Jämförelse mellan en träbro och en betongbro : En LCA-analys med fokus på koldioxidutsläpp samt en LCC-analys

Sammanfattning: This report is a thesis for college engineering program in structural engineering at Uppsala University and was commissioned by the Swedish contractor Svevia. The study aims to provide an overview of the most beneficial bridge material from both environmental and economic point of view. The life-cycle analysis covers only carbon dioxide emissions, since it is the most spoken of in today’s climate agenda. Furthermore, this study aims to highlight which parts, of the system boundary, that contributes to greater carbon emissions for the wood- and the concrete bridge. The life-cycle cost analysis was calculated with a lifespan of 40 years and covers the basic cost of investment, operating and maintenance, and decommissioning costs. The analyzed constructions in this study are existing projects that are almost completed. Both bridges were designed to handle loads up to 60 tons. The wooden bridge is a precast cross tense flat bridge while the concrete bridge is an in situ frame bridge. Since the analyzed constructions in this study differ from each other, the results are presented both as individual bridges and as a comparison study between wood and concrete material in which the functional unit is set to kgCO2 and kgCO2/unit area. To give the reader a clearer picture of the differences in carbon dioxide emissions an additional calculation was done, with an adopted traffic area of 144m2 for both the wooden bridge and the concrete bridge. For the life cycle cost estimation, the bridges’ individual results and a comparative analysis were done. For the comparative analysis between the wooden and the concrete bridge a common traffic area of 144 m2 was adopted.