Parametric study on hysteretic behavior of doubler plate-reinforced tubular T-joints after fire exposure

Abstract

To ensure the structural safety after fire exposure, the behavior of strengthened tubular joints needs to be studied. The finite element (FE) method is an effective tool for the research. In this paper, the hysteretic behavior of tubular T-joints reinforced with doubler plates after fire exposure is studied. To establish a reference point, a doubler plate-reinforced tubular T-joint specimen after exposure to fire was tested to failure under the cyclic axial loading at the brace end. The failure mode of the specimen was the cracking along the weld toe at the intersection of the doubler plate and brace. The experimental hysteretic curve and skeleton curve were compared with the FE results and good agreement was obtained. Thus, the FE method was verified and could be used to study the post-fire hysteretic behavior. A comprehensive parametric study was then conducted by varying different geometric parameters. It was found that parameter ε had little influence on the post-fire hysteretic behavior. On the other hand, the joints with a large γ or small β or ξ had a low capacity for post-fire hysteretic behavior.