Research Of Seismic Performance And Hysteresis Model Of Corroded Stirrups Confined Concrete Members With Flexure And Compression

Stirrup corrosion causes not only its own section decrease and Mechanicsperformance degradation, but also concrete cover cracking damage. The reducing ofability of corroded stirrups confining concrete causes component ductility reducing andseismic performance degradation. Based on the theoretical analysis and experimentalresearch methods, this article made a systematical study of seismic performance ofcorroded stirrups confined concrete members, mainly including the following content:This article made four concrete members with flexure and compression,electricity accelerated corrosion test was carried on to three of the four members. In thetest, the stirrups corroded seriously nonuniform, stirrups in the corner area corrodedseriously while the straight section corroded slightly. The corrosion product of not fullyoxidation exudated to specimens surface through concrete micropore. The quantity ofcorrosion product is proportional to the corrosion degree of stirrups. The corrosionproduct expansion caused concrete cover cracking, and crack were distributed alongthe longitudinal reinforcement direction in the specimens’corner part.Through the low repeated loading experiments of three corroded members andone non-corroded member, the influence degree of stirrups corrosion quantity tomembers’ failure process, failure form, hysteresis performance and energy dissipationcapacity were analyzed. The results showed that, due to the reducing of corrodedstirrups constraint function to concrete, the members’ seismic performance degradated; with the increase of stirrups corrosion quantity, the limit displacement decreased whenmembers damaged, the knead-approach-phenomenon in hysteresis curve was obviousgradually. The degree of strength reducing and stiffness attenuation increased, ductilityand enerty dissipation capacity reduced.Considering the influence of stirrups corrosion to the feature points of D-TRIhysteretic model, through the regression analysis of experiment data, the correspondingrelation of stirrups corrosion rate and yielding shear and yielding displacement, limitshear and limit displacement, failure shear and failure displacement of corrodedmembers and non-corroded member was established, the calculation formula ofhysteresis model of corroded stirrups confined concrete members with flexure andcompression was determined preliminarily.