Reliable seismic collapse assessment of short-period structures using new proxies for ground motion record selection

Yakhchalian, Masood; Amiri, Gholamreza Ghodrati; Eghbali, Mahdi

doi:10.24200/sci.2017.4162

Cited by 4 publications

(3 citation statements)

References 18 publications

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“…There are different efforts to improve this method and increase its accuracy in estimating the seismic performance of structures. Some researchers try to improve it by using optimization algorithms in the procedure [3][4][5][6] and others try to add some innovative complementary parameters in the selection process [7,8]. In order to amend the code-based method, it is important to understand the most significant properties of recorded ground motions which are related to the structural response.…”

Section: Introductionmentioning

confidence: 99%

A New Ground Motion Record Selection Procedure Based on the Effects of Spectral Shape and Period Elongation

2019

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One of the most prevalent ground motion Intensity Measures (IMs) is the spectral acceleration at the fundamental period of the structure. Previous research has shown that vectorizing scalar IMs leads to a more reliable structural response, particularly in the nonlinear region and near collapse. Furthermore, nonlinear behavior of ductile structures results in an elongation in the "effective period" of the structure. Therefore, this paper proposes a new approach for selecting ground motion records considering the effect of spectral shape and period elongation. This method contains two disaggregation analyses at the fundamental and elongated period of the structure. Nonlinear dynamic analysis is conducted on a set of reinforced concrete moment resisting frames designed based on ACI 318-05 as representatives of modern structures. Results show a considerable decrease in the median collapse prediction, margin against collapse and dispersion of the structural response. The presented approach can give a better prediction for the vulnerability of the structure toward collapse.

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Section: Introductionmentioning

confidence: 99%

A New Ground Motion Record Selection Procedure Based on the Effects of Spectral Shape and Period Elongation

2019

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“…Therefore, the reliable understanding of seismic collapse probability of structures (i.e., developing reliable collapse fragility functions) justifies using an optimal IM for collapse capacity prediction. It is noteworthy that another method for reliable seismic collapse assessment of structures is using proxies for ground motion record selection (e.g., Yakhchalian et al and Kohrangi et al). In this study, some scalar and vector‐valued IMs are considered; and the efficiency and sufficiency of the IMs for seismic collapse capacity prediction of RC SMRFs under fault‐normal components of near‐fault ground motions having forward directivity are investigated.…”

Section: Introductionmentioning

confidence: 99%

Reliable fragility functions for seismic collapse assessment of reinforced concrete special moment resisting frame structures under near‐fault ground motions

Yakhchalian

2019

Structural Design Tall Build

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Summary A collapse fragility function shows how the probability of collapse of a structure increases with increasing ground motion intensity measure (IM). To have a more reliable fragility function, an IM should be applied that is efficient and sufficient with respect to ground motion parameters such as magnitude (M) and source‐to‐site distance (R). Typically, pulse‐like near‐fault ground motions are known by the presence of a velocity pulse, and the period of this pulse (Tp) affects the structural response. The present study investigates the application of different scalar and vector‐valued IMs to obtain reliable seismic collapse fragility functions for reinforced concrete special moment resisting frames (RC SMRFs) under near‐fault ground motions. The efficiency and sufficiency of the IMs as the desirable features of an optimal IM are investigated, and it is shown that seismic collapse assessments by using most of the IMs are biased with respect to Tp. The results show that (Sa(T1), Sa(T1)/DSI) has high efficiency and sufficiency with respect to M, R, Tp, and scale factor for collapse capacity prediction of RC SMRFs. Moreover, the multiobjective particle swarm optimization algorithm is applied to improve the efficiency and sufficiency of some advanced scalar IMs, and an optimal scalar IM is proposed.

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“…This IM, which is derived from the geometric mean of pseudo-spectral accelerations over a range of periods, provides minimum dispersion for the entire set of purely P-Delta vulnerable frames with different number of stories and fundamental periods of vibration. Yakhchalian et al [11,12] proposed new proxies for ground motion record selection for seismic collapse assessment of short-period and long-period structures. Using these proxies causes reduction in collapse capacity dispersion.…”

Section: Introductionmentioning

confidence: 99%

Evaluation the P-Delta Effect on Collapse Capacity of Adjacent Structures Subjected to Far-field Ground Motions

2018

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In urban areas, adjacent structures can be seen in any insufficient distance from each other, because of economic and refusal of acquired minimum separation distance according to seismic previsions. Collapse capacity assessment of structures is one of the important objectives of performance-based seismic engineering. The purpose of this study is to consider the pounding phenomenon and P-Delta effect in seismic collapse capacity assessment of structures. For this purpose, 2-, 4-, 6- and 8-story adjacent structures with different conditions of separation distance among them, were modeled in the OpenSees software. Furthermore, Incremental Dynamic Analyses (IDAs) were performed using 78 far-field ground motion records to compute the collapse capacities of adjacent structures. The results obtained from IDAs for adjacent structures show that during pounding, taller structure reaches its collapse capacity earlier than shorter one. In addition, by considering the P-Delta effect and increasing the distance between adjacent structures, time of collapse and number of impacts increases. According to results, considering the P-Delta effect in modeling has significant influence in seismic collapse capacity assessment of pounding structures.

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Reliable seismic collapse assessment of short-period structures using new proxies for ground motion record selection

Cited by 4 publications

References 18 publications

A New Ground Motion Record Selection Procedure Based on the Effects of Spectral Shape and Period Elongation

A New Ground Motion Record Selection Procedure Based on the Effects of Spectral Shape and Period Elongation

Reliable fragility functions for seismic collapse assessment of reinforced concrete special moment resisting frame structures under near‐fault ground motions

Evaluation the P-Delta Effect on Collapse Capacity of Adjacent Structures Subjected to Far-field Ground Motions

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