A fast nonlinear response spectra analysis algorithm based on the theory of modal analysis and superposition is proposed to overcome the drawbacks of using the time-consuming nonlinear response history analysis in seismic design. Because linear modal analysis has found great acceptances in performance-based seismic engineering, it is here extended to the nonlinear domain by using the force analogy method that links the global responses with local inelasticity of the structure. Geometric nonlinearity is incorporated into the analysis through modifying the initial stiffness matrices due to gravity loads. By ignoring geometric stiffness update, the theory of modal analysis and superposition is easily incorporated into the proposed algorithm. Numerical simulation is performed to demonstrate the accuracy of the algorithm in capturing both the maximum global and local responses.
Proceedings Title: The Twelfth East Asia-Pacific Conference on Structural Engineering and Construction (EASEC-12)
Conference Dates: January 26-28, 2011
Conference Location: Kowloon,
Pub Type: Conferences
Nonlinear modal analysis, force analogy method, state space method, geometric nonlinearity, response spectra analysis.