Nonlinear Analysis of Reinforced Concrete Beams with Softening

Abstract

Softening of reinforced concrete sections at advanced curvatures in flexure is taken into account in collapse load analysis. The entire load-deflection curve for reinforced concrete beams up to collapse is analyzed by using the displacement control method. The analysis employs a linearized model to real moment-curvature relation and to clastic unloading from the plastic region. The result of analysis by the finite element method for the materials with strain-softening is shown to spurious sensitivity to the chosen element size. If the moment-curvature relations are modified for each element, based on the concept of concentrated inelastic rotations at plastic hinge, this problem can be overcome.