Safety Risk Assessment Of Highway Bridge Construction In Plateau And Mountainous Areas

In recent years,the national highway network in the eastern coastal areas is almost complete.In order to meet the market economy's transportation needs,and to gain access to connection hubs of Southeast Asia,South Asia and other areas and countries,the construction of fundamental transportation in our country began to shift to highlands,hilly areas and mountainous areas with complex and changeable terrains in a large scale.As an important way to cross valleys and rivers,Highway Bridge has become a key point in the future development of the transportation industry in China.Meanwhile,the statistical analysis of the bridge accident shows that there are a number of bridge accidents caused by inadequate construction;these frequent accidents resulted in large number of injuries and casualties and caused bad social impact.The construction risk of Highway Bridge in plateau mountain areas is more severe because of the special environments.Therefore,this paper studies the safety risk assessment of Highway Bridge construction in plateau mountain area.Through the research of related domestic and foreign literature and data,the status quo of risk assessment of bridges at home and abroad at the present stage is analyzed.plateau mountain area is defined,main construction methods and the selection of bridge types of Highroad Bridge in plateau mountain area is introduced based on analysis of construction characteristics.And four risk factors related to the safety of highway and bridge construction in plateau mountain area are clarified:the relationship among people,technology,environment and management.Through analysis of some typical cases of bridge construction in recent years,data about the types of bridges and and the parts of bridges that caused accidents are obtained.The detailed table of risk factors of highway bridges in mountainous areas and mountain regions is obtained by coupling WBS and RBS,and according to Delphi method and experts investigation method,key risk factors in the construction of roads and bridges in plateau mountains are examined from five aspects:construction personnel,construction management,construction technology,materials and tools,and natural disasters.Meanwhile,targeting the deficiencies in the traditional analytic hierarchy process,a method based on triangular fuzzy number correlation geometric feature and analytic hierarchy process(AHP)is put forward,namely fuzzy comprehensive evaluation method based on triangular fuzzy numbers(F-AHP),this method makes the calculation process more scientific.Based on actual engineering cases,with investigation data from bridge sites,geological exploration conditions,and technical specifications,the triangular fuzzy comprehensive evaluation method is combined with expert scoring method to assess the risks of the North Bridge project in Shengge Village,Changdu County,Tibet.And correspondingly,the probability of occurrence of accidents and the risk level of the bridge is obtained:the safety risk rating for the construction of the bridge is "Level Four" and slightly towards "Level Three".The risk assessment results prove that the comprehensive evaluation method can reflect the relationship between different kinds of risks during the construction of Highway Bridges in mountainous areas and correctly assess the risk status during the construction of highway bridges.It could benefit project site construction management,risk aversion and so on in a practical way,and it could also provides references for further research.