Simplified Simulation of New Load-Bearing Cold-Formed Steel Composite Walls with Two Failure Modes Under Fire Condition

New cold-formed steel composite walls with composite panels have replaced the conventional cold formed steel walls. Not a cavity insulation, but insulation sandwiched between two panels. The new composite wall has two failure modes. One is thermal bending buckling resulting from non-uniform temperature distribution, and the other is local buckling in the hot flange due to rapid reduction of mechanical properties. To evaluate the fire resistance of the new composite wall, it is necessary to simulate two types of failure modes. Therefore, simplified model with considering the axial constraint provided by lining board and method of modified linear expansion coefficient are proposed in this paper. Feasibility of the above two methods are verified by existing fire test, and the detailed modeling process in the finite element software is described. For new composite walls, two simulated methods should be combined considering to evaluate the fire resistance.