Tenth U.S. National Conference on Earthquake Engineering Frontiers of Earthquake Engineering July 21-25, 2014 Anchorage, Alaska 10NCEE

RAPID VISUAL SCREENING OF

BUILDINGS FOR POTENTIAL SEISMIC

HAZARDS: FEMA 154 AND 155 UPDATES

B. Lizundia1, S. Durphy

2, M. Griffin

3, A. Hortacsu

4, B. Kehoe

5, K.

Porter6, and B. Welliver

7

ABSTRACT

FEMA 154 Rapid Visual Screening of Buildings for Potential Seismic Hazards: A Handbook and

the companion publication FEMA 155: Supporting Documentation provide a methodology for

rapid visual screening of buildings. The Handbook provides a “sidewalk survey” approach that

enables classification of buildings into two categories: those that appear to be adequately safe

and those that may be seismically hazardous and should be evaluated in more detail by a design

professional experienced in seismic evaluation and design. The First Edition of the Handbook

was published in 1988, and it was updated to the Second Edition in 2002. The methodology has

been used extensively throughout the United States by private sector organizations and

government agencies to evaluate buildings, and it has served as a model for similar efforts in

other countries. In a project funded by FEMA, the Applied Technology Council is updating both

FEMA 154 and FEMA 155. Major enhancements in the Third Edition include improvements in

the screening form; an added optional more detailed level of screening; updates of the scoring

values; new reference guides for vertical and plan irregularities; additional building types;

improved consideration of additions, adjacent structures, and retrofits; an optional electronic

scoring methodology; new insight into risk; and more detailed discussion on how to run an

effective screening program.

1Principal, Rutherford + Chekene, San Francisco, CA 94105

2Senior Design Engineer, Rutherford + Chekene, San Francisco, CA 94105

3Principal, CCS Group, Chesterfield, MO 63017

4Associate Director of Projects, Applied Technology Council, Redwood Shores, CA 94065

5Associate Principal, Wiss Janney Elstner Associates, Emeryville, CA 94608

6Principal, SPA Risk LLC, Denver, CO 80207

7Principal, BHW Engineers, Draper, UT 84020

Lizundia B, Durphy S, Griffin M, Hortacsu A, Kehoe B, Porter K, and Welliver B. Rapid Visual Screening of

Buildings for Potential Seismic Hazards: FEMA 154 and FEMA 155 Updates. Proceedings of the 10th

National

Conference in Earthquake Engineering, Earthquake Engineering Research Institute, Anchorage, AK, 2014.

Tenth U.S. National Conference on Earthquake Engineering Frontiers of Earthquake Engineering July 21-25, 2014 Anchorage, Alaska 10NCEE

Rapid Visual Screening of Buildings for Potential Seismic Hazards:

FEMA 154 and FEMA 155 Updates

B. Lizundia1, S. Durphy

2, M. Griffin

3, A. Hortacsu

4, B. Kehoe

5, K. Porter

6, and B. Welliver

7

ABSTRACT FEMA 154 Rapid Visual Screening of Buildings for Potential Seismic Hazards: A Handbook and

the companion publication FEMA 155: Supporting Documentation provide a methodology for

rapid visual screening of buildings. The Handbook provides a “sidewalk survey” approach that

enables classification of buildings into two categories: those that appear to be adequately safe and

those that may be seismically hazardous and should be evaluated in more detail by a design

professional experienced in seismic evaluation and design. The First Edition of the Handbook was

published in 1988, and it was updated to the Second Edition in 2002. The methodology has been

used extensively throughout the United States by private sector organizations and government

agencies to evaluate buildings, and it has served as a model for similar efforts in other countries.

In a project funded by FEMA, the Applied Technology Council is updating both FEMA 154 and

FEMA 155. Major enhancements in the Third Edition include improvements in the screening

form; an added optional more detailed level of screening; updates of the scoring values; new

reference guides for vertical and plan irregularities; additional building types; improved

consideration of additions, adjacent structures, and retrofits; an optional electronic scoring

methodology; new insight into risk; and more detailed discussion on how to run an effective

screening program.

