| Abstract: | The present analysis is an attempt to determine the portion of a rectangular slab that is acting with its two parallel stiffening edge beams, through which prestressing loads are applied to the entire section, in resisting load. Employing the well known theories of bending of plates and beams, the constitutive equations governing the behaviour of this type of composite system are presented. In particular, the equation of compatibility of strains between the slab edges and the stiffening edge beams at their junctions is formulated. In doing this, the biaxial nature of the bending of the edge beams, ignored in earlier formulations 1], has been incorporated. The results of the present analysis show that, under transverse loading, the portion of the slab, called the effectiv width, that can be considered effective as a part of each of the stiffening edge beams in determining stresses and deflexions is not significantly different from that obtained for an unprestressed section or a simply reinforced section. The effective width of the slab when such a section is subjected to only prestressing loads however shows a significant difference. We conclude from this that a single table of effective widths could be adopted for design purposes when considering transverse bending of this type of composite system whether the section is prestressed or not. Typical stress distributions due to (i) prestress alone, (ii) transverse loading alone and (ii) combined prestress and transverse loading are presented to demonstrate that the present formulation is versatile enough to solve problems involving prestressed edge beams in this type of composite assembly. |
