Static Strength of T-Joints Reinforced with Doubler or Collar Plates. I: Experimental Investigations

One of the alternatives to enhance the strength of a tubular joint involves the application of doubler or collar plates as reinforcement. In order to gain understanding of the effect of plate reinforcement on the ultimate capacity, an experimental study has been conducted into the static behavior of axially loaded T-joints reinforced with a doubler plate or collar plate. The parameters investigated involve the type of loading (i.e., tension or compression), the configuration (unreinforced, collar plate reinforced, or doubler plate reinforced), the brace-to-chord diameter ratio (beta), and the chord diameter-to-chord wall thickness ratio 2(gamma). The general test arrangement, specimen details, and most relevant results (failure mechanism and load-deformation relationships) are presented. The experiments reveal a significant strength enhancement for both types of reinforced T-joints in comparison with the ultimate capacity of the corresponding unreinforced joints. The results of follow-up finite element simulations on plate reinforced joints are reported in a companion publication.