An evaluation and assessment of the California Seismic Safety Commission's Seismic Retrofit Practices Improvement Program, Proposition 122

20 Pages·2001·1.2 MB·English

by  California. Seismic Safety Commission

^valuation and Assessment of the
SANFRANCISCOPUBLICLIBRARY
nia Seismic Safety Commission's
3 1223 06256 1700
oeismic Hetrofit Practices Improvement Program
Proposition 122
REF
624 . 1762 SSC JUN 1 1 1M
C128e 2001-02
SAN FRANCISCO
April 2001 PUBLIC LIBRARY
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PUBLIC LIBRARY
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Table of Page
Contents
Introduction 2
Purpose of Report 3
Executive Summary 4
The Goals Used For the Retrofit Practices Improvement Program 5
Product 1 - Recommended Seismic Retrofit Provisions & Commentary 6
• Provisional Commentary for Seismic Retrofit, Product. 1.1, SSC 94-02
• Seismic Evaluation and Retrofit of Concrete Buildings
Volume 1 & 2 Product 1.2 & 1.3, SSC 96-01
Product 2- Earthquake Risk Management Tools 9
• Seismic Risk Management Tools, Product 2.1, SSC 94-05
• Seismic Risk Management Tools for DecisionMakers
Product 2.2, SSC 99-04, SSC 99-05 & 99-06
Product 3 -Short Term Research 11
• Review ofSeismic Research Results of Existing Buildings
Product 3.1, SSC 94-03
• Northridge Earthquake Building Case Studies
Product3.2, SSC 94-07
Product 4 - Retrofit Information and Education 13
• Seismic Safety Training for BuildingDesign & Enforcement Professionals,
Product 4.1, SSC 99-03
Recommended Actions to Complete the Program 15
Acknowledgements 16
Awards 16
Program Project Bibliography 16
1
Introduction Proposition 122, passed by the voters The Seismic Safety Commission was given
in the June 1990 general election, the responsibility of administering this
authorized the state to issue $300 portion ofthe Proposition 122 Program,
million in general obligationbonds for the which was to capitalize on the seismic
seismic retrofit ofstate-and local public retrofitexperience developed in the public
buildings ($250 million for state-owned and private sectors and use that experience
buildings and $50 million for local to improve seismic retrofitpractices applied
government essential services facilities). to governmentbuildings. The missionwas
to develop products (methodologies,
In response, the Department ofGeneral
techniques, educational material) for the
Services (DGS) undertook evaluation of
Seismic Retrofit Practices Improvement
statebuildings to determine their seismic
Program and make recommendations to
risk. Based on this process and criteria, 61
further the effectiveness ofthe Proposition
buildings were identified and funded for
seismic retrofit using thisbond money (this 122 program. The Commission identified
the most pressing needs ofthe timeby
information wasfurnished by the Office ofReal
Estate Services Division (RESD) as ofFY2000- surveying state and local government
agencies and seismic retrofit experts in the
2001). 132 local governmentessential
private sector. The critical needs were
servicesbuildings were retrofitted with the
bond money and local matching funds. described in the Commission's publication
More than 300 high-risk state buildings Breaking the Pattern. This program,
accomplished over a period oftenyears,
remain to be retrofitted and with at least
produced four products, which include
1200-1500 local governmentbuildings
seven projects, which are described in this
remaining to be retrofitted there is clearly
report. At the out-set ofthis program, the
a need to continue the program to retrofit
Commission created the Oversight Panel for
state buildings and to expand the state's
Proposition 122 Seismic Retrofit Practices
help to local governments.
Improvement Program which comprised of
Proposition 122 specified thatup to 1% or eleven members representing a broad
three million ($3,000,000) ofthe totalbond spectrum of the engineering design and
funds shallbe used to support an construction industry. It was charged with
earthquake research and development ensuring that the Commission's efforts met
program. And further, that these funds were the goals and priorities established inits
tobe used to: publication Breaking the Pattern. The Panel
1. Develop methods, techniques, and was to monitor the Program and report
technologies to identify and analyze back to the Commissionregularly.
existing potentially hazardous
buildings and facilities;
2. Develop methods, techniques and
technologies for seismic safety
retrofitting ofbuildings, and
3. Help developbuilding standards and
administrative regulations relating to
the retrofit ofbuildings for seismic
safety purposes.
2
Purpose of This report evaluates and assesses the
Report programs and products developed
under the Seismic Safety
Commission's Seismic Retrofit Practices
Improvement Program as well as providing
recommendations for future retrofit
programs involving the remaining state
buildings and a large number oflocal
government buildings that have known
levels ofseismic risk, and that the
Proposition 122 bond was unable to fund.
Executive Californians are fortunate that Project Summary
Summary seismic codes havebeenwritten
Product 1.1 (1994) Provisional Commentary
and enforced for the lasthalf
for Seismic Retrofit
century, making Californiabuildings more
* * *
resistant to withstand earthquakes than Products 1.2 and 1.3 (1996) Seismic
buildings located elsewhere. Still, the Evaluation and Retrofit ofConcrete
Buildings
messages from recentearthquakes are clear.
