Pedro Arduino, University of Washington
Effects of Geotechnical Uncertainties on EDPs—2352002
Steve Kramer (UW/F), Pedro Arduino (UW/F), Sarah Paulsen (UW/GS)The goal of the proposed project is to systematically investigate the effects of uncertainty in geotechnical parameters on uncertainty in engineering demand parameters (EDPs). The work will be accomplished in a hierarchical manner, beginning with relatively simple geotechnical models and site conditions and progressing to more complicated models and conditions. The EDPs will be simple, and selected to be consistent with those being used in PEER structural engineering investigations. The results will provide insights into the level of uncertainty inherent in ground motion predictions with the tools most commonly used in contemporary geotechnical engineering practice, and with more advanced tools developed by PEER.
Scott A. Ashford, University of California, San Diego
Performance of Lifelines Subjected to Lateral Spreading—2342002
Scott Ashford (UCSD/F), Chia-Ming Uang (UCSD/F), Teerawut Juirnarongrit (UCSD/PD), Ben Siegel (UCSD/GS), Lisa Everingham (UCSD/US)The overall project goal is to utilize the full-scale data assess current methods for estimating the effect of lateral spreading on pile foundations and pipelines, and develop new procedures if necessary. Specifically for Year 6, our objectives are to:
- Back calculate P-y curves for all specimens for both tests.
- Model Experiment 1 using OPENSEES.
Mike Bailey, San Diego Supercomputer Center
Advanced Visualization for Seismic Performance—4182002
Mike Bailey (SDSC/I)The objective of this project is to develop an advanced visualization toolkit for structural and geotechnical simulations. Visualization is necessary to investigate the response and performance of systems through simulation. The large models and varied ways of examining performance require new visual metaphors and methods of user interaction.
Paolo Bazzurro, AIR Worldwide Corporation
Parameterization of Non-Stationary Acceleration Time Histories—Lifelines 1G00
Paolo Bazzurro (AIR/I), Nicolas Luco (AIR/I), Norm Abrahamson (PG&E/I), Brian Chiou (Caltrans/I), Allin Cornell (Stanford/F), Joe Maffei (R&C/I), Maury Power (Geomatrix/I)The project is structured into two phases:
Phase I: Investigate whether "non-stationary" characteristics of seismograms, in addition to more conventional ground motion intensity measures (e.g., spectral values), can improve the accuracy in the prediction of structural seismic performance.
Phase II: Three tasks
- to provide the quantitative technical basis to establish the threshold limits beyond which earthquake record scaling introduces bias in the nonlinear response of structures (issue of particular interest to the PEER Lifelines Program's Design Ground Motion Library study).
- to provide the tools necessary for the synthetic time history validation criteria currently being developed by the PEER Lifelines Program (NGA Working Group #3). These criteria will consider the issue of nonlinear structural response.
- to provide a technical basis for some of the assumptions used in the PEER Lifelines Project 507 entitled "The Advanced Seismic Assessment Guidelines," which provided recommendations for "tagging" of buildings damaged by a mainshock and susceptible to an aftershock. These assumptions are also relevant to the follow-up applications PEER Lifelines Projects 508 and 509.
Advanced Seismic Assessment Guidelines—Lifelines 507
Allin Cornell (Stanford/F), Charles Menun (Stanford, F), Paolo Bazzurro (AIR/I), Maziar Matahari (Stanford/GS), Gee Liek Yeo (Stanford/GS), Joe Maffei (R&C/I)
The primary objective of this two-phase project is the development of a new level of guidelines for the assessment of existing buildings. The scope is limited to typical PG&E 1-3 story buildings often of older and mixed construction. The limit states considered are those of direct electrical-system-reliability interest, e.g., collapse and (red or yellow) tagging, the latter because of their operability implications. An advanced state-of-practice engineering is employed, e.g., the structural engineer will provide a nonlinear (NL) static pushover analysis (SPO). In keeping with sponsor-stated needs and recent SAC and PEER developments, the guidelines will incorporate both aleatory and epistemic uncertainty measures, and the guidelines’ output products will include limit-state “fragility curves”, i.e., curves of the probability of limit state given ground motion intensity (IM) level, that reflect these various uncertainties. The first-year objective has been a “beta-version” of these guidelines, using results of only the first year’s research and default methods and parameter values where necessary. Nonetheless this first-year version is “operational”, i.e., up to or beyond current practice in all respects, such that it is being tested by two top-level structural engineering firms in the second year.
