Seismic behavior of slender prestressed reinforced concrete short-leg walls

Abstract

To reduce the possible adverse effects of axial tensile force on reinforced concrete (RC) walls, bonded prestressed concrete (PC) walls are recommended for use in high-rise buildings. These could offer an initial axial compressive load to balance the possible axial tensile force of a RC wall induced by strong ground motions. In this study, three PC short-leg walls with a high-aspect-ratio of 2.0 were tested for various loading patterns, including constant axial forces and variable axial forces, combined with cyclic shear loading. Test results indicated that failure modes varied with loading patterns, including flexure-shear failure (coupled constant axial tension and cyclic shear loading), shear compression failure (coupled constant axial compression and cyclic shear loading), and flexure failure (coupled variable axial forces and cyclic shear loading). Variable axial forces led to the normalized tension-shear strength and compressive-shear strength of PC short-leg walls decreasing by 8.5% and 9.1%, respectively, and the tension-shear ultimate ratio decreasing by 35%. The ultimate drift ratio of PC short-leg walls ranged from 1.8% to 3.7%. Variable axial loads decreased the pre-yield secant stiffness in tension-shear and compression-shear loading, while the influence on post-yield secant stiffness was less pronounced. Variable axial forces did not increase the maximum crack width of PC short-leg walls, but clearly decreased the accumulated energy of PC short-leg walls as they changed the shape of hysteretic curves. Finally, a finite element model of PC short-leg walls was developed and the accuracy of the model was evaluated using experiment results, including its hysteretic characteristics and lateral displacement profiles.