Nonlinear FE Analyses of RC Skewed Slab Bridges

Abstract

Development of a program (NARCOS) for the nonlinear finite-element analysis of RC skewed slab bridges is outlined. The program is based on a layering formulation in which the cross section is divided into steel and concrete layers, with nonlinear material properties. Concrete layers are simulated with four-node plane stress and Mindlin plate elements; steel layers are modeled with plane stress elements. Transverse shear deformations are considered. Interlayer compatibility is satisfied by constraining in-plane displacements along common interfaces to be the same for adjacent layers. An efficient algorithm is used for assembly of the stiffness matrix and solution of the equilibrium equations. Comparison with experimental and other analytical results indicates the efficiency of procedures embodied in the program. The program is used to analyze different models of skewed slab bridges in order to assess the relative merits of two different methods of designing such bridges. Bridges designed with increased reinforcement at the obtuse corner have a higher crack-initiation load and a higher ultimate strength than bridges designed with uniform reinforcement in the slab.