Risk-adjusted design basis earthquake: a case study of Tehran megacity

Zaman, Mohammad A; Ghayamghamian, Mohammad Reza

doi:10.1007/s10518-019-00625-0

Cited by 11 publications

(4 citation statements)

References 33 publications

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“…Besides, the authors discussed the problems in the practical implementation of this approach and the alternative paths forward. Zaman and Ghayamghamian (2019) conducted a probabilistic seismic hazard analysis, and a risk-targeted map for Tehran was provided based on the derived hazard curves. Taherian and Kalantari (2019) presented a risk-targeted seismic design map for Iran, considering the seismic hazard models from different seismic hazard maps.…”

Section: Introductionmentioning

confidence: 99%

Risk-targeted hazard maps for Spain

Kharazian

Molina

Galiana-Merino

et al. 2021

Bull Earthquake Eng

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Many studies have demonstrated that the design of structures in a region through the uniform hazard principle does not guarantee a uniform collapse risk. Even in regions with similar Peak Ground Accelerations (PGAs) corresponding to the same mean return period, the seismic risk in terms of collapse probability will be significantly different mainly due to the shape of the hazard curves as well as uncertainties in structural capacities. In this paper, risk-targeted hazard mapping is being explored in peninsular Spain using a recently updated seismic hazard map. Since risk targeting involves multiple input parameters such as the model parameters of fragility curves, their variability was considered through their probability distribution as observed in reinforced concrete (RC) moment frame buildings, representing the most common building typology in Spain. The influence of the variation of these parameters on the risk results were investigated, and different assumptions for estimating the model parameters of fragility curves are illustrated. These assumptions were included in a fixed (generic) fragility curve or building-site-specific fragility curves. Different acceptable damage states (i.e., collapse and yielding) were considered concerning Spain’s seismicity level. Finally, the maps for risk-targeted design ground motions and risk coefficients are presented. It is outlined that the employment of risk-targeted analysis leads to the modifications for existing design ground motions due to the different shape of the hazard curves across Spain and considering the uncertainty of structural capacity. Moreover, it is found that using the building- and site-specific fragility curves could result in a more uniform seismic risk across the country.

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Section: Introductionmentioning

confidence: 99%

Risk-targeted hazard maps for Spain

Kharazian

Molina

Galiana-Merino

et al. 2021

Bull Earthquake Eng

View full text Add to dashboard Cite

show abstract

“…Besides, they discussed the problems in the practical implementation of this approach and the alternative forward paths. Zaman and Ghayamghamian (2019) performed the probabilistic seismic hazard analysis, and a risk-targeted map for Tehran was provided based on the hazard curves achieved. Taherian and Kalantari (2019) presented a risk-targeted seismic design map for Iran, considering the seismic hazard models from different seismic hazard maps.…”

Section: Introductionmentioning

confidence: 99%

Risk-targeted Maps for Spain

Kharazian

Molina

Galiana-Merino

et al. 2021

Preprint

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Many studies have demonstrated that the design of structures in the region through the uniform hazard principle does not guarantee the uniform collapse risk. Even in those regions with similar PGAs corresponding to the same mean return period, the seismic risk in terms of failure probability will be significantly different due to the structural capacity uncertainty. In this paper, the newly introduced method, known as risk targeting, is being explored in Spain using the recently updated seismic hazard map. Since risk targeting involves multiple input parameters such as model parameters of fragility curves, their variability is considered through their probability distribution corresponding to the RC moment frame building, which is the most common typology in Spain. The influence of variation of these parameters on the risk results are investigated and different assumptions for estimating the model parameters of fragility curves are illustrated. These assumptions are included in a fixed fragility curve (generic) or building-site-specific fragility curves. Different acceptable risk levels (i.e., collapse and yielding) were considered concerning the Spain seismicity level. Finally, the maps for risk-targeted design ground motion and risk coefficient are presented. It was outlined since the shape of the hazard curve across Spain is different and considering the uncertainty of structural capacity; the employment of risk-targeted analysis led to the modifications for existing design ground motions. Moreover, it was found that using the building- and site-specific fragility curves could provide better results.

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“…Such a generalization ignores the inherent differences in the reliability of various structural systems. This issue can be circumvented by reflecting this performance difference in the factors considered in seismic codes to account for nonlinearity, such as the response modification factor (Zaman and Ghayamghamian 2019). Another issue of this approach is that collapse is the sole consequence considered, and a wide range of damage is disregarded.…”

Section: Introductionmentioning

confidence: 99%

“…They concluded that although the design PGA insignificantly affects the initial construction cost, a change in the code is not warranted as it has minor benefits in terms of the reduction in the lifecycle cost. Zaman and Ghayamghamian (2019) emphasized the issues associated with the uniform hazard approach, and presented a risk-adjusted design PGA map for Tehran using the acceptance criteria of ASCE/SEI 7. Gudipati and Cha (2019) presented a framework for optimizing the target reliability of a portfolio of four buildings with steel special moment frames.…”

Section: Introductionmentioning

confidence: 99%

Quantification of Optimal Target Reliability for Seismic Design: Methodology and Application to Midrise Steel Buildings

Habibi

Varzandeh

Mahsuli

2021

Preprint

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Quantification of the optimal target reliability based on the minimum lifecycle cost is the goal standard for calibration of seismic design provisions, which is yet to be fully-materialized even in the leading codes. Deviation from the optimally-calibrated design standards is significantly more pronounced in countries whose regulations are adopted from the few leading codes with no recalibration. A major challenge in the quantification of optimal target reliability for such countries is the lack of risk models that are suited for the local construction industry and design practices. This paper addresses this challenge by presenting an optimal target reliability quantification framework that tailors the available risk models for the countries from which the codes are adopted to the local conditions of the countries adopting the codes. The proposed framework is showcased through the national building code of Iran, which is adopted from the codes of the United States, using a case study of three midrise residential steel building archetypes. The archetypes have various structural systems including intermediate moment-resisting frame (IMF) and special concentrically braced frame (SCBF). Each of these archetypes are designed to different levels of the base shear coefficient, each of which corresponds to a level of reliability. To compute the lifecycle cost, the initial construction cost of buildings is estimated. Next, robust nonlinear models of these structures are generated, using which the probability distribution of structural responses and the collapse fragility are assessed through incremental dynamic analyses. Thereafter, the buildings are subjected to a detailed seismic risk analysis. Subsequently, the lifecycle cost of the buildings is computed as the sum of the initial construction cost and the seismic losses. Finally, the optimal strength and the corresponding target reliability to be prescribed are quantified based on the notion of minimum lifecycle cost. The results reveal a 50-year optimal reliability index of 2.0 and 2.1 for IMF and SCBF buildings, respectively and an optimal collapse probability given the maximum considered earthquake of 16% for both systems. In the context on the case study of the national building code of Iran, the optimal design base shear for IMF buildings is 40% higher than the current prescribed value by the code, whereas that of SCBF buildings is currently at the optimal level.

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Risk-adjusted design basis earthquake: a case study of Tehran megacity

Cited by 11 publications

References 33 publications

Risk-targeted hazard maps for Spain

Risk-targeted hazard maps for Spain

Risk-targeted Maps for Spain

Quantification of Optimal Target Reliability for Seismic Design: Methodology and Application to Midrise Steel Buildings

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