Seismic Performance of Concrete-Filled Tube Column-Reinforced Concrete Slab Connections with Shearhead Keys

摘要

A combination of concrete-filled tube (CFT) columns and reinforced concrete (RC) two-way slabs (or RC flat plate systems with replacement of RC columns with CFT columns) has been developed to further enable rapid construction. This study presents full-scale cyclic test results of three CF7'column-RC slab connections and one conventional RC slab-column connection. Structural steel sections, often called shearheads by the American Concrete Institute, were welded to the CFT columns as keys for vertical interface shear transfer as well as partial punching shear reinforcement for slab-column connections. One CFT column-RC slab connection specimen was additionally reinforced by shear bands. Overall seismic performance of the tested CFT column-RC slab connections and RC slab-column connections was experimentally evaluated. The CFT column-RC slab connections exhibited larger lateral strength and deformability as well as better flexural transfer capacity and energy dissipation than those of the RC slab-column counterpart. The previously developed design equation for punching shear strength at the inner critical section has been proven to be reasonable for various cases with gravity and/or lateral loads.