth power method applied to the power spectral or point 

mobility plots obtained during the natural frequency tests. Special care 

should be taken to insure sufficient accuracy in the definition of resonant 

peaks in order to provide accurate damping values. 
56 3: Interim Protocol II – Shake Table Testing FEMA 461 

3.2.4.1 White Noise Tests 

A low-intensity 0.50-30 Hz, clipped-band, flat and acceleration-controlled 

white noise should be used to excite the test specimen in each of its principal 

configurations. A narrower frequency band may be used if justified by the 

anticipated natural frequencies of the test specimen. The root-mean-square 

intensity of the white noise signal should be limited to 0.05 ± 0.01 g. A lower 

input level may be used to avoid damage to the test specimen. The natural 

frequencies should be obtained from the resonant peaks of the acceleration 

power spectral density plots recorded by the in-line test response monitoring 

sensors. 

3.2.4.2 Single-Axis Acceleration-Controlled Sinusoidal Sweep Tests 

Alternatively, a single-axis acceleration-controlled sinusoidal sweep from 

0.50 to 30 Hz should be performed in each principal axis of the test specimen 

in order to determine its natural frequencies. The sweep rate should be two 

octaves per minute, or slower, to ensure adequate time to establish sufficient 

steady-state response of the test specimen. The peak intensity of the sweep 

should be limited to 0.1 ± 0.05 g. A lower input level may be used to avoid 

damage to the test specimen. The natural frequencies should be obtained 

from the peaks of the acceleration transmissibility plots recorded by the inline test response monitoring sensors. 

3.2.4.3 Resonance Tests 

A low-intensity acceleration-controlled sinusoidal input at the previously 

identified fundamental frequency should be used to excite the test specimen 

in each of its principal configurations. The intensity of the sinusoidal input 

should be established based on recorded or visual response such that no 

damage to the test specimen under this resonance condition occurs. The 

duration of the sinusoidal input should not exceed 20 times the previously 

identified fundamental period of the test specimen. Once a steady-state 

response is established, the input should be suddenly stopped and the free 

vibration response decay should be recorded by in-line test response 

monitoring sensors. The fundamental equivalent modal viscous damping 

ratio of the test specimen should then be established by the logarithmic 

decrement method applied to the free vibration response decay curves. 

3.2.4.4 Static Pull-Back Tests 

The fundamental frequency and equivalent modal viscous damping ratio of 

the test specimen can be established by the free-vibration decay measured by 
FEMA 461 3: Interim Protocol II – Shake Table Testing 57 

the in-line test response monitoring sensors as a result of a static pull-back 

test at the center of gravity of the test specimen. The intensity of the pullback force should be small enough to avoid damage to the test specimen. 

3.2.5 Performance Evaluation Tests 

The seismic performance of the test specimen should be evaluated under 

simulated input motions of increasing intensities representative of the motion 

at the single level of a building structure on which the test specimen is 

located. The simulated input motions described in Section 3.7 should be 

used. Test description and results should be documented for each intensity 

level in order to be used for the seismic fragility assessment of the test 

specimen. 

It should be anticipated that at the conclusion of the performance evaluation 

tests, the test specimen will have developed damage states resulting in loss of 

function or need for repair or replacement, but should not have experienced 

damaged states associated with potential life safety endangerment and should 

not have completely failed. 

For mechanical and electrical components, it is highly desirable that the test 

specimen be in operation during the performance evaluation tests. If 

operation of the test specimen during testing may cause a safety hazard, the 

functional operation of the test equipment should be verified between each 

performance evaluation test. If the test facility is unable to reproduce the 

operating conditions of the test specimen, the functional operation of the test 

equipment should be verified at the manufacturing facility at the conclusion 

of the performance evaluation tests. 

3.2.6 Failure Tests 

Higher intensities of the simulated motions used in the performance 

evaluation tests should be used to induce damage states that could pose life 

safety risks and damage states corresponding to incipient failure of the test 

specimen. Multiple failure tests may be conducted if the test specimen is 

composed of various subsystems that reach incipient failure separately at 

various intensities. A failure test description and the results of such testing 

should be documented for each intensity level in order to be used for the 

fragility assessment. Special care should be taken to assure the safety of the 

test personnel and to avoid damage to the testing equipment during the highlevel failure tests. 
58 3: Interim Protocol II – Shake Table Testing FEMA 461 

3.3 Intensities of Test Shaking 

Unless otherwise specified for a particular type of test specimen, the input 

motion parameter used to define intensity should be the peak spectral 

acceleration at the appropriate natural frequency for the specimen and 

damage state. 

The intensities of shaking used for system identification tests should be low 

enough to avoid any damage to the test specimen, as described in Section 

3.2.4. 

At least three different shaking intensities should be used for the performance 

evaluation tests described in Section 3.2.5. The intensities of the performance 

evaluation tests should be selected to induce damage states, the associated 

loss of function and repair or replacement. The intensity of the initial 

performance evaluation test should be based on the intensity estimates 

causing the damage states described in Section 3.2.4. In all cases, a 25% 

increase in intensity should be the minimum step size between intensity 

levels. 

The intensity of shaking for the failure tests described in Section 3.2.6 should 

induce damage states associated with potential risks to life safety or incipient 

failure. If multiple failure tests are conducted, each of the shaking intensities 

should induce a damage state for a particular subcomponent of the test 

specimen. The intensity of the failure tests can be estimated by extrapolation 

from the results of the performance evaluation tests or by other analytical 

means. A 25% increase in intensity should be the minimum step size between 

intensity levels. 

3.4 Directions of Shaking 

The system identification tests should be applied as single axis tests in each 

principal direction of the test specimen. The performance evaluation and 

failure tests should be applied as triaxial tests with simulated input motions 

applied simultaneously in all principal axes of the test specimen. 

Alternatively, biaxial (one horizontal and one vertical) performance 

evaluation and failure tests can be used. Horizontal (biaxial or uniaxial) 

performance evaluation and failure tests should be performed only if the 

effect of vertical motion on the seismic response of the test specimen is 

negligible. It may be acceptable to neglect the effect of vertical motion if the 

vertical fundamental frequency of vibration of the test specimen is at least 10 

times its horizontal fundamental frequency or if the vertical natural 
FEMA 461 3: Interim Protocol II – Shake Table Testing 59 

frequency of the test specimen falls outside the frequency range of the input 

motions specified in Section 3.7. 

3.5 Data Acquisition System 

All test data recorded should be acquired at a sampling rate of at least 10 

times the highest fundamental frequency identified in any principal direction 

of the test specimen with a minimum rate of 200 samples per second, or Hz. 

All data should be low-pass filtered by a block-wall type filter having a 

corner frequency of at least two times the highest natural frequency of 

interest in any principal directional but not exceeding 30 Hz. 

3.6 Test Plan 

A test plan should be prepared before the beginning of the testing sequence 

described in Section 3.2. The test plan should include documentation of the 

following: 

• the physical configuration of the test specimen including such details as 

dimensions and weight distribution, 

• the dimensions, arrangements, and specifications of the hardware used to 

connect the test specimen to the shake table, 

• a description of the monitoring instrumentation including an outline 

drawing of the test specimen showing the locations of all sensors using 

the same sensor numbering system as contained in the test report, 

• a description of the data acquisition parameters including sampling rates 

and filtering techniques, 

• a test schedule outlining the order of the system identification, 

performance evaluation and failure tests, including descriptions of 

damage states and methods of documentation, and 

• other details necessary to describe the testing fully. 

3.7 Input Motions 

This section provides input motions for performing the performance 

evaluation and failure tests described in Sections 3.2.5 and 3.2.6, 

respectively. 

The recommended shake table motions are narrow-band random sweep 

acceleration records, with scaled amplitudes depending on the sweep 

frequency, producing motions that have relatively smooth response spectra 
60 3: Interim Protocol II – Shake Table Testing FEMA 461 

amplitudes. Each record is phase-incoherent with the others. Commentary in 

Section C3.7 provides background on the generation of these records. 

Figures 3-1 and 3-2 plot the horizontal acceleration records recommended for 

use in the longitudinal and transverse directions, respectively. Figure 3-3 

plots the recommended acceleration record for vertical excitation of the test 

specimen. This vertical record is scaled to have a response spectrum that is 

approximately 80 percent of those for the longitudinal and transverse 

motions. Figure 3-4 plots the response spectra at 5 percent critical damping 

for the recommended horizontal and vertical motions. 

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Acceleration (g)

Figure 3-1 Recommended longitudinal input motion

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Acceleration (g)

Figure 3-2 Recommended transverse input motion 
FEMA 461 3: Interim Protocol II – Shake Table Testing 61 

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Acceleration (g)

Figure 3-3 Recommended vertical input motion

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

0.1 1 10 100

Frequency (Hz)

Spectral Acceleration (g)

Longitudinal

Vertical

Transversal

Figure 3-4 5% damped, acceleration response spectra for recommended 

longitudinal, transverse and vertical input motions

3.8 Time Stamping and Damage State Documentation 

The performance evaluation and failure tests should all be triaxial, as 

described in Section 3.4. The motions should be applied at increasing 

intensities, as described in Section 3.3. 
62 3: Interim Protocol II – Shake Table Testing FEMA 461 

Visual or other monitoring procedures should be implemented in order to 

identify the occurrence of the anticipated damage states in the test specimen 

as they occur during the performance evaluation and failure tests. When a 

damage state is identified, the time of occurrence of the damage state should 

be recorded in order to determine the center frequency of the motion that 

caused the damage state to occur. The amplitude of motion that caused the 

damage state should be defined by generating a test response spectrum of the 

predominant direction of the motion that, based on observations, caused the 

damage state (longitudinal, transverse or vertical). The test response 

spectrum should be generated for 10 seconds of shake table motion 

beginning 10 seconds prior to the maximum measured response causing the 

damage state to occur. The amplitude of the peak of this test response 

spectrum is designated as the amplitude causing the damage state to occur, 

and the frequency at this peak is the frequency causing the damage state to 

occur. Each damage state shall be documented in a plot showing the spectral 

amplitude versus center frequency. 

