Nonlinear FE Analyses of RC Skewed Slab Bridges

Abstract

Researchers explain the development of a program called NARCOS for the nonlinear finite-element analysis of reinforced concrete skewed slab bridges. The foundation of the program is a layering formulation in which the cross section is divided into steel and concrete layers with nonlinear material properties. Steel layers are simulated with plane stress elements; concrete layers are modeled with four-node plane stress and Mindlin plate elements. The program takes transverse shear deformations into account. 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. The efficiency of procedures embodied in the program are confirmed through comparison with experimental and other analytical results. Using NARCOS, different models of skewed slab bridges are analyzed 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.