PEER Reports

PEER Reports

Capacity-Demand-Diagram Methods for Estimating Seismic Deformation of Inelastic Structures: SDF Systems, PEER Report 1999-02

Anil K. Chopra
Rakesh K. Goel
1999

The ATC-40 and FEMA-274 documents contain simplified nonlinear analysis procedures to determine the displacement demand imposed on a building expected to deform inelastically. The Nonlinear Static Procedure in these documents, based on the capacity spectrum method, involves several approximations: The lateral force distribution for pushover analysis and conversion of these results to the capacity diagram are based only on the fundamental vibration mode of the elastic system. The earthquake-induced deformation of an inelastic SDF system is estimated by an iterative method requiring analysis...

Task 3: Characterization of Site Response General Site Categories, PEER Report 1999-03

Adrian Rodriguez-Marek
Jonathan D. Bray
Norman Abrahamson
1999

Seismic site response and the amplification of ground motions are significantly affected by the combined effect of the dynamic stiffness of the soil and the depth of the soil. Current design practice, however, either uses an oversimplified approach to soil classification (e.g., "soil" vs. "rock"), or ignores the effect of depth by accounting only for the average shear wave velocity over the upper 100 feet of a site profile (e.g., 1997 UBC). The significant quantity of ground motion data recorded in the 1994 Northridge and 1989 Loma Prieta, California, earthquakes provides an opportunity to...

Adoption and Enforcement of Earthquake Risk-Reduction Measures, PEER Report 1999-04

Peter J. May
T. Jens Feeley
Robert Wood
Raymond J. Burby
1999

These combined studies explore the socio-political implications of the seismic provisions of local building codes. Based on results from a national survey of building code officials, these three complementary studies explore (1) making building codes effective tools in earthquake hazard mitigation at the national level (2) the policy challenges of seismic mitigation in the western U.S., and (3) the role of policy entrepreneurs in the adoption of seismic-related provisions by local governments within California.

The conclusions of these studies are diverse, exploring various aspects...

Seismic Evaluation of 550 kV Porcelain Transformer Bushings, PEER Report 1999-05

Amir S. Gilani
Andrew S. Whittaker
Gregory L. Fenves
Eric Fujisaki
1999

Three 550 kV porcelain transformer bushings were evaluated for their response to severe earthquake shaking. The first bushing was similar to bushings currently in service in the United States; the other two bushings were modified versions of the first bushing. The modifications to the second and third bushings were intended to enhance seismic performance and included added tiers of springs, increased preload, and stiffer gaskets. The dynamic properties, vibration frequencies, and damping ratios of the bushings were evaluated from the experimental data. Tri-directional earthquake simulator...

Rocking Response and Overturning of Anchored Equipment under Seismic Excitations, PEER Report 1999-06

Nicos Makris
Jian Zhang
1999

This report investigates the transient rocking response of anchored electrical equipment and other anchored structures that can be approximated as rigid blocks. Practical issues that control over-turning, such as the effect of the vertical component of ground accelerations and the effect of the coefficient of restitution during impact, are also addressed.

The anchorages of equipment are assumed to have a pre-yielding linear behavior, a finite post-yielding strength, and some ductility. The nonlinear behavior of the restrainers in conjunction with the nonlinear dynamics of a rocking...

Documentation of Strengths and Weaknesses of Current Computer Analysis Methods for Seismic Performance of Reinforced Concrete Members, PEER Report 1999-07

William F. Cofer
1999

One of the future needs of the engineering community is a general computational platform for the seismic analysis of structures, structural components, and the interaction between structures and surrounding soil. However, before a large effort is expended, a thorough evaluation of current capabilities is required to establish the state of the art and to determine the direction that should be taken with regard to design needs and analytical approaches. A specific area of interest is the analysis of reinforced concrete components, including cracking and crushing of concrete and yield of...

Envelopes for Seismic Response Vectors, PEER Report 1999-08

Charles Menun
Armen Der Kiureghian
1999

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Performance Improvement of Long Period Building Structures Subjected to Severe Pulse-Type Ground Motions, PEER Report 1999-09

James C. Anderson
Vitelmo V. Bertero
Raul D. Bertero
1999

it has been known since the 1950s that under certain conditions, earthquake ground motions can consist of a limited number of strong acceleration pulses. These types of ground motions have come to be referred to as "pulse-type" ground motions. However, it has only been recently, following the Northridge earthquake (1994), that their importance for the earthquake resistant design of civil engineering structures has been recognized and introduced into the seismic provision of building codes through the introduction of the near-source factor [UBC, 1991-1997]. In an earlier paper [Anderson and...

U.S. Japan Workshop on Performance-Based Earthquake Engineering Methodology for Reinforced Concrete Building Structures, PEER Report 1999-10

Toshimi Kabeyasawa
Jack P. Moehle
1999

Process was reviewed fro the experiences of the 1994 Northridge Earthquake and the 1995 Hyogo-ken-Nanbu Earthquake until the action plan of the US-Japan cooperative research project. The Japan side started the project in 1998, which was reorganized into a five-year project under a new budget source of Grant-in-Aid for Scientific Research on Priority Area (Category B), Monbusho, from April 1999 until March 2003. Research topics and investigator groups on the Japan side are outlined, which have been planned under the common theme of "Us-Japan Cooperative Research in Urban Earthquake Disaster...

Performance Evaluation Database for Concrete Bridge Componentsand Systems under Simulated Seismic Loads, PEER Report 1999-11

Yael D. Hose
Frieder Seible
1999

Through lessons learned in recent earthquakes, the need for new seismic bridge design methodologies that consider structural performance explicitly and address the inelastic response of bridge structures more directly is recognized. Efforts are in progress to define and quantify limit states and associated performance goals to develop a multi-level bridge design methodology. A multi-level design approach can be implemented, however, only when structural behavior or limit states can accurately be characterized and assessed for the wide range of probable input or demands. The outlined...