Cumulative seismic damage assessment of reinforced concrete columns through cyclic and pseudo-dynamic tests

Abstract

Summary This paper presents the findings of a systematic experimental study conducted to investigate cumulative seismic damage in reinforced concrete columns. Fourteen identical large-scale concrete columns were fabricated and tested to failure. Experimental tests were conducted in two phases. Phase I testing included benchmark tests to characterize the monotonic force-deformation behavior and constant amplitude tests to determine the low-cycle fatigue characteristics of typical flexural columns. Phase II involved testing of concrete columns under a series of earthquakes of varying duration and magnitude. Low-cycle fatigue of the longitudinal reinforcing bars and confinement failure due to rupture of the confining hoops were the main failure modes in phase I. Phase II 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. A fatigue-based damage model is proposed based on the data obtained from the constant amplitude tests of phase I. The damage prediction of the model is assessed by using the response of three specimens tested in phase II and the data from the cyclic tests of six reinforced concrete columns reported in the literature. Results show that the proposed fatigue-based damage model offers a reliable means of assessing seismic structural performance. Copyright © 2016 John Wiley & Sons, Ltd.