[an NSF Graduated Center] The Pacific Earthquake Engineering Research Center (PEER) is a multi-institutional research and education center with headquarters at the University of California, Berkeley. Investigators from over 20 universities, several consulting companies, plus researchers at various State and Federal government agencies contribute to research programs focused on performance-based earthquake engineering in disciplines including structural and geotechnical engineering, geology/seismology, lifelines, transportation, risk management, and public policy. The PEER mission is to develop, validate, and disseminate performance-based seismic design technologies for buildings and infrastructure to meet the diverse economic and safety needs of owners and society. PEER's research defines appropriate performance targets, and develops engineering tools and criteria that can be used by practicing professionals to achieve those targets, such as safety, cost, and post-earthquake functionality. In addition to conducting research to develop performance-based earthquake engineering technology, PEER actively disseminates its findings to earthquake professionals who are involved in the practice of earthquake engineering, through various mechanisms including workshops, conferences and the PEER Report Series. PEER was established as a consortium of nine West Coast Universities in 1996 and gained status as a National Science Foundation Engineering Research Center in 1997. PEER graduated from NSF Funding in 2008 and is now supported by federal, state, local and regional agencies together with industry partners. Despite this funding shift, PEER continues to grow and remains an active earthquake engineering research center with a wide spectrum of technical activities and projects. PEER now has eleven Core Institutions but also actively involves researchers, educators, students, and earthquake professionals from across the US and worldwide. MISSION AND GOALS Developing seismic design technologies to meet the diverse economic and safety needs of owners and society The PEER mission is to develop and disseminate technologies to support performance-based earthquake engineering (PBEE). The approach is aimed at improving decision-making about seismic risk by making the choice of performance goals and the tradeoffs that they entail apparent to facility owners and society at large. The approach has gained worldwide attention in the past ten years with the realization that urban earthquakes in developed countries – Loma Prieta, Northridge, and Kobe – impose substantial economic and societal risks above and beyond potential loss of life and injuries. By providing quantitative tools for characterizing and managing these risks, performance-based earthquake engineering serves to address diverse economic and safety needs. There are three levels of decision-making that are served by enhanced technologies for performance-based earthquake engineering and that are focal points for PEER research. One level is that of owners or investors in individual facilities (i.e., a building, a bridge) who face decisions about risk management as influenced by the seismic integrity of a facility. PEER seeks to develop a rigorous PBEE methodology that will support informed decision-making about seismic design, retrofit, and financial management for individual facilities. A second level is that of owners, investors, or managers of a portfolio of buildings or facilities – a university or corporate campus, a highway transportation department, or a lifeline organization – for which decisions concern not only individual structures but also priorities among elements of that portfolio. PEER seeks to show how to use the rigorous PBEE methodology to support informed decision-making about setting priorities for seismic improvements within such systems by making clear tradeoffs among improved performance of elements of the system. A third level of decision-making is concerned with the societal impacts and regulatory choices relating to minimum performance standards for public and private facilities. PEER seeks to make technical contributions to development of performance-based codes and standards. The direct beneficiaries of more rigorous approaches to performance-based earthquake engineering are the owners, investors, and risk managers who face these decisions. All of us, of course, ultimately benefit from decisions about seismic risk that better address tradeoffs between the costs of reducing risks and the benefits resulting from seismic improvements. The clients for PEER advances in PBEE technologies are members of the engineering profession as broadly defined. Performance-based earthquake engineering is bringing about a change in the profession that alters both the role of earthquake engineers (broadening their involvement as consultants for management of earthquake risks) and the demands placed on the profession (changing the methods of risk evaluation, design, and engineering). PEER is working hand-in-hand with business and industry partners to understand how advances in PBEE affect engineering practice and the construction regulatory environment and to identify ways to lessen barriers to adoption and implementation of PBEE. In addition, PEER is very active in educating future generations of earthquake engineers and risk management professionals. As such, PEER seeks to make a major contribution to the development of the earthquake engineering profession. Despite advances in recent years in the use of performance-based earthquake engineering, existing technologies and methods for PBEE fall short on a number of grounds. Methods for seismic design or evaluation that currently are in widespread use are much less scientific and direct than the rigorous approach that we are developing. Although response of structures to strong ground motions in most cases is expected to be nonlinear, earthquake hazard today is represented by design maps through relatively simplistic single-parameter quantities such as linear spectral response. Likewise, structural evaluation and design commonly use linear analysis adjusted by factors whose values are based on tradition and limited earthquake experience rather than systematic performance considerations. Furthermore, engineering design and assessment generally focus on structural parameters and fail to quantify socio-economic parameters such as direct financial losses, downtime, and casualties. The result of this indirect and empirical approach is that seismic performance outcomes, as demonstrated in recent earthquakes, are highly variable and often at odds with stakeholder expectations. Seismic design in a technologically advanced society should be more scientifically based. It should provide information on expected seismic performance, measurable in terms that are meaningful to those who must make decisions about performance of facilities, networks or campuses, or the built environment in a broad context. And it should provide options for selecting optimal seismic performance to meet the diverse needs of owners and society. To meet this objective, we have visualized the implementation of performance-based earthquake engineering as a process involving distinct and logically related steps, illustrated in Figure 1.1. The first step is definition of the seismic hazard, which we have represented by the term intensity measure. The second step is determination of engineering demand parameters (e.g., deformations, velocities, accelerations) given the seismic input. This leads naturally to definition of damage measures such as permanent deformation, toppling of equipment, or cracking or spalling of material in structural components and architectural finishes. Finally, these damage measures lead to quantification of decision variables that relate to casualties, cost, and downtime. An essential element of performance-based earthquake engineering is the integration of issues across disciplinary boundaries. The central column of the figure suggests various steps that might be involved in a performance assessment of a system for a single earthquake event. The left side of the figure shows discrete variables that PEER has defined as part of its framework for performance-based earthquake engineering. The right side of the figure identifies the traditional disciplinary contributions to the problem. The solution of the earthquake problem clearly is a multi-disciplinary endeavor. The PEER programs in research, education, industry partnerships, and outreach are geared to producing the technology and human resources necessary to transition from current design and assessment methods to performance-based methods. The primary goal is to produce and test through research the fundamental information and enabling technologies required for performance-based earthquake engineering. The Education Program promotes earthquake engineering awareness in the general public, and attracts and trains undergraduate and graduate students to conduct research and to implement research findings developed in the PEER program. The Business and Industry Partner Program involves earthquake professionals, relevant industry, and earthquake information users in PEER activities to ensure the utility of the research and to speed its implementation. The Outreach Office presents the PEER activities and products to a broad audience including students, researchers, industry, and the general public. Ultimately, a PEER objective is to facilitate the development of practical guidelines and code provisions that will formalize performance-based earthquake engineering in practice, replacing some of the first-generation documents on this approach [e.g., FEMA 273, ATC 32, ATC 40, FEMA 354]. PEER is working closely with other organizations, including the Applied Technology Council and the Federal Emergency Management Agency, to develop and implement methodology that will form the basis of next-generation performance-based guidelines. Additionally, PEER produces models and data that are useful, useable, and used in industry. The process is aided by the involvement of practicing earthquake professionals in our program, who help guide and incorporate our research advances as they occur. As a result, the PEER program is an important contributor to national, state, and local efforts to reduce earthquake hazards that threaten the interests of the government, industry, and the general public.
