Numerically Simulated Structural Response of a Bearing Steel Frame with Joints of Varying Stiffness to Fully Developed Fire Conditions

The goal of this paper is to describe the qualitative and quantitative differences in the behaviour of a typical bearing steel frame substructure, as these differences manifest themselves through different translational susceptibility values describing horizontal loads on the other parts of the frame, and through different rotational susceptibility values for beam-tocolumn joints resulting from their distinct designs (and, consequently, distinct load resistance/stiffening, as a result of employing, or not employing, various types of stiffener ribs). [...]while this girt, although significantly weakened during the fire, is still able to transfer loads, the axial compression force that has been previously generated inside it dissipates completely and the girt enters the axial ten sion phase. [...]of all this, the degree of column bending gradually decreased, causing girt deflections to grow. [...]joints could not fully go through all stages of the internal force redistribution process, which was easily achieved by similar frames with more rigid joints.