Experimental study on cyclic shear behavior of low-aspect-ratio prestressed concrete walls under variable axial tension- compression forces

In order to investigate the seismic behavior of prestressed concrete (PC) walls, the loading protocol of the shear walls subjected to variable axial tension-compression forces and cyclic shear loading was proposed. Quasi-static cyclic shear loading tests were conducted on three prestressed concrete walls that had the shear-to-span ratio of 1.0, where one specimen was under a constant axial tensile force, another under a constant axial compressive force, and the other under variable axial tension-compression forces. The failure modes, hysteretic responses, strength, deformation capacity, lateral stiffness, and residual crack width of PC wall specimens were investigated, and they were compared to those of the steel reinforced concrete (SRC) wall and reinforced concrete (RC) wall. The test results indicate that the PC wall specimen under a constant axial tensile force failed in web shear failure mode, the wall under a constant compressive force failed in diagonal compression failure mode, and the wall under variable axial tension-compression forces failed in shear compression failure mode. The variable axial tension-compression forces decrease the tensile-shear strength and compressive-shear strength of the PC wall specimens by 18.7% and 10.5%, respectively. The PC wall specimens under the constant axial tensile force and variable axial tension-compressive forces have the ultimate drift ratio ranging from 1.2% to 1.6%, which exceeds the inelastic drift limit of 1/100 specified in the Chinese technical specification for concrete structures of tall buildings (JGJ 3-2010). Because the PC wall specimen with the constant axial compressive force had the maximum shear load exceeding the upper limit of the wall's shear strength, it failed in diagonal compression failure at a small ultimate drift ratio of 0.6%. The PC wall specimen has similar lateral stiffness, strength, and deformation capacity as the SRC wall specimen. The former has smaller residual crack width than the latter, indicating superior reparability of PC walls. Because the prestressed force controls the development of thorough horizontal cracks and prevents the shear sliding failure along the horizontal cracks, the PC wall specimen with high axial tensile force has significantly larger lateral stiffness and strength than conventional RC wall specimen. In general, the PC walls show excellent seismic behavior and thus can be used as an effective approach to improve the seismic performance for walls subject to tension load in high-rise buildings. © 2022, Editorial Office of Journal of Building Structures. All right reserved.