Analysis of the punching behavior of RC flat slabs with horizontal and vertical shear reinforcement

Abstract

Punching failure is one of the major drawbacks of using flat slabs in the design of reinforced concrete structures. Punching shear analysis is very complicated which appears clearly in the large variation of the equations used by the different codes in calculating the punching shear capacity. There are many factors that affect the punching shear capacity of an element. This current research aims to investigate the contribution of two of these factors which are the horizontal flexural reinforcement, and the vertical shear reinforcement in the form of stirrups. Following the experimental program conducted at the reinforced concrete laboratory of the Faculty of Engineering at Cairo University, Egypt and verification using the finite non-linear analysis software (ANSYS 15), good correlation was observed between the analytical models and their corresponding experimental data. This proves that ANSYS 15 allows for studying the punching behavior of the flat slab in more details which could not be monitored in the laboratory. As a result, a detailed parametric study as well as comparison with some design codes was conducted using thirteen full scale flat slab specimens in order to simulate real life problems. The specimens had a loaded span of 2000 mm and a total thickness of 250 mm. The variables under study were the flexural reinforcement ratio and stirrups spacing and diameter in order to further enhance the understanding of the behavior of flat slabs in punching.