EVALUATION OF NONLINEAR BEHAVIOR OF MOMENT-RESISTING REINFORCED CONCRETE FRAME USING THE RESPONSE SURFACE METHOD

In recent years, there has been an increasing interest in studying the eect of dierent parameters on the nonlinear behavior of moment resisting reinforced concrete structures. However, it seems that simultaneous evaluation of some parameters needs a comprehensive statistical analysis. This paper describes a logical investigation into the seismic behavior of a ve storey moment resisting reinforced concrete structure under cyclic lateral load, using an inelastic analysis computer program named IDARC. The response surface method was used for the experimental design and analysis of the interaction eect of 4 factors: column dimension ratio, longitudinal and shear reinforcement, column connement and eectiveness coecient, on the overall damage index and stiness degradation of the structure. Using the central composite design method, each 4 factors were dened over 5 levels. 25 IDARC models were analyzed and 4 responses obtained: Damage index at drifts equal to 1.5%, 3% and 4% of the structure height, and the tangent of stiness degradation in a linear area, were taken from each model. A computer program, named; Design Expert 7, was used for statistical analysis. Results show that in linear areas, the drift equals 1.5% of the structure height. The overall damage index is aected by the column dimension ratio, longitudinal reinforcement and the column connement eectiveness coecient. However, in nonlinear areas, where the drift equals 4% of the structure height, the damage index is aected by the column dimension ratio and longitudinal reinforcement. In linear areas, the eect of shear reinforcement, and, in nonlinear areas, the eect of shear reinforcement and the column connement eectiveness coecient, on the overall damage index of the structure, is negligible. Furthermore, results show that the stiness degradation of the structure is aected by the column dimension ratio, longitudinal reinforcement and the column connement eectiveness coecient. However, the eect of shear reinforcement on the stiness degradation of the structure is negligible. The presented numerical model can be used for prediction of the damage index.