The record primarily responsible for the occurrence of the damage state 

should be notch filtered with respect to frequency and time as described in 

Section 3.9 below, and the testing should be continued at larger intensities in 

all three directions. 

3.9 Notch Filtering of Input Motions 

Notch filtering of the input motions may be used to remove energy near the 

excitation frequency that has already caused a damage state to occur. This 

notch filtering may become necessary in order to cause other damage states 

to occur at different frequencies and higher amplitudes of the input motions. 

The width of the notch should be 1/3 octave. Table 3-1 shows the time and 

corresponding center frequency for the central portion of the three input 

records. Each data point in this table represents a 1/24 octave decrease in 

frequency, and 0.417 seconds in time. The notches should be centered (to 

the nearest 1/24 octave) at the excitation frequency causing the damage state. 

The notch should begin at 100 percent of the full record at 1/6 octave above 

the excitation frequency causing the occurrence of the damage state, then 

decrease linearly in time to 0 percent in 0.417 seconds (1/24 octave lower in 

frequency). The notch should be held constant at 0 percent for 2.917 seconds 

(7/24 octave), then ramp up linearly in 0.417 seconds (1/24 octave) to 100 

percent of the record. Additional notches should be created when other 

damage states occur. 
FEMA 461 3: Interim Protocol II – Shake Table Testing 63 

Table 3-1 Time versus Center Frequency for Central Portion of Input Motions 

Octave Time (s) Center 

Frequency (Hz) 

Octave Time (s) Center 

Frequency (Hz) 

Full 10.000 16.000 20.417 7.772 

 10.417 15.545 20.833 7.551 

 10.833 15.102 21.250 7.336 

 11.250 14.672 21.667 7.127 

 11.667 14.254 22.083 6.924 

 12.083 13.849 22.500 6.727 

 12.500 13.454 22.917 6.536 

 12.917 13.071 1/3 23.333 6.350 

1/3 13.333 12.699 23.750 6.169 

 13.750 12.338 24.167 5.993 

 14.167 11.986 24.583 5.823 

 14.583 11.645 25.000 5.657 

 15.000 11.314 25.417 5.496 

 15.417 10.992 25.833 5.339 

 15.833 10.679 26.250 5.187 

 16.250 10.375 1/3 26.667 5.040 

1/3 16.667 10.079 27.083 4.896 

 17.083 9.792 27.500 4.757 

 17.500 9.514 27.917 4.621 

 17.917 9.243 28.333 4.490 

 18.333 8.980 28.750 4.362 

 18.750 8.724 29.167 4.238 

 19.167 8.476 29.583 4.117 

 19.583 8.234 Full 30.000 4.000 

Full 20.000 8.000 

3.10 Testing Equipment 

For the purpose of executing the test sequence described in Section 3.2, it is 

recommended that the testing laboratory generally complies with the 

requirements of a national or international accreditation criterion such as 

International Accreditation Service Report AC89, Accreditation Criteria for 

Testing Laboratories (IAS, 2006), or Institute of Electrical and Electronic 

Engineers Standard No. 344-2004, Recommended Practice for Seismic 

Qualification of Class 1E Equipment for Nuclear Power Generating Stations

(IEEE, 2004) as well as the testing requirements of the Network for 

Earthquake Engineering Simulation. 

3.10.1 Shake Tables 

The shake table and its components should have sufficient reserve capacity 

under the payload of the test specimen to simulate adequately the input 

motions described in Section 3.7. 
64 3: Interim Protocol II – Shake Table Testing FEMA 461 

In terms of achieving the requirements of Sections 3.7 and 3.11, the 

following shake table performance parameters shall be identified and 

confirmed against the imposed demand due to the required test sequence and 

test specimen characteristics of Section 3.2, and input motion characteristics 

as described in Section 3.7. 

• Nominal payload at a prescribed performance level of the shake table, 

typically defined by the maximum mass (kg) that can be supported when 

the shake table is driven at a peak acceleration of 1 g. 

• Nominal maximum achievable acceleration amplitude (in g’s) at a 

reduced shake table performance (when the shake table supports the 

maximum test specimen mass (in kg), but the acceleration is typically 

limited by the vertical actuator dynamic force capacity or the supporting 

bearing system in the case of uniaxial or biaxial shake tables). 

• Maximum static and dynamic actuator capacities in units of force. 

• Peak-to-peak stroke in units of length. 

• Maximum achievable velocity at the payload in units of length per 

second. 

• Operational frequency bandwidth (minimum and maximum, in Hz) at the 

maximum acceleration amplitude. 

3.10.2 Instrumentation and Monitoring 

Measurements should be made of all response parameters that significantly 

affect the test specimen behavior and which will be used to evaluate and 

quantify important dynamic characteristics and damage states. Video 

recorders with time stamping capabilities should also be used to capture the 

behavior of the test specimen and determine the times of occurrence of 

various damage states. 

If required, an extensive instrumentation design should be carried out and 

included in the final test report as described in Section 3.11. Accordingly, the 

model, type, location and orientation of instrumentation should be described 

and uniquely identified. The location and orientation of the instrumentation 

fixed to the test specimen should be reported relative to a common reference 

coordinate system. 

The minimum required instrumentation is limited to that which clearly 

provides useful information for evaluating and quantifying the seismic 

fragility of the test specimen and should be located where it will provide data 
FEMA 461 3: Interim Protocol II – Shake Table Testing 65 

that are representative of the entire test specimen. For this purpose, the 

following minimum instrumentation requirements should be implemented. 

• Accelerometers to measure applied acceleration levels in two principal 

horizontal and one vertical axis of the shake table are required. Reference 

control accelerometers should be mounted on the shake table at a 

location near the base of the test specimen. 

• Accelerometers to measure the absolute acceleration response of the test 

specimen are required. Accelerometers oriented in two principal 

horizontal and one vertical axis should be used to determine the 

acceleration response of the test specimen. The accelerometers should be 

located at a minimum of three different locations within the test 

specimen. Three locations should be identified as (i) just above the shake 

table – test specimen interface (connection point), (ii) the computed (or 

assumed) center of mass of the test specimen, and (iii) the top of the test 

specimen. This permits the recording of the average acceleration 

response in the three axes. 

• If significant torsional or rocking response, or both, of the test specimen 

is expected, two sets of accelerometers should be located at all three 

locations, such that global torsional and rocking response can be 

captured effectively. 

• Ideally, accelerometers should be located at those points within the test 

specimen that reflect the response associated with the fundamental 

natural frequencies. Accordingly, precise locations of these 

accelerometers may be determined based on either preliminary 

computational analysis of the test specimen or low-intensity system 

identification tests, as described in Section 3.2.4. 

• Displacement (position) transducers to measure the absolute and relative 

deformation response of the test specimen are required. Displacement 

transducers should be used to determine deformation response of the test 

specimen. The displacement transducers should be located at the location 

of each one of the accelerometers such that deformations are measured in 

the same direction as the corresponding accelerometer. 

• Load cell washers to measure anchor forces are required. Axial load cell 

washers should be used to determine anchor forces (tension and 

compression) during the various stages of the test sequence. 

Sensors should have a minimum operational frequency range of 0.5 to 100 

Hz. Load cell washers should have a minimum capacity of three times the 

tributary weight of the test specimen applied to a single washer. 
66 3: Interim Protocol II – Shake Table Testing FEMA 461 

Instrumentation, in addition to the minimum recommended, should be 

required wherever there is a concern regarding a condition that may affect 

the test specimen response. Typical reasons to require additional 

instrumentation may be to check design assumptions, to provide data to 

evaluate specific problems such as excessive cracking (using, for example, 

strain gages), to provide data to support design of remedial modifications, 

and to provide data to evaluate effectiveness of remedial work. 

Instrument calibrations should conform to National Institute of Standards and 

Technology traceable primary standards. The instruments shall be 

recalibrated once every year and these calibrations shall be verified before 

each test. 

3.10.3 Data Acquisition 

Data acquisition system(s) used during testing should allow continuous, realtime recording of dynamic sensor data at predefined sampling rates (number 

of samples per second, or Hz) and should support continuous recording and 

storage of sensor data on digital storage device(s). 

All test data recorded during the test program should be acquired at a 

sampling rate and low-pass filtered according to the requirements given in 

Section 3.5. 

Data acquisition system calibration should conform to National Institute of 

Standards and Technology traceable primary standards. The data acquisition 

system should be recalibrated once every year. These calibrations should be 

verified before each test. 

The reference time for all test data, including from all sensors and videos, 

should be common to allow for post-test analysis. 

3.10.4 Safety Procedures 

Testing presents several safety issues that must be considered during testing. 

