Risk Assessment And Preventive Measures Of The Concrete Skew Continuous Beam Bridge During Launching Construction

In recent years, the risk assessment research of bridge engineering is more and morevalued by the engineering circles with the rapid development of bridge construction.The Ministry of transport has also successively promulgated many standard system toguide bridge risk assessment. At present, based on the standard requirement, the riskassessment of bridge engineering is generally confined to the large span, high pier,complicated technology or special structure bridges, but it makes no demands on thesmall or medium span bridges. However, some small or medium span bridges whichused some special construction methods or complex structure can also cause risks bythe construction characteristics and difficulties. According to actual situation of bridgeconstruction, it is necessary to conduct risk assessment for this kind of bridge. LiuyangRiver Bridges of Yingpan road in Changsha city as the engineering background in thispaper is not far from meeting the requirements of risk assessment, but it has thecharacteristics of large slope skewed continuous beam bridge launching construction,which is faced with greater risks than the general launching construction assessment,so it needs to proceed with risk assessment. In this paper, firstly the relevanttheoretical knowledge of risk and risk assessment is discussed; secondly a relativelydetailed introduction about the analysis methods and the characteristics of currentproject risk assessment is provided; finally by comprehensively identifying the riskfactors of each subentry construction project in the progress of launching constructionand using a risk model to calculate the overall risks of the whole launchingconstruction, the corresponding prevention and controlling methods are offered.First of all, starting from the appearing problems during the operation of box girderlaunching, comprehensive identification which is for important risk factors of projectquality, enterprise reputation, and corporate economy which related with launchingconstruction is identified comprehensively, and then these complex factors areseparated into relatively simple basic units.Secondly, using the finite element model to have a simulated calculation for eachlaunching construction in the various operating conditions, judging and analyzing thecalculation which is in order to find the most unfavorable launching construction andthe weakest region of structures, then identifying possible risks of construction.According to the conclusions of the risk identification, a hierarchical model and risk assessment system is established by analytic hierarchy process. The evaluation methodused in this article is the professional investigation method combined the analytichierarchy process and fuzzy mathematical theory together, and quantify the risk whichare defined as indicators and finally acquire the overall risk of launching construction.This method is different from the past single method which can quantify indexeffectively.Finally, based on the risk assessment results, the corresponding risk controllingmeasures are proceed well to ensure the jacking construction carried out smoothly,simultaneously providing good references in order to identify risks and to providetheory and measures for the safe implementation of the future similar concrete boxgirder launching construction.