| Summary: | 碩士 === 國立臺北科技大學 === 環境工程與管理研究所 === 106 === As Taiwan is located in Circum Pacific Seismic Belt, it is important to increase the strength of bridges in Taiwan. According to reinforcement specification for reinforced concrete bridges of highway of Ministry of Transportation and Communications R.O.C, the reinforcement of bridges is defined as the improvement of bridge strength, stiffness, or loading capacity to ensure the safety of bridges and further extending the useful life. In a context of sustainable development and energy sparing, a life cycle assessment (LCA) may be useful tool for making good choices. Literature review showed that most of the LCA studies focused on green material, and mainly for comparing the environmental impacts before and after construction. In contrast, LCA studies seldom examine the environmental impacts of different reinforcement methods of construction. The objective of the present study is to evaluate and compare the environmental impacts of different types of bridge reinforcement methods, and to identify carbon emission hotspots for bridge reinforcement methods. There are three reinforcement methods are evaluated in this study. Three reinforcement methods are as follows: add steel shock absorber, add concrete block absorber, add shear key.
The functional unit of this study is the reinforcement of the bridge deck per cubic meter, and the normal state of the PLA (performance level A) after maintaining a moderate earthquake. The data of this study are provided by an engineering consultant company in Taiwan, including the construction materials and energy of machine equipment, and then finding the corresponding emission factor to calculate the carbon footprint of different bridge reinforcement methods.
The result shows that the carbon footprint of add steel shock absorber is 52,033 kg CO2e/M3, the carbon footprint of add concrete block absorber is 26,651 kg CO2e/M3, and the carbon footprint of add shear key is 18,565 kg CO2e/M3. The results of this study indicate that the raw material stage is the main cause of carbon emissions, and most of them are caused by concrete, cement and steel. The impact of the construction phase on the earthquake-resistant reinforcement construction can’t be ignored. The construction phase accounts for more than 30% of the three reinforcement methods, while the machine that mainly affects the construction stage is a rubber-wheeled crane because the fuel consumption of the rubber-wheeled crane is slightly higher than other machines, which in turn cause the rubber wheeled cranes to emit more carbon than others.
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