Flexural behavior of clad rack beam-to-column bolted connections at high temperatures

The fire resistance of beam-to-column connections affects the safety of clad racks under fire conditions. However, existing research lacks studies on the behavior of these special connections at high temperatures. This study investigates the fire resistance of clad rack beam-to-column bolted connections (CRBCs). Firstly, single cantilever tests of CRBCs at temperatures of 20 °C, 300 °C, 400 °C, 500 °C, 600 °C, and 700 °C are carried out. The failure modes of the CRBCs at 600 °C and below are identical to that at ambient temperature, while the failure mode at 700 °C is different. The stiffness and strength of the CRBCs decrease with the increasing temperature. Subsequently, an FE model considering the high-temperature metal fracture is established, which can accurately simulate the typical failure mechanisms and satisfactorily predict the full range moment-rotation behavior of CRBCs. Furthermore, parametric analyses are conducted to investigate the influences of related parameters on the failure mechanism, initial rotational stiffness, and flexural capacity of CRBCs. Finally, theoretical models based on the component method are established for calculating the initial rotational stiffness and flexural capacity of CRBCs at high temperatures, respectively. The comparison of the theoretical model, experimental results, and numerical results indicates that the theoretical model can accurately calculate the mechanical properties of CRBCs at high temperatures. The findings of this study can provide a reference for the analysis and design of the fire resistance of clad rack structures.