Despite our codes and world-renowned Product2.1 (1994) Seismic Risk
expertise, many ofour olderbuildings and Management Tools
other structures remain vulnerable to
Product 2.2 (1999) Seismic Risk
earthquake damage.
Management Tools for DecisionMakers
The Legislature is tobe commended for
Product 3.1 (1994) Review ofSeismic
its response to state and local government
Research Results
buildings damaged by the Loma Prieta
Earthquake of 1989 and its foresight in its Product3.2 (1994) Northridge Earthquake
enactment ofthe $300 million Earthquake Building Case Studies
Safety and Public Buildings Rehabilitation Product4.1 (1999) Seismic Safety Training
BondAct. TheAct was passed by the voters forBuilding Design and Enforcement
in 1990. From this bond money over 190 Professionals
buildings havebeen seismically retrofitted.
Summary of Recommended
The Seismic Safety Commission's focus was
Future Actions
to capitalize onthe experience inthe public
and private sectors and improve seismic More work remains tobe done. There
retrofit practices for governmentbuildings. remain more than 300 state buildings atthe
With the $3 million set aside for its Seismic highest risk levels and 1200-1500 local
Retrofit Improvement Program, the governmentbuilding tobe retrofitted with
Commission developed fourmain an estimated cost of$1.4 to $1.5billion.
conceptual products (methodologies, There is a need to expand the state program
techniques and educational material) and to retrofit statebuildings, and for the state
seven projects for its Program over the span to assist local governments in retrofitting
of tenyears. theirbuildings.
Product Summary The Commission's Seismic Retrofit
Improvement Program needs tobe
Product 1 - Recommended Retrofit promoted, monitored and in some cases,
Provisions and Commentary
updated. It is imperative thatthe concepts
Product 2 - Earthquake Risk Management and elements ofthe program notbe
Tools forgotten or lost. Itneeds tobe expanded in
the following areas:
Product3 -Short Term Research
1. Include retrofitprovisions for other
Product4 -Retrofit Information
types ofconstructionnot covered inthe
current program.
2. Increase and improve outreach ofthe
seismic risk management tools
developed.
3. Curricula and training to include
builders, trades, local government
officials, practicing design
professionals, and recent graduates.
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The Goals The intent ofthe Proposition 122 The goals ofthis Program were to:
Used for Program was to provide products Help develop professional practices to
the Retrofit that increase the cost effectiveness of evaluate the ability ofolderbuildings
retrofitting governmentbuildings and assist to withstand earthquakes;
Practices
governments and in as much as possible the Help improve retrofit design and
Improvement private sector, to make informed decisions construction;
Program about seismic safety. The Program's goal Judge the effectiveness ofretrofits;
was to increase public safety and enhance and determine theirbenefits and costs.
quality and consistency in retrofit designs Increase awareness ofbenefits of
and construction. The Commission's structural and non-structural retrofit
representatives met with key professionals ofbuildings.
including engineers, architects, building Enhance awareness ofneed for
officials, state and local government planning and risk management.
officials, emergency services personnel,
and state agencies, and asked:
> What are the problems encountered in
seismic retrofitting practice, regulation,
or administration?
> What research and development is
needed over both the short and long
terms to improve the economy and
efficiency of seismic retrofitting?
t> Ifyou could recommend only one
activity as the single most important to
fund under this program, what would
it be? Their near-unanimous response
in 1991 was the development of seismic
retrofit standards, practices and
guidelines. The Commission's
publication Breaking the Pattern, defined
and emphasized the goals, priorities
and criteria from which the Program
evolved.
5
Recommended Seismic Retrofit Provisions and CorrWentary
Product
1
TOPICS OFPRODUCT1: Provisional Commentary for
# * * Management of seismic risk Seismic Retrofit Product. 1.1,
SSC 94-02
General principals ofseismic design
Seismic hazard evaluation Objectives
Site response • To develop a report summarizing the
New and existing building materials present state ofknowledge and practice
Design and construction provisions for ofseismic retrofit forbuildings,
focusing on three primary structural
seismic retrofit
types that are vulnerable to poor
Provisions for individualbuilding types performance and collapse in
earthquakes:
The Provisions and Commentary were 1. Non-ductile concrete frame buildings;
developed in a three-stage process: 2. Older concretebuildings employing walls
1. Broad philosophical statement of and frames for seismic resistance; and
objective for the design 3. Building frame systems relying on
2. Core ofguiding principles unreinforced masonry walls for
stability.
3. Set of provisions for achieving
acceptable seismic performance Targeted Audience
ofretrofits
• Writers of future seismic retrofit
building standards.
