Experimental and numerical investigations on the collapse behaviour of RC flat slab structures

It has been well recognized that reinforced concrete (RC) flat slab structures are prone to collapse under their heavy-weight following an initial failure such as a punching shear failure that happened at a slab-column connection and column removal. In this study, the collapse behaviour of such building structures is investigated both experimentally and numerically. In the experimental part, a 1/3-scale flat slab structure is statically tested to complete collapse using distributed weights to examine the formation and development of alternative load paths over a local failure. The obtained experimental data then are used to validate LS-Dyna numerical models, which enable a parametric study on the collapse resistance of flat slab structures with several variables of interest, including the aspect ratio of slab panels, the locations of initial column failure, the concrete strength and slab reinforcement ratios. It is numerically shown that the aspect ratio has significant effects on the collapse behaviour with the highest collapse resistance attributed to the flat slab with square panels. Meanwhile, the corner column loss is the most critical scenario leading to a structural collapse.