Construction Safety Risk Evaluation Of PL Steel Girder Cable-stayed Bridge With Walking Push Based On Two-dimensional Cloud Model

In recent years,bridge as a transportation hub,greatly facilitate the interchange between the two places.Our country bridge construction technology has been developed at rapid speed and is located at the forefront of the world.With advantages of light quality,big span,unique structure and high efficiency in the construction,steel girder cable-stayed bridge has been widely adopted in bridge construction,and the appearance of the new technology type pushing up of steel girder cable-stayed bridge provides a new way for pushing up of steel girder.At the same time,the construction safety of steel girder cable-stayed bridge increases a lot of risks,which directly affects the social economy and personnel life safety,and brings inestimable social impact.Therefore,it is necessary to identify the potential uncertain risk factors in construction,adopt an effective and accurate evaluation model to study and judge the risks,take the results as the basis,take the safety goal as the guidance,then put forward the risk response strategy and do a good job of risk early warning.This paper takes the walking jacking construction of steel girder cable-stayed bridge as the research object.Firstly,based on the research status of construction safety risk evaluation and jacking technology at home and abroad,combined with the characteristics and formation mechanism of walking jacking construction safety risk,and based on the construction principle of index system,an initial risk element list based on 5M1 E theory and literature research is established.Based on the questionnaire data,factor analysis method is used to complete the index screening,and finally the index system of safety risk evaluation of steel truss girder cable-stayed bridge is constructed.Then,the COWA operator is used to give weight to weaken the influence of extreme value of subjective score,and then the two-dimensional cloud model is used to construct the safety risk assessment model of steel truss girder cable-stayed bridge by taking into account the two dimensions of risk probability and consequence.Finally,the feasibility of the model is verified in the walking jacking construction of PL Bridge.The main research results are as follows:Firstly,the safety risk evaluation index system of steel truss girder cable-stayed bridge is established,which includes 5 first-level indexes such as personnel factors,material factors and equipment factors and 24 second-level indexes.Secondly,a comprehensive evaluation model based on COWA operator-two-dimensional cloud model is constructed.Third,by observing the output cloud image and verifying the calculation of proximity,the risk level of PL bridge walking push construction is determined as "medium risk".The risk evaluation results are consistent with the actual construction,indicating that the risk index system and evaluation model constructed in this paper have certain guiding significance.Fourthly,after comprehensive analysis of all factors,it is found that environmental factors are at "low risk",while personnel,materials and equipment,technology and management risk factors are at "medium risk".Then the risk control measures are put forward in order to provide reference for similar construction.