The thesis addresses the design of reinforced concrete wide beam solid slabs for which international design standards like BS8110, EC2 and ACI318 provide no guidance. Currently, the only commonly available UK guidance on the design of wide beam slabs is provided by The Concrete Centre (TCC). The TCC design method assumes that support moments, about an axis parallel to the direction of wide beam span, are uniformly distributed along beams. The TCC approach is questionable since elastic finite element analysis shows the transverse bending moment distribution to be far from uniform and sharply peaked near columns. The research was motivated by concern that crack widths could be excessive in wide beam slabs designed for uniformly distributed transverse moments.
Nonlinear finite element analysis (NLFEA) is used to investigate the influence on structural response of varying the distribution of transverse flexural reinforcement along wide beams. Uniform and banded transverse reinforcement arrangements are considered. The banded arrangement is based on the elastic moment field. The influence of compressive membrane action (CMA) on flexural resistance is investigated. The thesis also considers the influence of transverse reinforcement distribution, one-way loading from the beam and slab continuity on punching resistance at internal and edge columns. Punching resistance is investigated with NLFEA using solid elements as well as EC2 and the critical shear crack theory as implemented in fib MC2010.
A design method is developed for wide beam slabs on the basis of parametric studies. It is proposed that transverse reinforcement should be provided in two bands depicted “column band” and “span band”. The width of the column band is shown to vary linearly with wide beam span. The proposed procedure for banding transverse reinforcement is shown to effectively reduce steel strains and, hence, crack widths as well as enhance punching shear resistance.