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

Abstract

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. software that can be used for moment curvature, force deflection and axial force bending moment analysis for a reinforced concrete member under various loading conditions. Tab. 6 presents the experimental observations at the end of particular cycles for each specimen reported in Acun (2010) and Figure 14. Increments of damage index under each cycle for specimen (a) 1D2, (b) 2D3, (c) 3D4, (d) 4D5, (e) 5DV1 and (f) 6DV2.

Effects of variation in loading protocol on the strength and deformation capacity of ductile reinforced concrete beams

“…The monotonic test was able to sustain its lateral load carrying capacity at upward of 15% drift, at which point the actuator reached its stroke limit and the test had to be stopped. Similar discrepancies between monotonic and cyclic tests have been obtained for reinforced concrete columns in previous test programs . However, the decay in lateral stiffness or resistance of specimens CYC and CYC‐NOEQ were similar despite the differences in loading protocol.…”

“…Similar discrepancies between monotonic and cyclic tests have been obtained for reinforced concrete columns in previous test programs. 12,14,34 However, the decay in lateral stiffness or resistance of specimens CYC and CYC-NOEQ were similar despite the differences in loading protocol. This limited effect of the number of loading cycles below 2.2% drift is further investigated in the following analysis by considering the other test specimens.…”

Experimental tests for improving buildability of construction methods for high‐strength concrete columns in high‐rise buildings

“…However, because high‐strength concrete columns have high compressive strength, they can show brittle fracture behaviors depending on the method of reinforcement that is used. Therefore, verifying that the columns used in construction have sufficient stiffness and deformation capacity is extremely important . In addition, when high‐strength concrete is used for construction of high‐rise buildings, it is difficult to weld the steel reinforcement and steel members because of the narrow column width due to a decrease in the cross‐section of the column, thereby causing construction delay in many cases.…”

Data‐driven modeling and prediction on hysteresis behavior of flexure RC columns using deep learning networks

“…According to engineering knowledge, structural hysteresis behavior is of great value in structural seismic performance. The corresponding restoring force curve is the straightforward means to comprehensively reveal the nonlinear mechanical properties and energy dissipation characteristics of structural components and substructures 6–8 . Some model‐based methods have been employed to simulate and predict the RC members hysteresis behaviors for damage detection and prognosis 9 .…”