Analysis of 2-way R.C. Slabs Under Concentrated Load. A Review of the Egyptian Code 203-2007 Provisions.

Abstract:
The analysis of rectangular two-way slabs subjected to concentrated load uniformly distributed over defined area after dispersion down in the two directions to the reinforcement is a practically important case. As presented by Egyptian code for design and construction of concrete structures ECCS 203-2007, the analysis of this problem can be performed by using the elastic analysis or by using an approximate method which depends on the distribution of the concentrated load in the two directions by the ratio of the long length and short length of the rectangular slab. Significant differences between the results of these methods must take our attention. An alternative approximate method for determining the bending moments of the slab under study in the two directions directly is investigated in this paper based on the elastic analysis. Two closed-form expressions were obtained which describe the relation between the bending moments and all the factors that affect in it (the span ratio, the dimensions ratio of the loaded area and the ratio between the short span to the parallel length of the loaded area). Comparisons between the straining actions in the two directions resulting from the present analysis and that from the existing approximate method of the ECCS 203-2007 with the straining actions obtained by international codes as British Standards BS8110 and that obtained by finite element method are given also in this paper.