Building Performance and Loss Measures—1222002
James Beck (Caltech/F), Keith Porter (Caltech/F), Rustem Shaikhutdinov (Caltech/GS)The objectives of this project are to develop and illustrate the damage- and loss-analysis portions of PEER’s PBEE methodology for modern structures with high-value equipment and contents. We are focusing on elucidating and illustrating the analysis of two important aspects of seismic performance—operational failure and life-safety failure—associated with equipment and content damage. We are also examining repair cost and repair duration, although in less detail, and including in our analyses the performance of some architectural elements, probably gypsum wallboard partitions on metal-stud framing.
[Full Report]
Gregory C. Beroza, Stanford University
Physically Based Source Input for Strong Ground Motion Simulation—Lifelines 1C08
Greg Beroza (Stanford/F), Mariagiovanna Guatteri (Stanford/PD), Seok Goo Song (Stanford/GS)The goal of this project is to develop a library of rupture models for scenario earthquakes that are consistent with both the scaling and spatial variability of slip determined for past earthquakes and with simple notions of earthquake faulting physics.
Simulation of Enhanced-Performance Post-Tensioned Bridge Piers—5362002
Sarah Billington (Stanford/F)
The overall goal of this study is to demonstrate how the PEER PBEE methodology can accelerate the adoption of new bridge design technologies by quantitatively assessing the performance enhancement provided by these technologies. The first detailed objective is to identify the damage measures (DMs) of unbonded post-tensioned (UBPT) bridge piers (an enhanced performance system) that relate to decision variables (DVs) relevant to bridge performance, such as safety, functionality and repair time. Promising engineering demand parameters (EDPs) that characterize and quantify the appropriate DMs of unbonded post-tensioned bridge piers will then be identified. The second objective is to simulate recent cyclic and seismic experiments on UBPT bridge piers using detailed finite element analyses as well as simple macro-models with the goal of modeling and predicting accurately various EDPs.
Soil-Foundation-Structure Interaction of Deep Foundations in Liquefied Ground—2312002
Ross Boulanger (UCD/F), Scott Brandenberg (UCD/GS), Dongdong Chang (UCD/GS)The objectives of this project are to develop and validate nonlinear p-y, t-z, and q-z material models for OpenSees-based simulations of the seismic response of deep foundations in liquefied and laterally spreading ground.
[Full Report]
GIS Modeling of the University Campus—1242002
Stephanie Chang (UW/F), Anthony Falit-Baiamonte (UW/GS)
The primary objective of this project is to model the benefits of improved seismic performance of the UCB Life Sciences Building (LSB) from the standpoint of campus functionality. The project thus focuses on benefits other than those to the LSB occupants themselves. A secondary objective is to demonstrate how these benefits can be incorporated in a benefit-cost analysis or other comparison to the investment costs.
[Full Report]
Practitioner Critique of PEER Bridge Analysis Methodology—3322002
William Nascimento (LAN/I), Mohan Char (LAN/I)
Review Assessment and Design Methodologies of Performance Based Earthquake Engineering developed by PEER with emphasis on practical design applicability.
Mary Comerio, University of California, Berkeley (Thrust Area 1 Co-Leader)
Data Development for Loss Modeling: Nonstructural Hazard Mitigation in the Life Science Building Testbed—1202002
Mary Comerio(UCB/F), Ryan Smith (UCB/GS), Jung In Kim (UCB/GS)The first goal is coordination of the UC Science Testbed—holding meetings, sharing data, and completing the Testbed Report. The second goal is to provide building contents data for fragility studies in database and GIS formats for loss modeling. The third goal is to assemble data on downtime to be used in loss modeling.
