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10NCEE
Tenth U.S. National Conference on Earthquake Engineering
Frontiers of Earthquake Engineering
July 21-25, 2014
Anchorage, Alaska
RAPID VISUAL SCREENING OF
BUILDINGS FOR POTENTIAL SEISMIC
HAZARDS: FEMA 154 AND 155 UPDATES
B. Lizundia1, S. Durphy2, M. Griffin3, A. Hortacsu4, B. Kehoe5, K.
Porter6, and B. Welliver7
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.
1
Principal, Rutherford + Chekene, San Francisco, CA 94105
Senior Design Engineer, Rutherford + Chekene, San Francisco, CA 94105
3
Principal, CCS Group, Chesterfield, MO 63017
4
Associate Director of Projects, Applied Technology Council, Redwood Shores, CA 94065
5
Associate Principal, Wiss Janney Elstner Associates, Emeryville, CA 94608
6
Principal, SPA Risk LLC, Denver, CO 80207
7
Principal, BHW Engineers, Draper, UT 84020
2
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.
10NCEE
Tenth U.S. National Conference on Earthquake Engineering
Frontiers of Earthquake Engineering
July 21-25, 2014
Anchorage, Alaska
Rapid Visual Screening of Buildings for Potential Seismic Hazards:
FEMA 154 and FEMA 155 Updates
B. Lizundia1, S. Durphy2, M. Griffin3, A. Hortacsu4, B. Kehoe5, K. Porter6, and B. Welliver7
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]
1
Principal, Rutherford + Chekene, San Francisco, CA 94105
Senior Design Engineer, Rutherford + Chekene, San Francisco, CA 94105
3
Principal, CCS Group, Chesterfield, MO 63017
4
Associate Director of Projects, Applied Technology Council, Redwood Shores, CA 94065
5
Associate Principal, Wiss Janney Elstner Associates, Emeryville, CA 94608
6
Principal, SPA Risk LLC, Denver, CO 80207
7
Principal, BHW Engineers, Draper, UT 84020
2
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 forceresisting 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
Sloping Site
(a)
(b)
Unbraced
Cripple Wall
Weak and/or
Soft Story
Out-of-Plane
Setback
(a)
(b)
(c)
(d)
(a)
(b)
Vertical Irregularity Reference Guide.
Severity
Level 1 Instructions
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.
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.
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).
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.
Table 1.
Vertical Irregularity Reference Guide (continued).
Vertical Irregularity
In-plane
Setback
Short
Column/Pier
(a)
(a)
Severity
Level 1 Instructions
(b)
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).
(b)
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.
Moderate
Apply if the floors of the building do not
align or if there is a step in the roof level.
(c)
Split Levels
Table 2.
Plan Irregularity
Plan Irregularity Reference Guide.
Severity
Level 1 Instructions
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.
Torsion
(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
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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.