Research Areas
The PEER research program aims to provide data, models, and software tools to support a formalized performance-based earthquake engineering methodology. Within the broad field of earthquake engineering, PEER's research currently is focused on six thrusts, these being Building Systems, Bridge and Transportation Systems, Lifelines Systems, Earthquake Hazard Characteristics, Social Sciences and Information Technologies/Data Science in support of the methodology implementation.
The PEER research program funds and coordinates research in support of the PEER mission in performance-based earthquake engineering. The broad scope of the mission requires an equally broad research agenda. The program includes elements of fault rupture; transmission of seismic waves from the source to the site; local site response as affected by local geologic conditions; interaction among the soil, foundation, and structure components; analysis of system dynamic response; assessment of the performance of the structural and nonstructural systems; consequences in terms of casualties, capital costs, and post-earthquake functionality; and decision-making to respond to earthquake effects or to change the design parameters to effect improved performance.
To accomplish its research program, PEER involves researchers from the earth sciences, engineering, and social sciences communities, who work together to develop an integrated approach to the performance-based earthquake engineering problem.
BUILDING SYSTEMS
The Building Thrust Area combines research from several areas: Loss Modeling and Decision Making, Geotechnical Performance, Assessment and Design Methodology, and Structural and Nonstructural Performance. The advances made in each thrust area and in the testbeds shaped the decision to create the Building Thrust Area.
Tall Buildings Initiative
Concrete Grand Challenge
PEER BRIDGE PROGRAM
1. Maintenance/Sustainability
Objectives:Develop cost effective methods for assessing the structural health of a bridge. Create repair techniques to prolong a bridge’s functional life. Assess innovative design and material options that will minimize life-cycle costs.
2. New Materials
Objectives: Perform evaluation and trial application of new construction materials such as high strength reinforcing steel, stainless steel, ultra-high-performance concrete, light-weight concrete, and composite materials.
3. Bridge Modeling & Analysis
Objective: Develop improved methods for assessing structural demand and performance.
4. Accelerated Bridge Construction
Objective: Develop techniques and structural systems that increase the speed of construction and minimize disruption to the traveling public.
5. Performance Based Earthquake Engineering (PBEE)/Bridge and System Reliability
Objectives: Develop bridge design methods that include seismic performance targets at different hazard levels. Investigate how different performance targets impact the performance of the transportation network following a major earthquake.
6. Foundations & Walls
Objective: Improve the geotechnical design of bridge foundations and retaining walls to improve performance and cost efficiency.
7. Intelligent Design Tools/Bridge Design Aids
Objective: Develop new tools and methods that take advantage of artificial intelligence to accelerate the bridge design process.
TRANSPORTATION SYSTEMS RESEARCH PROGRAM
The purpose of the PEER TSRP is to reduce the impacts of earthquakes on California’s transportation systems, including highways and bridges, port facilities, high speed rail, and airports. We expect that the research will utilize and extend PEER performance based earthquake engineering methodologies, integrating fundamental knowledge, enabling technologies, and systems. We further expect that the research program will integrate seismological, geotechnical, structural, hydrodynamic and socio-economical aspects of earthquake and tsunami engineering, and involve theoretical, computational, experimental and field investigations. The program also encourages vigorous interactions between practitioners and researchers.
LIFELINES SYSTEMS
The goal of the PEER Lifelines program is to improve seismic safety and reliability of lifeline systems. The projects in this program are primarily user-driven research projects, with strong collaboration among sponsoring lifelines organizations and PEER researchers. They range from engineering characterization of ground motions, to local soil response, to response of bridge structures, to performance of electric substation equipment.
The PEER Lifelines program has successfully brought together multidisciplinary teams of practicing engineers (geotechnical, structural); scientists (geologists, seismologists, social scientists); funding agencies (Federal, State of California, private industry); academicians, and end-users. An example of such successful multidisciplinary collaboration that was funded by the Lifelines Program is the NGA West Program that has resulted in major advances in characterization of seismic hazard, especially in the western United States.
Another unique characteristic of the PEER Lifelines program is its diverse, and mostly non-NSF, sources of funding. PEER Lifelines research projects are primarily funded by the following agencies:
California Department of Transportation(link is external)
Pacific Gas & Electric Company
The lifelines research projects are organized into eight topics:
Earthquake Ground Motion
Site Response
Permanent Ground Deformation
Substation Equipment
Substation Building
Bridge Structures
Network System Seismic Risk
Emergency Response
DATA SCIENCES
The goal of this Thrust areas is to develop new simulation models and methods for performance-based earthquake engineering assessment and design methodologies, develop modern simulation software tools taking advantage of information technology advances, deliver the software tools to the community, and educate students in simulation methods and information technology applications in earthquake engineering.
