Seismic Assessment of Reinforced Concrete Frameworks through Advanced Pushover Analysis and Nonlinear Response of a SDOF Oscillator

This paper presents an integrated system for advanced structural analysis and seismic performance evaluation of 2D reinforced concrete frameworks. The advanced non-linear inelastic static analysis employed herein uses the accuracy of the fibre elements approach for large deflection inelastic frame analysis and address its efficiency and modelling shortcomings both to element level, through the use of only one element to model each physical member of the frame, and to cross-sectional level through the use of path integral approach for numerical integration of the cross-sectional nonlinear characteristics. Evaluation of the seismic performance is achieved with an approach that uses nonlinear time-history analysis (NTHA) of a single degree-of-freedom (SDOF) oscillator. The inelastic ductility and displacement demand is determined directly from accelerograms, without graphical or numerical approximations. Several computational examples are given to validate the effectiveness of the proposed method, the reliability and time saving of the code. The influence of the accuracy of the second-order nonlinear inelastic analysis methods involved in the modelling of the selected RC frame in conjunction with the distributions of the pushover lateral loads is pointed out. The proposed procedure is developed in the framework of Eurocode 8 design methodology, as reliable tool ready to be implemented into everyday design practice for advanced analysis, pushover analysis, and seismic performance evaluation of RC frame structures.