Effect of Reinforced Opening on Punching Shear of Flat Slab

Opening is inevitable in structural slab. Consequently, the punching shear capacity remarkably reduces, and becomes more crucial for Flat Slab. Subtracting the control perimeter, adding shear reinforcement, increasing slab thickness are the treatment method written in building design code on matter relating the opening within slab. The presenting thesis addresses the variation in punching shear capacity of Structural Flat slab due to the open at the critical zone adjacent to the column. This study conducted on the simulation of 3D FEM in software ABAQUS. A 3D FEM of reinforcement concrete slab was created and calibrated base on the sample of SB1. Opening, which is creating negative effect to the slab punching shear capacity, is later reinforced either by flexural rebar or beam reinforcement to investigate the mechanical performance variation of structural flat slab in term of punching shear capacity. Conforming to the statement of ACI, PCA, and EC2, the FEA results indicate the drop of structural slab’s performance once there is the opening adjacent to column. Reinforcing the Opening by deformed rebar does contribute to punching shear capacity and the level of contribution varies based on the reinforcement type, length, and quantity. Deformed rebar reinforcing as the flexural reinforcement type increases the capacity proportional to the embedment length of rebar yet the amount of rebar exceeding the interrupted rebar by the opening contributes less to punching capacity. The contribution in punching shear capacity of the flexural reinforcement case tends to reach a constant value once the embedment length of rebar reaching the tension development length limited by ACI code. However, comparing to the case of having no opening, the contribution could not compensate the lost attribute in punching shear capacity due to the opening. As for one direction of beam reinforcement case, the beam’s rebar perpendicular to column provides better result than the parallel direction. Both cases of one direction reinforcing contribute to punching shear capacity less than the case of two-direction reinforcing. Based on the proposed opening dimension in the thesis, there is only the two-direction reinforcing that could compensate the lost attribute due to the opening. Moreover, the simulation also illustrates the exceeding punching shear capacity contribution with the two-direction beam reinforcing type. However, the increasing of punching shear capacity in this case does not exceed the maximum punching capacity of slab with reinforcement limited by the ACI and EC2