A Rational Approach to Control of Slab Deflections


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Title: A Rational Approach to Control of Slab Deflections

Author(s): B . Vijaya Rangan and Arthur E . McMullen

Publication: Journal Proceedings

Volume: 75

Issue: 6

Appears on pages(s): 256-262

Keywords: building codes; concrete slabs; deflection; flat concrete plates; flat concrete slabs; span-depth ratio: structural analysis; structural design; thickness: two-way slabs.

Date: 6/1/1978

Limitation of long-term deflection is an important consideration in the design of flat plates and flat slabs. In this paper an expression is developed that relates the span-depth ratio of a slab to the relevant parameters. Since this expression is not suitable for design purposes, a parametric study was performed which permitted development of design equations. Correlation between predicted long-term deflection and the small amount of field data available is excellent. Comparison with two codes of practice indicates that the use of the minimum slab thicknesses specified by these codes can result in deflections which in many cases will be objectionable. Finally, the ease with which the proposed equations can be used is illustrated in a design example.