[Full Report]
Joel Conte, University of California, San Diego
Computational Reliability for Design—4132002
Joel Conte (UCSD/F), Yuyi Zhang (UCSD/GS), Gabriel Acero (UCSD/GS), Quan Gu (UCSD/GS)
- Develop, implement, and document sensitivity and reliability analysis modules in OpenSees to facilitate solution of the PEER PBEE framework equation
- Identify and model uncertainties (characterizing the seismic loading, system parameters, modeling assumptions, etc.) and track their propagation through nonlinear earthquake response analysis (using OpenSees) for the Humboldt Bay Bridge testbed structure
- Demonstrate the various ingredients required in the solution of the PEER probabilistic framework equation as well as their integration for the Humboldt Bay Bridge testbed structure
- Investigate seismic reliability assessment of non-ductile structures with degrading components
C. Allin Cornell, Stanford University
Parameterization of Non-Stationary Acceleration Time Histories—Lifelines 1G00
Paolo Bazzurro (AIR/I), Nicolas Luco (AIR/I), Norm Abrahamson (PG&E/I), Brian Chiou (Caltrans/I), Allin Cornell (Stanford/F), Joe Maffei (R&C/I), Maury Power (Geomatrix/I)The project is structured into two phases:
Phase I: Investigate whether "non-stationary" characteristics of seismograms, in addition to more conventional ground motion intensity measures (e.g., spectral values), can improve the accuracy in the prediction of structural seismic performance.
Phase II: Three tasks
- to provide the quantitative technical basis to establish the threshold limits beyond which earthquake record scaling introduces bias in the nonlinear response of structures (issue of particular interest to the PEER Lifelines Program's Design Ground Motion Library study).
- to provide the tools necessary for the synthetic time history validation criteria currently being developed by the PEER Lifelines Program (NGA Working Group #3). These criteria will consider the issue of nonlinear structural response.
- to provide a technical basis for some of the assumptions used in the PEER Lifelines Project 507 entitled "The Advanced Seismic Assessment Guidelines," which provided recommendations for "tagging" of buildings damaged by a mainshock and susceptible to an aftershock. These assumptions are also relevant to the follow-up applications PEER Lifelines Projects 508 and 509.
Methodology for Selection of Input Ground Motions for PBEE and Propagation of Uncertainty—3172002
C. Allin Cornell (Stanford/F), Fatemeh Jalayer (Stanford/GS), Jack Baker (Stanford/GS)
This project is designed to continue and bring to a level of completion the main issues of the Year 5 work statement: uncertainty propagation, IM sufficiency and efficiency investigations, and record selection/processing. The last two subjects are viewed, novelly, as being strongly inter-related.
Advanced Seismic Assessment Guidelines—Lifelines 507
Allin Cornell (Stanford/F), Charles Menun (Stanford, F), Paolo Bazzurro (AIR/I), Maziar Matahari (Stanford/GS), Gee Liek Yeo (Stanford/GS), Joe Maffei (R&C/I)
The primary objective of this two-phase project is the development of a new level of guidelines for the assessment of existing buildings. The scope is limited to typical PG&E 1-3 story buildings often of older and mixed construction. The limit states considered are those of direct electrical-system-reliability interest, e.g., collapse and (red or yellow) tagging, the latter because of their operability implications. An advanced state-of-practice engineering is employed, e.g., the structural engineer will provide a nonlinear (NL) static pushover analysis (SPO). In keeping with sponsor-stated needs and recent SAC and PEER developments, the guidelines will incorporate both aleatory and epistemic uncertainty measures, and the guidelines’ output products will include limit-state “fragility curves”, i.e., curves of the probability of limit state given ground motion intensity (IM) level, that reflect these various uncertainties. The first-year objective has been a “beta-version” of these guidelines, using results of only the first year’s research and default methods and parameter values where necessary. Nonetheless this first-year version is “operational”, i.e., up to or beyond current practice in all respects, such that it is being tested by two top-level structural engineering firms in the second year.