The goal was to be a primary resource for • Retrofit design professionals and
seismic retrofit guidelines until building building officials.
standards were developed with the help of • Government agency personnel and
professional organizations and adopted by policymakers charged with
professional organizations and state implementing seismic retrofitprograms.
agencies authorized to develop standards
Products
such as the Division ofthe StateArchitect
(DSA), State Historical Building Safety A documentthat:
Board and local governments. Another goal • Summarizes existing retrofit design
was to address different levels ofbuilding practice and technology in the form
performance, expected casualty rate, of a provisional commentary.
damage to the structure and estimated time • Points the way to the development
to restore buildings to service from their ofretrofit design guidelines and
damaged condition. provisions
Documents developed under this product
included:
6
—
The completed report identifies areas where Assessment and Effectiveness
adequate knowledge and consensus exists, This product was helpful inmany
key gaps in knowledge, and
important ways. First, its compilation
recommendations for how those gaps might
ofearly attempts at characterizing
be addressed with future studies. Topics
performance-based seismic engineering
include:
provided a historical platform for future
1. Seismic performance objectives and developmentbyboth Product 1.2 as well
definitions. asATC 33 (Applied Technology Council)
2. Seismic forces as applied to existing (afederal sponsoredprogram to develop
"Guidelines and Commentaryfor the Seismic
buildings.
Rehabilitation ofBuildings"). Current terms
3. Determination ofcapacities of such as "Immediate Occupancy" and
existing buildings to resist seismic "Damage Control" gained acceptance with
forces.
this product. In addition, a section on life
—
4. Public tolerance ofearthquake and function threatening falling hazards
damage. from nonstructural components of
5. Movement (or drift) in existing buildings or their contents was added.
buildings during earthquakes. Early concerns abouthow to express
uncertainty in performance-based seismic
6. Past performance of retrofitted
engineering identified the need for future
buildings in earthquakes.
ongoing research in this areaby
7. Retrofit alternatives and their organizations such as Pacific Earthquake
selection.
Engineering Research (PEER) Consortium
8. Buildings with irregular ofUniversities for Research Earthquake
configurations. Engineering (CUREE -formerly CUREe,
California Universitiesfor Research Earthquake
9. Seismic performance ofwall
Engineering) and others. The report also laid
materials.
out decision-making strategies forbuilding
10. Techniques to strengthen walls. owners to consider when confronted with
vulnerable buildings. This paved the way
for future products 2.1 and 2.2. The
Product's evaluation of analytical methods
forboth the demand from earthquakes and
the capacity ofbuildings gave direction to
Product 1.2 as well asATC 33.
Seismic Evaluation and Retrofit of (Applied Technology Council), FEMA273
Concrete Buildings, Volume 1 & 2 (Federal EmergencyManagement) and its
Products 1.2 & 1.3. SSC 96-01 capacity spectrum analytical method is now
recognized as an alternative method in that
Objectives
publication.
• To develop a recommended method
DivisionIII-R (followed by IV-R Code) and
and commentary for the seismic
regulations were developed by the Division
evaluation and retrofit ofolder concrete
buildings. (Product 1.2) ofthe StateArchitect and, more recently
revised to VI-Rby the Real Estate Services
• To include the effects of foundation
response on the seismic performance Division ofthe Department ofGeneral
ofexisting concretebuildings. Services for all state ownedbuildings
(Product 1.3) including the University of California and
California State Universitybuildings.
Targeted Audience
The foundation provisions are more
• The primary audience is retrofit design detailed than those available inATC 33,
professionals.
the predecessor to FEMA273, "NEHRP
• The secondary audiences are
(National Earthquake Hazard Reduction
government agency personnel and
policymakers charged with Program) Guidelines for the Seismic
implementing retrofit programs. Rehabilitation ofBuildings". Several key
• An audience-interest spectrum was foundation provisions havebeen
included at thebeginning ofeach incorporated into later editions and
FEMA
chapter to directbuilding owners, included in 356 "Pre-standard for
architects, regulation enforcement the Seismic Rehabilitation ofBuildings."
officials, engineers and analysts to Accounting for foundation response in
those chapters that would best serve existingbuildings can often save
their needs. considerable construction cost and
Products disruption while gaining a more realistic
• A two-volume set containing detailed expectation ofthe future performance of
recommendations for how to evaluate retrofitted buildings.
and retrofit concretebuildings and Four case studies served to illustrate the
foundation systems. strengths and limitations ofperformance
• Four case studies summarizing how based engineering. They provide a
the methods work. powerful graphical tool for educating new
• Acost-effectiveness study showing the design professionals and training more
variation ofcosts for different seismic experienced design professionals who are
performance objectives for retrofits. otherwise unfamiliar with this new type of
• Workshops involving potential users engineering. Additional case studies have
ofretrofit products to incorporate their sincebeenperformed by FEMA underits
feedback.
project to develop and assess national
Assessment and Effectiveness seismicrehabilitationguidelines (FEMA
343, "Case Studies: AnAssessment ofthe
The objectives were met. During the first NEHRP
Guidelines for the Seismic
year ofthis project, the Commission
Rehabilitation ofBuildings").
identified that insufficient attention was
devoted to the effect foundations have on * *
building performance. As a result, the
Commission expanded the scope ofthis
project and added Product 1.3. These
products were well received in the retrofit
industry. They were developed
simultaneously and helped formed the
basis for the concrete provisions inATC 33
8