Probabilistic Constant-Strength Ductility Demand Spectra

A procedure is presented to develop probabilistic constant-strength ductility demand spectra based on statistical analyses of the results of comprehensive dynamic time history simulations of bilinear single-degree-freedom systems. The procedure offers an approach to estimate both the mean and standard deviation of the ductility demand, given the normalized strength and fundamental system period. The probabilistic distribution of the ductility demands conditional on normalized strength and natural period is validated through goodness-of-fit test. The effects of post-yield stiffness ratio on ductility demand are also investigated. The proposed spectra can allow the treatment of the frequency content and peak intensity measure of the ground motion separately, and describe the state variation of a structure from elastic to inelastic as a function of the peak ground acceleration, which enables its application in stochastic seismic displacement analysis and probabilistic seismic demand analysis. An illustrative example of a seven-story planar frame structure is presented to demonstrate the applicability and utility of the proposed methodology.

[1]  A. Chopra,et al.  Inelastic Deformation Ratios for Design and Evaluation of Structures: Single-Degree-of- Freedom Bilinear Systems , 2004 .

[2]  Rafael Riddell,et al.  Inelastic deformation response of SDOF systems subjected to earthquakes , 2002 .

[3]  Eduardo Miranda,et al.  Statistical Evaluation of Approximate Methods for Estimating Maximum Deformation Demands on Existing Structures , 2005 .

[4]  Nelson Lam,et al.  The ductility reduction factor in the seismic design of buildings , 1998 .

[5]  Rafael Riddell,et al.  Inelastic design spectra accounting for soil conditions , 1995 .

[6]  Sang Whan Han,et al.  Determination of ductility factor considering different hysteretic models , 1999 .

[7]  Dimitrios Vamvatsikos,et al.  Incremental dynamic analysis , 2002 .

[8]  Peter Fajfar,et al.  Capacity spectrum method based on inelastic demand spectra , 1999 .

[9]  Arturo Tena-Colunga.  Displacement ductility demand spectra for the seismic evaluation of structures , 2001 .

[10]  Peter Fajfar,et al.  Consistent inelastic design spectra: Strength and displacement , 1994 .

[11]  Eduardo Miranda,et al.  Evaluation of site-dependent inelastic seismic design spectra , 1993 .

[12]  W. J. Conover,et al.  Practical Nonparametric Statistics , 1972 .

[13]  E. Miranda.  Estimation of Inelastic Deformation Demands of SDOF Systems , 2001 .

[14]  Anil K. Chopra,et al.  Capacity-Demand-Diagram Methods for Estimating Seismic Deformation of Inelastic Structures: SDF Systems , 1999 .