Experimental and analytical investigation of new concrete filled FRP tube beam-column connections

•A new CFFT beam-column connection is investigated experimentally and analytically.•The experimental optimal embedded depth is two times the depth of the CFFT beam.•The flexural capacity of CFFT and failure mode were estimated using design equations.•Bond-stress distribution approach is proposed to estimate the optimal embedded depth.•The calculated optimal embedded depth was in a good agreement with the experimental. Researchers have extensively investigated the behavior of concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs) as beams or columns individually, while the beam-column connections of such elements remain to be investigated. The current study is focused at developing and investigating a simple and practical CFFT beam-column connection. The proposed connection is made of a steel connection to connect the CFFT beam to the CFFT column. The steel connection is attached to the CFFT beam using a high-performance epoxy cement-grout between the HSS tubing and the CFFT beam. The steel connection is fixed to the CFFT columns using eight high-strength bolts. Four different lengths of the steel connection are tested to study the required embedment length of the CFFT beams inside the HSS tubing. The experimental results show that the optimal embedment length required to induce flexural failure of the CFFT beam is two times the depth of the CFFT beam (i.e. FRP tube depth). Analytical equations are developed to calculate the flexural capacity of the CFFT beam and estimate the optimal embedment length required to achieve its nominal flexural capacity.