Study on the fire damage of air-supported membrane structures considering the combustion performance of welded seams

In recent years, research on the air-supported membrane structures in fire scenarios mainly focused on the high-temperature mechanical properties of materials. In contrast, combustion performance and pyrolysis failure of material and welded seams received little attention. In this paper, combustion tests were first conducted to determine damage times and damage temperatures of welded seams and membrane materials. Subsequently, based on the kinetic solution method for the pyrolysis equation, a parameter estimation method was proposed to acquire the empirical values of key pyrolysis parameters for welded seams, including heating rate, the reference temperature, the pyrolysis range, the specific heat capacity, and the coefficient of thermal conductivity. The effectiveness of this method was also verified by test data of membrane material. The pyrolysis parameters calculated by this method demonstrated high consistency with experimental results, with the difference in damage time being no >10 s. Finally, a structural fire simulation was performed, incorporating the presence of welded seams and their pyrolysis parameters into the model, significantly improving the correlation between the numerical model and actual structures. The simulation analysis revealed that when the heat source is close to the membrane surface or has high power, the roof experiences pyrolysis-controlled failure, with the welded seams being damaged before the membrane material. It will rapidly reduce the internal pressure and increase the risk of structural collapse. Therefore, the fire protection design of air-supported membrane structures should focus on slowing down the rise in temperature of the roof (especially at the lap welded seams).