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Title: Concrete Flat Plates of Optimum Thickness: Serviceability and Strength—Part II: Strength

Author(s): Ramez B. Gayed and Amin Ghali

Publication: Symposium Paper

Volume: 353


Appears on pages(s): 164-180

Keywords: concrete slabs; critical section; design; flat plate; flexure; punching shear; reinforcement ratio; yield-line.

DOI: 10.14359/51737117

Date: 7/1/2022

The optimum thickness of a concrete flat plate is the best or the most favourable for an objective. The most common objective is often miuimum cost; however, it can also be noise insulation, least vibration or plane soffit, with or without beams or drop panels. The minimum cost is often achieved by the smallest thickness that avoid excessive deflection in service. With small thickness, reinforcement is commonly needed for safety against shear failure. Part II: Strength, presents the design of shear and flexural reinforcements to resist punching shear of slabs whose thickness has been decided. Slabs directly supported on columns without beams or column heads are considered. Punching shear is an inaccurate term used for shear failure, at inclined surface, adjacent to a column. Headed Stud Shear Reinforcement (HSSR) is used in current practice to resist shear failure. The presented equations apply to HSSR and stirrups, except where stated otherwise.