Effect of the axial compression ratio on the seismic behavior of resilient concrete walls with concealed column stirrups

The axial compression ratio is one of the important factors affecting the seismic performance of reinforced concrete (RC) walls. Thus, the axial compression ratio is critical in the seismic design of RC walls. In addition to the axial compression ratio, the other significant experimental parameter is the stirrup form of the boundary elements. To study the effect of the axial compression ratio and the stirrup form on the seismic behavior of ductile RC walls reinforced by prestressed concrete strands, four full-scale concrete walls were constructed and subjected to reversed cyclic lateral loading while experiencing constant axial compression, with axial load ratios set at 0.17 and 0.26. The considered stirrup forms of the boundary elements are circular and compound, respectively. All specimens exhibit significant drift-hardening capability with a small residual drift and a small crack width. The ultimate capacity, ductility, stiffness and attenuation process, hysteretic characteristics, energy dissipation capacity, residual deformation, and maximum and residual crack width of the shear walls are compared and analyzed. The experimental results and comparisons between the two groups of shear walls with different axial compression ratios and stirrup forms of concealed columns are presented. The characteristics of the envelope curve are also analyzed, and a simplified bilinear envelope curve model is proposed to better fit the test results.