The American Concrete Institute (ACI) presented results of three concrete-filled tube (CFT) column and reinforced concrete (RC) slab connections and one conventional RC slab-column connection.
Seismic Performance of Concrete-Filled Tube Column-Reinforced Concrete Slab Connections with Shearhead Keys says a combination of CFT columns and RC two-way slabs (or RC flat plate systems with replacement of RC columns with CFT columns) have been developed to further enable rapid construction.
Structural steel sections (shearheads) were welded to the CFT columns as keys for vertical interface shear transfer as well as partial punching shear reinforcement for slab-column connections.
ACI says one CFT column-RC slab connection specimen was additionally reinforced by shear bands. Also, the overall seismic performance of the tested CFT column-RC slab connections and RC slab-column connections was 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," ACI adds.
This paper was written by Cheol-Ho Lee, Thomas H.-K. Kang, Jin-Won Kim, Jin-Kyu Song, and Sanghee Kim.
