Progressive collapse mode induced by slab-column joint failure in RC flat plate substructures: A new perspective
Zhi Yang, Xuekang Guo, Yi Li, Hong Guan, Mengzhu Diao, Junkun Wang, Wenjun Huang
Abstract
Majority of progressive collapse incidents of concrete flat plate structures were caused by slab overloading in the form of punching shear failure at a slab-column joint, which exhibit distinctive resistance mechanism from those triggered by column losses. Relevant studies on the slab overloading scenario are scarce. To fill this gap in research and to broaden the perspective on different collapse modes, an experimental test was conducted on a 1/3-scale 2 × 2-bay flat plate substructure specimen by applying an increased downward uniform load on the slab, until the structure was completely damaged following the initial punching shear failure at the interior slab-column joint and was unable to take any further load. In addition, the flexural capacity of the specimen was evaluated using the yield line theory, and an analytical model was also proposed to estimate the post-punching peak load of the specimen. Finally, the experimental results obtained from this study were compared to those of a similar test under an interior column removal scenario. Comparisons indicate that the specimen under the slab overloading scenario displays better collapse resistance than that under the column removal scenario. Nevertheless, the residual resistant capacity of the overloaded specimen may not be adequate enough to prevent the collapse of the entire structure after the initial punching failure.