Collapse Resistance of Composite Structures with Various Optimized Beam–Column Connection Forms

Steel–concrete composite structures are widely used in composite frame structures and super high-rise buildings. However, the lack of relevant building design standards to ensure their structural stability under extreme conditions has led to potential failures in beam–column connections due to excessive loads. These failures can trigger the progressive collapse of high-rise buildings, resulting in severe casualties. In this study, a comparative numerical analysis was conducted to evaluate the collapse resistance of composite structures in the event of a middle-column loss scenario, focusing on six commonly used beam–column connections. The results show that while the six connections exhibit minimal differences under normal operating conditions, they display significant variations when subjected to extreme loads. Furthermore, a design concept is proposed to enhance the collapse capacity of these structures, and its effectiveness is validated via analysis.