Analytical investigation of the influence of various void shape and spacing on the load-bearing behavior of concrete hollow core slabs

The self-weight of a structure is of great importance as it directly affects the cost of the structure. With concrete slabs being one of the biggest and heaviest structural members in buildings, it is essential to devise novel ways to reduce the self-weigh of slabs without significant reduction in the load-carrying capacity. One of such solutions that can be used to reduce the self-weight of slabs is the use of hollow-core slabs. In addition to the reduction in self-weight with the use of hollow-core slabs, a reduction in the cost and workmanship associated with the production of the slabs can be achieved. In this context, this analytical study was carried out to investigate the effect of various void shapes and spacings on the load-bearing behaviour of hollow-core slabs using the Finite Element Analysis (FEA) program ANSYS. Slabs with a uniform dimension of 2600 mm × 1200 mm × 140 mm with the same reinforcement are designed with various void shapes of the same area of 1963.5 mm 2 (Group 1) and spacing (Group 2). The outcome of this study showed the presence of hollows in the slabs resulted in a reduction in the load-bearing capacity of the slabs. Nonetheless, the use of elliptical void shape was found to be optimum among other shapes and increasing the void spacing to 120 mm can be used to increase the capacity of the slabs. On a positive note, the presence of voids in the slabs resulted in a reduction in self-weight in the range of 9.2%–15.1%.