Introduction

The FEMA 154 Report [1], Rapid Visual Screening of Buildings for Potential Seismic Hazards:

A Handbook, is the first of a two-volume publication on a recommended methodology for rapid

visual screening of buildings for potential seismic hazards. The technical basis for the

methodology, including the scoring system and its development, is contained in the companion

FEMA 155 Report [2], Rapid Visual Screening of Buildings for Potential Seismic Hazards:

Supporting Documentation. Some text in this paper is taken directly or modified from that in [1]

1Principal, Rutherford + Chekene, San Francisco, CA 94105

2Senior Design Engineer, Rutherford + Chekene, San Francisco, CA 94105

3Principal, CCS Group, Chesterfield, MO 63017

4Associate Director of Projects, Applied Technology Council, Redwood Shores, CA 94065

5Associate Principal, Wiss Janney Elstner Associates, Emeryville, CA 94608

6Principal, SPA Risk LLC, Denver, CO 80207

7Principal, BHW Engineers, Draper, UT 84020

Lizundia B, Durphy S, Griffin M, Hortacsu A, Kehoe B, Porter K, and Welliver B. Rapid Visual Screening of

Buildings for Potential Seismic Hazards: FEMA 154 and FEMA 155 Updates. Proceedings of the 10th

National

Conference in Earthquake Engineering, Earthquake Engineering Research Institute, Anchorage, AK, 2014.

and [2]. Both FEMA 154 and FEMA 155 are third editions of similar documents first published

by FEMA in 1988 [3, 4] and updated in 2002 [5, 6].

The rapid visual screening (RVS) procedure has been developed to identify, inventory,

and screen buildings that are potentially seismically hazardous. Once identified as potentially

seismically hazardous, such buildings should be further evaluated by a design professional

experienced in seismic evaluation and design to determine if, in fact, they are hazardous. The

RVS procedure uses a sidewalk survey of a building and a Data Collection Form, which the

surveyor completes by visual observation of the building from the exterior, and if possible, the

interior. The Data Collection Form (Figs. 1 and 2) contains space for building identification

information, including its use and size, a photograph of the building, sketches, and pertinent data

related to seismic performance. Based on the data collected during the survey, a score is

calculated that provides an estimation of the expected seismic performance of the building.

Completion of the Data Collection Form in the field begins with identifying the building

type, which is characterized by the structural materials and primary structural seismic force-

resisting system. Basic Scores for various building types are provided on the form, and the

screener circles the appropriate one. The screener modifies the Basic Score by identifying and

circling Score Modifiers, which are related to observed performance attributes, and which are

then added to (or subtracted from) the Basic Score to arrive at a Final Score. Fig. 1 shows the

Level 1 form. A more detailed screening of the building can be documented by using the

optional Level 2 form on the second page of the Data Collection Form and shown in Fig. 2. This

optional form, which has been added in the Third Edition, allows the user to adjust the Final

Score with additional modifiers. All Basic Scores and Score Modifiers relate to the probability

of building collapse, should severe ground shaking occur. Final Scores typically range from 0 to

7, with higher scores corresponding to better expected seismic performance and a lower potential

for collapse in a design earthquake. Note that Figs. 1 and 2 are drafts; revisions are anticipated.

Buildings may be reviewed from the sidewalk without the benefit of building entry,

structural drawings, or structural calculations. Reliability and confidence in building attribute

determination are increased, however, if the structural framing system can be verified during

interior inspection, or using construction documents. Training in proper implementation of the

RVS method is also important, and FEMA has funded training programs for many years. An

average of 15 to 30 minutes per building in the field is expected for a Level 1 exterior screening.

Additional time is needed if the interior is accessed or if a Level 2 screening is performed.

The entity that decides to conduct an RVS program may be a state government, city

council, private company, school district, or other organization and is designated as the “RVS

Authority.” Use of RVS on a community-wide basis enables the RVS Authority to divide

screened buildings into two categories: those that are expected to have acceptable seismic

performance, and those that may be seismically hazardous and should be studied further. A

Final Score of 2 is suggested as a “cut-off,” based on present seismic design criteria.

