Ground Motion Selection in the Near-Fault Region considering Directivity-Induced Pulse Effects

Tarbali, Karim; Bradley, Brendon; Baker, Jack W.

doi:10.1193/102517eqs223m

Cited by 46 publications

(29 citation statements)

References 66 publications

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“…We note that both records have similar IP(T 1 ) values (1750 and 1280 cm 2 /s 2 ) for the pulse and non–pulse‐like records, respectively, and they lead to similar peak displacements even though one is a pulse record and one is a nonpulse record. In line with previous studies, scaled pulse‐like motions do not necessarily produce a higher demand than the non–pulse‐like motions . In subsequent sections, we will discuss the significance of including the IP(T 1 ) as part of the vector‐valued IM in the prediction of structural performance using the larger subsets with 40 pulse‐like and non–pulse‐like record pairs.…”

Section: Evaluating the Efficiency And Sufficiency Of The [Sa(t1) Ipsupporting

confidence: 69%

“…In line with previous studies, scaled pulse-like motions do not necessarily produce a higher demand than the non-pulse-like motions. 11,30 In subsequent sections, we will discuss the significance of including the IP(T 1 ) as part of the vector-valued IM in the prediction of structural performance using the larger subsets with 40 pulse-like and non-pulse-like record pairs.…”

Section: Inelastic Response Of Sdof Systemmentioning

confidence: 99%

“…For the pulse‐like records, Kohrangi et al demonstrated that the average spectral acceleration over a period range together with a hazard consistent T p /T 1 ratio form an efficient and sufficient IM. More recently, Tarbali et al proposed a record selection methodology based on generalized conditional intensity measure (GCIM) that considers the directivity pulse effects in the target IM distributions by incorporating these effects in the PSHA. They demonstrated that the consideration of a suite of IMs, conditioned at the target hazard level, leads to a set of ground‐motion time series that capture the near‐fault characteristics of velocity pulses without explicitly considering the velocity pulse parameters in the ground‐motion selection process.…”

Section: Introductionmentioning

confidence: 99%

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A vector‐valued intensity measure for near‐fault ground motions

Zengin

Abrahamson

2020

Earthq Engng Struct Dyn

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Near-fault ground motions containing high energy and large amplitude velocity pulses may cause severe damage to structures. The most widely used intensity measure (IM) is the elastic spectral acceleration at the fundamental period of the structure (Sa(T 1 )); however, Sa(T 1 ) is not a sufficient IM with respect to the effects of the pulse-like ground motions on structural response. For nearfault ground motions, including pulse-like and non-pulse-like time histories, we propose a vector-valued IM consisting of a new IM called instantaneous power (IP(T 1 )) and the Sa(T 1 ). The IP(T 1 ) is defined as the maximum power of the bandpass-filtered velocity time series over a time interval of 0.5T 1 . The IP(T 1 ) is period-dependent because the velocity time series is filtered over a period range (0.2T 1 -3T 1 ). This allows the IP(T 1 ) to represent the power of the near-fault ground motions relevant to the response of the structure. Using two-dimensional models of the 2-and 9-story steel-frame buildings, we show that the proposed [Sa(T 1 ), IP(T 1 )] vector IM gives more accurate estimates of the maximum inter-story drift and collapse capacity responses from near-fault ground motions than using the vector IM consisting of the Sa(T 1 ), the presence of the velocity pulse, and the period of the velocity pulse. Moreover, for the structures considered, for a given Sa(T 1 ), the IP(T 1 ) is more strongly correlated with structural damage from near-fault ground motions than the combination of the velocity pulse and pulse period. K E Y W O R D Snear-fault ground motions, pulse, record selection, vector-valued intensity measure

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Section: Evaluating the Efficiency And Sufficiency Of The [Sa(t1) Ipsupporting

confidence: 69%

Section: Inelastic Response Of Sdof Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A vector‐valued intensity measure for near‐fault ground motions

Zengin

Abrahamson

2020

Earthq Engng Struct Dyn

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“…Baker and Cornell 2006). More advanced record selection procedures might be used to improve this aspect, such as the conditional spectrum (Lin et al 2013) or the generalised conditioned intensity measure (GCIM; Bradley 2010) approaches, as discussed for example in Tarbali et al (2019). However, the approach used here is deemed acceptable for the aims of this study, since only the relative quantification of the different epistemic-uncertainty effects is investigated.…”

