PEER Reports

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...

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...

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....

The Route 14/Interstate 5 Separation and Overhead bridge, a curved ten-span structural concrete structure, partially collapsed in the 1994 Northridge earthquake. The primary objective of this study is to ascertain the cause of failure by comparing estimates of the capacities and demands of various components in the bridge. A secondary objective is to examine earthquake modeling and analysis recommendations for highway bridges. As part of the examination, nonlinear static analysis (pushover analysis) is used to determine the capacity of a frame. Linearized analyses are compared with...