The RVS procedure can be implemented relatively quickly and inexpensively to develop

a list of potentially hazardous buildings without the high cost of performing a detailed seismic

analysis of every individual building. If a building receives a score above the specified cut-off

score, the building is considered to have adequate seismic resistance to prevent collapse during a

design level earthquake. The building score reflects probability of collapse or partial collapse

only, and is not meant to be an indicator of the probability that the building will be usable

following an earthquake. If a building receives a low score on the basis of this RVS procedure, it

should be evaluated by a professional engineer having experience in seismic evaluation and

design. On the basis of a detailed evaluation, engineering analyses, and other applicable

procedures, a final determination of the seismic adequacy and the need for retrofit can be made.

Typically, an evaluation using ASCE/SEI 41-13 [7] will be most appropriate for those buildings

that require a detailed structural evaluation. Identification of selected nonstructural hazards is

included in the methodology. Where further nonstructural evaluation is recommended based on

the results of the rapid visual screening, FEMA E-74 [8] can be used.

Roles

The target audience for FEMA 154 includes (1) those agencies or organizations that are

considering conducting a rapid visual screening program and (2) the screeners who will conduct

the evaluations. The screeners can be structural engineers, architects, design professionals,

building officials, construction contractors, firefighters, architectural or engineering students, or

other individuals with general familiarity or background in building design or construction.

Because of the rapid nature of the evaluation, the requirement for familiarity with building

design or construction is critical in accurate determinations of building characteristics.

During the planning stage, the RVS Authority will need to select both a Program

Manager and a Supervising Engineer. The Program Manager oversees management and

administration of the RVS program. The Supervising Engineer should be a structural engineer

with a background in seismic evaluation, whose role may include establishing criteria and

reviewing results. RVS programs have a wide range of goals and seismic safety objectives, and

they have constraints on budget, completion schedule, and accuracy, which must be considered

when planning the program.

Screening Forms

The Third Edition Level 1 Data Collection Form has been reorganized such that information and

observations are at the top; and the extent of review, identification of hazards, and the actions

that need to be taken are identified at the bottom. For each of 17 FEMA Model Building Types, a

table provides Basic Scores and Score Modifiers for different attributes. These include building

height, soil type, building code context, vertical irregularity, and plan irregularity. The Action

Required box identifies whether a detailed structural evaluation is required because (1) the Final

Score was under the cut-off score, (2) the building type is unknown or not covered in the table,

or (3) another hazard is present, like a significantly damaged structural system. The Level 2 form

contains a series of statements used to acquire more detailed information about the building. The

statements are similar to those in the Tier 1 evaluation of ASCE/SEI 41, but are designed so that

they can be answered using only visual observation of the building and without engineering

calculations. Topics covered include vertical and plan irregularities, redundancy, pounding,

retrofits, and building specific questions. By completing this optional level, a more refined score

can be obtained. The Level 2 form also has a section with questions regarding selected

nonstructural hazards that could represent a risk to life. Since these hazards do not affect the

collapse probability of the building, they do not modify the Final Score, but provide a means of

identifying whether a more detailed evaluation of nonstructural seismic hazards is recommended.

Plan and Vertical Irregularity Guides

Tables 1 and 2 show guides that have been developed to help screeners, who may not be

engineers, identify common vertical and plan irregularities that can impact the expected seismic

performance of the building. Vertical irregularities are further split into moderate and severe

categories. An unbraced cripple wall in a woodframe house is a moderate irregularity since it is

unlikely to lead to overall superstructure collapse even if the cripple wall fails. On the other

hand, a multi-family woodframe residential building with a weak story due to parking on the

ground level is a severe irregularity since this has led to building collapse in past events.

Analytical calculations, based in part on the OSHPD HAZUS procedures contained in the

California Building Code requirements for hospitals and discussed in [9], have been used to

refine the Score Modifiers associated with each deficiency.