NATURAL HAZARDS
Tsunami Research Program
PEER’s tsunami research program is to develop an effective methodology for damage analyses for critical structures and lifelines: e.g. nuclear and fossil power plants, liquefied natural gas and oil storage facilities, civilian and military ports, emergency tsunami shelters, transportation corridors including coastal bridges, and important public facilities (fire and police stations, hospitals, and schools). Failure of critical coastal structures and lifelines likely lead to loss of life, delays in emergency response, and long-term economic impacts.
This research focus is a crucial gap in tsunami research efforts currently being conducted elsewhere. PEER’s methodology development – called Performance-Based Tsunami Engineering (PBTE) – will ultimately expand and extend the existing Performance-Based Earthquake Engineering (PBEE) methodology.
Fire Following Earthquake
The California Seismic Safety Commission has funded the PEER Center to conduct research related to fire following earthquakes. Prof. Charles Scawthorn, a Visiting Scholar at the PEER Center, is leading the study entitled Water Supply in Regard to Fire Following Earthquake. This work is supported from the Commissions Research Program.
The purpose of the study is to review the current status of emergency water supply in California vis-a-vis needs for fires following earthquake and provide a series of recommendations for improvements if and where needed. Issues to be discussed include fire ignitions following earthquakes, the status of the states urban water systems, the status of urban fire departments emergency water supply, and opportunities to enhance emergency water supply systems.
SOCIAL SCIENCES
Defining the Links Between Planning, Policy Analysis, Economics and Earthquake Engineering
Facilities & Resources
Laboratories The PEER-UC Berkeley lab at the Richmond Field Station partners with private industry and performs shaking table testing of critical equipment— e.g., emergency power generators, air handlers, electrical switchgear—under varying earthquake excitations. The shaking table testing is performed to ensure compliance with seismic regulations and to confirm the effectiveness of seismic retrofit strategies with the goal of reducing damage and injury in the event of an earthquake. 17025-2005 IAS Lab Accreditation for AC156 and IEEE-693 Testing The PEER-UC Berkeley Lab is accredited by IAS (TL450), to perform both AC-156 and IEEE-693 test protocols utilizing the 6 DOF Shaking Table. The Shaking Table is able to impose the highest required amplitude inputs of both of these standards. IEEE693, Recommended Practice for Seismic Design of Electrical Substations - These recommendations include discussions of qualification of each equipment type. Design recommendations consist of seismic criteria, qualification methods and levels, structural capacities, performance requirements for equipment operation, installation methods, and documentation. AC156, Seismic Certification by Shake-table Testing of Non-structural Components - This standard establishes criteria for a specific input motion, duration, and range of frequencies to which nonstructural components should be subjected. Earthquake Simulator Laboratory The signature piece of testing equipment at the PEER-UC Berkeley Lab is the six degree-of-freedom Shaking Table, the largest in the United States, and one of the largest in the world. The PEER-UC Berkeley Lab also houses a Large Scale Structures Lab consisting of a 20' x 60' strong floor with an integrated, reconfigurable, modular reaction wall. A comprehensive inventory of both static and dynamic hydraulic actuators, ranging from 5 kips to 2000 kips, along with an inventory of other test hardware and components are available to accommodate both simple single degree of freedom test setups as well as multi-axis custom test configurations. In addition, the PEER-UC Berkeley Lab houses large and small damper test machines, a 200 kip and a 4,000 kip uniaxial load frame, along with all of the associated control, measurement and data acquisition equipment required to operate the Lab's various test machines. The PEER facility also houses a Micro Lab for smaller scale experiments in self-equilibrating testing frames. The PEER-UC Berkeley Lab is at the forefront in the development of both hybrid control and digital image processing for the measurement of continuous strain fields. The PEER-UC Berkeley Lab demonstrates best-practice protocol in its general Lab operation and maintains an IAS accreditation, related to the Shaking Table testing of both AC-156 and IEEE-693 test protocols. The PEER-UC Berkeley Lab has a long history of successfully providing the engineering community testing facilities, the staffing expertise to execute a given project, and the academic background to provide appropriate data analysis, design input and overall project management. The PEER-UC Berkeley Lab is available to write both academic style reports, along with AC156 and IEEE-693 reports submitted to regulatory agencies. See the "Service to Industry" web page for more information. A welding shop, machine shop and electronics shop, along with dedicated control rooms, conference rooms and a suite of offices are also located at the PEER-UC Berkeley Lab facility. The PEER-UC Berkeley Labs are available to both the research community and to private industry that may require large capacity testing services. Published recharge rates are utilized in the development of project budgets. Priority in scheduling a given test always favors the research community, and time is made available to commercial clients on a time-available basis. Earthquake Simulator (Shaking Table) The Earthquake Shaking Table, dedicated in 1972, was the first modern Shaking Table and is still the largest six-degree-of-freedom (6 DOF) Shaking Table in the United States. The Shaking Table is configured to produce three translational components of motion; vertical and two horizontal, plus three rotational components; pitch, roll and yaw. These 6 DOF can be programmed to reproduce any wave form within the capacities of force, velocity, displacement and frequency of the Shaking Table system. The Shaking Table which weighs100 kips can subject structures, weighing 100,000 pounds, to horizontal accelerations of 1.5 G. Given that Shaking Table performance is a function of mass, overturning and model interaction, actual system performance is a function of these variables. Models exceeding 150,000 pounds have been successfully tested on the PEER-UC Berkeley Shaking Table. A 10-ton bridge crane services the Shaking Table Lab. The concrete shaking table is heavily reinforced, with both traditional reinforcement and post-tensioning tendons. Structurally, the table may be considered as a one foot thick diaphragm, stiffened by central transverse ribs that extend below the table's bottom surface. The eight hydraulic actuators that drive X and Y motion, along with yaw, are attached between the Shaking Table foundation and the tables transverse ribs. The four vertical actuators, as well as the test structure, are attached to the table by post-tensioning rods, inserted through a 3' x 3' matrix of 2-5/8" conduits, penetrating the Shaking Table surface. The length of the actuator assemblies, ranging from 8'-8" in the vertical direction and 10'-6" in the horizontal direction, serve to effectively de-couple the degrees of freedom motion. The high performance capabilities of the actuators, along with corrective commands from the sophisticated, MTS 469D controller, complete the de-coupling. Six Degree-of-Freedom Shaking Table The signature piece of testing equipment at the PEER-UC Berkeley Lab is the Six Degree-of-Freedom Shaking Table, the largest in the United States, and one of the largest in the world. The PEER-UC Berkeley Lab also houses a Large Scale Structures Lab consisting of a 20' x 60' strong floor with an integrated, reconfigurable, modular reaction