Study On Scene Evidence And Finite Element Analysis Of Bridge Accidents

In recent years,domestic and foreign bridge accidents have occurred frequently,resulting in a large number of casualties and major economic losses.It has become particularly important to analyze the causes of bridge accidents.The traditional bridge accident analysis often focuses on finite element simulation of the mechanical properties of the bridge structure,lacking the use of first-hand information on the site of the bridge accident.This article proposes to comprehensively consider the site wreckage photos,videos and construction drawings,or in the absence of some firsthand site data,supplement the data from multiple different levels,analyze the failure mode of the bridge,and construct a realistic finite element model for scientific and reasonable analysis Bridge accidents,restore the causes of accidents and provide systematic ideas and solutions.The accident data of the Dongjiang Bridge in Heyuan,Guangdong is relatively complete,including photos of the wreckage,two different angles of video and construction drawings.Based on the on-site monitoring video of Guangdong Dongjiang Bridge's bridge collapse in the span direction,combined with the analysis of the accidental on-site driving recorder to analyze the lateral collapse process,the bridge damage origin,the formation of plastic hinges and the structural strength failure process of the development were restored,and the bridge pier was initially determined.The lateral deviation is the main reason for the collapse of the bridge.On this basis,combined with the existing construction drawings,a finite element model of the suspended arch was constructed to further simulate the destruction process of the structure and analyze the influencing factors,indicating that the temperature effect contributed little to the collapse of the structure.The Chongqing Light Rail Bridge contains photos and videos of the wreckage on the site,and construction drawings were not publicly reported.Based on this,this article uses photogrammetry technology to restore the external contour information of the structure through the photo of the wreckage,and compares it with the bridge with the same span to preliminarily determine the geometry and material information of the structure.The unbalanced load causes the rigid body rotation of the structure is the failure mode of the bridge.Since the reinforcement has little effect on the rotation of the rigid body,finite element model is established on the basis of comprehensive consideration of the structural geometric information,bulk weight,weight and strength of the closed section,and the control parameters of the collapse process are systematically analyzed.The results of the study show that,by making full use of the photos and videos of the wreckage on the site,the multi-source information coupling that can be used for the analysis of bridge accidents contained in the site can be explored.Based on the qualitative determination of the bridge failure mode,further integration of various engineering information can build a relatively refined finite element model can realize the scientific analysis of the cause of the accident.