Experimental investigation of FRP-strengthened tubular T-joints under axial compressive loads

• Experimental study proved the efficacy of strengthening tubular T-joints with FRP.
• Ultimate capacity enhancement resulted from FRP application on the tubular T-joint.
• The reinforced joint experienced a finely moderated state of stress and deflection.
• The FRP had a substantial contribution in load bearing without exhibiting failure.
• The saddle region and the ovalized areas were crucial in ply failure viewpoint.

This paper describes an experimental program conducted on steel welded tubular T-joints fabricated from circular hollow tube brace and chord members. In order to gain an understanding of the effect of the fiber reinforced polymers on the ultimate capacity, an experimental study has been conducted into the static behavior of axially loaded T-joints in compression and reinforced with FRP composites. The tests were performed by supporting the chord member of the specimen along its entire length with a compression force applied to the chord face by the brace member. Two tests were performed. The first test which served as the reference for comparison was an un-strengthened joint and the second test was an identical joint with FRP reinforcement. A typical glass/vinyl ester composite was used for wrapping the joint. The general test arrangement, specimen details, and most relevant results are presented. The experiments revealed a significant strength enhancement and improved joint behavior for the reinforced T-joint in comparison with the ultimate capacity of the corresponding unreinforced joint. A finite element analysis was also employed to validate the analytical results which in turn showed to have a good correlation and consequently the perfect bond numerical model was justified.