Rules and procedures that are intended to assure the safety of all laboratory 

users, personnel, and visitors, should be provided and implemented by the 

testing facility. The requirements and procedures should include but should 

not be limited to: 

• professional laboratory safety procedures as mandated by the testing 

facility to minimize hazard and danger to persons in the test area, 

• a minimum distance to the laboratory equipment and test specimen 

before, during and after the experiments, because shake table testing may 
FEMA 461 3: Interim Protocol II – Shake Table Testing 67 

cause a test specimen to rock and topple, and, in the extreme case, the 

entire test specimen, or parts of it, may dislodge and become airborne 

hazards, and 

• personal safety during all test procedures, including safe practices during 

post-test examination: hardhats, protective eyewear, clothing, gloves and 

safety shoes as appropriate. 

3.11 Test Report 

A test report, including the corrected (as-tested) test plan described in 

Section 3.6 should be prepared. More specifically, the following items 

should be included in the main body of the test report along with additional 

observations and concluding remarks addressing the test objectives. 

Sufficient information should be provided to allow for potential reproduction 

of the test conditions and the results. 

3.11.1 Test Specimen Description 

The test specimen should be identified and the overall layout and general 

dimensions stated. The test plan should be constructed following the 

requirements of Section 3.6 and included as a part of the final test report. The 

documentation of the test plan should include the test sample selection 

rationale, test configuration, connection and support details and installation 

procedures. Supplemental data, such as manufacturers’ specifications and 

assembly instructions for the test specimen, can be included as part of an 

appendix. 

The model, type, location and orientation of instrumentation should be 

described and uniquely identified. The location and orientation of the test 

specimen and its instrumentation should be made relative to a common 

reference coordinate system. 

3.11.2 List of Specimens Tested 

The sequence of tests, including all subelements described in Section 3.2, 

should be listed in the order in which testing occurred. Deviations from the 

intended test procedure outlined in Section 3.6 should be highlighted and 

justifications for these deviations provided. Results of the pretest inspection 

and functional compliance verification described in Section 3.2 should be 

included in the test report. 
68 3: Interim Protocol II – Shake Table Testing FEMA 461 

3.11.3 Preliminary System Identification Tests and Report 

Requirements 

The results of the system identification tests can depend on the amplitude of 

motion or displacement. The amplitude and duration of the system 

identification tests should be documented by the characteristic parameter 

applied, such as the maximum acceleration of sine sweep or the initial 

displacement of the static pullback tests. 

For each test sequence, the natural frequencies and damping values obtained 

from the single-axis system identification tests as described in Section 3.2 

should be reported. The appropriate plots of the acceleration power spectral 

density or transmissibility should be included for the identification of the 

natural frequency, and the decay curves should be included for identification 

of the damping values. Documentation should include both the raw data (e.g., 

measured response during sine sweeps and from free vibration tests) as well 

as the calculated values of frequencies of vibration and damping ratios. 

3.11.4 Measured Fidelity Data 

Comparison of the input drive signal and the resulting output should be made 

for individual motion time-histories in each principal direction. The various 

required horizontal and vertical input motion response spectra described in 

Section 3.7 should be compared with their corresponding test response 

spectra on the same plot at each intensity of shaking, as defined in Section 

3.3. 

The input motion response spectrum should be computed based on the input 

motion time histories described in Section 3.7, scaled to the intensity of 

Section 3.3, and the test response spectrum should be computed based on 

instrumentation located at the connection point of the test specimen. A 

damping value of 5% of critical should be used for scaled input motion 

response spectrum and test response spectrum, as specified in Section 3.7. 

The Maximum Response Spectra (MRS) at each intensity, should meet but 

not exceed by more than 30% the input motion response spectrum in the 

frequency range between 0.5 and 32 Hz. 

3.11.5 Performance and Failure Test Evaluations 

A clear description of the intended functionality of the test specimen should 

be outlined and definition of performance and anticipated damage states 

should be given as described in Section 3.2.3. Upon the completion of each 

shake table test, an indication of each damage state achieved should be 
FEMA 461 3: Interim Protocol II – Shake Table Testing 69 

documented. Justification of interpolation between the damage states should 

be included to develop appropriate fragility data. Based on the measured 

data, fragility curves should be plotted according to the calculations outlined 

in Section 1.3. 

3.11.6 Photographs and Video Recordings 

Photographs should be taken of critical components such as the overall 

layout of the test specimen, joints and connections prior to test and during the 

performance evaluation and failure tests. Video recordings of the timehistories should also be taken to document the dynamic response of the test 

specimen. 

All photographs and video recordings submitted as part of the report should 

be in digital format and should be included as an appendix in the form of a 

CD-ROM. The digital photographs should be taken at a sufficient resolution 

for clear viewing of the subject and be electronically stored using a 

nonproprietary file format. Videos taken of the test specimen should be 

digitized at the highest practical resolution and stored using nonproprietary 

compression methods. A description key of the electronic files should be 

included as part of the appendix. 

FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 71 

Chapter C3 

Commentary on Interim Protocol 

II – Shake Table Testing

Chapter C3 contains commentary for sections 3.1, 3.2, 3.7, 3.9, and 3.10 of 

Interim Protocol II – Shake Table Testing. Commentary is not provided for 

the other sections. 

C3.1 General 

C3.1.1 Scope 

Although the emphasis of this interim shake table testing protocol is on 

development of data used for seismic fragility quantification, the procedures 

established herein could also be used for the seismic qualification of singlelevel motion-sensitive components and systems. In this case, the resulting 

seismic qualification procedure should be reviewed by a panel independent 

from the testing laboratory to ensure that it fulfils the seismic qualification 

requirements of the specimen under test.

C3.2 Test Procedures 

C3.2.2 Pretest Inspection and Functional Verification 

It is highly desirable that the test specimen be operational during the pretest 

inspection and also during the entire fragility test program. Several damage 

states could be associated with functional operation of the test equipment and 

could therefore only be captured if the test equipment were operating during 

testing. Reproducing operational conditions may require the test facility to 

upgrade their power supply input (e.g., higher voltage) or make special 

arrangements to handle potentially hazardous materials (e.g., refrigerant or 

oil). 

C3.2.3 Definition and Documentation of Functional Performance 

and Anticipated Damage States 

Damage states should be identified as they occur in the test specimen. 

Examples of damage states are: 
72 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

• unintended action, e.g., tripping a switch, 

• repair required, e.g., minor leaks, 

• replacement required, 

• short-term loss of functionality, 

• long-term loss of functionality, and 

• life safety, e.g., spill of hazardous materials, fire, or catastrophic 

collapse. 

Clear definitions of functional performance and anticipated damage states are 

necessary since a level of performance for one test specimen (e.g., an oil leak 

in a rotational bearing) may correspond to a failure mode for another test 

specimen (e.g., an oil leak in a transformer bushing). Identification of target 

damage states corresponding to the principal performance measures, that is, 

direct economic loss, occupancy or function impairment, and casualties, is 

required in order to compute seismic fragility curves for the test specimen.

C3.7 Input Motions 

The shake table motions used to define the fragility (or capacity) of 

equipment are based on work done by the U.S. Army Construction 

Engineering Research Laboratory (Wilcoski et al., 1997). The motions are 

narrow-band, random, sweep records generated by a Matlab routine. For 

records generated for this protocol, the band-width is 1/3 octave and the 

center frequency of the records sweeps from 0.5 Hz up to 32 Hz, at a rate of 

6 octaves per minute (the frequency doubles every 10 seconds), for a total 

signal duration of 60 seconds. 

Table C3-1 shows the variables used in the Matlab routine to generate these 

records. The Matlab routine was developed to sweep up from a low 

frequency to a high value, but the records needed for this protocol sweep 

down in frequency, so the generated records were inverted. Table C3-1 

shows that the beginning sweep rate can differ from the ending sweep rate, 

implying some variation in the sweep rate, and permitting, for example, a 

sweep rate that varies linearly with time and logarithmically with frequency. 

The records developed here, however, used a constant sweep rate of 6 

octaves per minute. The Matlab routine generates a broad-band random 

signal with the lower frequency limit of 1/6 octave less (0.45 Hz) than the 

lowest frequency of interest (0.5 Hz) and high frequency limit 1/6th octave 

above (35.92 Hz) the highest frequency of interest (32 Hz). The routine then 

sweeps high- and low-pass filters over the record, where the low-pass filter is 
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 73 

1/3 octave greater than the high-pass at any moment in time. The resulting 

unitless records are each 60 seconds long, and they can be plotted with a dual 

abscissa axis of time and center frequency. Each generated record was 

inverted with respect to time, so the center frequency decreased from 32 to 

0.5 Hz. Figures C3-1 through C3-5 show example records that were used in 

the development of the longitudinal record. 

Table C3-1 Narrow-Band Random Signal Generation Matlab 

Routine Parameters 

Parameter Values Used for ATC-58 Records 

Sample Rate (Hz) 100 

Beginning Sweep Rate 

(octaves/min) 

6 

Ending Sweep Rate (octaves/min) 6 

Beginning Center Frequency (Hz) 0.5 

Ending Center Frequency (Hz) 32 

Filter Bandwidth (octaves) 1/3 

Filter Error (octaves) 0.2 

0 10 20 30 40 50 60

-16

-12

-8

-4

0

4

8

12

16

Amplitude

Time (sec.)

32 16 8 4 2 1 0.5

Center Frequency (Hz.)

