Between the 1950’s and 1970s, a large increase in bridge construction was realized accompanying a large increase in infrastructure. The increase in traffic intensity and weight results in that many of these bridges are now in need of reevaluation, possibly resulting in renovation or renewal. Meanwhile human-caused adverse environmental effects are increasingly impacting the world, of which the infrastructure sector is a large contributor.
This thesis provides a study into more sustainable renewal projects. The objective of this study is to provide a design which will increase the sustainability of renewing bascule bridges. The approach for this study is to:
• Literature review to set a scientific basis for this thesis project.
• Design study to explore the possibilities for bridge leaf design.
• Summary, conclusions, and recommendations to conclude the research project.
To design a more sustainable alternative the “Design for sustainable infrastructure” is followed. The ambitions identified following the “Ambition web” methodology highlights a great influence of a structural engineer in environmental sustainability. Key opportunities to increase environmental sustainability include reusing structural elements, maintaining or reducing the mass of the bridge leaf and designing the structure to fit inside the footprint of the current bridge.
The design process starts by applying “Circular design principles” to design a variant which reuses most of the available elements. Following variants increasingly differ from the current structure by removing elements, changing the materials from of the elements, or using free forming opportunities of FRP to come to new designs.
The sustainability performance is strongly dependent on the current state of the structure. Reusing the main structure and renewing only the deck can reduce the environmental impact of the bridge leaf by up to 53%, while not increasing the mass or requiring more space. Redesigning the entire structure with a full FRP structure can reduce the environmental impact by up to 48% and could reduce the mass of the bridge leaf by up to 33%. For both scenarios, the use of FRP, with a balsa core and partly recycled resins, was thus beneficial for the sustainability of a bascule bridge renewal project.