PEER Reports

PEER Reports

Stiffness Analysis of Fiber-Reinforced Elastomeric Isolators, PEER Report 2001-05

Hsiang-Chuan Tsai
James M. Kelly
2001

The reinforcing elements of multi-layer elastomeric isolation bearings, which are normally steel plates, are replaced by a fiber reinforcement. The fiber-reinforced isolator is significantly lighter and could lead to a much less labor-intensive manufacturing process. In contrast to the steel-reinforced islolator, which is assumed to be rigid both in extension and in flexure, the fiber-reinforced isolator is assumed flexible in extension, but completely without flexural rigidity. This report presents theoretical approaches for analyzing the compressive stiffness and bending stiffness of...

Development of an Electrical Substation Equipment Performance Database for Evaluation of Equipment Fragilities, PEER Report 2001-06

Thalia Anagnos
2001

A database has been developed that documents the performance of substation equipment in 12 California earthquakes. The equipment in the database is owned by the Pacific Gas and Electric Company, the Los Angeles Department of Water and Power, Southern California Edison and the California Department of Water Resources. The majority of data relates to equipment operating at 220/230 kV and 500 kV. The database is organized into an Excel 5.0 spreadsheet with 68 data fields describing earthquake location, ground motion, site location and conditions, equipment characteristics, performance of...

The Rocking Spectrum and the Shortcomings of Design Guidelines, PEER Report 2001-07

Nicos Makris
Dimitrios Konstantinidis
2001

This report is concerned with the superficial similarities and fundamental differences between the oscillatory response of a single-degree-of-freedom (SDOF) oscillator (regular pendulum) and the rocking response of a slender rigid block (inverted pendulum). The study examines the distinct characteristics of the rocking spectrum and compares the observed trends with those of the response spectrum. It is shown that the rocking spectrum complements the response spectrum as an indicator of the shaking potential of earthquakes since it reflects kinematic characteristics of the ground motions...

Experimental and Computational Evaluation of Reinforced Concrete Bridge Beam-Column Connections for Seismic Performance, PEER Report 2001-08

Clay J. Naito
Jack P. Moehle
Khalid M. Mosalam
2001

Proper design of reinforced concrete bridge beam-column connections is imperative for the behavior of the bridge structure. While in the past this area was overlooked, resulting in bridge structure damage and in some cases collapse, current methods have overcompensated for these shortcomings. The presented research shows that current joint design requirements in the state of California produce conservative designs (i.e., joints with excessive amounts of reinforcement). The joints in these systems are capable of supporting the intended flexural mechanism, but at the cost of constructability...

Ground Motion Evaluation Procedures for Performance-Based Design, PEER Report 2001-09

Jonathan P. Stewart
Shyh-Jeng Chiou
Jonathan D. Bray
Robert W. Graves
Paul G. Somerville
Norman A. Abrahamson
2001

The principal objective of the Pacific Earthquake Engineering Research Center (PEER) is to develop a sound, scientific ba sis for performance-based earthquake engineering. The development of this methodology includes three vital steps:

Evaluation of the distribution of ground motion intensity measures at a site, given certain seismological variables (i.e., fault characteristics, position of site relative to faults, etc.). Intensity measures may consist of traditional parameters such as spectral acceleration or duration, or newly defined parameters found to be useful for particular...

Amplification Factors for Spectral Acceleration in Active Regions, PEER Report 2001-10

Jonathan P. Stewart
Andrew H. Liu
Yoojoong Choi
Mehmet B. Baturay
2001

Empirical relationships are developed to predict amplification factors for 5% damped spectral acceleration (period range T = 0.01 – 5 s) as a function of site category. Amplification is evaluated by normalizing ground motion intensity measures from recordings by reference motions derived from modified attenuation relationships for active regions. The Abrahamson and Silva attenuation relationship for rock sites was used for the derivation of reference motions, with modifications to account for event terms and rupture directivity effects.

Strong motion sites are classified according...

Analytical and Experimental Study of Fiber-Reinforced Elastomeric Isolators, PEER Report 2001-11

James M. Kelly
Shakhzod M. Takhirov
2001

Theoretical and experimental analyses are carried out for the mechanical characteristics of multi-layer elastomeric isolation bearings where the reinforcing elements, normally steel plates, are replaced by a fiber reinforcement. The fiber-reinforced isolator, in contrast to the steel-reinforced isolator (which is assumed to be rigid both in extension and flexure), is assumed to be flexible in extension, but completely without flexure rigidity.

The influence of fiber flexibility on the mechanical properties of the fiber-reinforced isolator, such as the vertical and horizontal...

Development of Geotechnical Capabilities in OpenSees, PEER Report 2001-12

Boris Jeremic
2001

The PEER OpenSees project covers research on the “Next Generation Analytical Platform for Nonlinear Dynamic Analysis.” This report presents in some detail work performed for the “Development of Geotechnical Capabilities in OpenSees,” PEER project 2132000-3 started in May 2000. This report describes:

Development and implementation of the universal, template constitutive driver for OpenSees; Development of fully coupled, solid–fluid formulation; Development and implementation of visualization tools for solids in OpenSees; Examples of soil-foundation-structure interaction simulations; and...

Modeling Soil Liquefaction Hazards for Performance-Based Earthquake Engineering, PEER Report 2001-13

Steven L. Kramer
Ahmed-W. Elgamal
2001

The first widespread observations of damage attributed to liquefaction were made in the 1964 Niigata, Japan, and 1964 Alaska earthquakes. In numerous earthquakes since, liquefaction has been deemed responsible for significant damage to buildings and bridges. Liquefaction has been studied extensively over the past 35 years, and substantial advances have been made in understanding the development and effects of this phenomenon. These advances have led to a series of practical procedures for evaluating the potential for occurrence and for estimating its effects. These procedures, however, are...

Rocking Response of Equipment Anchored to a Base Foundation, PEER Report 2001-14

Nicos Makris
Cameron J. Black
2001

This study concentrates on the rocking response of rigid equipment supported on a foundation base. In most cases heavy electrical equipment is anchored on a concrete base with plan dimensions that are larger than the footprint of the equipment. In the event that the strength of the restrainers, Fu is sufficiently large and the ground acceleration is sufficiently strong, the equipment will engage its foundation in rocking motion. On the other hand, if the restrainers are too fragile they will fracture and eventually the equipment will rock atop its foundation base....