wall. A comprehensive inventory of both static and dynamic hydraulic actuators, ranging from 5 kips to 2000 kips, along with an inventory of other test hardware and components are available to accommodate both simple single degree of freedom test setups as well as multi-axis custom test configurations. In addition, the PEER-UC Berkeley Lab houses large and small damper test machines, a 200 kip and a 4,000 kip uniaxial load frame, along with all of the associated control, measurement and data acquisition equipment required to operate the Lab's various test machines. The PEER facility also houses a Micro Lab for smaller scale experiments in self-equilibrating testing frames. The PEER-UC Berkeley Lab is at the forefront in the development of both hybrid control and digital image processing for the measurement of continuous strain fields. Single Degree of Freedom Table The PEER Single Degree of Freedom Shaking Table has a maximum stroke of +/-20 inches. The platform is 7' x 19'. The payload can be as high as 200 kips, with lateral capacity of 150 kips. The controller is connected to a SCRAMNet ring buffer; hence, this shaking table is capable of performing real-time hybrid simulation. This platform is ideal for projects requiring large displacement such as seismically isolated structures. Small Damper Test Machine The small damper test machine is designed for the testing of small to mid size dampers, friction devices and other structural components. The test machine consists of two, dynamic servo-hydraulic actuators installed in a self equilibrating system that consists of two, dynamic servo-hydraulic actuators and a reaction frame. The actuators generate vertical displacement that develops a compression or tension load in the damper or friction device attached between the top and bottom platens of the test machine. The system capacity is 445 kN (100 kips) at 0.50 m/sec (20 in/sec) during dynamic tests. In static loading, the actuators have a peak-to-peak stroke limit of 500 mm (20 in). Large Damper Test Machine The Large Damper, uniaxial test machine, is designed for the testing of full-size dampers. The test machine is a self-reacting system comprised of a dynamic, servo-hydraulic actuator and a reaction frame. The actuator generates a displacement that develops a compression or tension load in the damper which is attached between the actuator and the reaction frame. The actuator can deliver 900 kN (200 kips) at 0.38 m/sec (15 in/sec) during dynamic tests. In static loading, the actuator delivers a 1560 kN (346 kips) static force with a peak-to-peak stroke limit of (600 mm) 24 in. Big Press A Southwark-Emery, 4,000-kip Load Frame, originally built in 1932, was moved from the main campus and installed at the current PEER-UC Berkeley Lab in 1964. The uniaxial load frame can impose a 4,000 kip compression load and a 3,000 kip tension load. The maximum horizontal clearance between the vertical columns is 10'. The maximum length of a compression test element is 33.5 feet. In tension, the maximum specimen length is 22 feet. The stroke limit is 48" and the maximum rate of loading, at full capacity, is 0.071 inches per second. A dedicated hydraulic system provides high pressure oil to the 4,000 kip Load Frame. The load measuring emery-capsule and the associated electronic read-outs are routinely calibrated with NIST traceable equipment and procedure. A 12 ton bridge crane is accessible to the entire Lab where the 4,000 kip Load Frame is sited. A dedicated 8 ton crane and a perimeter elevator platform, provide additional utility to the 4,000 kip Load Frame. The below the crane hook ceiling height of the Lab is 65' and the truck entry door to the Lab is 11' wide and 16' tall. The 4,000 kip Load Frame is routinely utilized for research projects and is also available to commercial clients who require large loads to complete their required testing. An inventory of test machine specific hardware is maintained by PEER, as well as transducers, controllers and data systems. Reaction Wall and Floor The structural tie-down floor is located on the east end of the main bay of the laboratory. The overall plan dimensions of the tie-down slab are 20 x 60 ft. The slab has 2-1/2 inch holes located in an array of 36 inch on center over the 20 x 60 ft area. The test floor provides a completely versatile facility for testing large structural assemblies. Static or dynamic loads may be applied to specimens using tie rods, hydraulic actuators and steel loading frames. The test floor was designed to act as a hollow box girder in the longitudinal direction and as a vierendeel girder in the transverse. Fleet of Actuators Specs https://peer.berkeley.edu/laboratories
Partner Organizations
University of California at Berkeley
Oregon State University
University of California - Davis
University of California - Irvine
University of California at Los Angeles
California Institute of Technology (Caltech)
Stanford University
University of California - San Diego
University of Nevada - Reno
University of Washington
University of Southern California (USC)
Abbreviation |
PEER
|
Country |
United States
|
Region |
Americas
|
Primary Language |
English
|
Evidence of Intl Collaboration? |
|
Industry engagement required? |
Associated Funding Agencies |
Contact Name |
Grace Kang
|
Contact Title |
Communications Director
|
Contact E-Mail |
g.kang@berkeley.edu
|
Website |
|
General E-mail |
peer_center@berkeley.edu
|
Phone |
(510) 642-3437
|
Address |
325 Davis Hall
University of California
Berkeley
CA
94720-1792
|
[an NSF Graduated Center] The Pacific Earthquake Engineering Research Center (PEER) is a multi-institutional research and education center with headquarters at the University of California, Berkeley. Investigators from over 20 universities, several consulting companies, plus researchers at various State and Federal government agencies contribute to research programs focused on performance-based earthquake engineering in disciplines including structural and geotechnical engineering, geology/seismology, lifelines, transportation, risk management, and public policy. The PEER mission is to develop, validate, and disseminate performance-based seismic design technologies for buildings and infrastructure to meet the diverse economic and safety needs of owners and society. PEER's research defines appropriate performance targets, and develops engineering tools and criteria that can be used by practicing professionals to achieve those targets, such as safety, cost, and post-earthquake functionality. In addition to conducting research to develop performance-based earthquake engineering technology, PEER actively disseminates its findings to earthquake professionals who are involved in the practice of earthquake engineering, through various mechanisms including workshops, conferences and the PEER Report Series. PEER was established as a consortium of nine West Coast Universities in 1996 and gained status as a National Science Foundation Engineering Research Center in 1997. PEER graduated from NSF Funding in 2008 and is now supported by federal, state, local and regional agencies together with industry partners. Despite this funding shift, PEER continues to grow and remains an active earthquake engineering research center with a wide spectrum of technical activities and projects. PEER now has eleven Core Institutions but also actively involves researchers, educators, students, and earthquake professionals from across the US and worldwide. MISSION AND GOALS Developing seismic design technologies to meet the diverse economic and safety needs of owners and society The PEER mission is to develop and disseminate technologies to support performance-based earthquake engineering (PBEE). The approach is aimed at improving decision-making about seismic risk by making the choice of performance goals and the tradeoffs that they entail apparent to facility owners and society at large. The approach has gained worldwide attention in the past ten years