Quasi-static analysis of biaxial voided slabs with openings

In this paper, 3D nonlinear finite element analyses (FEA) were conducted using the ABAQUS program to investigate the openings' influences on voided slabs' structural behaviors. In these FEAs, the quasi-static solution was adopted, and the concrete behavior was represented by the concrete damaged plasticity model (CDPM). CDPM parameters were calibrated versus voided slab's test results taken from the literature. The calibrated FEA model's efficiency to describe the opening effect was then verified by matching with external experimental observations of conventional slabs with openings. Finally, a parametric study was implemented, in which eleven slabs' models with or without openings were contrasted. The considered variables were the size, shape, arrangement, and location of openings. The FEA results showed that the openings adversely affected the mechanical properties of voided slabs, and they became more influential as the interrupted reinforcement bars due to openings increased. However, constructing the opening near the support far away from the zone of high flexural stresses resulted in slight deteriorations in the strength, stiffness, and toughness of voided slabs.