The Earthquake Response of Deteriorating Systems

Applied Mechanics

Gates, Nathan Craig ; Iwan, Wilfred D.

University:California Institute of Technology

Department:Engineering and Applied Science

关键词: Applied Mechanics;   

Others  :  https://thesis.library.caltech.edu/10143/1/Gates_NC_1977.pdf

美国|英语

来源: Caltech THESIS

【 摘 要 】

This thesis is concerned with the earthquake response ofdeteriorating systems. A model for stiffness degrading ordeteriorating systems is used to describe six different single-degree-of-freedom systems. A numerical investigation of theresponse of these six systems is performed using an ensemble oftwelve earthquakes. The response is studied at nine nominalperiods of oscillation. The numerical results are presented asresponse spectra corresponding to six different ductilities.

An approximate analytical method for calculating the earthquakeresponse of deteriorating systems from a linear responsespectrum is presented. The method, called the average stiffnessand energy method, is based upon the premise that a linear systemmay be defined which is in some sense equivalent to the deterioratingsystem. The criterion for equivalence in this method is thatthe average stiffness of the deteriorating system be equal to thestiffness of the linear system and the average energy dissipatedby the linear system be the same as the average energy dissipatedby the deteriorating system.

The new analytical method is compared to existing methods.Comparison with the numerical results is also made. Based uponthese comparisons, it is concluded that the average stiffness andenergy method represents a significant improvement over currentlyavailable methods for predicting the earthquake response ofdeteriorating and nondeteriorating systems.