Monetary analysis on the embodied environmental impact of highway bridges

In order to evaluate embodied environmental impact of highway bridges quantitatively and scientifically, as well as dig out the key points of reducing the negative environmental impacts, a monetary analysis model of highway bridges under environmental impact was established based on the life cycle assessment method and the willingness-to-pay theory. It can integrate the environmental impact evaluation results into the economic dimension to give them both environmental and economic meaning. The model was applied to analyze the Wubuhe Bridge on Chongqing-Changsha Expressway and explore the distribution characteristics of the environmental impact values of the four parts, which were the basic structure, lower structure, upper structure, and bridge deck system from the perspectives of time and space. Meanwhile, the MATLAB software was adopted to perform Monte Carlo simulation and analyze the uncertainty of the environmental impact value in each specific construction process. The results indicate that the production stage of materials is the key point for controlling the embodied environmental impacts. The global warming is particularly significant among various types of impacts on environment. The environmental impact values of the base, lower, and upper structures gradually increase from bottom to top during the material production stage, and decrease during the construction stage. The piling drilling machinery, hoisting and vertical transportation machinery, and pumping machinery are the key types of machinery, which are main contributors to the environmental impact value during the construction stage. The overall uncertainty of main girder-concrete is the largest, followed by bridge pier-concrete, and taking the coefficient of variation as a measure, the uncertainty of reinforcement construction is less than that of the corresponding concrete construction process, while the uncertainty of total environmental impact is lower than that of various types of environmental impact. The research findings are in accordance with engineering reality, validating the applicability of the model as well as providing scientific basis and beneficial references for the environmental impact assessment of highway bridges. © 2024, Central South University Press. All rights reserved.