with the realization that urban earthquakes in developed countries – Loma Prieta, Northridge, and Kobe – impose substantial economic and societal risks above and beyond potential loss of life and injuries. By providing quantitative tools for characterizing and managing these risks, performance-based earthquake engineering serves to address diverse economic and safety needs. There are three levels of decision-making that are served by enhanced technologies for performance-based earthquake engineering and that are focal points for PEER research. One level is that of owners or investors in individual facilities (i.e., a building, a bridge) who face decisions about risk management as influenced by the seismic integrity of a facility. PEER seeks to develop a rigorous PBEE methodology that will support informed decision-making about seismic design, retrofit, and financial management for individual facilities. A second level is that of owners, investors, or managers of a portfolio of buildings or facilities – a university or corporate campus, a highway transportation department, or a lifeline organization – for which decisions concern not only individual structures but also priorities among elements of that portfolio. PEER seeks to show how to use the rigorous PBEE methodology to support informed decision-making about setting priorities for seismic improvements within such systems by making clear tradeoffs among improved performance of elements of the system. A third level of decision-making is concerned with the societal impacts and regulatory choices relating to minimum performance standards for public and private facilities. PEER seeks to make technical contributions to development of performance-based codes and standards. The direct beneficiaries of more rigorous approaches to performance-based earthquake engineering are the owners, investors, and risk managers who face these decisions. All of us, of course, ultimately benefit from decisions about seismic risk that better address tradeoffs between the costs of reducing risks and the benefits resulting from seismic improvements. The clients for PEER advances in PBEE technologies are members of the engineering profession as broadly defined. Performance-based earthquake engineering is bringing about a change in the profession that alters both the role of earthquake engineers (broadening their involvement as consultants for management of earthquake risks) and the demands placed on the profession (changing the methods of risk evaluation, design, and engineering). PEER is working hand-in-hand with business and industry partners to understand how advances in PBEE affect engineering practice and the construction regulatory environment and to identify ways to lessen barriers to adoption and implementation of PBEE. In addition, PEER is very active in educating future generations of earthquake engineers and risk management professionals. As such, PEER seeks to make a major contribution to the development of the earthquake engineering profession. Despite advances in recent years in the use of performance-based earthquake engineering, existing technologies and methods for PBEE fall short on a number of grounds. Methods for seismic design or evaluation that currently are in widespread use are much less scientific and direct than the rigorous approach that we are developing. Although response of structures to strong ground motions in most cases is expected to be nonlinear, earthquake hazard today is represented by design maps through relatively simplistic single-parameter quantities such as linear spectral response. Likewise, structural evaluation and design commonly use linear analysis adjusted by factors whose values are based on tradition and limited earthquake experience rather than systematic performance considerations. Furthermore, engineering design and assessment generally focus on structural parameters and fail to quantify socio-economic parameters such as direct financial losses, downtime, and casualties. The result of this indirect and empirical approach is that seismic performance outcomes, as demonstrated in recent earthquakes, are highly variable and often at odds with stakeholder expectations. Seismic design in a technologically advanced society should be more scientifically based. It should provide information on expected seismic performance, measurable in terms that are meaningful to those who must make decisions about performance of facilities, networks or campuses, or the built environment in a broad context. And it should provide options for selecting optimal seismic performance to meet the diverse needs of owners and society. To meet this objective, we have visualized the implementation of performance-based earthquake engineering as a process involving distinct and logically related steps, illustrated in Figure 1.1. The first step is definition of the seismic hazard, which we have represented by the term intensity measure. The second step is determination of engineering demand parameters (e.g., deformations, velocities, accelerations) given the seismic input. This leads naturally to definition of damage measures such as permanent deformation, toppling of equipment, or cracking or spalling of material in structural components and architectural finishes. Finally, these damage measures lead to quantification of decision variables that relate to casualties, cost, and downtime. An essential element of performance-based earthquake engineering is the integration of issues across disciplinary boundaries. The central column of the figure suggests various steps that might be involved in a performance assessment of a system for a single earthquake event. The left side of the figure shows discrete variables that PEER has defined as part of its framework for performance-based earthquake engineering. The right side of the figure identifies the traditional disciplinary contributions to the problem. The solution of the earthquake problem clearly is a multi-disciplinary endeavor. The PEER programs in research, education, industry partnerships, and outreach are geared to producing the technology and human resources necessary to transition from current design and assessment methods to performance-based methods. The primary goal is to produce and test through research the fundamental information and enabling technologies required for performance-based earthquake engineering. The Education Program promotes earthquake engineering awareness in the general public, and attracts and trains undergraduate and graduate students to conduct research and to implement research findings developed in the PEER program. The Business and Industry Partner Program involves earthquake professionals, relevant industry, and earthquake information users in PEER activities to ensure the utility of the research and to speed its implementation. The Outreach Office presents the PEER activities and products to a broad audience including students, researchers, industry, and the general public. Ultimately, a PEER objective is to facilitate the development of practical guidelines and code provisions that will formalize performance-based earthquake engineering in practice, replacing some of the first-generation documents on this approach [e.g., FEMA 273, ATC 32, ATC 40, FEMA 354]. PEER is working closely with other organizations, including the Applied Technology Council and the Federal Emergency Management Agency, to develop and implement methodology that will form the basis of next-generation performance-based guidelines. Additionally, PEER produces models and data that are useful, useable, and used in industry. The process is aided by the involvement of practicing earthquake professionals in our program, who help guide and incorporate our research advances as they occur. As a result, the PEER program is an important contributor to national, state, and local efforts to reduce earthquake hazards that threaten the interests of the government, industry, and the general public.