Figure C3-1 Generated narrow-band random signal, Ran16 record. 
74 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

0 10 20 30 40 50 60

-16

-12

-8

-4

0

4

8

12

16

Amplitude

Time (sec.)

32 16 8 4 2 1 0.5

Center Frequency (Hz.)

Figure C3-2 Generated narrow-band random signal, Ran18 record. 

0 10 20 30 40 50 60

-16

-12

-8

-4

0

4

8

12

16

Amplitude

Time (sec.)

32 16 8 4 2 1 0.5

Center Frequency (Hz.)

Figure C3-3 Generated narrow-band random signal, Ran22 record. 
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 75 

0 10 20 30 40 50 60

-16

-12

-8

-4

0

4

8

12

16

Amplitude

Time (sec.)

32 16 8 4 2 1 0.5

Center Frequency (Hz.)

Figure C3-4 Generated narrow-band random signal, Ran31 record. 

0 10 20 30 40 50 60

-16

-12

-8

-4

0

4

8

12

16

Amplitude

Time (sec.)

32 16 8 4 2 1 0.5

Center Frequency (Hz.)

Figure C3-5 Generated narrow-band random record, Ran34 record. 

The records plotted in Figures C3-1 through C3-5 were selected because they 

have relatively smooth response spectra. Figure C3-6 plots the response 

spectra for each record, using 5% of critical damping. This shows that the 

response spectra for even the selected records varies significantly. Therefore, 

it was decided to splice together, in time, selected portions of all five records 
76 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

0

5

10

15

20

25

30

35

40

45

0.1 1 10 100

Frequency (Hz)

Spectral Acceleration (no units)

Ran16

Ran18

Ran22

Ran31

Ran34

Spliced

Figure C3-6 Response spectra for selected longitudinal records (5% of critical damping). 

to create a spliced longitudinal record. Through this process, portions of 

records in time (and frequency due to the correlation) were selected that had 

fairly uniform amplitude cycles and a relatively flat response spectra, while 

portions of records that had very large or small amplitudes, or response 

spectra amplitudes that varied significantly were discarded. The records 

were spliced by shifting portions of records slightly in time as needed to 

transition smoothly from one source record to another, so that the frequency 

content of the records would be preserved. As expected, the resulting record 

began to look somewhat like a sine sweep record, but retained some random 

content. Figure C3-7 shows that the spliced longitudinal record had more 

uniform and reduced amplitudes relative to the source records in Figures 

C3-1 through C3-5. Figure C3-6 also plots the response spectrum for the 

spliced record, showing more uniform but reduced amplitude. 

The spliced record was then scaled so that the response spectra amplitude 

would be approximately 1 g between 2 and 32 Hz. Below 2 Hz, the record 

was scaled so that the spectral displacement would be uniform. The scale was 

defined in the frequency domain by comparing the spectrum for the spliced 

record in Figure C3-6 with these goals. The same scale was then converted to 

the time domain, to scale the record shown in Figure C3-7. A response 

spectrum was generated from the resulting scaled record, which was again 

compared with the goals and the scale was adjusted as needed, and the process 

repeated until the achieved response spectra matched the goals of 1 g above 2 
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 77 

Hz and a uniform displacement spectra below. Figure C3-8 plots the final 

scale in the frequency domain, while Figure C3-9 plots the same scale in the 

time domain. Figure C3-10 plots the scaled longitudinal record (Long_3), 

without the frequency scale, and Figure C3-11 plots the response spectra. The 

Long_3 record name indicates the 3rd scale was final. 

-4

-3

-2

-1

0

1

2

3

4

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-7 Spliced longitudinal record. 

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0 1 10 100

Frequency (Hz)

Scale (g)

Figure C3-8 Scale used for the longitudinal record, plotted in the frequency 

domain. 
78 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Scale (g)

Figure C3-9 Scale used for the longitudinal record, plotted in the time domain. 

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Acceleration (g)

Long_3

Figure C3-10 Scaled narrow-band random longitudinal record, Long_3. 
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 79 

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

0.1 1 10 100

Frequency (Hz)

Spectral Acceleration (g)

Longitudinal, Long_3

Vertical, Vert_3

Transversal, Trans_2

Figure C3-11 Response spectra for scaled narrow-band random records. 

The same process was repeated for generating transverse and vertical 

records. However, a greater number (namely, 100) of narrow-band random 

records and response spectra were generated, providing a greater selection of 

records from which to splice the transverse and vertical records. From these 

one hundred records, records were selected that had a relatively uniform 

response spectrum within selected frequency ranges. Table C3-2 lists the 

records selected for the transverse and vertical motions, and shows the 

frequency ranges that had relatively uniform response spectrum amplitudes. 

Table C3-2 Narrow-Band Random Records Used for Splicing 

Transverse and Vertical Records 

Record Name Frequency Range with Uniform Spectra 

Transverse Records 

Ran 7 0.5 – 3 Hz; 7 – 10 Hz 

Ran 30 0.5 – 1.2 Hz; 2 – 3.5 Hz; 14 – 29 Hz 

Ran 55 2 – 5 Hz 

Ran 84 5 – 32 Hz 

Vertical Records 

Ran 9 0.5 – 1.2 Hz; 3 – 5.5 Hz 

Ran 20 0.5 – 1.0 Hz; 12 – 28 Hz 

Ran 21 2 – 5.1 Hz 

Ran 68 1.2 – 2 Hz; 4 – 9.5 Hz 

Ran 90 7 – 32 Hz 

Ran 98 0.5 – 1.2 Hz; 6 – 20 Hz 
80 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

Figures C3-12 through C3-15 plots those records selected for the transverse 

record, and Figure C3-16 plots the response spectra for them. Careful 

inspection of Figure C3-16 shows that the Ran 84 record had the most 

uniform response spectra of those selected for splicing the transverse record. 

For this record a greater effort was made to use many of the higher amplitude 

cycles of the original records, while still not using portions of the records that 

were either very high or low relative to other cycles in the frequency range of 

interest. Ran 84 was used for much of the transverse spliced record. Figure 

C3-17 plots the spliced transverse record. This spliced record decreased in 

amplitude relative to the source records, but not as dramatically as the 

longitudinal record. The source records plotted in Figures C3-12 through 

C3-15 show significant modulation in the amplitude of cycles, while the 

spliced record in Figure C3-17 reduces this effect, by splicing portions of 

source records that have similar amplitudes. Figure C3-16 plots the response 

spectrum for this spliced record, showing the more uniform and slightly 

reduced amplitudes. The transverse spliced record is called Spliced_2 in 

both Figures C3-16 and C3-17, because the splicing process was improved 

after the response spectrum of the initial spliced record revealed that 

improvements could be made. This was done by observing that response 

spectra of some source records better matched the spectrum of the spliced 

record in particular frequency regions. 

The transverse spliced record was then scaled so the response spectrum 

spectral acceleration would be approximately 1 g above 2 Hz, and have a 

uniform spectral displacement below 2 Hz. This scaling was accomplished 

in the same way as for the longitudinal record, and Figure C3-18 and C3-19 

plot the resulting scale in both the frequency and time domain, respectively. 

Figure C3-20 plots the scaled transverse record, and the response spectrum is 

included in Figure C3-11 (Trans_2). The Trans_2 name for this record 

indicates that the 2nd trial scale was the final scale used for this record. 

Table C3-2 shows the narrow-band random source records that were used to 

create the vertical record. These are plotted in Figures C3-21 through C3-26, 

and Figure C3-27 plots their response spectra. Figure C3-28 plots the spliced 

vertical record. This spliced record also reduced the modulation seen in the 

source records (Figures C3-21 through C3-26) by splicing portions of source 

records that have similar amplitudes. The response spectrum for the spliced 

record plotted in Figure C3-27 has more uniform and reduced amplitudes 

than the source records. The vertical record is called Spliced_2 in both 

Figures C3-27 and C3-28, because of splicing improvements similar to that 

of the transverse record. 
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 81 

-10

-8

-6

-4

-2

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-12 Generated narrow-band random signal, Ran7 record. 

-10

-8

-6

-4

-2

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-13 Generated narrow-band random signal, Ran30 record. 
82 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

-10

-8

-6

-4

-2

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-14 Generated narrow-band random signal, Ran55 record. 

-10

-8

-6

-4

-2

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-15 Generated narrow-band random signal, Ran84 record.
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 83 

0

5

10

15

20

25

30

35

40

45

50

0.1 1 10 100

Frequency (Hz)

Spectral Acceleration (no units)

Ran7

Ran30

Ran55

Ran84

Spliced_2

Figure C3-16. Response spectra of selected transverse records (5% of critical damping).

-6

-4

-2

0

2

4

6

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-17 Spliced transverse record (Spliced_2).
84 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0 110 100

Frequency (Hz)

Scale (g)

Figure C3-18 Scale used for the transverse record, plotted in the frequency domain

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Scale (g)

Figure C3-19 Scale used for the transverse record, plotted in the time domain.
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 85 

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Acceleration (g)

Trans_2

Figure C3-20 Scaled narrow-band random transverse record.

-10

-8

-6

-4

-2

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-21 Generated narrow-band random signal, Ran9 record.
86 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

-10

-8

-6

-4

-2

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-22 Generated narrow-band random signal, Ran20 record. 

-10

-8

-6

-4

-2

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-23 Generated narrow-band random signal, Ran21 record.
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 87 

-10

-8

-6

-4

-2

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-24 Generated narrow-band random signal, Ran68 record. 

