Testing and analysis of composite floor systems under peripheral column removal scenarios

This paper presents an experimental study on the behaviour of a composite floor system with end-plate connections under a peripheral column removal scenario. The floor system comprised bridging beams, peripheral supporting columns and concrete floor with profile decking. In the specimen design, end-plate connections were used for the primary beam-column joints, and bolted web connections were adopted for beam-beam joints. Due to the constraints in structural laboratory, the two-bay by one-bay floor was scaled down to a 1/3 scaled model. A special loading scheme was designed so that displacement-controlled six-point loads were applied to the floor in order to represent uniformly distributed loads on the floor. Test results showed that the floor system could develop tensile membrane action to prevent progressive collapse. However, with increasing vertical displacement, the endplate at the beam-column joints fractured and the concrete in the composite floor was crushed. In the end, conclusions were drawn to shed light on the design of composite floor systems against progressive collapse.