Abbreviation |
PEER
|
Country |
United States
|
Region |
Americas
|
Primary Language |
English
|
Evidence of Intl Collaboration? |
|
Industry engagement required? |
Associated Funding Agencies |
Contact Name |
Grace Kang
|
Contact Title |
Communications Director
|
Contact E-Mail |
g.kang@berkeley.edu
|
Website |
|
General E-mail |
peer_center@berkeley.edu
|
Phone |
(510) 642-3437
|
Address |
325 Davis Hall
University of California
Berkeley
CA
94720-1792
|
Research Areas
The PEER research program aims to provide data, models, and software tools to support a formalized performance-based earthquake engineering methodology. Within the broad field of earthquake engineering, PEER's research currently is focused on six thrusts, these being Building Systems, Bridge and Transportation Systems, Lifelines Systems, Earthquake Hazard Characteristics, Social Sciences and Information Technologies/Data Science in support of the methodology implementation.
The PEER research program funds and coordinates research in support of the PEER mission in performance-based earthquake engineering. The broad scope of the mission requires an equally broad research agenda. The program includes elements of fault rupture; transmission of seismic waves from the source to the site; local site response as affected by local geologic conditions; interaction among the soil, foundation, and structure components; analysis of system dynamic response; assessment of the performance of the structural and nonstructural systems; consequences in terms of casualties, capital costs, and post-earthquake functionality; and decision-making to respond to earthquake effects or to change the design parameters to effect improved performance.
To accomplish its research program, PEER involves researchers from the earth sciences, engineering, and social sciences communities, who work together to develop an integrated approach to the performance-based earthquake engineering problem.
BUILDING SYSTEMS
The Building Thrust Area combines research from several areas: Loss Modeling and Decision Making, Geotechnical Performance, Assessment and Design Methodology, and Structural and Nonstructural Performance. The advances made in each thrust area and in the testbeds shaped the decision to create the Building Thrust Area.
Tall Buildings Initiative
Concrete Grand Challenge
PEER BRIDGE PROGRAM
1. Maintenance/Sustainability
Objectives:Develop cost effective methods for assessing the structural health of a bridge. Create repair techniques to prolong a bridge’s functional life. Assess innovative design and material options that will minimize life-cycle costs.
2. New Materials
Objectives: Perform evaluation and trial application of new construction materials such as high strength reinforcing steel, stainless steel, ultra-high-performance concrete, light-weight concrete, and composite materials.
3. Bridge Modeling & Analysis
Objective: Develop improved methods for assessing structural demand and performance.
4. Accelerated Bridge Construction
Objective: Develop techniques and structural systems that increase the speed of construction and minimize disruption to the traveling public.
5. Performance Based Earthquake Engineering (PBEE)/Bridge and System Reliability
Objectives: Develop bridge design methods that include seismic performance targets at different hazard levels. Investigate how different performance targets impact the performance of the transportation network following a major earthquake.
6. Foundations & Walls
Objective: Improve the geotechnical design of bridge foundations and retaining walls to improve performance and cost efficiency.
7. Intelligent Design Tools/Bridge Design Aids
Objective: Develop new tools and methods that take advantage of artificial intelligence to accelerate the bridge design process.
TRANSPORTATION SYSTEMS RESEARCH PROGRAM
The purpose of the PEER TSRP is to reduce the impacts of earthquakes on California’s transportation systems, including highways and bridges, port facilities, high speed rail, and airports. We expect that the research will utilize and extend PEER performance based earthquake engineering methodologies, integrating fundamental knowledge, enabling technologies, and systems. We further expect that the research program will integrate seismological, geotechnical, structural, hydrodynamic and socio-economical aspects of earthquake and tsunami engineering, and involve theoretical, computational, experimental and field investigations. The program also encourages vigorous interactions between practitioners and researchers.
LIFELINES SYSTEMS
The goal of the PEER Lifelines program is to improve seismic safety and reliability of lifeline systems. The projects in this program are primarily user-driven research projects, with strong collaboration among sponsoring lifelines organizations and PEER researchers. They range from engineering characterization of ground motions, to local soil response, to response of bridge structures, to performance of electric substation equipment.
The PEER Lifelines program has successfully brought together multidisciplinary teams of practicing engineers (geotechnical, structural); scientists (geologists, seismologists, social scientists); funding agencies (Federal, State of California, private industry); academicians, and end-users. An example of such successful multidisciplinary collaboration that was funded by the Lifelines Program is the NGA West Program that has resulted in major advances in characterization of seismic hazard, especially in the western United States.