-10

-8

-6

-4

-2

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-25 Generated narrow-band random signal, Ran90 record.
88 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

-10

-8

-6

-4

-2

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-26 Generated narrow-band random signal, Ran98 record. 

0

5

10

15

20

25

30

35

40

45

50

55

60

0.1 1 10 100

Frequency (Hz)

Spectral Acceleration (no units)

Ran9

Ran20

Ran21

Ran68

Ran90

Ran98

Spliced_2

Figure C3-27 Response spectra of selected vertical records (5% of critical damping).
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 89 

-6

-4

-2

0

2

4

6

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Amplitude (no units)

Figure C3-28 Spliced vertical record (Spliced_2). 

The vertical spliced record was then scaled so the response spectrum spectral 

acceleration would be approximately 0.8 g above 2 Hz, and have a uniform 

spectral displacement below 2 Hz. This scaling was accomplished in the 

same way as for the two horizontal records, and Figures C3-29 and C3-30 

plot the resulting scale in both the frequency and time domain, respectively. 

Figure C3-31 plots the scaled vertical record, and the response spectrum is 

included in Figure C3-11 (Vert_3). The Vert_3 name indicates that the 3rd

trial scale was the final scale used for this record. 

C3.9 Notch Filtering of Input Motions 

It is possible that once a damage state has been caused by a particular 

excitation frequency and at a given amplitude, this damage state will be 

undesirably accentuated if the input motions are amplified in subsequent 

tests. This situation could prevent the occurrence and identification of other 

damage states. To alleviate this situation, notch filtering of the input motions 

may be used to remove energy near the excitation frequency that has already 

caused a damage state to occur. 

Once a frequency has been removed from the input motions by notch 

filtering, that frequency will have negligible effect on higher damage levels. 

If different damage levels are dominated by the same frequency but by 

different intensities, notch filtering will prevent the occurrence of these other 
90 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1 1 10 100

Frequency (Hz)

Scale (g)

Figure C3-29 Scale used for the vertical record, plotted in the frequency domain

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Scale (g)

Figure C3-30 Scale used for the vertical record, plotted in the time domain.
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 91 

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (sec)

Acceleration (g)

Vert_3

Figure C3-31 Scaled narrow-band random vertical record.

damage states. Therefore, the use of notch filtering must be assessed 

carefully during the experimental program. 

C3.10 Testing Equipment 

Major testing equipment required to execute the test sequence described in 

Section 3.2 is categorized in the following four groups. 

1. A shake table is used to apply dynamic motion in one, two or three axes. 

It includes the platen structure upon which the test specimen is mounted 

and other subcomponents such as actuators, and electrical or hydraulic 

power. Most of the shake tables used for fragility testing are of the type 

driven by servo-hydraulic actuator systems that can deliver the best 

performance requirements of large force, velocity and stroke under large 

payloads (the total weight of the test specimen and other fixtures). 

2. A control system can be either an analog or digital electronic system and 

is used to control the motions of the shake table. 

3. Instrumentation (or sensors) measure physical quantities such as 

displacement, acceleration, velocity, strain, and force. Key 

considerations include (a) the proper identification of sensors for the 

purpose of collecting response data, and (b) sensor location, coordinate 

reference system, measurement characteristics, constraints, and sensor 

attachment methods. 
92 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

4. Data acquisition includes equipment and appropriate software that is 

used to facilitate the reading, processing and recording of sensor output. 

C3.10.1 Shake Tables 

Typically, performance of a shake table is limited by the actuator stroke (i.e., 

displacement) at low frequencies, actuator velocity (servo capacity) at 

intermediate frequencies, and the ratio of actuator force to payload at higher 

frequencies. The velocity limit is controlled primarily by the flow capacity of 

the actuators’ servo-valves as well as the pump and accumulator flow 

capacities. At higher frequencies, however, the shake table performance is 

acceleration-limited, the achievable peak acceleration being equal to the ratio 

of maximum actuator force capacity to the payload of the test specimen. 

The operation of a real-time controller for a shake table system may be 

challenging due to the requirements of matching the time-history, response 

spectrum or power spectral density (PSD) between the target input motion 

and achieved input motion. The requirements must be met by the operator of 

the shake table due to the liability of an over-test, e.g., that may subsequently 

damage the test specimen. 

The parameters affecting control-system design include: 

1. payload (mass of the test specimen), 

2. test specimen resonance, response nonlinearity and force feedback, 

3. input motion, and 

4. mechanical and performance limits of the earthquake simulator system. 

Typically, controllers used in servo-hydraulic systems have a limited 

frequency bandwidth. Earthquake simulator controllers use advanced analog 

or digital controllers that incorporate displacement, velocity and acceleration 

signals for improved earthquake simulator response. Displacement, velocity 

and acceleration signals provide the low, intermediate and high frequency 

components necessary to create the desired earthquake simulator response to 

meet the input motion demand. The feedback signals are used to create and 

modify the drive signal for the earthquake simulator actuator(s). 

Ideally, in order to achieve the required shake table response and conform to 

the recommendations of this protocol, the controller must know the 

feedbacks a-priori to create the proper corrected drive signal for the shake 

table actuators. However, this information is typically not available unless 

the test specimen is subjected to pretests of the prescribed levels of input 

motion to measure the shake table feedbacks so as to then modify the 
FEMA 461 C3: Commentary on Interim Protocol II – Shake Table Testing 93 

subsequent drive signal. The risk of multiple testing of the same test 

specimen may, however, damage the test specimen before meeting the 

requirements. 

There are several unique advantages of shake table testing of the type 

targeted by this interim protocol. The test specimen is generally lightweight 

and may therefore have low resonant feedback at the resonant frequency of 

the shake table – hydraulic system assembly (i.e., there is negligible shake 

table – test specimen interaction). These two advantages allow the shake 

table control system to compensate to meet the target acceleration timehistory before the test specimen is placed on the shake table. If the test 

specimen is lightweight (low payload) relative to the shake table system, the 

shake table can be operated without the specimen in place. This allows the 

shake table system to converge on the target input motion through a process 

called iteration. 

To iterate an input motion time-history, first a forward transfer function must 

be computed. This can be done by operating the table at a low-level random 

motion and computing the forward transfer function between the feedback 

and the reference signals. This function represents the shake table response in 

the frequency domain. Once this function is known, it can be used to amplify 

or attenuate the frequency components of the input time history and create a 

drive time-history. For example, if a 5 Hz, 1 g, sine wave is commanded to 

the table, and the table responds with a 2 g sine wave, the transfer function at 

5 Hz has a gain of 2. If the command is then modified to 5 Hz at 0.5 g, then 

the table response would be 1g which is the target acceleration originally 

intended. This new command is called the drive signal. 

In theory, the drive signal will produce a feedback identical to the target 

acceleration time-history. However, in reality, nonlinear oil flow through the 

valves and actuators, and the test specimen response prevents this “first 

iteration” from exactly matching the target. It is therefore necessary to take a 

percentage of the error between the target and the feedback and add it to the 

drive signal. In effect, the system compensates for the nonlinearity of the 

shake table response. This process shall be repeated as many times as 

necessary until the shake table feedback matches the target motion. It is 

apparent that multiple iterations are necessary. This prevents the procedure 

from being used when the test specimen is attached to the shake table system. 

Real time adaptive control techniques can also be used to converge on the 

target motion, but these techniques take time to “anticipate” and modify the 

future drive signals. These are more complex techniques, which require 
94 C3: Commentary on Interim Protocol II – Shake Table Testing FEMA 461 

significant understanding on the part of the operator, and need to be used 

with caution even by experienced operators. 

C3.10.2 Instrumentation and Monitoring 

Within the context of this interim shake table testing protocol, the purpose of 

instrumentation and monitoring should be to record and monitor various 

types of response characteristics and behavior of the test specimen when 

subjected to the test sequence specified in Section 3.2. Hence, sufficient 

response monitoring instrumentation should be used to allow recording and 

determination of accelerations, velocities, absolute and relative 

displacements, strains and forces. The sensors used for this purpose should 

allow consistent measurement at various stages of response, such as in the 

proportionality range, nonproportionality range, and during failure of the test 

specimen. 
FEMA 461 A: Determination of Fragility Functions Based on Laboratory Data 95 

Appendix A 

Determination of Fragility 

Functions Based on Laboratory 

Data

A.1 Purpose 

This appendix describes the process used to develop nonstructural 

component fragility functions based on laboratory testing. These fragility 

functions will be used to assess the seismic performance of a building 

containing a number of structural and nonstructural components as part of the 

performance-based seismic design process. 

A.2 Background 

Nonstructural component seismic fragility functions are mathematical 

expressions that indicate the conditional probability that a nonstructural 

component will experience damage equal to or more severe than a particular 

level, given that it experiences earthquake-induced demands of a particular 

intensity. The intensity of earthquake shaking can be expressed in the form 

of maximum imposed displacements, velocities or accelerations, or a 

combination of these parameters. Fragility functions typically are expressed 

in the form: 

[ ]zEDPDSDPzg DSi )( ≥= i =

where: 

D is the damage sustained by the component. 

DSi is a specific damage state, such as initiation of cracking of a 

partition, a piece of electrical equipment developing a short, or a 

mechanical seal on a pressure-containing component losing integrity. 