Section: Ground-motion Record Setsmentioning

confidence: 99%

Material Property Uncertainties versus Joint Structural Detailing: Relative Effect on the Seismic Fragility of Reinforced Concrete Frames

2021

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This paper investigates the relative effect of material properties and structural details in the joint panels on seismic fragility of existing reinforced concrete (RC) frames. Five building classes with different structural details (particularly in the joint panels) and material characteristics are defined according to different past design codes, for a three-and a six-storey archetype geometry. Based on non-linear static or non-linear dynamic analysis procedures, results from the study show that the effect of structural details on seismic fragility of the considered structures is negligible for damage states involving an essentially-elastic behaviour. Conversely, this is much higher for the life-safety and near-collapse damage states, and it is considerably higher than the one due to materials. Therefore, in the diagnosis phase, higher emphasis should be given to on-site investigations on the actual reinforcement content/layout rather than to invasive material testing. The uncertainty related to the structural details described herein is practically related to the exterior, rather than interior, joint panels. Cover removal for one of those joints could potentially eliminate this specific uncertainty. As a practical action, a good practice for the in-situ testing of RC frames

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“…This analysis method does not require a site-specific, hazard-consistent selection of records (e.g. according to Tarbali et al 2019), and it is therefore deemed appropriate if the derived fragility relationships are used for portfolio-type applications. Using cloud analysis also allows one to adopt none-to-low scaling factors for the selected records.…”

Section: Fragility/vulnerability Derivationmentioning

confidence: 99%

Accounting for directivity-induced pulse-like ground motions in building portfolio loss assessment

Gentile

Galasso

2020

Bull Earthquake Eng

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Earthquake-induced pulse-like ground motions are often observed in near-source conditions due to forward-directivity. Recent worldwide earthquakes have emphasised the severe damage potential of such pulse-like ground motions. This paper introduces a framework to quantify the impact of directivity-induced pulse-like ground motions on the direct economic losses of building portfolios. To this aim, a simulation-based probabilistic risk modelling framework is implemented for various synthetic building portfolios located either in the fault-parallel or fault-normal orientations with respect to a case-study strike–slip fault. Three low-to-mid-rise building typologies representative of distinct vulnerability classes in the Mediterranean region are considered: non-ductile moment-resisting reinforced concrete (RC) frames with masonry infills, mainly designed to only sustain gravity loads (i.e. pre-code frames); moment-resisting RC infilled frames designed considering seismic provisions for high ductility capacity (i.e. special-code frames); special-code steel moment-resisting frames. Monte Carlo-based probabilistic seismic hazard analysis is first performed, considering the relevant modifications to account for the pulse-occurrence probability and the resulting spectral amplification. Hazard curves for sites/buildings located at different distances from the fault are obtained, discussing the spatial distribution of the hazard amplification. A set of pulse-like ground motions and a set of one-to-one spectrally-equivalent ordinary records are used to perform non-linear dynamic analysis and derive fragility relationships for each considered building typology. A vulnerability model is finally built by combining the derived fragility relationships with a (building-level) damage-to-loss model. The results are presented in terms of intensity-based and expected annual loss for synthetic portfolios of different sizes and distribution of building types. It is shown that, for particularly short-period structures (e.g. infilled RC frames), the influence of near-source directivity can be reasonably neglected in the fragility derivation while kept in place in the hazard component. Overall, near-source directivity effects are significant when estimating losses of individual buildings or small portfolios located very close to a fault. Nevertheless, the impact of pulse-like ground motions on losses for larger portfolios can be considered minimal and can be neglected in most of the practical large-scale seismic risk assessment applications.

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Ground Motion Selection in the Near-Fault Region considering Directivity-Induced Pulse Effects

Cited by 46 publications

References 66 publications

A vector‐valued intensity measure for near‐fault ground motions

A vector‐valued intensity measure for near‐fault ground motions

Material Property Uncertainties versus Joint Structural Detailing: Relative Effect on the Seismic Fragility of Reinforced Concrete Frames

Accounting for directivity-induced pulse-like ground motions in building portfolio loss assessment

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