Curved structures in waffle slab construction

Horizontally-curved concrete waffle slab structures are sometimes used as superstructures of bridges and as floor slabs in large exhibition halls. The idealization of a horizontally-curved wide structure as a curved beam or an assemblage of curved beams leads to inaccurate results. Although the finite element technique can be used to analyse the structural response of horizontally-curved structures, trial solutions have shown that the finite difference method is a more attractive alternative since it requires fewer equations. In using this latter method accurate estimates of the structure's orthotropic rigidities are required. An analytical study is undertaken to investigate the structural efficiency of a curved waffle slab system in comparison with conventional alternatives, such as the solid slab and girder-slab systems. The feasibility of using an equivalent orthotropic plate system to predict the elastic behaviour of curved concrete waffle slab structures is examined. The analytical results are verified and substantiated by tests on horizontally curved concrete waffle slab models subjected to concentrated and uniformly distributed loads.