Seismic Risk-informed Decision Model Analysis Considering Subjective Risk Attitude

Seismic disaster has caused tremendous loss to human society in terms of wealth loss and casualties.To enhance seismic resistance of human society,it's necessary to study the strategy of mitigating seismic risk of built environment.Based on existing seismic risk analysis frame and seismic design theory,this study applies decision-making model of economics to engineering decision-making problem.By using data and analysis result of Chinese residents' risk aversion attitude,this study investigates the influence to seismic risk mitigation strategy caused by decision-maker's subjective risk aversion and psychology of risk perception.In this study,several solutions to seismic risk are illustrated from different perspectives,and the optimal solution is obtained in different decision situations.The first step is calibrating risk aversion coefficient to represent the degree of risk aversion.The probability distribution of risk aversion coefficient of Chinese residents is obtained by analyzing data of China Household Finance Survey(CHFS)and Chinese finance market.The empirical formula to calculate risk aversion coefficient is given by regression analysis of common influence factors.The analysis results show that the range of Chinese residents' risk aversion coefficient is between 1 and 17,with mean of 7.72 and median of 4.52.Generally,when the age increases 1 year,the risk aversion coefficient decreases 0.9%;when the financial assets increase 10,000 RMB,the risk aversion coefficient decreases 0.284%.Recognizing the fact that the minimum life-cycle cost design criteria doesn't take subjective risk attitude of decision maker into account,this study adopts utility theory as a classical decision model to investigate the influence of risk aversion embedded in decision-making process under seismic risk.The analysis results show that public decision maker(from the view of society)could mitigate seismic risk by raising seismic design level.The optimal seismic design level improves with the rising degree of risk aversion.Private decision maker(from the view of property owner)could utilize earthquake insurance contract to transfer seismic risk.Earthquake insurance premium which property owner could afford increases,as the degree of risk aversion rises or seismic resistance of structures declines.Finally this study applies seismic risk-informed decision model considering subjective risk attitude to optimal strategy problems,taking typical brick-wood buildings in Chinese rural area as an example.The analysis results show that rural inhabitants with risk aversion coefficient above 4.65 will retrofit their buildings to mitigate seismic risk.The highest level of earthquake insurance premium that rural inhabitants will accept are given in two different insurance schemes.The critical insurance premium and risk aversion coefficients are given for four mixed strategies.