Another unique characteristic of the PEER Lifelines program is its diverse, and mostly non-NSF, sources of funding. PEER Lifelines research projects are primarily funded by the following agencies:
California Department of Transportation(link is external)
Pacific Gas & Electric Company
The lifelines research projects are organized into eight topics:
Earthquake Ground Motion
Site Response
Permanent Ground Deformation
Substation Equipment
Substation Building
Bridge Structures
Network System Seismic Risk
Emergency Response
DATA SCIENCES
The goal of this Thrust areas is to develop new simulation models and methods for performance-based earthquake engineering assessment and design methodologies, develop modern simulation software tools taking advantage of information technology advances, deliver the software tools to the community, and educate students in simulation methods and information technology applications in earthquake engineering.
NATURAL HAZARDS
Tsunami Research Program
PEER’s tsunami research program is to develop an effective methodology for damage analyses for critical structures and lifelines: e.g. nuclear and fossil power plants, liquefied natural gas and oil storage facilities, civilian and military ports, emergency tsunami shelters, transportation corridors including coastal bridges, and important public facilities (fire and police stations, hospitals, and schools). Failure of critical coastal structures and lifelines likely lead to loss of life, delays in emergency response, and long-term economic impacts.
This research focus is a crucial gap in tsunami research efforts currently being conducted elsewhere. PEER’s methodology development – called Performance-Based Tsunami Engineering (PBTE) – will ultimately expand and extend the existing Performance-Based Earthquake Engineering (PBEE) methodology.
Fire Following Earthquake
The California Seismic Safety Commission has funded the PEER Center to conduct research related to fire following earthquakes. Prof. Charles Scawthorn, a Visiting Scholar at the PEER Center, is leading the study entitled Water Supply in Regard to Fire Following Earthquake. This work is supported from the Commissions Research Program.
The purpose of the study is to review the current status of emergency water supply in California vis-a-vis needs for fires following earthquake and provide a series of recommendations for improvements if and where needed. Issues to be discussed include fire ignitions following earthquakes, the status of the states urban water systems, the status of urban fire departments emergency water supply, and opportunities to enhance emergency water supply systems.
SOCIAL SCIENCES
Defining the Links Between Planning, Policy Analysis, Economics and Earthquake Engineering
Facilities & Resources
Laboratories The PEER-UC Berkeley lab at the Richmond Field Station partners with private industry and performs shaking table testing of critical equipment— e.g., emergency power generators, air handlers, electrical switchgear—under varying earthquake excitations. The shaking table testing is performed to ensure compliance with seismic regulations and to confirm the effectiveness of seismic retrofit strategies with the goal of reducing damage and injury in the event of an earthquake. 17025-2005 IAS Lab Accreditation for AC156 and IEEE-693 Testing The PEER-UC Berkeley Lab is accredited by IAS (TL450), to perform both AC-156 and IEEE-693 test protocols utilizing the 6 DOF Shaking Table. The Shaking Table is able to impose the highest required amplitude inputs of both of these standards. IEEE693, Recommended Practice for Seismic Design of Electrical Substations - These recommendations include discussions of qualification of each equipment type. Design recommendations consist of seismic criteria, qualification methods and levels, structural capacities, performance requirements for equipment operation, installation methods, and documentation. AC156, Seismic Certification by Shake-table Testing of Non-structural Components - This standard establishes criteria for a specific input motion, duration, and range of frequencies to which nonstructural components should be subjected. Earthquake Simulator Laboratory The signature piece of testing equipment at the PEER-UC Berkeley Lab is the six degree-of-freedom Shaking Table, the largest in the United States, and one of the largest in the world. The PEER-UC Berkeley Lab also houses a Large Scale Structures Lab consisting of a 20' x 60' strong floor with an integrated, reconfigurable, modular reaction wall. A comprehensive inventory of both static and dynamic hydraulic actuators, ranging from 5 kips to 2000 kips, along with an inventory of other test hardware and components are available to accommodate both simple single degree of freedom test setups as well as multi-axis custom test configurations. In addition, the PEER-UC Berkeley Lab houses large and small damper test machines, a 200 kip and a 4,000 kip uniaxial load frame, along with all of the associated control, measurement and data acquisition equipment required to operate the Lab's various test machines. The PEER facility also houses a Micro Lab for smaller scale experiments in self-equilibrating testing frames. The PEER-UC Berkeley Lab is at the forefront in the development of both hybrid control and digital image processing for the measurement of continuous strain fields. The PEER-UC Berkeley Lab demonstrates best-practice protocol in its general Lab operation and maintains an IAS accreditation, related to the Shaking Table testing of both AC-156 and IEEE-693 test protocols. The PEER-UC Berkeley Lab has a long history of successfully providing the engineering community testing facilities, the staffing expertise to execute a given project, and the academic background to provide appropriate data analysis, design input and overall project management. The PEER-UC Berkeley Lab is available to write both academic style reports, along with AC156 and IEEE-693 reports submitted to regulatory agencies. See the "Service to Industry" web page for more information. A welding shop, machine shop and electronics shop, along with dedicated control rooms, conference rooms and a suite of offices are also located at the PEER-UC Berkeley Lab facility. The PEER-UC Berkeley Labs are available to both the research community and to private industry that may require large capacity testing services. Published recharge rates are utilized in the development of project budgets. Priority in scheduling a given test always favors the research community, and time is made available to commercial clients on a time-available basis. Earthquake Simulator (Shaking Table) The Earthquake Shaking Table, dedicated in 1972, was the first modern Shaking Table and is still the largest six-degree-of-freedom (6 DOF) Shaking Table in the United States. The Shaking Table is configured to produce three translational components of motion; vertical and two horizontal, plus three rotational components; pitch, roll and yaw. These 