EDP is an engineering demand parameter, used to quantify the intensity of 

shaking that the component or system is subjected to as described 

above. 

Seismic fragility functions will typically be represented as lognormal 

functions, characterized by a median value and a variance. For a given 
96 A: Determination of Fragility Functions Based on Laboratory Data FEMA 461 

damage state DSi, the median value of z, zˆ , is that value of z at which there 

is a 50% probability that damage will equal or exceed the specified level. 

The variance, typically represented by the parameter β, is the standard 

deviation of the natural logarithm of the values of z at which the damage is 

evaluated. Figure A-1 shows a representative nonstructural component 

seismic fragility function. In this particular function, the median value of z

has a value of 1. The variance has a value of 0.25. As can be seen, at a 

shaking intensity level z =1, there is 50% probability that the component will 

be damaged to damage state DSi, or a more severe level. At a shaking 

intensity level z = 0.7 there is approximately a 10% chance that the 

component will be damaged to DSi, or a more severe level. At a shaking 

intensity level z = 1.4, there is approximately a 90% chance that the 

component will be damaged to damage state DSi, or a more severe level. 

Figure A-1 Hypothetical nonstructural component fragility function 

The variability exhibited by nonstructural component seismic fragility 

functions can be attributed to a variety of factors, including: 

• random variations in the character of shaking at a given level of intensity 

– for example, if shaking intensity, z, is represented by the peak 

acceleration input experienced by the component, one earthquake may 

provide that peak value several times during the event, while other 

events, of similar intensity, may reach that peak value only one time, 

• random variation in the strength or displacement capacity of the unit 

itself, owing to variability in the materials of its construction and the way 

in which the component is manufactured, and 
FEMA 461 A: Determination of Fragility Functions Based on Laboratory Data 97 

• random variation in the manner in which the component is installed in 

the building, including, for example, the strength of anchors attaching the 

component to the structure. 

Nonstructural component fragility functions can be established in several 

ways including: 

Earthquake performance data. In this method, an attempt is made to 

investigate the performance of a number of actual installations of the 

component that have experienced shaking of differing intensities. If a large 

number of the components have been subjected to shaking of different 

intensities, it is possible to develop directly a distribution of the percentage 

of components subjected to a given intensity of shaking that have been 

damaged to different levels and directly construct the fragility function. 

Simulation. In this method, a mathematical model of the component is 

developed and a simulation is performed to predict the damage sustained by 

the component when subjected to shaking. A large number of simulations 

must typically be performed to explore the effect of variation of ground 

motion character, manufacturing quality, and installation quality. 

Laboratory testing. In this method, a representative sample of components 

is subjected to laboratory testing that represents the response of the 

components to actual shaking. As with simulation, ideally, a large number of 

tests should be performed to permit exploration of the effect of variation of 

ground motion character, manufacturing quality and installation quality on 

component behavior. 

This appendix describes, in a general manner, the procedures that should be 

used to develop nonstructural component seismic fragility functions using 

laboratory testing. 

A.3 General Procedure 

As indicated in Section A.2, ideally, data from a large number of tests, that 

explore variability in shaking character, manufacturing quality, and 

installation quality would be available. However, since testing is typically 

expensive, data from only a limited number of tests will be available. 

Therefore, development of nonstructural component seismic fragility 

functions will require the application of some expert judgment to extrapolate 

the available data. 

Development of nonstructural component seismic fragility functions should 

be conducted by a panel of experts. This panel should include engineers 

familiar with structural reliability methods and probabilistic analysis, 
98 A: Determination of Fragility Functions Based on Laboratory Data FEMA 461 

earthquake engineering experts and engineers familiar with the manufacture, 

installation and function of the particular component. Researchers who 

performed the testing upon which the seismic fragility will be based should 

be participants in the panel although these researchers should not be the sole 

members of the panel. 

Data available from the test should include a description of the components 

tested, the test setup, the loading applied and for each test, the various 

damage states observed and the loading level at which each damage state 

occurred. 

The panel should evaluate the following factors: 

• the extent to which the test setup represents the actual installed condition 

of the component in a building and the extent that the laboratory setup 

may result in a systematic bias in the values of the loading at which the 

damage occurs, 

• the variability of the reported values for which the damage state occurs 

and apparent repeatability of results from test to test, 

• the insight of the researcher who performed the test, regarding the critical 

parameters that control the damageability of the component, including 

for example, the rigidity and strength of base anchorage or other bracing, 

the combined effects of multi-axial loading, whether the component is 

functioning at the time of the loading, and any other factors that appear 

to affect behavior – these factors should be reported together with the 

researcher’s insight as to the extent of the affect of each such parameter, 

and 

• the variability in performance of similar types of components exhibiting 

similar behaviors as established by other seismic fragility development 

efforts. 

Considering these data, the panel should establish values for the median and 

variance, as previously described. The median value should not be different 

from the median value of the reported test data unless there is specific reason 

to believe that the test setup resulted in identifiable bias in the results. 

Generally, in order to establish a reliable estimate of the variance, based on 

test data alone, a large number of tests (in excess of 10) will need to be 

performed. Lacking such data, the variance should be established on the 

basis of expert judgment considering the identified factors that affect 

behavior, an evaluation of the amount of variability possible in each of these 

factors, the amount that variability in each of these factors will likely affect 
FEMA 461 A: Determination of Fragility Functions Based on Laboratory Data 99 

the results, and an understanding of the degree of correlation, if any, between 

these various factors and the performance. 

When establishing these fragility parameters, the panel must bear in mind 

that the intent is to establish unbiased predictions of fragility that neither 

over-predict nor under-predict the probability that the component will 

experience a given level of damage at a given level of shaking. The 

nonstructural component seismic fragility function should account only for 

the variability inherent in the behavior of the particular type of component. 

Variability in other external factors that can affect the performance of the 

component, but which are not directly related to the component should not be 

included in the fragility variability. Examples of variability that should not 

be included in nonstructural component seismic fragility functions include 

the following: 

• uncertainty in the intensity of ground shaking, 

• uncertainty in the response of the supporting structure, and 

• uncertainty in the consequences of damage of the component. 

The fragility parameters should be presented in a report, which is prepared by 

the panel, and which includes the following: 

• a description of the component and the installation condition for which 

the fragility applies, 

• identification of the panel members and their qualifications, 

• a description of the damage state(s) for which the fragilities apply, 

including, in a qualitative manner, discussion of the consequences of this 

damage (for example, component will not function, component will leak, 

component must be repaired, or component must be replaced), 

• a description of the data and factors considered by the panel, and 

• the panel’s recommendation for the median and variance. 

FEMA 461 References 101 

References

ASCE, 2002, Prestandard and Commentary for the Seismic Rehabilitation of 

Buildings, FEMA- 356 Report, prepared by the American Society of 

Civil Engineers for the Federal Emergency Management Agency, 

Washington, D.C. 

ATC, 1992, Guidelines for Cyclic Seismic Testing of Components of Steel 

Structures, ATC-24 Report, Applied Technology Council, Redwood 

City, California. 

ATC, 1996, Seismic Evaluation and Retrofit of Concrete Buildings, ATC-40 

Report, Applied Technology Council, Redwood City, California. 

ASTM, 2003, Standard Practices for Cycle Counting on Fatigue Analysis, 

ASTM-1049, American Society for Testing and Materials, 

www.astm.org. 

EERC, 1996, Performance-Based Seismic Design of Buildings – An Action 

Plan for Future Studies, FEMA 283 Report, prepared by the Earthquake 

Engineering Research Center for the Federal Emergency Management 

Agency, Washington, D.C. 

EERI, 2000, Action Plan for Performance-Based Seismic Design, FEMA349 Report, prepared by the Earthquake Engineering Research Institute 

for the Federal Emergency Management Agency, Washington, D.C. 

IAS, 2006, Accreditation Criteria for Testing Laboratories, Report AC 89, 

International Accreditation Service, Whittier, California. 

IEEE, 2004, Recommended Practice for Seismic Qualification of Class 1E 

Equipment for Nuclear Power Generating Stations, IEEE Standard No. 

344-2004, Institute of Electrical and Electronics Engineers, Piscataway, 

New Jersey. 

Krawinkler, H., et al., 1983, Recommendations for Experimental Studies on 

the Seismic Behavior of Steel Components and Materials, John A. Blume 

Center Report No. 61, Department of Civil Engineering, Stanford 

University. 

Krawinkler, H., Parisi, F., Ibarra, L., Ayoub, A., and Medina, R., 2001, 

Development of a Testing Protocol for Wood Frame Structures, CUREE 
102 References FEMA 461 

Publication No. W-02, Consortium of Universities for Research in 

Earthquake Engineering. 

