Quantification of sustainability principles in bridge projects

Quantifying civil engineering projects in terms of sustainability and meeting carbon dioxide reduction targets is a new challenge for the civil engineering industry. While the development of carbon accounting tools has helped to identify areas of bridge design and construction which have the greatest carbon dioxide emissions, quantifying sustainability overall has been less well studied. The sustainability index for bridges described in this paper is a significant step towards facilitating systematic quantification of the sustainability of schemes through a simple, graphical tool. The output identifies where improvements can be made on a design and allows comparison of alternatives. It can be used throughout the design process to monitor decisions, the success of design changes and to inform decisions on future projects, thereby improving the sustainability of designs. The overall sustainability index rating enables targets to be set for the desired sustainability performance of bridges produced by an organisation. The methodology can be adopted by clients so that, once the key attributes are set and weighted accordingly, designs can be benchmarked across their whole bridge stock. This paper presents the background to the development of the sustainability index, its key features and examples of its use and benefits.