6 DOF can be programmed to reproduce any wave form within the capacities of force, velocity, displacement and frequency of the Shaking Table system. The Shaking Table which weighs100 kips can subject structures, weighing 100,000 pounds, to horizontal accelerations of 1.5 G. Given that Shaking Table performance is a function of mass, overturning and model interaction, actual system performance is a function of these variables. Models exceeding 150,000 pounds have been successfully tested on the PEER-UC Berkeley Shaking Table. A 10-ton bridge crane services the Shaking Table Lab. The concrete shaking table is heavily reinforced, with both traditional reinforcement and post-tensioning tendons. Structurally, the table may be considered as a one foot thick diaphragm, stiffened by central transverse ribs that extend below the table's bottom surface. The eight hydraulic actuators that drive X and Y motion, along with yaw, are attached between the Shaking Table foundation and the tables transverse ribs. The four vertical actuators, as well as the test structure, are attached to the table by post-tensioning rods, inserted through a 3' x 3' matrix of 2-5/8" conduits, penetrating the Shaking Table surface. The length of the actuator assemblies, ranging from 8'-8" in the vertical direction and 10'-6" in the horizontal direction, serve to effectively de-couple the degrees of freedom motion. The high performance capabilities of the actuators, along with corrective commands from the sophisticated, MTS 469D controller, complete the de-coupling. Six Degree-of-Freedom Shaking Table The signature piece of testing equipment at the PEER-UC Berkeley Lab is the Six Degree-of-Freedom Shaking Table, the largest in the United States, and one of the largest in the world. The PEER-UC Berkeley Lab also houses a Large Scale Structures Lab consisting of a 20' x 60' strong floor with an integrated, reconfigurable, modular reaction wall. A comprehensive inventory of both static and dynamic hydraulic actuators, ranging from 5 kips to 2000 kips, along with an inventory of other test hardware and components are available to accommodate both simple single degree of freedom test setups as well as multi-axis custom test configurations. In addition, the PEER-UC Berkeley Lab houses large and small damper test machines, a 200 kip and a 4,000 kip uniaxial load frame, along with all of the associated control, measurement and data acquisition equipment required to operate the Lab's various test machines. The PEER facility also houses a Micro Lab for smaller scale experiments in self-equilibrating testing frames. The PEER-UC Berkeley Lab is at the forefront in the development of both hybrid control and digital image processing for the measurement of continuous strain fields. Single Degree of Freedom Table The PEER Single Degree of Freedom Shaking Table has a maximum stroke of +/-20 inches. The platform is 7' x 19'. The payload can be as high as 200 kips, with lateral capacity of 150 kips. The controller is connected to a SCRAMNet ring buffer; hence, this shaking table is capable of performing real-time hybrid simulation. This platform is ideal for projects requiring large displacement such as seismically isolated structures. Small Damper Test Machine The small damper test machine is designed for the testing of small to mid size dampers, friction devices and other structural components. The test machine consists of two, dynamic servo-hydraulic actuators installed in a self equilibrating system that consists of two, dynamic servo-hydraulic actuators and a reaction frame. The actuators generate vertical displacement that develops a compression or tension load in the damper or friction device attached between the top and bottom platens of the test machine. The system capacity is 445 kN (100 kips) at 0.50 m/sec (20 in/sec) during dynamic tests. In static loading, the actuators have a peak-to-peak stroke limit of 500 mm (20 in). Large Damper Test Machine The Large Damper, uniaxial test machine, is designed for the testing of full-size dampers. The test machine is a self-reacting system comprised of a dynamic, servo-hydraulic actuator and a reaction frame. The actuator generates a displacement that develops a compression or tension load in the damper which is attached between the actuator and the reaction frame. The actuator can deliver 900 kN (200 kips) at 0.38 m/sec (15 in/sec) during dynamic tests. In static loading, the actuator delivers a 1560 kN (346 kips) static force with a peak-to-peak stroke limit of (600 mm) 24 in. Big Press A Southwark-Emery, 4,000-kip Load Frame, originally built in 1932, was moved from the main campus and installed at the current PEER-UC Berkeley Lab in 1964. The uniaxial load frame can impose a 4,000 kip compression load and a 3,000 kip tension load. The maximum horizontal clearance between the vertical columns is 10'. The maximum length of a compression test element is 33.5 feet. In tension, the maximum specimen length is 22 feet. The stroke limit is 48" and the maximum rate of loading, at full capacity, is 0.071 inches per second. A dedicated hydraulic system provides high pressure oil to the 4,000 kip Load Frame. The load measuring emery-capsule and the associated electronic read-outs are routinely calibrated with NIST traceable equipment and procedure. A 12 ton bridge crane is accessible to the entire Lab where the 4,000 kip Load Frame is sited. A dedicated 8 ton crane and a perimeter elevator platform, provide additional utility to the 4,000 kip Load Frame. The below the crane hook ceiling height of the Lab is 65' and the truck entry door to the Lab is 11' wide and 16' tall. The 4,000 kip Load Frame is routinely utilized for research projects and is also available to commercial clients who require large loads to complete their required testing. An inventory of test machine specific hardware is maintained by PEER, as well as transducers, controllers and data systems. Reaction Wall and Floor The structural tie-down floor is located on the east end of the main bay of the laboratory. The overall plan dimensions of the tie-down slab are 20 x 60 ft. The slab has 2-1/2 inch holes located in an array of 36 inch on center over the 20 x 60 ft area. The test floor provides a completely versatile facility for testing large structural assemblies. Static or dynamic loads may be applied to specimens using tie rods, hydraulic actuators and steel loading frames. The test floor was designed to act as a hollow box girder in the longitudinal direction and as a vierendeel girder in the transverse. Fleet of Actuators Specs https://peer.berkeley.edu/laboratories
Partner Organizations
University of California at Berkeley
Oregon State University
University of California - Davis
University of California - Irvine
University of California at Los Angeles
California Institute of Technology (Caltech)
Stanford University
University of California - San Diego
University of Nevada - Reno
University of Washington
University of Southern California (USC)