Punching shear strength and post-punching behavior of CFT column to RC flat plate connections

This paper summarizes full-scale test results on CFT (concrete filled tube) column to RC (reinforced concrete) flat plate connections subjected to gravity loading. CFT construction is gaining wide acceptance due to its various structural and constructional advantages. However, efficient details for CFT column to RC flat plate connections have not been proposed yet. Based on the strategies that maximize economical field construction, several connecting schemes were proposed and tested in this study. Test results showed that the proposed connections can exhibit punching shear strength and connection stiffness exceeding those of RC flat plate counterparts. A semi-analytical procedure is presented to model the behavior of CFT column to RC flat plate connections. The parameters needed to model the behavior from elastic to post-punching range are calibrated based on the test data of this study. The application of the proposed model to progressive collapse analysis is also illustrated.