Bridges

The paper presents a whole life cycle analysis of bridges and civil structures with due consideration of environment and economic aspects. The study is presented considering variables of constituent materials components so as to reduce the greenhouse gas emissions (GHG) with due consideration of 'cradle to grave' analogy. The focus of this study was on single span and multi span bridges in the road environment. The environmental analysis considered the material variables like supplementary cementitious materials (SCM) in concrete, reinforcement and structural steel raw material source and process of manufacturing. The lifecycle analysis was conducted for concrete and structural steel bridges and the impact of integral and non-integral structures was studied considering the carbon price and maintenance requirements. The critical analysis also considered recyclability and circularity of materials at the end of service life. In the economic analysis, due consideration was given to the cost of steel and including lifecycle maintenance cost. To understand the synergy between environment and economic aspects, the Life Cycle Index was developed where depending upon the client requirements and focus on either lifetime sustainability or initial cost, the sensitivity analysis can be conducted to help in decision making process. It is noted that for concrete structures with higher SCM replacement there is greater reduction in carbon emissions however the steel structures produced by 'green steel' has better outcome considering lighter structures and major circularity benefits at the end of service life. There are further materials noted in the paper that can help in reducing GHG emissions and should be explored further based on the project requirements. At the end it is interpretated that the whole life cycle analysis is important in decision making for sustainability and new materials should be tried beyond standards and specifications with the support of governing authorities to improve sustainability on the projects.