Computationally efficient seismic risk analysis for engineering structures using seismic hazard deaggregation

2014 ◽  
pp. 4343-4350
Author(s):  
Zhao-Liang Wang ◽  
Shun-Hao Ni ◽  
Wei-Chau Xie ◽  
Mahesh Pandey
Keyword(s):  
Risk Analysis ◽  
Seismic Hazard ◽  
Seismic Risk ◽  
Computationally Efficient ◽  
Seismic Risk Analysis ◽  
Engineering Structures

Resource Allocation Model Toward Seismic Water Pipeline Risk Mitigation Measures

2019 ◽  
Author(s):  
Elnaz Peyghaleh ◽  
Tarek Alkhrdaji
Keyword(s):  
Resource Allocation ◽  
Risk Analysis ◽  
Seismic Hazard ◽  
Seismic Risk ◽  
Distribution Systems ◽  
Risk Mitigation ◽  
Mitigation Measures ◽  
Seismic Risk Analysis ◽  
Allocation Model ◽  
Proposed Model

Abstract History of earthquake’s damages have illustrated the high vulnerability and risks associated with failure of water transfer and distribution systems. Adequate mitigation plans to reduce such seismic risks are required for sustainable development. The first step in developing a mitigation plan is prioritizing the limited available budget to address the most critical mitigation measures. This paper presents an optimization model that can be utilized for financial resource allocation towards earthquake risk mitigation measures for water pipelines. It presents a framework that can be used by decision-makers (authorities, stockholders, owners and contractors) to structure budget allocation strategy for seismic risk mitigation measures such as repair, retrofit, and/or replacement of steel and concrete pipelines. A stochastic model is presented to establish optimal mitigation measures based on minimizing repair and retrofit costs, post-earthquake replacement costs, and especially earthquake-induced large losses. To consider the earthquake induced loss on pipelines, the indirect loss due to water shortage and business interruption in the industries which needs water is also considered. The model is applied to a pilot area to demonstrate the practical application aspects of the proposed model. Pipeline exposure database, built environment occupancy type, pipeline vulnerability functions, and regional seismic hazard characteristics are used to calculate a probabilistic seismic risk for the pilot area. The Global Earthquake Model’s (GEM) OpenQuake software is used to run various seismic risk analysis. Event-based seismic hazard and risk analyses are used to develop the hazard curves and maps in terms of peak ground velocity (PGV) for the study area. The results of this study show the variation of seismic losses and mitigation costs for pipelines located within the study area based on their location and the types of repair. Performing seismic risk analysis analyses using the proposed model provides a valuable tool for determining the risk associated with a network of pipelines in a region, and the costs of repair based on acceptable risk level. It can be used for decision making and to establish type and budgets for most critical repairs for a specific region.

scholarly journals Spatial Seismic Hazard Variation and Adaptive Sampling of Portfolio Location Uncertainty in Probabilistic Seismic Risk Analysis

2019 ◽  
Author(s):  
Christoph Scheingraber ◽  
Martin Käser
Keyword(s):  
Risk Analysis ◽  
Seismic Hazard ◽  
Seismic Risk ◽  
Adaptive Sampling ◽  
Variance Reduction ◽  
Loss Rate ◽  
Insurance Industry ◽  
Rate Variation ◽  
Seismic Risk Analysis ◽  
Location Uncertainty

Abstract. Probabilistic Seismic Risk Analysis is widely used in the insurance industry to model the likelihood and severity of losses to insured portfolios by earthquake events. Due to geocoding issues of address information, risk items are often only known to be located within an administrative geographical zone, but precise coordinates remain unknown to the modeler. In the first part of this paper, we analyze spatial seismic hazard and loss rate variation inside administrative geographical zones in western Indonesia. We find that the variation of hazard can vary strongly not only between different zones, but also between different return periods for a fixed zone. However, the spatial variation of loss rate displays a similar pattern as the variation of hazard, without depending on the return period. We build upon these results in the second part of this paper. In a recent work, we introduced a framework for stochastic treatment of portfolio location uncertainty. This results in the necessity to simulate ground motion on a high number of sampled geographical coordinates, which typically dominates the computational effort in Probabilistic Seismic Risk Analysis. We therefore propose a novel sampling scheme to improve the efficiency of stochastic portfolio location uncertainty treatment. Depending on risk item properties and measures of spatial loss rate variation, the scheme dynamically adapts the location sample size individually for insured risk items. We analyze the convergence and variance reduction of the scheme empirically. The results show that the scheme can improve the efficiency of the estimation of loss frequency curves.

