Localized Life Cycle Environmental Impact Assessment Of Bridge Based On Mid-point Model

Bridge, as an important part of modern transportation system, has a profound influence on our country’s economic development and social progress. However, China’s rapid development of bridge construction poses a growing environmental problem. In order to cater to the trend of sustainable development in construction industry, it is important to esTablelish Chinese localized bridge life cycle inventory (LCA) and conduct localized bridge life cycle assessment (LCA). The native bridge-LCA and comprehensive LCI data can be used to guild the quantitative design, construction and maintenance of Chinese bridges.This article focused on the series of critical issues in bridge-LCA, such as:lack of proper life cycle data in bridge, inaccuracy and incompletion of working condition of bridge data, lack of native bridge-LCA, etc. This paper conducted the following research works:1. On the basis of mid-point damage model of life cycle impact assessment, this paper esTablelished a native bridge life cycle assessment system and determined the bridge LCA evaluation boundary and scope combining with the characteristics of bridge engineering. Chinese characteristic factor, standardized coefficient and the weight coefficient of mid-point damage model of LCIA were introduced into the evaluation of the bridge-LCA system,2. According to the boundary and scope of bridge life cycle assessment, this paper collected and completed a large number of input and output inventorying data of the basic construction materials and energy used in bridge engineering,3. Based on the native bridge-LCA, this paper conducted a computational environment impact analysis of different materials, resources and energy related to four stages of bridges such as production, construction, maintaince and demolition, obtains environmental impact potential and environmental impact characteristic value of materials, resources and energies per volume unit or weight unit4. Combined with a case study, this paper focused on the maintaince phase and made a computational environment impact analysis of different bridge reinforcement method through a case of T-shapedsimple-supported beam bridge with low bearing capacity. In order to determine the optimal bridge reinforcement scheme in consideration of environment sustainable, this paper compared the environmental impact of the commonly used four kinds of strengthening methods (enlarge cross section method, paste steel plate reinforced method, paste the fiber reinforced composite reinforcement method and the external prestressed strengthening method).And this paper contrasted and analyzed the environmental impact of different aspects in bridge maintaince phase, including bridge deck resurfacing, Operating power, strengthening, rerouting traffic.5. At last, this paper made the environmental impact analysis on material production stage, construction stage, maintaince stage and the demolition stage of the bridge respectively and then determined the main environment effect of each phase. From the perspective of life cycle of the whole bridge, this paper compared and analyzed the environmental effect between different stages, and obtained the resource of environmental impact potential. Then this paper determined the stages to decrease the effects of the different environment types.