| This thesis presents a simplified method based on direct and energy formulations for nonlinear analysis of reinforced concrete frame structures. In the simplified method, a reinforced concrete member is modeled by an equivalent member of homogeneous nonlinear material with a derived stress-strain relationship, which satisfies the requirement that the equivalent member has the same moment-curvature behavior as the original member. One advantage of the simplified method is its simplicity which can be easily implemented in most structural analysis computer programs with nonlinear modeling capabilities. The developed model can accurately predict the nonlinear hysteretic responses of reinforced concrete structures with frame members of arbitrary shapes and reinforcing details under severe earthquake excitations. Modules of the simplified method are developed for implementation in the Open System for Earthquake Engineering Simulation framework. Numerical examples of different types of structures are analyzed using the present simplified method under monotonic, cyclic and earthquake loadings. The effects of concrete confinement, steel hardening, stiffness degradation, pinching, and strength deterioration and softening, are simulated in the developed simplified method. Results from the simplified method agree well with finite element and fiber layer models, as well as with experimental testing results. |