Additional Third Edition Revisions and New Features

Besides reorganization of the Level 1 form, addition of the optional Level 2 form, creation of the

vertical and plan irregularity reference guides, and the nonstructural hazard data collection, the

Third Edition has a number of other enhancements and revisions. These include the following:

• Mobile homes and multi-story, multi-family woodframe residential buildings were added.

• Pounding and adjacency are now considered with explicit procedures and Score Modifiers.

• Better guidance for screening buildings with additions is provided.

• The three seismicity regions used in the Second Edition have been expanded to five regions.

• A minimum score has been set as a floor for the worst combination of Score Modifiers.

• The Level 2 form includes consideration of existing retrofits.

• An optional electronic scoring methodology has been provided.

• Additional information has been provided on how to run an effective RVS program,

including required and optional tasks and associated resources needs.

• Additional discussion on how to use the results of RVS for seismic advocacy has been added.

Upcoming Tasks

The Third Edition update is a three-year effort. In the final year, between September 2013 and

September 2014, the final versions of FEMA 154 and FEMA 155 will be completed. FEMA 154

is essentially complete. The remaining tasks include finalizing FEMA 155 which describes the

technical basis and assumptions for the project, developing updates to the FEMA 154 training

programs used to educate potential screeners, and refining the Basic Scores and Score Modifiers.

The Basic Scores in the Second Edition were developed using an earlier set of fragility curves

once used with the HAZUS software. The Third Edition scoring study will develop a more

current and consistent set of fragility curves and uncertainty parameters and will more explicitly

analyze the impact of various irregularities on collapse potential.

Figure 1. Level 1 Data Collection Form for High Seismicity.

Figure 2. Level 2 Data Collection Form for High Seismicity.

Table 1. Vertical Irregularity Reference Guide.

Vertical Irregularity Severity Level 1 Instructions

Sloping Site

Varies Apply if there is more than a one-story slope from one side of the building to the other. Evaluate as Severe for W1 buildings as shown in Figure A; evaluate as Moderate for all other building types as shown in Figure B.

Unbraced Cripple Wall

Moderate Apply if unbraced cripple walls are observed in the crawlspace of the building. This applies to W1 and W1A building types. If the basement is occupied, consider this condition as a soft story.

Weak and/or Soft Story

Severe Apply: a) For a W1 house with occupied space over a garage with limited or short wall lengths on both sides of the garage opening.

b) For a W1A building with an open front at the ground story (such as for parking).

c) When one of the stories has less wall or fewer columns than the others (usually the bottom story). d) When one of the stories is taller than the others (usually the bottom story).

Out-of-Plane Setback

Severe Apply if the walls of the building do not stack vertically in plan. This irregularity is most severe when the vertical elements of the lateral system at the upper levels are outboard of those at the lower levels as shown in Figure A. The condition in Figure B also triggers this irregularity. If nonstacking walls are known to be nonstructural, this irregularity does not apply.

Apply the setback if greater than or equal to 2 feet.

(a) (b)

(a) (b)

(c) (d)

(a) (b)

Table 1. Vertical Irregularity Reference Guide (continued).

Vertical Irregularity Severity Level 1 Instructions

In-plane Setback

Moderate Apply if there is an in-plane offset of the lateral system. Usually, this is observable in braced frame (Figure A) and shear wall buildings (Figure B).

Short Column/Pier

Severe Apply if:

a) Some columns/piers are much shorter than the typical columns/piers in the same line. b) The columns/piers are narrow compared to the depth of the beams. c) There are infill walls that shorten the clear height of the column.

Note this deficiency is typically seen in older concrete and steel building types.

Split Levels

Moderate Apply if the floors of the building do not align or if there is a step in the roof level.

(a) (b)

(a) (b)

(c)

Table 2. Plan Irregularity Reference Guide.

Plan Irregularity Severity Level 1 Instructions

Torsion Severe Apply if there is good lateral resistance in one direction, but not the other, or if there is eccentric stiffness in plan (as shown in Figures A and B; solid walls on two or three sides with walls with lots of openings on the remaining sides).

Non-Parallel Systems

Severe Apply if the sides of the building do not form ninety-degree angles.

