Dynamic Risk Assessment of Large Bridge Construction

Abstract:

To solve the problem of dynamic changes in risk assessment of large-scale bridge engineering， the structure-risk decomposition identification method was used to complete the preliminary identification of risk elements. Beside the DEMATEL was introduced to identify dynamic assessment risk elements， and the risk element transmission network was extracted. Moreover， Bayesian network and Genie software were applicated together with the reverse reasoning and sensitivity analysis to perform Bayesian probability calculation on the risk element transfer network， for obtaining the main risk element transfer chain and the key risk elements. This method was used to conduct the dynamic risk assessment of the whole construction process of the Wufengshan Yangtze River Bridge. The results show that 234 dynamic risk elements， 104 key risk elements and the corresponding main risk chains were identified in the whole bridge construction. The probability values of “high-speed railway driving safety”before construction and after the completion of the main girder were found to be 0.065 2 and 0.009 1 respectively. The related key risk elements are uneven settlement of caisson， linear deviation of main cable and so on. The main risk chain is uneven settlement of caisson →position change of anchor body → displacement of anchoring system → deviation of main cable line shape → uneven deformation of sling → line shape change of main girder → insufficient smoothness of railway bridge surface → driving safety of high-speed railway.

Key words:bridge engineering;risk assessment;risk element transfer;Bayesian network