Nonlinear Finite Element Analysis of Deteriorated RC Slab Bridge

Applications of nonlinear finite element analysis (NLFEA) to complete structures have been limited. The study reported in this paper examined the reliability of NLFEA to assess strength and stiffness of a three-span reinforced concrete slab bridge that was loaded to failure in the field. The researchers at the University of Cincinnati and Delft University of Technology, in The Netherlands, conducted preliminary analyses that were then compared to the measured responses. These analyses indicate a significant influence of tensile behavior of concrete in the postcracking range, and the level of slab membrane force that is directly affected by the assumed horizontal support conditions at the slab-abutment connections. Reasonable correlation of the measured responses was possible by removing the horizontal restraints at the slab-abutment connections. Howver, such models do not simulate the observed behavior at the abutments. The shear keys at the slab-abutment connections would not permit free horizontal movements, yet the slab can rotate about the shear keys. The resulting rotation would reduce the membrane force that can be developed. An improved model incorporating this behavior produced better results than the original model assuming full horizontal restraints at the abutments.