Seismic Risk Analysis of Regular Girder Bridge Subjected to Mainshock-Aftershock Sequences

2021 ◽  
Author(s):  
LIBO CHEN ◽  
Jianhong Zhou ◽  
Qiluan Zhou
Keyword(s):  
Risk Analysis ◽  
Seismic Hazard ◽  
Seismic Risk ◽  
Structural Damage ◽  
Damage Model ◽  
Earthquake Sequence ◽  
High Rate ◽  
Seismic Risk Analysis ◽  
Aftershock Sequences ◽  
Seismic Disaster

Abstract When a structure is subjected to an earthquake sequence, the high rate of aftershocks after the mainshock and cumulative damage caused by the earthquake sequence make the structure very dangerous. Considering the uncertainty in seismic occurrences, structural damage is often predicted using a seismic risk analysis. This approach has become a main measure for seismic disaster assessment, and provides a reasonable reference for post-earthquake emergency response decision-making and pre-earthquake seismic design. Therefore, it is of great significance to study a seismic risk analysis considering the effect(s) of aftershocks. In this study, the aftershock hazard is estimated for a post-mainshock environment based on an aftershock probabilistic seismic hazard analysis. Considering the uncertainty regarding the mainshock and aftershock occurrences, in addition to the functional relationship between the mainshock and aftershock parameters, the aftershock seismic hazard is estimated for the pre-mainshock environment. The mainshock fragility and aftershock fragility of regular girder bridges are evaluated based on the Kunnath damage model. Finally, considering the damage accumulation in bridge structures, the seismic hazard and seismic fragility are combined to establish a post-mainshock aftershock seismic risk framework and pre-mainshock mainshock-aftershock seismic risk analysis framework. Based on these, the mainshock risk and mainshock-aftershock risk are compared to verify the importance of considering the aftershock effects in seismic disaster assessments. The aftershock risks for the bridges of different post-mainshock damage states are compared, and the influence of the initial damage after the mainshock on the damage to the structure in the post-mainshock environment is studied.

scholarly journals Spatial seismic hazard variation and adaptive sampling of portfolio location uncertainty in probabilistic seismic risk analysis

2020 ◽  
Vol 20 (7) ◽  
pp. 1903-1918
Author(s):  
Christoph Scheingraber ◽  
Martin Käser
Keyword(s):  
Risk Analysis ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Risk ◽  
Adaptive Sampling ◽  
Variance Reduction ◽  
Loss Rate ◽  
Rate Variation ◽  
Seismic Risk Analysis ◽  
Location Uncertainty

Abstract. Probabilistic seismic risk analysis is widely used in the insurance industry to model the likelihood and severity of losses to insured portfolios by earthquake events. The available ground motion data – especially for strong and infrequent earthquakes – are often limited to a few decades, resulting in incomplete earthquake catalogues and related uncertainties and assumptions. The situation is further aggravated by the sometimes poor data quality with regard to insured portfolios. For example, due to geocoding issues of address information, risk items are often only known to be located within an administrative geographical zone, but precise coordinates remain unknown to the modeler. We analyze spatial seismic hazard and loss rate variation inside administrative geographical zones in western Indonesia. We find that the variation in hazard can vary strongly between different zones. The spatial variation in loss rate displays a similar pattern as the variation in hazard, without depending on the return period. In a recent work, we introduced a framework for stochastic treatment of portfolio location uncertainty. This results in the necessity to simulate ground motion on a high number of sampled geographical coordinates, which typically dominates the computational effort in probabilistic seismic risk analysis. We therefore propose a novel sampling scheme to improve the efficiency of stochastic portfolio location uncertainty treatment. Depending on risk item properties and measures of spatial loss rate variation, the scheme dynamically adapts the location sample size individually for insured risk items. We analyze the convergence and variance reduction of the scheme empirically. The results show that the scheme can improve the efficiency of the estimation of loss frequency curves and may thereby help to spread the treatment and communication of uncertainty in probabilistic seismic risk analysis.

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