Research On The Construction Safety Risk Management Of Unequal Span And Variable Cross Section Continuous Beam Bridge

With the rapid development of modern technology,the machinery,equipment,materials,etc.used in construction are also constantly being updated.The technology used in bridge construction has been significantly improved,and the types are also developing in a diversified direction.Unequal span and variable cross-section continuous beam bridge project has the particularity of demand in traffic engineering projects.However,compared with the traditional equal span and equal cross-section continuous beam construction,the main structure of the bridge fluctuates greatly,the construction technologies are more complex,and has higher requirements for specialization,and the construction safety problem is particularly prominent.Based on a review of the studies on bridge construction safety risks at home and abroad,as well as the engineering background of the actual needs of bridge construction safety management,this study explored the safety risk management in the construction process of unequal span and variable cross-section continuous beam bridge.The main research work and conclusions are as follows:(1)By exploring the construction process and construction characteristics of unequal span and variable section continuous beam bridge,as well as the case analysis of bridge construction safety accidents,the construction safety risk factors of unequal span and variable section continuous beam bridge were preliminarily identified.Then,using analogy induction and Delphi method,five types of first-class risk indicators and 20 specific second-class risks are determined from two aspects of physical risk and organizational risk factors.The construction safety evaluation index system of unequal span and variable cross-section continuous beam bridge is finally established.(2)Taking the construction project of HS Super Major Bridge as the engineering background,combined with the construction safety risk evaluation index system of unequal span and variable cross-section continuous beam bridge established in this paper,the weight of construction safety risk evaluation index was determined by analytic hierarchy process.Based on this,the proportion of risk factors such as construction technology,natural environment and construction management is obtained.The construction safety risk of HS super major bridge is evaluated by fuzzy comprehensive evaluation method.The results shown that the construction safety risk assessment results of HS super bridge were at a medium low level,and the overall risk was basically controllable.However,due to the large weight of construction technology risk and construction management risk,the risk occurrence coefficient was high.Therefore,the HS super major bridge project needs to pay attention to the prevention and control of safe construction risks.(3)On the basis of determining the safety management decision according to the importance of risk factors from the risk assessment results,corresponding risk prevention and control measures were put forward respectively for five risks,namely construction technology risks,natural environment risks,construction management risks and secondary risks,namely construction materials,equipment risks and personnel risks.At the same time,it also supplemented the countermeasures and suggestions for the construction safety risk control of the HS super bridge project from the perspective of establishing a safety risk supervision system.This study would expand and enrich the existing research on construction safety management of continuous beam,and also provided a meaningful reference for the in-depth study of construction safety of unequal span and variable cross-section continuous beam bridge in the future.The research results not only provided guidance and help for the construction safety risk management of HS super bridge,but also provided a certain reference for the construction safety risk management of complex construction projects such as unequal span and variable cross-section continuous beam bridge in China.