Flexural Behavior of Lightweight Aggregate Concrete Shear Walls with Boundary Element

Abstract

This study examined the effects of the unit weight of concrete (ωc) on the flexural performance of shear walls with different amounts (Ash) of transverse reinforcement in the boundary elements. Six shear wall specimens with barbell-shaped cross sections were tested up to failure under a constant axial load and cyclic lateral loads. Backbone curves determined using the cyclic lateral load–displacement of shear walls were compared with predictions obtained using the two-dimensional (2D) nonlinear laminar approach to examine the effect of ωc on the confinement pressure provided by the transverse reinforcement. The test results indicated that lightweight aggregate concrete (LWAC) shear walls exhibited a smaller displacement ductility ratio and cumulative work damage indicator than their normal-weight concrete (NWC) shear wall counterparts. The conservatism of the ACI 318-19 approach using the equivalent stress block for estimating the moment capacity of shear walls was somwhat affected by ωc or Ash. Meanwhile, the confinement by transverse reinforcement in the boundary elements tended to decrease with a decrease in ωc, which resulted in earlier damage to the longitudinal reinforcement and a faster reduction in the applied load at the post-peak performance for LWAC shear walls than for NWC ones with the same Ash. The current 2D nonlinear laminar approach can accurately estimate the overall flexural performance of shear walls made using different types of concrete.