Re-entrant Corner

Severe Apply if there is a reentrant corner, i.e., the building is L, U, T, or + shaped, with projections of more than 10 feet. Where possible, check to see if there are seismic separations where the wings meet. If so, evaluate for pounding.

Diaphragm Openings

Severe Apply if there is a opening that has a width of over 50% of the width of the diaphragm at any level.

Beams do not align with columns

Severe Apply if the exterior beams do not align with the columns in plan. Typically, this applies to concrete buildings, where the perimeter columns are outboard of the perimeter beams.

(a) (b)

Acknowledgments

The work forming the basis for this publication was conducted by ATC pursuant to a contract

with FEMA. The substance of such work is dedicated to the public. The Project Technical

Director is Bret Lizundia. The Project Technical Committee includes Michael Griffin, William

T. Holmes, Brian Kehoe, Keith Porter, and Barry Welliver. Sarah Durphy and Charles Kircher

are Project Working Group members. The Project Review Panel is chaired by Charles

Scawthorn and includes Tim Brown, Mel Green, Laura Kelly, Stephanie King, John Osteraas,

Steve Sweeney, and Christine Theodoropoulos. Ayse Hortacsu and Tom McLane serve as

Project Managers for ATC. For FEMA, Michael Mahoney is the Project Officer, Erin Walsh is

the Task Monitor, and John Gillengerten is the Technical Monitor.

The authors are solely responsible for the accuracy of statements or interpretations

contained in this publication. No warranty is offered with regard to the results, findings and

recommendations contained herein, either by FEMA, ATC, or its directors, members, or

employees. These organizations and individuals do not assume any legal liability or

responsibility for the accuracy, completeness, or usefulness of any of the information, product or

processes included in this publication.

References 1. FEMA, Rapid Visual Screening of Buildings for Potential Seismic Hazards: A Handbook, Third Edition.

Prepared by the Applied Technology Council for the Federal Emergency Management Agency, Washington

D.C., FEMA 154 Report, in development.

2. FEMA, Rapid Visual Screening of Buildings for Potential Seismic Hazards: Supporting Documentation, Third

Edition. Prepared by the Applied Technology Council for the Federal Emergency Management Agency:

Washington, D.C., FEMA 155 Report, in development.

3. FEMA, Rapid Visual Screening of Buildings for Potential Seismic Hazards: A Handbook. Prepared by the

Applied Technology Council for the Federal Emergency Management Agency, Washington D.C., FEMA 154

Report, 1988.

4. FEMA, Rapid Visual Screening of Buildings for Potential Seismic Hazards: Supporting Documentation.

Prepared by the Applied Technology Council for the Federal Emergency Management Agency: Washington,

D.C., FEMA 155 Report, 1988.

5. FEMA, Rapid Visual Screening of Buildings for Potential Seismic Hazards: A Handbook, Second Edition.

Prepared by the Applied Technology Council for the Federal Emergency Management Agency, Washington

D.C., FEMA 154 Report, 2002.

6. FEMA, Rapid Visual Screening of Buildings for Potential Seismic Hazards: Supporting Documentation, Second

Edition. Prepared by the Applied Technology Council for the Federal Emergency Management Agency:

Washington, D.C., FEMA 155 Report, 2002.

7. ASCE, Seismic Evaluation and Retrofit of Existing Buildings. ASCE/SEI 41-13, American Society of Civil

Engineers: Reston, VA, ASCE/SEI 41-13 report, in press.

8. FEMA, Reducing the Risks of Nonstructural Earthquake Damage – A Practical Guide, Fourth Edition,

prepared by the Applied Technology Council for the Federal Emergency Management Agency: Washington,

D.C., FEMA E-74 Report, 2011.

9. Tokas C and Lobo R, 2009, Risk Based Seismic Evaluation of Pre-1973 Hospital Buildings Using the HAZUS

Methodology. Proceedings of the 2009 ATC & SEI Conference on Improving the Seismic Performance of

Existing Building and Other Structures, San Francisco, 2009.