Structural Behaviour of Voided Flat Slab With Various Void Ratios Under Vertical Loading

In recent modern buildings, voided slabs have been implemented because of the high reduction of their weight up to 35 %. Also, CO₂ emission takes place which was developed from mass concrete. Due to percentage reduction of concrete, it leads to help the pollution free environment, eco-friendly and also more sustainable. On voided flat slabs, a minimal study has been recorded. In this current study, an approach has been made to study the effect of the position of voids in the voided flat slabs. Two groups of seven specimens each, one slab in each group was a controlled flat slab specimen with zero number of voids kept as a reference specimen, while the others were voided slabs. In each group, the number of voids were used based on the positions. The designation of the specimens is made depending on the number of voids placed and the diameter of the rebar used in the specimens. Group-A was reinforced with 8 mm diameter rebars, and Group-B was reinforced with 6 mm diameter rebars. The parameters of the study are the void positions and the rebar diameter. The specimens were subjected to a gradually concentrated load through the short column up to failure. The load carrying capacity of both voided and controlled flat slabs tested have almost same. It indicates that, the inactive concrete below the neutral axis where high density polyethylene (HDPE) recycled hollow spheres have been provided in the flat slab has shown no impact on load carrying capacity of the test specimens. However, the presence of the punching shear can be seen in the specimens where the voids are positioned near the columns and supports. Besides, ABAQUS program (A finite element based software) was used to perform the finite element analysis for profoundly illustrating the experimental findings and performing a parametric study. It is concluded that the concrete has no role at below the neutral axis of structural voided flat slab cross-section for all specimens including controlled specimens (0VS6, 0VS8). Also, it is noticed that the finite element analysis obtained results have shown more or less same as experimental results. From the present study, it is evident that behaviour of voided flat slabs are different from simply supported voided flat slabs.