Long-term deflections analysis of reinforced concrete flat plates under construction loads.

Title: Long-term deflections analysis of reinforced concrete flat plates under construction loads.
Authors: Boussouf, Abdel-Hafid.
Date: 1990
Abstract: Relatively large construction loads applied to immature slabs with their low elastic moduli will cause large initial elastic deflections. The high applied stress/developed strength ratio will cause significant creep, resulting in large long-term deflections. Shrinkage, while not related to construction loads, also contributes to long-term deflections. Studies reported by many investigators showed that the long-term deflections cannot be ignored in the design process and that the contribution of the effects of the construction loads cannot be ignored. The influence of the construction loads on the long-term deflection serviceability means that the construction process cannot be independent of the design considerations. However, ACI 318 and CSA A23.3, specify maximum span thickness ratios for which deflections need not be considered. A computer investigation of the long-term deflections for flat plates, of typical dimensions, was effected using a finite element analysis program for several possible load histories. The study indicated that the present span thickness recommendations of ACI 318 and CSA A23.3 would not necessarily prevent excessive deflections. The study also indicates that, in most cases, the code requirement of total deflection not to exceed l/240 was critical and could not be met.
URL: http://hdl.handle.net/10393/5999
CollectionTh├Ęses, 1910 - 2010 // Theses, 1910 - 2010
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