Gregory Deierlein, Stanford University (PEER Deputy Director for Research)
Development and Validation of Performance Models—4122002
Gregory Deierlein (Stanford/F), Rohit Kaul (Stanford/GS), Arash Altoontash (Stanford/GS)
High fidelity simulations are essential to the PEER PBEE methodology to accurately model seismic response, damage and collapse of buildings and bridges. Central to the effort of thrust area 4 is the development of OpenSees (Open System for Earthquake Engineering Simulation) - a versatile computing framework that integrates analysis models for seismic hazard, ground motions, soil response, soil-foundation structure interaction, and structural response. The focus of this project (4122002) is to develop and validate generalized hinge models for simulating strength and stiffness degradation in reinforced-concrete structures. Emphasis is on spring assemblies, generalized hinge elements, and cyclic hysteretic models for beam-columns and their connections that are sufficiently robust to capture highly nonlinear response at collapse, yet practical for application to large systems.
Full-Scale Frame Test Validation of Simulation and Performance Demands—4202002
Greg Deierlein (Stanford/F), Paul Cordova (Stanford/GS)
This is a collaborative project between researchers at PEER and the National Center for Earthquake Engineering Research (NCREE) in Taiwan to utilize data from a full-scale frame test to validate structural simulation and performance models. Specific goals of the project are to:
- assess the accuracy of OpenSees simulation models through detailed comparisons with data from a full-scale moment frame test and complementary subassembly tests,
- collect and evaluate test data to develop relationships between engineering demand parameters and structural damage measures, and
- benchmark the seismic performance of a modern (IBC 2000 compliant) three-story building frame system.
Armen Der Kiureghian, University of California, Berkeley
Computational Reliability Tools for Design—4142002
Armen Der Kiureghian (UCB/F), Jerome Sackman (UCB/F), Junho Song (UCB/GS)
Develop, implement, and document reliability and response sensitivity methods in the OpenSees computational simulation framework. Apply to test-bed examples to assess reliability.
Analytical Models for Electrical Equipment Connected by Rigid Buses—Lifelines 401b
Armen Der Kiureghian (UCB/F), Terje Haukaas (UCB/GS)
This project extends previous work on analytical modeling of the interaction effect between electrical substation equipment connected by rigid buses. The goal is make refinements to interaction analysis by accounting for the prevailing uncertainties in the ground motion and equipment characteristics. Comparison with tests conducted by other PEER researchers are made.
Douglas Dreger, University of California, Berkeley
Calibration of Basin Simulations—Lifelines 1A03
Steven Day (SDSU/F), Douglas Dreger (UCB/F), Shawn Larsen (LLNL/I), Kim Olsen (UCSB/O), Arben Pitarka (URS/I), Robert Graves (URS/I),
Jacobo Bielak (CMU/F), Antonio Fernandez (CMU/GS)
Currently, the reliability assessment module connected to OpenSees is capable of:
- first order (FORM) reliability analysis,
- second-order (SORM) reliability analysis, and
- simulation analysis with importance sampling, for any number of limit-state functions and for linear or nonlinear static problems.
The limit-state functions are defined by the user as analytical expressions involving response quantities from the finite element model or the basic random variables. Importance measures of the uncertain parameters entering the model are computed. This can be useful information in practical design. Furthermore, a graphical user interface has been developed to provide an on-screen guideline to users employing the OpenSees+Reliability program package.
Marc Eberhard, University of Washington
Database and Acceptance Criteria for Column Tests—5282002
Marc Eberhard (UW/F), Mike Berry (UW/GS), Haili Camarillo (UW/GS)
The goal of this project is to develop and calibrate tools for assessing reinforced concrete column seismic performance, including data and models for both seismically conforming (ductile) and non-conforming (brittle) columns.
