Funded by the National Science Foundation’s Research Initiation Grant. Investigators – Y. H. Chai and K. M. Romstad.
Abstract: Although the potential for cumulative damage of structures during long duration earthquakes is generally recognized, most design codes do not explicitly take into the damage potential of such events. The traditional use of displacement ductility factor as an implicit damage parameter in design codes is inadequate, since it is implicitly assume that structural damage occurs only due to the maximum deformation and is independent of the number of non-peak inelastic cycles or plastic strain energy dissipation. This project addressed the issues in the cumulative damage assessment of structures using energy-based linear damage model and the classical low-cycle fatigue damage model. A methodology for the formulation of duration-dependent inelastic design spectra is proposed.
Key Publications:
- Y. H. Chai, K. M. Romstad, and S. M. Bird (1995), “Energy-Based Linear Damage Model for High-Intensity Seismic Loading”, Journal of Structural Engineering, ASCE, Vol. 121, No. 5, pp. 857-864.
- Y. H. Chai and K. M. Romstad (1997), “Correlation Between Strain-Based Low-Cycle Fatigue and Energy-Based linear Damage Models”, Earthquake Spectra, Vol. 13, No. 2, pp. 191-209.
- Y. H. Chai, P. Fajfar and K. M. Romstad (1998), “Formulation of Duration-Dependent Inelastic Seismic Design Spectrum”, Journal of Structural Engineering, ASCE, Vol. 124, No. 8, pp. 913-921.
- Y. H. Chai and P. Fajfar (2000), “A Procedure for Estimating Input Energy Spectra for Seismic Design”, Journal of Earthquake Engineering, Vol. 4, No. 4, pp.539-561.
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S. K. Kunnath and Y. H. Chai (2004), “Cumulative Damage-Based Inelastic Cyclic Demand Spectrum”, Earthquake Engineering and Structural Dynamics, Vol. 33, pp. 499-520.
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Y. H. Chai (2005), “Incorporating Low-Cycle Fatigue Model into Duration-Dependent Inelastic Design Spectra“, Earthquake Engineering and Structural Dynamics, Vol. 34, pp. 83-96.