Elevated temperature resistance of welded tubular joints under axial load in the brace member

Results of the numerical simulation were compared with calculation results using the design equations in Eurocode EN 1993-1-2 [3] and CIDECT design guide [16] but replacing the yield stress of steel at ambient temperature by those at elevated temperatures. It is found that for gap K- and N-joints and for T-, Y- and X-joints with the brace member under axial tensile load, this approach is suitable. However, for CHS T-, Y- and X-joints under brace compression load, this method overestimates the ultimate load carrying capacity of the joint. In fact, for these situations, the joint strength reduction at increasing temperatures follows more closely the reduction in the elastic modulus of steel at elevated temperatures.