Ahmed Elgamal, University of California, San Diego (Thrust Area 2 Leader)
3D Simulation of Seismic Ground Deformation in OpenSees—2202002
Ahmed Elgamal (UCSD/F), Zhaohui Yang (UCSD/PD), Jinchi Lu (UCSD/GS)This project complements other ongoing efforts related to the open computational simulation platform OpenSees (led by Professor Greg Fenves). Specifically, the project is focused on:
- adding new geotechnical simulation capabilities,
- calibration of these capabilities using available data sets,
- advancing the spatial simulation capabilities,
- integrating the Soil and Structural simulation components,
- exploring the seismic response of combined large-scale soil-structure systems, and
- advancing the PEER Humboldt Bay Bridge Testbed efforts.
Recent work has been addressing:
- Further development of the three-dimensional (3D) analysis capabilities for nonlinear soil-structure systems,
- Related Parallel-processing challenges (in collaboration with Prof. Kincho Law, Prof. Greg Fenves and the San Diego Supercomputing Center), and
- Computational developments related to spatial definition of ground motion (in collaboration with Prof. Jacobo Bielak and Prof. Joel Conte).
Gregory Fenves, University of California, Berkeley (Thrust Area 4 Leader)
PEER Analysis Platform for Demand Simulation—4102002
Gregory Fenves (UCB/F), Filip Filippou (UCB/F), Frank McKenna (UCB/PD), Silvia Mazzoni (UCB/PD), Michael Scott (UCB/GS), Asfin Saritas (UCB/GS)
The goal of this project is to advance the research for simulation capability of structural and geotechnical systems for performance-based earthquake engineering. The simulation software developed in the project utilizes advances in information technology and computing methods, and the development is collaborative, with an open-source methodology, that engages a large number of researchers in PEER and many outside PEER. The primary products of the project are:
- new models and methods for simulation of earthquake performance;
- and open-source software framework, OpenSees, that incorporates the latest research and computing technology; and
- a committed group of developers and users in the research community.
Simulation of structural and geotechnical systems is a key step in PEER PBEE methodologies. The PEER assessment methodology relies on simulation to compute engineering demand parameters and in some cases damage measures. PEER has embarked on software development because existing simulation software is inadequate for a number of reasons: models of behavior are too simplified, particularly for reinforced concrete; little support for soil-foundation-structure interaction; closed or antiquated software architecture makes it difficult to research new simulation methods; generally slow adoption of information technology; does not expose students to modern software engineering and computer science.
The OpenSees website is http://opensees.berkeley.edu/
Seismic Qualification and Fragility Testing of 500kV Disconnect Switches—Lifelines 411
Gregory Fenves (UCB/F), Shakhzod Takhirov (UCB/O), Don Clyde (UCB/O)
Project 411 consisted of seismic qualification and fragility testing of 500kV disconnect switch. Qualification by shake table testing is intended to demonstrate that the disconnect switch and appurtenant equipment satisfy the requirements of IEEE 693-1997 at the high qualification level. Tests at two RRS levels (0.25g, pga and 0.5g, pga), the Performance Level (1.0g, pga), and fragility tests are included in the test program.
André Filiatrault, University of California, San Diego
Performance Evaluation of Gypsum Wallboard Partitions—5322002
André Filiatrault (UCSD/F), José Restrepo (UCSD/F), Andrew Bersofsky (UCSD/GS)
The objectives of this project are to develop data and models to characterize the performance of gypsum wallboard partitions, of the type common to modern office, hotel, and laboratory buildings.
Substation Equipment Interaction-Experimental Models of Rigid Bus Connectors—Lifelines 402
André Filiatrault (UCSD/F), Christopher Stearns (UCSD/GS)
The three main objectives are:
- Perform quasi-static testing of rigid buses of different shapes, including offsets and bends.
