Title

Cumulative seismic damage of circular bridge columns: Variable amplitude tests

Authors

Authors

A. El-Bahy; S. Kunnath; W. Stone;A. Taylor

Comments

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Abbreviated Journal Title

ACI Struct. J.

Keywords

bridges (structures); cyclic loads; damage; ductility; Construction & Building Technology; Engineering, Civil; Materials; Science, Multidisciplinary

Abstract

The findings from an experimental study to investigate cumulative seismic damage in reinforced concrete circular bridge piers is presented. Twelve identical quarter-scale bridge columns, designed in accordance with current AASHTO specifications, were fabricated and tested to failure. Results from Phase I testing, which included constant amplitude tests to determine the low-cycle fatigue characteristics of the bridge column, were presented in a companion paper. This paper summarizes results of variable amplitude testing that focused on the effects of load pth on cumulative damage. The imposed displacement histories were obtained form analytical simulations of the model column subjected to a sequence of earthquakes of varying duration and magnitude. Test observations indicate that failure is generally initiated by confinement inadequacy and the rupture of the transverse spiral reinforcement. The tests also demonstrated the potential for low-cycle fatigue fracture of the main longitudinal steel when the specimen was subjected to relatively larger displacement amplitudes, typically in excess of 4 percent lateral drift. A fatigue-based damage model, derived from the constant-amplitude tests completed in Phase I testing, was applied to the observed response of the six specimens tested in this phase. Findings from the study indicate that the energy capacity of members is ductility-dependent and that fatigue-based damage models offer a reliable means of assessing seismic structural performance.

Journal Title

Aci Structural Journal

Volume

96

Issue/Number

5

Publication Date

1-1-1999

Document Type

Article

Language

English

First Page

711

Last Page

719

WOS Identifier

WOS:000085762300005

ISSN

0889-3241

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