Wilcoski, J., Gambill, J.B., and Smith, S.J., 1997, CERL Equipment Fragility 

and Protection Procedure (CEFAPP), USACERL Technical Report 

97/58, U.S. Army Construction Engineering Research Laboratory, 

Champaign, Illinois. 
FEMA 461 Acronyms 103 

Acronyms

ASTM American Society for Testing and Materials 

ATC Applied Technology Council 

CalTech California Institute of Technology 

CD-ROM compact disk, read-only memory 

CUREE Consortium of Universities for Research in Earthquake 

Engineering 

FEMA Federal Emergency Management Agency 

ICC International Code Council 

ICC ES ICC Evaluation Service 

IMRS input motion response spectrum 

LVDT linear variable differential transformer 

MAE Center Mid-America Earthquake Center 

MCEER Multidisciplinary Center for Earthquake Engineering 

Research 

MDOF multi degree of freedom 

MRS maximum response spectrum 

NEES Network for Earthquake Engineering Simulation 

NIST National Institute for Standards and Technology 

PEER Center Pacific Earthquake Engineering Research Center 

PSD power spectral density 

SDOF single degree of freedom 

FEMA 461 Project Participants 105 

Project Participants

Project Management 

Christopher Rojahn, 

Project Executive Director 

Applied Technology Council 

201 Redwood Shores Parkway, Suite 240 

Redwood City, California 94065 

Ronald O. Hamburger, 

Project Technical Director 

Simpson Gumpertz & Heger 

The Landmark @ One Market, Suite 600 

San Francisco, California 94105 

FEMA Oversight 

Mike Mahoney, Project Officer 

Federal Emergency Management Agency 

500 C Street, SW 

Washington, DC 20472 

Robert D. Hanson, Technical Monitor 

(Federal Emergency Management Agency) 

2926 Saklan Indian Drive 

Walnut Creek, California 94595-3911 

Project Management Committee 

Christopher Rojahn, Chair 

Ronald Hamburger, Co-Chair 

Jon Heintz, Ex-officio 

Applied Technology Council 

201 Redwood Shores Parkway, Suite 240 

Redwood City, California 94065 

William T. Holmes, 

Steering Committee Chair (ex-officio) 

Rutherford & Chekene 

55 Second Street, Suite 600 

San Francisco, California 94105 

John Gillengerten 

Office of Statewide Health 

Planning and Development 

1600 9th St., Room 420 

Sacramento, California 95814 

Peter May 

University of Washington 

Box 353530 

Seattle, Washington 98195 

Jack P. Moehle 

University of California Berkeley 

325 Davis Hall – MC 1792 

Berkeley, California 94720 

Maryann T. Phipps 

Estructure 

8331 Kent Court, Suite 100 

El Cerrito, California 94530 
106 Project Participants FEMA 461 

Project Technical Committee 

Ronald O. Hamburger, Chair 

Christopher Rojahn, Ex-officio 

Robert Bachman 

Consulting Structural Engineer 

25152 La Estrada Drive 

Laguna Niguel, California 92677 

Craig D. Comartin 

Comartin Engineers 

7683 Andrea Avenue 

Stockton, California 95207-1705 

Jon Heintz 

Applied Technology Council 

201 Redwood Shores Parkway, Suite 240 

Redwood City, California 94065 

Jack P. Moehle 

University of California Berkeley 

325 Davis Hall – MC 1792 

Berkeley, California 94720 

Maryann T. Phipps 

Estructure 

8331 Kent Court, Suite 100 

El Cerrito, California 94530 

Andrew S. Whittaker 

University at Buffalo 

Dept. of Civil Engineering 

230 Ketter Hall 

Buffalo, New York 14260 

Steering Committee 

William T. Holmes, Chair 

Rutherford & Chekene 

55 Second Street, Suite 600 

San Francisco, California 94105 

Dan Abrams 

Mid-America Earthquake Center 

University of Illinois 

2118 Newmark Civil Engineering Lab 

205 N. Mathews 

Urbana, Illinois 61801 

Deborah B. Beck 

Beck Creative Strategies LLC 

531 Main Street, Suite 313 

New York, New York 10044 

Randall Berdine 

Fannie Mae 

3900 Wisconsin Avenue, NW 

Washington, DC 20016-2892

Roger D. Borcherdt 

U.S. Geological Survey 

345 Middlefield Road, MS977 

Menlo Park, California 94025 

Michel Bruneau 

MCEER, University at Buffalo 

105 Red Jacket Quadrangle 

Buffalo, New York 14261-0025 

Terry Dooley 

ACE Mentor Program 

c/o Morley Builders 

2901 28th Street, Suite 100 

Santa Monica, California 90405 

Amr Elnashai 

Mid-America Earthquake Center 

University of Illinois 

1241 Newmark Lab 

205 N. Mathews 

Urbana, Illinois 61801 
FEMA 461 Project Participants 107 

Steering Committee (continued) 

Mohammed Ettouney 

Weidlinger Associates, Inc. 

375 Hudson Street 

New York, New York 10014-3656 

Jack Hayes 

NEHRP Director 

National Inst. of Standards & Technology 

100 Bureau Drive, MS 8610 

Gaithersburg, Maryland 20899-8610 

William J. Petak 

University of Southern California 

School of Policy Planning and Development 

MC 0626 

Los Angeles, California 90089 

Randy Schreitmueller 

FM Global 

1301 Atwood Avenue 

Johnston, Rhode Island 02919 

Jim W. Sealy, Architect 

1320 Prudential Drive, No 101 

Dallas, Texas 75235-4117 

Jon Traw 

Traw Associates Consulting 

14435 Eastridge Drive 

Whittier, California 90602-2745 

Product 1 Team 

Ronald L. Mayes, Team Leader 

Simpson Gumpertz & Heger 

The Landmark @ One Market, Suite 600 

San Francisco, California 94105 

Daniel Alesch 

(formerly with University of Wisconsin) 

909 Forest Hill Drive 

Green Bay, Wisconsin 54311-5927 

Bruce R. Ellingwood 

Georgia Institute of Technology 

790 Atlantic Drive 

Atlanta, Georgia 30332-0355 

James O. Malley 

Degenkolb Engineers 

225 Bush Street, Suite 1000 

San Francisco, California 94104 

Structural Performance Products Team 

Andrew S. Whittaker, Team Leader 

University at Buffalo 

Dept. of Civil Engineering 

230 Ketter Hall 

Buffalo, New York 14260 

Gregory Deierlein 

Stanford University 

Dept. of Civil & Environmental Engrg 

240 Terman Engineering Center 

Stanford, California 94305-4020 

Andre Filiatrault 

MCEER, University at Buffalo 

105 Red Jacket Quadrangle 

Buffalo, New York 14261-0025 

John Hooper 

Magnusson Klemencic Associates 

1301 Fifth Avenue, Suite 3200 

Seattle, Washington 98101 

Andrew T. Merovich 

A. T. Merovich & Associates, Inc. 

1950 Addison Street, Suite 205 

Berkeley, California 94704 
108 Project Participants FEMA 461 

Nonstructural Performance Products Team 

Robert Bachman, Team Leader 

Consulting Structural Engineer 

25152 La Estrada Drive 

Laguna Niguel, California 92677 

David Bonowitz 

Office of Court Construction & Mgmt. 

Judicial Council of California 

Administrative Office of the Courts 

455 Golden Gate Avenue 

San Francisco, California 94102-3688 

Philip J. Caldwell 

Square D Company 

1990 Sandifer Blvd. 

Seneca, South Carolina 29687 

Andre Filiatrault 

MCEER, University at Buffalo 

105 Red Jacket Quadrangle 

Buffalo, New York 14261-0025 

Robert P. Kennedy 

RPK Structural Mechanics Consulting, Inc. 

28625 Mountain Meadow Road 

Escondido, California 92026 

Gary McGavin 

McGavin Architecture 

447 LaVerne Street 

Redlands, California 92373-6015 

Eduardo Miranda 

Stanford University 

Civil & Environmental Engineering 

Terman Room 293 

Stanford, California 94305-3707 

Keith Porter 

Consulting Engineer 

769 N. Michigan Avenue 

Pasadena, California 91104 

Shake Table Testing Protocol Team 

Andre Filiatrault, Team Leader 

MCEER, University at Buffalo 

105 Red Jacket Quadrangle 

Buffalo, New York 14261-0025 

Philip J. Caldwell 

Square D Company 

1990 Sandifer Blvd. 

Seneca, South Carolina 29687 

Peter Dusicka 

Portland State University 

Dept. of Civil & Environmental Engineering 

P.O. Box 751 

Portland, Oregon 97207-0751 

Tara Hutchinson 

University of California, San Diego 

Jacobs School of Engineering 

9500 Gilman Drive, MC 0085 

La Jolla, California 92093-0085 

Ahmad Itani 

University of Nevada, Reno 

Dept. of Civil Engineering 

Mail Stop 258 

Reno, Nevada 89557-0152 

Eduardo Miranda 

Stanford University 

Civil & Environmental Engineering 

Terman Room 293 

Stanford, California 94305-3707 

Gokhan Pekcan 

University of Nevada, Reno 

Dept. of Civil Engineering 

Mail Stop 258 

Reno, Nevada 89557-0152 
FEMA 461 Project Participants 109 

Shake Table Testing Protocol Team (continued)

Andrei M. Reinhorn 

University at Buffalo 

Dept. of Civil Engineering 

231 Ketter Hall 

Buffalo, New York 14260 

Jose Restrepo 

University of California, San Diego 

9500 Gillman Drive 

La Jolla, California 92093-0085 

James Wilcoski 

U.S. Army Engineer Research and Development 

Center 

Construction Engineering Research Laboratory 

P.O. Box 9005 

Champaign, Illinois 61826-9005 

Racking Testing Protocol Team 

Helmut Krawinkler, Team Leader 

Stanford University 

Civil Engineering Department 

Stanford, California 94305-4020 

David Bonowitz 

Office of Court Construction & Mgmt. 

