PEER Reports

PEER Reports

PEER Report 2022/03: "Moment Resisting Frames Coupled with Rocking Walls Subjected to Earthquakes"

June 17, 2022

PEER has published Report No. 2022/03: "Moment Resisting Frames Coupled with Rocking Walls Subjected to Earthquakes." It was authored by Mehrdad Aghagholizadeh, Department of Civil and Environmental Engineering, University of Southern California and Nicos Makris, Department of Civil and Environmental Engineering, Southern Methodist University, Dallas, Texas.

Access the report and 2 page summary. Access the...

Moment Resisting Frames Coupled with Rocking Walls Subjected to Earthquakes, PEER Report 2022-03

Mehrdad Aghagholizadeh
Nicos Makris

The high occupancy levels in urban multistory buildings, in association with current safety considerations inevitably leads to a reconsideration of performance objectives. In view of the appreciable seismic damage and several weak-story failures (some at mid-height) of multistory buildings that have been documented after major earthquakes, there has been a growing effort to develop an alternative hybrid structural system by coupling the response of moment resisting frames with rigid/stiff walls which are allowed to uplift and rock during ground shaking; therefore, enforcing a uniform drift...

Capacity Limit States for Nonductile Bridge Columns, PEER Report 2022-01

Jin Zhou
Sashi K Kunnath

The ShakeCast software platform, used by the California Department of Transportation (Caltrans), utilizes near real-time ground shaking maps generated by the US Geological Survey in conjunction with demand and capacity models, to evaluate the likely damage to all bridges in the vicinity of an earthquake event. The ability to estimate with reasonable accuracy the likelihood and extent of damage to bridges following an earthquake is crucial to post-...

Micro-Inspired Continuum Modeling Using Virtual Experiments, PEER Report 2022-02

Jose E. Andrade

This report describes the methodology and advances reached for the project “Micro-Inspired Continuum Modeling Using Virtual Experiments.” The objective of this project was to develop new hardening rules for the most common plasticity constitutive models by using accurate micromechanical simulations that can capture the main features of granular behavior under cyclic loading — a crucial feature for earthquake engineering applications. To achieve this objective, laboratory experiments were performed and scanned with X-ray computed tomography (CT). The sample processed with CT was used as...

Seismic Performance of Well-Confined Concrete Bridge Columns, PEER Report 1998-01

Dawn E. Lehman
Jack P. Moehle

Recent earthquakes in California and abroad have provided performance data demonstrating that large losses can result from inadequate performance of highway bridges. An experimental and analytical research program was undertaken to characterize the response of well-confined, circular cross section, concrete bridge columns subjected to lateral loading. In the experimental investigation, columns with varying longitudinal reinforcement ratios and aspect ratios were tested in the laboratory to characterize the response of modern bridge columns to lateral loads. In the analytical investigation...

Seismic Evaluation of 196 kV Porcelain Transformer Bushings, PEER Report 1998-02

Amir S. Gilani
Juan W. Chavez
Gregory L. Fenves
Andrew S. Whittaker

Two identical 196 kV porcelain transformer bushings were evaluated for their response to severe earthquake shaking. Tri-directional earthquake simulator testing was undertaken to investigate the dynamic response of the bushing, to provide data for correlation with the analytical studies, to qualify one of the bushings for moderate earthquake shaking (per IEEE 693), and to evaluate the response of one bushing to extreme shaking effects. For earthquake testing, the bushing was mounted at 20° to the vertical in a stiff support frame. Spectrum-compatible ground motion records derived from...

Repair/Upgrade Procedures for Welded Beam to Column Connections, PEER Report 1998-03

James C. Anderson
Xiaojing Duan

Experimental and analytical studies are conducted on four repair/upgrade details for welded moment connections. The first of these seeks to improve the weld material without doing anything to the beam and column sections at the joint (weld enhancement). The simplest of these removes the cracked weld material and replaces it with a more ductile, notch-tough weld material (weld replacement). A more recently developed procedure places a layer of weld material having a higher notch toughness on top of the existing welds (weld overlay).

The second weld repair/retrofit detail considers...

Defining the Links between Planning, Policy Analysis, Economics, and Earthquake Engineering, PEER Report 1998-04

Mary Comerio
Peter Gordon

The recently established PEER Center is committed to integrating social science and earthquake engineering research. How should integration proceed? What can social scientists contribute to PEER’s interest in performance-based engineering? These and other questions were addressed at a PEER Workshop on Planning, Policy Analysis and Economics in Earthquake Research which was convened (May 14-15, 1998) to help develop an appropriate research agenda.

Generally, it appears that whereas performance-based engineering seeks optimal solutions to the achievement of given standards, social...

Rocking Response and Overturning of Equipment under Horizontal Pulse-Type Motions, PEER Report 1998-05

Nicos Makris
Yiannis Roussos

In this report the transient rocking response of electrical equipment subjected to trigonometric pulses and near-source ground motions is investigated in detail. First the rocking response of a rigid block subjected to a half-sine pulse motion is reviewed. It is shown that the solution presented by Housner (1963) for the minimum acceleration amplitude of a half-sine pulse that is needed to overturn a rigid block is incorrect. In reality, under a half-sine pulse, a block overturns during its free vibration regime and not at the instant that the pulse expires, as was assumed by Housner....

Effect of Damping Mechanisms on the Response of Seismically Isolated Structures, PEER Report 1998-06

Nicos Makris
Shih-Po Chang

In this report the efficiency of various dissipative mechanisms to protect structures from pulse-type and near-source ground motions is examined. It is first shown that under such motions the concept of equivalent linear damping has limited meaning since the transient response of a structure is more sensitive to the nature of the dissipation mechanism, rather than to the amount of energy dissipated per cycle. Subsequently, physically realizable cycloidal pulses are introduced, and their resemblance to recorded near-source ground motions is illustrated. The study uncovers the coherent...