Research On Endpoint Damage Assessment Method Of Bridge Life Cycle Environmental Impact

The bridge is an integral part of the modern transport system, one of the major factors affecting the city's economic development and social progress, and to a certain extent marked social and economic development level of a country or region. However as the bridge industry developing at a world wonder scale and speed, the environmental problems it brought become more obvious. Sustainable development has become the trend of international structural engineering, in which ecological sustainability is the most important. The main objective of sustainable development is to protect ecosystems, protect human health, and preserve ecological resources. Thus, to solve environmental problems caused by bridge construction have long-term significance to promote the sustainable development of bridge structure. Bridges not only in materials production stage and construction stage directly or indirectly consume a variety of energy and resources and blow off air pollutants, but also in operational stage and abandonment stage. In order to correctly guiding the bridge structure sustainable development, it's in great need to make systematic analyses and quantitative evaluations of bridges'environmental performance throughout the life cycle, on the one hand to raise people's awareness of the bridge life cycle environmental impact; the other hand to provide evaluation tools to improve the life-cycle environmental impact of the bridge.The research project is funded by the Nature Science Foundation of Hubei Province in China (2008CDB367), and the Southern Taizi Lake Bridge in Wuhan was analyzed as a typical case. Based on the systematical analysis of life cycle assessment theory, a life cycle impact assessment system of bridge was built. An endpoint damage assessment model of life cycle environmental impact for bridges was built based on the Eco-indicator 99 model, the main research results are as follows:1. The life-cycle of bridge was divided into 5 stages:bridge design, raw materials processing, construction, operation, and demolition. Based on the systematical analysis of life cycle assessment impact assessment theory and the typical methods, a life cycle environmental impact assessment system for the bridge was built. The key issues as goal and scope definition, the quality requirements of evaluation data and collection methods of evaluation data are analyzed in detail; 2. Based on Eco-indicator99 model, Human health,ecosystem damage and resource depletion were selected as three endpoint types of environmental impact. The various sub-types of three endpoint types were discussed. And then the quantitative methods, normalization values and weights were identified. Finally a endpoint damage model for evaluating life cycle environmental impact of bridges was built.3. Finally, the Southern Taizi Lake Bridge in Wuhan was analyzed as a typical case study. The results show that the main environmental damage impact of bridges is the damage to resources, followed by human health, and ecosystem quality.