The Analysis Of Environmental Impact Assessment In The Highway Bridge Life Cycle

At present,the scale of China's transportation infrastructure construction has been growing,which has exacerbated the crisis of energy resources and environmental problems.In the design,construction and operation of the highway bridge,it will not only consume a large amount of resources and cause a large number of pollutants emissions,but also cause costly economic losses.In order to meet the requirements of sustainable development in the bridge construction,it is of great significance to carry out comprehensive quantitative analysis of environmental impact on the whole life cycle of Highway Bridge.In this paper,the life cycle assessment method is applied to the field of highway bridge.The quantitative evaluation model of life cycle environmental impact in the highway bridge and the analysis model of life cycle environmental cost has been established.Taking a prestressed simply supported continuous girder bridge deck of Wu-Shen expressway in Guangdong province,the environmental impact characteristics of the bridge life cycle is studied by using the environmental and monetary indicators,and the existing problems of data's uncertainty and sensitivity in the evaluation process has been analyzed,which provide a reliable quantitative analysis system for the EIA of highway bridge and provide the basis for the sustainable development of bridge construction.The main completed tasks are as follows:(1)Based on the technical framework of life cycle assessment and adopting ecological index method,an analytical model of the end failure and quantitative calculation method for the life cycle environmental impact assessment of highway bridge have been established.A program of “highway bridge LCA” is compiled to analyze the case bridge,and point out the characteristics and its formation reasons in the bridge's various stages of life cycle and environmental impact.(2)According to the definition of the environmental cost in the bridge project life cycle,this paper follows the operational,comprehensive,dynamic principle and the corresponding assumptions,the environmental impact cost of highway bridge is reasonably divided.This paper discusses the specific quantitative methods of each cost,and uses the analytic hierarchy process(AHP)to determine the weight factors of different costs,and establishes the analysis model of the environmental impact cost for the bridge.Through compiling the calculation program the of “highway bridge LCEIC”,the case of the bridge is analyzed,from the perspective of monetary indicators to measure the environmental impact of the bridge in the whole life cycle.(3)This paper studies the data quality problems in the life cycle assessment and environmental impact cost analysis of Highway Bridges.Including the use of Monte Carlo techniques,combined with Crystal Ball software,the random sampling simulation is used to obtain the environmental indicators of different life stages on the Bridge case,the statistics of environmental impact costs and the contribution degree of each factor to the uncertainty of the results;By using the method of artificial neural network,using MATLAB software to establish the sensitivity analysis network model of bridge life cycle assessment,and the connection weights between neurons in each layer are extracted respectively,the sensitivity coefficients of each environmental factor to the evaluation results were calculated.According to the result of data quality analysis,it can adjust the factors which have great influence,and provide valuable reference for the improvement of bridge design,construction or maintenance scheme.