Short reinforced concrete column capacity under biaxial bending and axial load

The paper describes the development of a simple theoretical approach in est imating the capacity of short reinforced concrete (RC) columns under biaxia l bending and axial load. The developed approach considers the nonlinear st ress-strain relations of concrete and reinforcing steel and does not make t he assumption about the limiting strain of extreme compression fiber of con crete. The solution is obtained using a nonlinearly constrained optimizatio n algorithm. The approach was used to estimate the theoretical capacities o f many tested RC columns found in the literature. A probabilistic analysis of the modeling errors was carried out using the ratios of the test-to-pred icted results. The probabilistic analysis was extended to include two simpl ified theoretical methods: the reciprocal load method given by Bresler and the failure surface method given by Hsu.