Title:
Performance of Existing Bridge Columns under Cyclic Loading—Part 1: Experimental Results and Observed Behavior
Author(s):
Omar A. Jaradat, David I. McLean, and M. Lee Marsh
Publication:
Structural Journal
Volume:
95
Issue:
6
Appears on pages(s):
695-704
Keywords:
bridges (structures); columns (supports); ductility; earthquake-resistant structures; shear strength
DOI:
10.14359/583
Date:
11/1/1998
Abstract:
This investigation was conducted to investigate the flexural and shear performance of older columns for purposes of seismic assessment and retrofit design, particularly with regard to assessing the residual strengths present in degraded hinge regions. In this first part of a two-part paper, experimental observations and results of tests on eight reduced-scale specimens that incorporated deficiencies present in older bridge columns are presented. The columns were fixed against rotation at both the top and bottom to enable shear transfer, even after a flexural hinging region degrades. Test variables included column aspect ratio, longitudinal reinforcing ratio, lap splice length, and retrofitting detail. Shear failures were observed both outside and within the plastic hinge regions. In those specimens failing in flexure, plastic hinge regions with poor confinement and lap splices experienced rapid flexural strength degradation. However, the degraded spliced region continued to carry the shear and axial loads applied through the column.