Flexural Behavior of Lightweight Aggregate Concrete Shear Walls with Boundary Element

This study examined the effects of the unit weight of concrete (${\omega }_c$) on the flexural performance of shear walls with different amounts ($A_{sh}$) 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 ${\omega }_c$ 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 ${\omega }_c$ or $A_{sh}$. Meanwhile, the confinement by transverse reinforcement in the boundary elements tended to decrease with a decrease in ${\omega }_c$, 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 $A_{sh}$. The current 2D nonlinear laminar approach can accurately estimate the overall flexural performance of shear walls made using different types of concrete.