Shear strength of interior beam–column joints with lightweight aggregate concrete

Abstract

Lightweight aggregate concrete (LWAC) elements can effectively reduce dead load and improve the seismic resistance capacity of building structures. However, the shear performance of LWAC remains questionable due to its specific brittle failure mechanism. In this work, four one-third-scale LWAC interior beam–column joints were prepared and tested under reversed quasi-static cyclic loading. Two levels of axial compressive forces and joint transverse reinforcement ratios were considered for each specimen to quantify and analyse the shear performance of LWAC joints. The test results indicate that all LWAC specimens experienced shear failure at the joint core and presented satisfactory shear resistance capacity in terms of shear strength, displacement ductility, stiffness degradation and energy dissipation compared to normal-weight concrete (NWC) specimens. The test results were used to examine the applicability and accuracy of six shear design models based on the behaviour of NWC elements for LWAC beam–column joints. A comparison of the results indicated that there is no apparent difference between the ultimate shear strengths of LWAC and NWC specimens, and all six previously proposed shear equations examined can accurately predict the ultimate shear strength of LWAC interior beam–column joints.