Inelastic behaviour of reinforced concrete hyperbolic paraboloid saddle shell

Abstract The ultimate behaviour of a hyperbolic paraboloid (HP) saddle shell under uniformly distributed loading has been examined by a finite element computer program developed on a Cray Y-MP. The mesh convergence is studied using three progressively refined finite element mesh models, 16 × 16, 32 × 32 and 64 × 64, for the elastic and inelastic analyses. It is shown that the 32 × 32 mesh model gives a solution that is very close to that given by the 64 × 64 mesh model, thus showing a convergence. The inelastic analysis shows that the shell has a tremendous capacity to redistribute the stresses. At the ultimate, the concrete cracks and the reinforcement yieldings are spread out all over the shell, indicating that the stress distribution in the shell is approaching that given by the classical membrane theory. The nonlinear analysis shows that the current design method is acceptable and that the lower bound theorem applies to the HP saddle shell design for the problem that was studied.