Multivariate Analysis Of Risk Assessment Method During Construction Period For Mountain Bridges

Mountain area accounts for most of our country’s land area, there are considerabledifficulties in construction and use for those highway bridges with a curve, longitudinal slope,high pier and long span.The limitations of its complexity, the complexity of the externalenvironment of uncertainty and the project itself as well as the people prediction abilityresulting in the mountain bridge has a great risk. So far the concreted, perfect risk sciencesystem has not been formed, those related researches still mainly in between eachapplications of industry risk, mainly rely on extensive exchanges of researchers, step by step.In view of this, the theoretical method and specific of mountain bridge risk assessment is verysignificant.In this paper, on the basis of systematically summarized the risk assessment, thetheoretical framework of the mountain bridge construction period of risk assessment, and putforward the risk assessment distinguishing method, probability estimation method, themethod for measuring the loss model. The fuzzy comprehensive method, vulnerability theory,neural network theory, the improved HCR human factors analysis method is applied to therisk assessment on the project, to get a reliable risk analysis results.This paper takes Hubei province of Yichang to Badong Expressway on several typicalmountainous area highway bridges as background. According to the bridge structurecharacteristics and the nature of possible environmental hazards, this paper tests and appliesrisk assessment method presented in this paper:1.Establish a bridge construction period of earthquake risk assessment method, XiangxiRiver bridge model is built by using Opensee finite element software, the earthquake waveobtained by IDA analysis of24seismic wave, input these seismic waves to the bridgestructure model, obtained the corresponding seismic response, select failure strength criterionas the structural failure criteria, using RBF neural network make the Monte Carlo samplingcome true, finally get the seismic risk of failure probability;2.Establish a bridge construction period of landslide and debris flow risk assessmentmethods, use the fuzzy comprehensive method analysed the landslide and debris flow ofXiangxi River Bridge,got the result of landslide and debris flow risk probability and risk andvulnerability assessment; 3.Use finite element software MIDAS to establish the Shennong River Bridge(140m+320m+140m prestressed concrete cable-stayed bridge over Twin Towers) modelconstruction stage, the human factor analysis theory, theoretical vulnerability of Shennongstream of construction phase of the analysis of the application of improved HCR (due to poreblockage, prestress tension process).As well as fall, broken wire hanging basket research onthe analysis, then obtain the risk assessment results.Through the various risk factors assessment study, the following research results of thispaper obtained:1.Set up the bridge construction risk assessment element model consists of the bridgeconstruction of risk identification, risk analysis, risk evaluation and risk control. Among them,proposed models based on the structural vulnerability, improved HCR method and analysis ofman-machine system accident probability risk analysis, constructed the structure failureprobability model during construction, and the probability risk assessment model of multiplefactors and the multiple factor risk loss model.2.Establish the construction period of earthquake risk assessment method based on thecombination of the finite element analysis method and the neural network, using finiteelement software Opensee to establish the bridge model, implementation of Monte Carlosampling using RBF neural network, then get the bridge seismic risk probability of failure.3.Establish a bridge construction period of landslide and debris flow risk assessmentmethod, proposed the vulnerability assessment of risk assessment methods and the bridgestructure method of bridge structure based on the effect of the theory of fuzzy comprehensiveevaluation of landslide and debris flow disaster.