Judicial Council of California 

Administrative Office of the Courts 

455 Golden Gate Avenue 

San Francisco, California 94102-3688 

Barry J. Goodno 

Georgia Institute of Technology 

790 Atlantic Drive 

Atlanta, Georgia 30332-0355 

Steven Kuan 

Office of Housing & Construction Standards 

P.O. Box 9844, Stn Prov Govt 

Victoria, B.C. Canada V8W 9T2 

Joseph R. Maffei 

Consulting Structural Engineer 

427 Thirteenth Street 

Oakland, California 94612 

Ali M. Memari 

Pennsylvania State University 

Dept. of Architectural Engineering 

104 Engineering Unit A 

University Park, Pennsylvania 16802-1416 

Jose Restrepo 

University of California, San Diego 

9500 Gillman Drive 

La Jolla, California 92093-0085 

Chia-Ming Uang 

University of California, San Diego 

409 University Center 

La Jolla, California 92093-0085 

Component Cyclic Testing Protocol Team 

Manos Maragakis, Team Leader 

University of Nevada, Reno 

Dept. of Civil Engineering 

Mail Stop 258 

Reno, Nevada 89557-0152 

George Antaki 

Westinghouse Savannah River Company 

Savannah River Site, Building 730-1B/214 

Aiken, South Carolina 29808 

Scott Campbell 

Kinetics Noise Control 

6300 Frelan Place 

Dublin, Ohio 43017 

Robert Kennedy 

RPK Structural Mechanics Consulting, Inc. 

28625 Mountain Meadow Road 

Escondido, California 92026 
110 Project Participants FEMA 461 

Component Cyclic Testing Protocol Team (continued) 

Praveen Malhotra 

FM Global Research 

1151 Boston-Providence Turnpike 

Norwood, Massachusetts 02062 

Sami Masri 

University of Southern California 

Dept. of Civil Engineering 

Los Angeles, California 90089-2531 

John F. Silva 

Hilti Inc. 

84 Mt. Rainier Drive 

San Rafael, California 94903 

Risk Management Products Team 

Craig D. Comartin, Team Leader 

Comartin Engineers 

7683 Andrea Avenue 

Stockton, California 95207-1705 

Brian J. Meacham, Team Associate Leader 

Arup 

1500 West Park Drive, Suite 180 

Westborough, Massachusetts 01581 

C. Allin Cornell 

Stanford University 

Dept of Civil & Environmental Engineering 

Terman Engineering Center 

Stanford, California 94305 

Gee Heckscher 

Architectural Resources Group 

Pier 9 The Embarcadero 

San Francisco, California 94111 

Charles Kircher 

Kircher & Associates, Consulting Engineers 

1121 San Antonio Road, Suite D-202 

Palo Alto, California 94303-4311 

Farzad Naeim 

John A. Martin & Associates, Inc. 

1212 S. Flower Street, 4th Floor 

Los Angeles, California 90015 

Robert D. Weber 

R.D. Weber & Associates, Inc. 

9784 Ice Box Canyon Court 

Las Vegas, Nevada 89117 

Publication and Management Support Services 

A. Gerald Brady, Editor 

735 DeSoto Drive 

Palo Alto, California 94303 

Bernadette Hadnagy, Operations Manager 

Applied Technology Council 

201 Redwood Shores Parkway, Ste 240 

Redwood City, California 94065 

Peter N. Mork 

I.T. Manager 

Applied Technology Council 

201 Redwood Shores Parkway, Ste 240 

Redwood City, California 94065 
FEMA 461 Workshop Participants 111 

Workshop Participants

FEMA/ATC-58 Workshop on 

Interim Protocols for Seismic Performance 

Assessment Testing of Nonstructural Components

November 4-5, 2004 

Doubletree Hotel, San Francisco Airport 

835 Airport Blvd. 

Burlingame, California 

Dennis Alvarez 

USG Corporation 

35350 Chester Road 

Avon, Ohio 44011 

George Antaki 

WGI 

Savannah River Site, 730-1B 

Aiken, South Carolina 29808 

Robert Bachman 

R.E. Bachman, Consulting Structural Engineer 

880 Dartmouth Street 

San Francisco, California 94134 

John Caffrey 

University of Southern California 

Dept. of Civil & Environmental Engineering 

KAP 268, Mail Code: 2531 

Los Angeles, California 90089 

Philip J. Caldwell 

Square D/Schneider Electric 

1990 Sandifer Blvd. 

Seneca, South Carolina 29682 

Scott Campbell 

Kinetics Noise Control 

6300 Irelan Place 

Dublin, Ohio 43017 

James A. Carlson 

Seismic Source Company 

P.O. Box 586 

Springfield, Nebraska 68059 

Mary Comerio 

University of California, Berkeley 

Dept. of Architecture, M/C 1800 

Berkeley, California 94720 

Craig D. Comartin 

CDComartin Engineering 

7683 Andrea Avenue 

Stockton, California 95207-1705 

Peter Dusicka 

Portland State University 

Dept. of Civil & Environmental Engineering 

P.O. Box 751 

Portland, Oregon 97207-0751 

Andre Filiatrault 

MCEER, SUNY at Buffalo 

Red Jacket Quadrangle 

Buffalo, New York 14032 

William E. Gates 

URS Corporation 

915 Wilshire Blvd., Suite 700 

Los Angeles, California 90017 

Jeff Gatscher 

Schneider Electric 

1010 Airpark Center Drive 

Nashville, Tennessee 37211 

Barry Goodno 

Georgia Institute of Technology 

School of Civil Engineering 

790 Atlantic Drive 

Atlanta, Georgia 30332-0355 
112 Workshop Participants FEMA 461 

Nathan C. Gould 

ABS Consulting Inc. 

1844 Lackland Hills Pkwy. 

St. Louis, Missouri 63146 

Bernadette Hadnagy 

Applied Technology Council 

201 Redwood Shores Pkwy., Suite 240 

Redwood City, California 94065 

Ronald Hamburger 

Simpson Gumpertz & Heger 

The Landmark @ One Market, Suite 600 

San Francisco, California 94105 

Robert Hanson 

FEMA 

2926 Saklan Indian Drive 

Walnut Creek, California 94595-3911 

Brian Kehoe 

Wiss, Janney, Elstner Associates, Inc. 

2200 Powell Street, Suite 925 

Emeryville, California 94608 

Robert P. Kennedy 

RPK Structural Mechanics Consulting, Inc. 

28625 Mountain Meadow Road 

Escondido, California 92026 

Charles Kircher 

Kircher & Associates 

1121 San Antonio Road, Suite D-202 

Palo Alto, California 94303-4311 

Helmut Krawinkler 

Stanford University 

Dept. of Civil Engineering 

Stanford, California 94305-4020 

Steven Kuan 

Public Works & Government Services Canada 

800 Burrard Street, Room 641 

Vancouver, BC Canada V6Z 2V8 

Richard Lloyd 

Mason Industries 

2101 West Crescent Avenue, Suite D 

Anaheim, California 92801 

Joe Maffei 

Rutherford & Chekene 

427 Thirteenth Street 

Oakland, California 94612 

Mike Mahoney 

Federal Emergency Management Agency 

500 C Street, SW, Room 404 

Washington, DC 20472 

Manos Maragakis 

University of Nevada, Reno 

Dept. of Civil Engineering 

Mail Stop 258 

Reno, Nevada 89557 

Sami Masri 

University of Southern California 

Dept. of Civil Engineering, MC 2531 

Los Angeles, California 90089-2531 

Ali M. Memari 

Pennsylvania State University 

Dept. of Architectural Engineering 

104 Engineering Unit A 

University Park, Pennsylvania 16802-1416 

Kelly Merz 

ARES Corporation 

3010 Old Ranch Parkway 

Seal Beach, California 90740 

Eduardo Miranda 

Stanford University 

Dept. of Civil & Environmental Engineering 

Terman Room 293 

Stanford, California 94305-4020 
FEMA 461 Workshop Participants 113 

Gokhan Pekcan 

University of Nevada, Reno 

Dept. of Civil Engineering 

Mail Stop 258 

Reno, Nevada 89557 

Andrei M. Reinhorn 

University at Buffalo 

Dept. of Civil Engineering 

231 Ketter Hall 

Buffalo, New York 14260 

Jose Restrepo 

University of California at San Diego 

9500 Gillman Drive, Dept. 0085 

La Jolla, California 92093-0085 

Christopher Rojahn 

Applied Technology Council 

201 Redwood Shores Pkwy., Suite 240 

Redwood City, California 94065 

Anshel Schiff 

Precision Measurement Instruments 

27750 Edgerton Road 

Los Altos Hills, California 94022 

John Silva 

Hilti Inc. 

84 Mt. Rainier Drive 

San Rafael, California 94903 

Don Smith 

Wyle Laboratories 

7800 Highway 20 West 

Huntsville, Alabama 35806 

Greg Soules 

Chicago Bridge and Iron Co. 

2103 Research Forest Drive 

One CB&I Plaza 

The Woodlands, Texas 77380-2624 

William Staehlin 

Division of the State Architect 

1225 R Street 

Sacramento, California 95814 

Chris Tokas 

OSHPD 

1600 9th Street, Room 420 

Sacramento, California 95814 

Chia-Ming Uang 

University of California, San Diego 

Structural Engineering Department 

409 University Center 

La Jolla, California 92093-0085 

James Wilcoski 

ERDC-CERL 

P.O. Box 9005 

Champaign, Illinois 61826-9005