Experimental and parametric study on the post-fire behavior of tubular T-joint

One of the major hazards offshore is fire result from leakage of gas or oil. The aim of this work is to study the residual strengths of the T-joints after fire exposure and the influence of geometric parameter. The paper presents experimental and numerical results of the post-fire behavior of tubular T-joints. Three tests are carried out, in which one is under ambient temperature and the other two under heating and cooling phase. It is found that both experimental and numerical results demonstrate that the failure of the tubular T-joint is due to the local buckling of the Circular Hollow Section (CHS) joints, by which the finite element model is validated. The experimental and numerical results also indicate that the axial load level and the heating and cooling history have more significant effects on the compressive stiffness of T-joints than on the residual strength. The parameters, wall thickness ratio-τ, diameter ratio-β and chord diameter/thickness ratio-γ are chosen in the parametric analysis. It is indicated that the parameters, β and γ have more significant effects on load-bearing capacity of the T-joint than the parameter, τ, when the T-joint go through the same elevated temperature.

► The higher the axial load, the greater the residual deformation of the T-joints.
► The pre-load has no significant effects on the residual strength of the T-joints.
► Ratio-β and ratio-γ can be improve the residual strength of the T-joint.
► Ratio-τ has limited effects on. residual strength of the T-joint.