Experimental Studies On Seismic Behavior Of Corroded Squat RC Shear Walls Under Artificial Climate Environment

The buildings with large space in ground floor have been widly applied in ourcountry. However, the lateral stiffness of the ground floor is seriously weakened as theresults of the need of large space in the ground floor. As the bay and depth of thebottom frame are relatively wide, a certain amount of squat RC shear walls should berequired to improve the lateral stiffness. At present, both at home and abroad, study ofthe bearing capacity and seismic behavior of squat RC shear wall have made muchachievement, but they didn't consider the influence of environmental factors on thecomponent durability. In coastal areas, the internal rebars of RC components arecorroded by the salt fog environment, which causoing a series of performancegradation and damaging to the structure reliability severely.Based on the six squat RC shear walls subjected to different degrees of salt fogcorrosion with low reversed cyclic loading, studying the degraded rule of the seismicperformance index of corroded squat RC shear walls under artificial climateenvironment, including strength, stiffness, ductility and energy dissipation, with thedifferent axial compression ratio and the various corrosion degree of internal rebar. Theresearch demonstrates that with the axial compression ratio increasing, the bearingcapacity and stiffness of corroded components increase, while the ductility and energydissipation capacity descend. As the corrosion degree of internal rebar increasing, thebearing capacity and ductility of the components drop, the stiffness degradationaggravates gradually, and the energy dissipation capacity decrease constantly.Determining the restoring force model is the basis of the structural elastic-plastic seismic response analysis. The restoring force model considering the influences ofenvironmental factors differs from intact component obviously. According toexperimental data analysis, the corroded squat RC shear wall's skeleton curve issimplified to tri-linear model without considering the decline part, the skeleton curveformula of feature points is obtained by fitting which considering the influence of theaxial compression ratio and the reinforcement corrosion rate of transverse distribution.Based on the modified vertex point type of restoring force model, taking strength andstiffness degradation into account, the calculation formulas of unloading stiffness andstrength degradation are built, and the corresponding hysteresis rules are put forward,the restoring force model of corroded squat RC shear wall is established under salt fogenvironment. Finally, the drawing steps of calculated hysteresis curve are given, andthe calculated hysteretic curve and test hysteretic curve are compared. The results showthat the presented restoring force model has good applicability and can accuratelydescribe the restoring force characteristics of corroded squat RC shear wall underreversed cyclic loading.