Code‐based record selection methods for seismic performance assessment of buildings

Abstract

Summary The recent concerns regarding the seismic safety of the existing building stock have highlighted the need for an improvement of current seismic assessment procedures. Alongside with the development of more advanced commercial software tools and computational capacities, nonlinear dynamic analysis is progressively becoming a common and preferable procedure in the seismic assessment of buildings. Besides the complexity associated with the formulation of the mathematical model, major issues arise related with the definition of the seismic action, which can lead to different levels of uncertainty in terms of local and global building response. Aiming to address this issue, a comparative study of different code‐based record selection methods proposed by Eurocode 8, ASCE41‐13 and NZS1170.5:2004 is presented herein. The various methods are employed in the seismic assessment of four steel buildings, designed according to different criteria, and the obtained results are compared and discussed. Special attention is devoted to the influence of the number of real ground motion records selected on the estimation of the mean seismic response and, importantly, to the efficiency that is achieved when an additional selection criteria, based on the control of the spectral mismatch of each individual record with respect to the reference response spectrum, is adopted. The sufficiency of the methods with respect to the pairs of M–R of the selected group of records and the robustness of the scaling procedure are also examined. The paper closes with a study which demonstrates the suitability of a simplified probability‐based approach recently proposed for estimating mean seismic demands. Copyright © 2015 John Wiley & Sons, Ltd.

Simplified procedure for the estimation of local inelastic deformation demands for seismic performance assessment of buildings

“…regular distribution of stiffness and strength over their height), similarly to the findings of Fragiadakis et al . Nonlinear chord rotation estimates are also associated with a significant level of uncertainty as a result of the method adopted for selecting and scaling ground motions, as discussed in detail by Araújo et al . This variability propagates to the comparison between linear elastic and nonlinear chord rotations, being more representative for building GB (Figure (a)).…”

“…The elastic spectrum and spectral mismatching results are presented in Figure . This additional criterion has been demonstrated by Araújo et al to significantly reduce the variability in the structural response estimates. The analyses were performed for the Damage Limitation (DL), Significant Damage (SD) and Near Collapse (NC) limit states, as defined by EC8‐3 for return period values T r of 225, 475 and 2475 years, which correspond to Peak Ground Acceleration (PGA) values of 0.091, 0.15 and 0.451 g, respectively.…”

Evaluation of Current Code Criteria Selecting Ground Motions for Dynamic Analysis: Assessment of structural responses

“…Araújo et al [4] assessed the ground motion selection procedures and criteria provided in various seismic provisions such as Eurocode 8, NZS1170.5 and ASCE 41-13. They reported that the use of seven recorded ground motions in RHA, as proposed by codes for determining mean seismic demands, was adequate if additional control of the spectrum mismatch was adopted.…”

13.14: Seismic assessment and strengthening of existing steel moment‐resisting frame buildings: the European EC8‐3 and current challenges

“…In Europe, the revision of part 3 of Eurocode 8 (EC8-3) [1], which is the part of the Eurocodes that specifically address this issue, has been set as a first priority and new changes are expected to be included in the new generation of Eurocodes that is to be published in 2020. Several works recently conducted by the authors [2][3][4][5][6][7] have highlighted a number of inconsistences and limitations of EC8-3 regarding the particular case of existing steel moment-resisting steel frame buildings. This paper hence aims at providing a discussion on the limitations of the current version of EC8-3, the studies that have been undertaken in order to overcome those deficiencies and future research needs.…”