Effect of opening size and location on punching shear behaviour of two-way RC slabs

The effects of opening size and location on the punching shear behaviour of two-way reinforced concrete (RC) slabs were investigated. The experimental study was carried out on eight experimental specimens with openings at different variable locations and a reference specimen with no opening. Two-way square slabs (2000 x 2000 x 120 mm) were tested by applying an axial load from the top of a square column (200 x 200 mm) located at the centre of the slab specimen. The test specimens studied had different opening sizes (300 x 300 mm and 500 x 500 mm) and locations: each size of opening was positioned in parallel and diagonal locations adjacent to the column and 300 mm from the column. The effects of varying size and location of openings on the punching shear behaviour of two-way RC slabs were interpreted by examining the slabs' bearing capacities, stiffnesses and energy consumption capacities obtained from test results. The load-carrying capacities of the test specimens were calculated using the equations of ACI 318, Eurocode 2 and TS 500 and the values were compared with experimental results. In addition, the accuracy of the code equations in predicting the load-carrying capacity of the test specimens was assessed. The test results indicate that the punching shear resistance decreases with an increase in opening size and it notably decreases for openings adjacent to the column compared with openings located away from the column.