Multi-hazard Risk Assessment For High Piers And Towers Of Sea-span Suspension Bridges Based On Bayesian Network

Sea-span suspension bridge is a typical long-span bridge with complex structure and high flexibility.Due to long-term exposure to complex disaster environment,common earthquake disasters,high wind speed,and large sea water velocity in tidal action will cause different degrees of damage to them.As the main load-bearing structure and towering structure of sea-span suspension bridge,high piers and towers bear the possible effects of various extreme loads,so the disaster risk is extremely high.Quantitative assessment of its disaster risk is conducive to accurately quantify the damage consequences under the action of multiple disasters,and provides theoretical support for the development of risk prevention and control measures,which has an important guiding significance.In this paper,according to the structural characteristics of high piers and towers of sea-crossing suspension Bridges and the multi-disaster environmental conditions,a multi-disaster risk assessment method based on Bayesian network is established,and the Lingdingyang Bridge,which is under construction in the deep-middle passage project,is taken as the object to verify and evaluate the method.The main work is as follows:This paper analyzes the disaster factors of high piers and towers of sea-span suspension bridge and puts forward a multi-disaster risk assessment method based on Bayesian network.Aiming at the multi-disaster risk analysis of the high piers and towers of the sea-crossing suspension bridge,a multi-disaster risk assessment model of the high piers and towers of the sea-crossing suspension bridge based on Bayesian network is established by using the reasoning principle of Bayesian network and the characteristics of the display dependence between nodes.Combined with the multi-disaster risk decision-making method,a comprehensive multi-disaster risk mechanism flow for high piers and towers of sea-span suspension Bridges with universal applicability is proposed.Based on the multi-disaster risk analysis of high piers and towers of sea-crossing suspension bridge,the damage probability of Lingdingyang Bridge project with multi-disaster risks is calculated.Based on the relevant design data of Lingdingyang Bridge,a simplified model of the bridge tower and transition piers of Lingdingyang Bridge was established to determine the disaster intensity index and its annual exceedance probability,and the damage index was determined by analyzing the bending moment curvature of the concerned section.The multi-hazard risk assessment framework of high piers and towers for sea-crossing suspension bridge based on Bayesian network was completed for Lingdingyang Bridge.Based on the indicators and parameters of Lingdingyang Bridge project,a disaster risk assessment model for high piers and towers of Lingdingyang Bridge based on Bayesian network is established.The risk assessment results of earthquake disaster and tidal scour disaster are calculated and analyzed,and the reliability and applicability of the disaster risk assessment framework in this paper are verified.According to the multi-disaster risk assessment framework of the high piers and towers of the sea-crossing suspension bridge based on Bayesian network proposed in this paper,the multi-disaster risk assessment of the high piers and towers of the Lingdingyang Bridge is completed.