Seismic drift and ductility demands and their dependence on ground motions

doi:10.1016/S0141-0296(02)00174-8

Engineering Structures

Volume 25, Issue 5, April 2003, Pages 637-653

https://doi.org/10.1016/S0141-0296(02)00174-8 Get rights and content

Abstract

Implementation of performance-based earthquake engineering necessitates the probabilistic evaluation of engineering demand parameters that can be related to variables, such as monetary losses, on which quantitative seismic performance assessment can be based. The purpose of this paper is to identify relevant demand parameters, quantify these parameters for regular frame structures, and illustrate how statistically representative relationships between these parameters and ground motion intensity measures can be established. Emphasis is on the development of such relationships for ordinary ground motions, and on issues that have to be addressed in order to establish relationships between demand parameters and near-fault ground motions.

Section snippets

The performance-based earthquake engineering context

Conventionally, seismic demands refer to response parameters that are useful for engineering design decision-making, such as roof drift, story drifts, or local deformations such as plastic hinge rotations. Recent design guidelines, such as FEMA 273 [1] and SEAOC Vision 2000 [2], place limits on ‘acceptable’ values of response parameters, implying that exceedance of these acceptable values constitutes violation of a performance objective (a selected performance level that should be met at a

Ground motion issues

Ideally, assessment of demands and their uncertainties necessitates the availability of sets of acceleration time histories that represent the seismic hazard at different return periods, and describe intensity, frequency content, and duration with sufficient comprehensiveness so that central values and measures of dispersion of the demand parameters can be determined with confidence and efficiency. At this time there is no established procedure to select such sets of ground motions. On the

Frame structures used in this study

The purpose of the following sections is to illustrate the sensitivity of seismic demands in multi-story frame structures to ground motion intensity and frequency characteristics. For this purpose, generic single-bay frames are believed to be adequate to represent elastic and inelastic structural characteristics. In the following sections only nine-story frames with a period of 0.9 s (0.1 N) and 1.8 s (0.2 N) are considered. The results summarized in this paper are part of a comprehensive study

Drift and ductility demands for nine-story generic frames, ordinary ground motions

This section is concerned with the evaluation of engineering demand parameters, EDPs, for generic frames subjected to ordinary records of the type discussed in Section 2.1. Inelastic behavior at plastic hinge locations of the components of the generic frames is described by springs that exhibit a bilinear moment–rotation backbone curve and peak-oriented hysteretic properties. The latter implies that, after unloading, the reloading path is directed towards the largest peak of all previous

Drift and ductility demands for nine-story generic frames, near-fault ground motions

In Alavi and Krawinkler [9] an extensive study is reported on the response of generic frames of the type summarized in Section 3 subjected to a set of near-fault ground motion with forward directivity and to equivalent pulses. The most salient conclusions drawn from the study on MDOF systems are:

•
For relatively long period structures (T₁>T_p), a traveling wave effect is predominant (see Fig. 9) and the distribution of elastic story shear forces over the height is sensitive to the ratio T₁/T_p, and

Conclusions

Implementation of performance-based earthquake engineering necessitates the probabilistic evaluation of EDPs that can be related to variables, such as monetary losses, on which quantitative seismic performance assessment can be based. The process of probabilistic seismic demand analysis requires careful selection of sets of ground motions that represent the intensity and frequency characteristics of interest at the various hazard levels at which performance is to be evaluated (duration is

Acknowledgements

The work discussed in this paper is part of a multi-year research program on seismic demand evaluation. This research is supported by the NSF sponsored Pacific Earthquake Engineering Research (PEER) Center. Past work on near-fault ground motion effects has been supported by the National Science Foundation through Grant CMS-9812478 of the US–Japan Cooperative Research Program in Urban Hazard Mitigation, by a grant from the CUREe/Kajima Research Program, and by the California Department of

References (13)

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Recommended seismic design criteria for new steel moment-frame buildings
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Dynamic P-delta effects for flexible inelastic steel structures
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Relating SMRFs seismic drift demands to element deformation demands
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(2002)
1997 Edition: NEHRP recommended provisions for seismic regulations for new buildings
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There are more references available in the full text version of this article.

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View full text

Seismic drift and ductility demands and their dependence on ground motions

Abstract

Section snippets

The performance-based earthquake engineering context

Ground motion issues

Frame structures used in this study

Drift and ductility demands for nine-story generic frames, ordinary ground motions

Drift and ductility demands for nine-story generic frames, near-fault ground motions

Conclusions

Acknowledgements

NEHRP guidelines for the seismic rehabilitation of buildings

Vision 2000, performance based seismic engineering for buildings

Recommended seismic design criteria for new steel moment-frame buildings

Dynamic P-delta effects for flexible inelastic steel structures

ASCE J Struct Eng

Relating SMRFs seismic drift demands to element deformation demands

AISC Eng J

1997 Edition: NEHRP recommended provisions for seismic regulations for new buildings