Enhancing the blast resistance of steel frame connections through design optimization

This study investigates the performance of steel frame connections subjected to blast loading using finite element analysis (FEA). The yield line theory was employed to design the connection end plate, and nine different connection configurations were analyzed by modifying the base model. These configurations explored variations in end plate thickness, bolt diameter, and the presence of stiffeners and doubler plates. The significance of this research lies in its potential to improve the safety and resilience of structures against blast loads, which are critical for protecting infrastructure and human life in extreme events. The results revealed that the base model exhibited a brittle failure mode with a maximum displacement of 210 mm and failure through bolt shearing and end plate rupture. Increasing the end plate thickness in Model 2 eliminated end plate failure but led to bolt yielding. Models incorporating stiffeners (Models 4 and 5) improved energy absorption but caused stress concentrations in the column, while doubling plates in Model 7 enhanced energy absorption in both the beam and column, mitigating bolt failures and achieving a balance between strength and ductility. Compared to the Model 1, Models 7, 8, and 9 demonstrated superior performance in reducing the column's proportion of the total energy absorption, with a reduction in plastic deformation energy absorption by the column (ratios of 0.37, 0.28, and 0.27, respectively) compared to the base model (0.4). Moreover, the results provide actionable insights for developing blast-resistant steel frame design guidelines, particularly emphasizing the integration of doubling plates and stiffeners to enhance safety and resilience. This work has significant implications for improving the performance of steel structures in critical infrastructure applications.