Construction Risk Assessment Of Multi-arch Bridges

Muti-arch bridge is widely used in China and abroad because of its beautiful shape,high bearing capacity and smooth shape.While its construction process is very complex,construction accidents caused by structural stiffness,pouring sequence,temperature stress and other factors have often occurred.It is particularly important to carry out the construction risk assessment to ensure the safety of the project.This paper focuses on risk assessment of mutiarch bridges across the bridge project which is on the highway from Whitefish Bay Town to Dangbi Town.The specific research contents and results are as follows:(1)On the basis of analysis of domestic and international bridge risk research results,according to the structure characteristics of muti-arch bridge,the comprehensive identification of hierarchical decomposition-WBS-RBS-expert survey method was used to identify risk factors in the bridge construction process.A system of risk identification was established and 46 specific factors were identified.(2)The DEA theory was involved in the AHP.The risk factors were sorted by its importance,which would help to find out the main influencing factors,such as the construction personnel quality,the risk of arch scaffolding.Risk factor evaluation was defined to determine the risk level of the whole process of the bridge construction by the theory of fuzzy comprehensive.The result was low and it could be acceptable.Single risk factors were estimated,including two parts of probability and consequences of size.According to the ALARP risk matrix,risk factor level was identified.The highest level was III level,which would be reduced by corresponding measures.(3)Risk factor were dealed with according to the risk assessment results.The general risk factors were given its corresponding decision-making database and the key factors were the focus of analysis to ensure that the level of risk must be declined to an acceptable level.The strength,stiffness and stability of the arch scaffolding were calculated for making corresponding adjustments to the arch scaffolding erection,dismantling frame sequence and arch filler.Professionals were sent to carry out strict construction monitoring of the bridge.The research can provide support for the evalution method of the multi-arch bridges,which can be used as a reference for the evaluation of similar bridge types.It has a certain guiding significance to improve the bridge risk assessment theory further.