- Coordinate with on-going projects 403, 404 and 408 to refine properties and representation of generic equipment, and modification of input motions of equipment appendages
- Perform shake table tests of several pairs of refined generic equipment interconnected by rigid bus of different shapes, including improved connectors.
Filip Filippou, University of California, Berkeley
PEER Analysis Platform for Demand Simulation—4102002
Gregory Fenves (UCB/F), Filip Filippou (UCB/F), Frank McKenna (UCB/PD), Silvia Mazzoni (UCB/PD), Michael Scott (UCB/GS), Asfin Saritas (UCB/GS)
The goal of this project is to advance the research for simulation capability of structural and geotechnical systems for performance-based earthquake engineering. The simulation software developed in the project utilizes advances in information technology and computing methods, and the development is collaborative, with an open-source methodology, that engages a large number of researchers in PEER and many outside PEER. The primary products of the project are:
- new models and methods for simulation of earthquake performance;
- and open-source software framework, OpenSees, that incorporates the latest research and computing technology; and
- a committed group of developers and users in the research community.
Simulation of structural and geotechnical systems is a key step in PEER PBEE methodologies. The PEER assessment methodology relies on simulation to compute engineering demand parameters and in some cases damage measures. PEER has embarked on software development because existing simulation software is inadequate for a number of reasons: models of behavior are too simplified, particularly for reinforced concrete; little support for soil-foundation-structure interaction; closed or antiquated software architecture makes it difficult to research new simulation methods; generally slow adoption of information technology; does not expose students to modern software engineering and computer science.
The OpenSees website is http://opensees.berkeley.edu/
Robert W. Graves, URS Corporation
Empirical Characterization of Basin Effects on Site Response—2252002
Jonathan Stewart (UCLA/F), Yoojong Choi (UCLA/GS), Robert Graves (URS/I)This Year 6 project is an extension of the Year 5 project having the same title. As described in the original project proposal, the general intent of this work is to develop a statistically robust engineering model for characterizing basin effects on ground motion intensity measures (IMs). The approach taken is to evaluate residuals between data and predictions, and correlate these residuals to basin geometric parameters. The predictions used to evaluate the residuals will, to the extent possible, remove the effects of site, path, and shallow ground response in an average sense, so that the deviations from data can be attributed to basin response.
Calibration of Basin Simulations—Lifelines 1A03
Steven Day (SDSU/F), Douglas Dreger (UCB/F), Shawn Larsen (LLNL/I), Kim Olsen (UCSB/O), Arben Pitarka (URS/I), Robert Graves (URS/I),
Jacobo Bielak (CMU/F), Antonio Fernandez (CMU/GS)
Currently, the reliability assessment module connected to OpenSees is capable of:
- first order (FORM) reliability analysis,
- second-order (SORM) reliability analysis, and
- simulation analysis with importance sampling, for any number of limit-state functions and for linear or nonlinear static problems.
The limit-state functions are defined by the user as analytical expressions involving response quantities from the finite element model or the basic random variables. Importance measures of the uncertain parameters entering the model are computed. This can be useful information in practical design. Furthermore, a graphical user interface has been developed to provide an on-screen guideline to users employing the OpenSees+Reliability program package.
Jon A. Heintz, Degenkolb Engineers
Evaluation and Assessment of PBEE Methodology—3292002
Jon Heintz (Degenkolb/I), Robert Pekelnicky (I), Rose Katz (I)This project is a continuation of Year 5 work. The objective is to provide an engineering practitioner’s assessment of the PEER PBEE methodology through a detailed comparison with current state-of-practice techniques. Year 5 focused on providing an independent evaluation of the expected performance of the building. Year 6 will focus on designing seismic rehabilitation for the Van Nuys testbed building, and comparing results with designs developed using the PEER PBEE methodology.
Next set of investigators (Hutchinson-Moehle) Back to Year 6 Research page