Safety Risk Analysis And Countermeasures Of Bridge Design For Urban Rail Transit

In recent years,the construction of China’s urban rail transit network is in the ascendant.Bridges are the key structure.Due to the special nature of the bridge location environment,there are many potential risk sources.Once an engineering accident occurs,it will cause huge economic losses and social impact.Practice has proved that many accidents or problems have certain relevance to the design.However,the research on the risk assessment methods of urban rail transit bridges in China is still in its infancy.In order to reduce the safety risk of rail transit bridge design,it is necessary to strengthen its safety risk analysis and countermeasure research,and establish and improve the design risk control system.This paper systematically studies the risk characteristics,main problems and countermeasures of urban rail transit bridges in the design stage.The main research contents of this article include:1)The core position of design risk in the risk management of urban rail bridges is demonstrated.The design safety risk analysis process including risk source identification,risk level assessment,selection of evaluation schemes and risk countermeasure formulation is summarized,which is a process from qualitative to quantitative,and then from quantitative to qualitative.Combining with the practical experience,the technical risk measures for the common bridge construction condition risk and its own structure risk are proposed,and a set of safety risk analysis framework suitable for rail transit bridge engineering design is established.2)Based on the characteristics of urban rail transit project,four common situations in which urban railway bridge design risks are prominent are summarized: parallel urban roads,crossing(through)existing lines,assembly-type construction and sudden extreme events.By using the fuzzy synthesis method and combining with the weight coefficient,the risk level of each sub-item and the overall risk level are obtained,and the quantitative evaluation criteria are summarized.3)Taking Wuxi to Jiangyin intercity rail transit project as an example,the design risk of urban rail transit bridge project is deeply discussed and studied.Based on the assessment standard,the risk level is preliminarily judged,and the degree of risk hazard is quantitatively analyzed by means of bridge settlement safety evaluation,construction and operation impact evaluation,structural safety inspection and seismic safety evaluation.According to the calculation results,the safety parallel net distance between urban rail bridge and road bridge is given,the road safety protection special program is summarized,the safety evaluation standard and monitoring program for iron safety are integrated,the safety assurance measures for assembled structure of structure checking + intelligent operation and maintenance are proposed and the seismic checking and construction measures are summarized.The elaboration of this paper can provide some reference and help to the units engaged in the engineering design of rail transit Bridges.