Flexural tests on composite basement walls with socket-type shear connectors

This study examined the effect of a developed socket-type shear connector (SSC) on the flexural behavior of a composite basement wall. Twelve composite basement walls (CBW) composed of cast-in-place piles (CIPs) produced with H-shaped steel beams or reinforcing steel bars were prepared by varying the arrangement method and amount of SSC. Two-point loading was applied to simply supported CBW specimens. The test results showed that the CBW specimens with higher amounts of SSC had a higher effective stiffness in the elastic state and moment capacity in the ultimate state, irrespective of the cross-sectional details of the CIP. These trends were particularly prominent for the CBW specimens when SSC used a reinforced steel plate. The post-peak behavior of CBW specimens subjected to a simulated load with a negative external moment, in particular, tended to be more ductile. Consequently, a higher degree of composite action was fully exerted on the composite walls with higher SSC amounts. The nominal partially composite-to-full composite flexural capacity ratios (Mpc/Mfc) of the CBW specimens subjected to the simulated loads with positive and negative external moments can be calculated as 0.83 and 0.91, and 0.79 and 0.90, respectively, at 0.5 and 0.75ηsc using established equations for the sectional details of CBWs with SSC, where ηsc is the normalized shear connector capacity specified in AISC 360-16.