Span-Depth Ratios for One-Way Members Based on ACI 318 Deflection Limits.

Span-depth ratio (ℓ/h) expressions are developed for steel-reinforced concrete one-way slabs and beams to satisfy deflection control and flexural strength requirements. The expressions are presented as functions of reinforcement ratio and specified deflection-to-span limit. A comparative study is performed to evaluate the effects of effective moment of inertia, shrinkage restraint, construction loads, sustained live load, long-time deflection multiplier, support conditions, and deflection limits on the resulting span-depth ratios. A comparison is also made with minimum thickness values prescribed by ACI 318 that are a function of span and support conditions only. Effects of various input parameters are considered in examples involving a simply supported rectangular beam and an interior span of a continuous one-way slab. The results of the study indicate some of the limitations associated with the ACI 318 minimum thickness requirements. [ABSTRACT FROM AUTHOR]