EVALUATION OF MINIMUM THICKNESS REQUIREMENTS FOR RC TWO-WAY SLABS FOR DEFLECTION CONTROL
Volume Title: ICASGE2025
Paper ID : 1044-ICASGE-FULL (R1)
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Abstract
Practical engineers usually use minimum thickness provisions to fulfill deflection limit state requirements, especially at the beginning of their design. This paper evaluates the efficiency of deflection limit state requirements for two-way solid slabs as provided by various international codes, including ACI318-19, ECP203-2020, ECP203-2007, Eurocode2, and BS8110-1997. Using finite element models, the study calculates the required minimum thickness for deflection limits (short span/250) and compares these results with recommendations from the studied codes. A comprehensive parametric study examines the effects of slab spans, aspect ratios, slab continuity, yield stress of reinforcement, applied live load, and concrete strength on the required slab thickness. The findings reveal that most codes, except the Egyptian code, inadequately account for slab boundary conditions. ACI318-19 results are unconservative for simply supported slabs and change to conservative for continuous slabs. For all the studied codes, the minimum required slab thickness increases with the increase of the yield stress; fy, in contrast to that of Eurocode2. ECP203-2007 results are more accurate compared with ECP203-2020 and other codes. The effect of boundary condition is more noticeable for continuous short spans than that for continuous long spans. Eurocode 2 equation need serious modifications to capture the actual slab behavior according to different boundary conditions.
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