Integrating bridge maintenance life cycle assessments into bridge design for improved sustainable decision making

Balogun, Teslim Bamidele

Abstract

Environmental sustainability issues are being considered across many construction sectors, emerging from global concerns on resource depletion and CO2 emissions. Whilst construction sectors are minimising the environmental impact of their activities and the associated CO2 and GHG emissions, not many of these environmental issues are factored into the early design stage of bridges to facilitate design choices. Consequently, environmental impacts of bridge maintenance activities are not factored into the bridge design process. Doing so can potentially reveal the overall environmental performance of the bridge and enhance design choices. The LCA environmental tool is gaining ground across many construction sectors, because of its capacity to reveal the environmental impacts of process and services. LCA has been only minimally explored for bridges, and its integration into the early design process has not been seriously attempted. In fact, only a small volume of literature has considered LCA application to bridge maintenance activities, and that without considering the scope for influencing sustainable bridge design decisions through stakeholders’ input.
The research was undertaken to provide insights and recommendations for incorporating LCA result of bridge maintenance methods at the early design stage to aid sustainable design choices. The study employed an explanatory mixed-method approach. The study conducted a thorough literature review to understand and explore the environmental aspect of sustainability in bridges and the trend and usefulness of LCA results in the bridge industry. Results revealed that not many environmental matters are considered for bridge design and maintenance, and that LCA application for bridges is limited to comparison of materials, components and structural types. As such, this study launches an LCA analysis of some major maintenance activities of concrete, steel, and masonry bridge, which is mainly assumed for other studies. Data required for the LCA analysis was derived from secondary sources (that is, literature) and verified by industry experts through an online survey. Purposive sampling strategy was employed in selecting relevant experts. Verified data were combined with primary data obtained in the SimaPro database used to conduct the LCA analysis. Results revealed expansion joint and bearing replacement as key sources for high environment impact in concrete and steel bridge, whereas saddling rehabilitation had the most impact for masonry bridge. The overall comparison revealed masonry bridge as the least environmentally impactful bridge on account of the selected maintenance actions.
Through a semi-structured interview, the study presented the derived result to bridge design experts to verify and reveal the usefulness of the result. Experts revealed the emergence of masonry bridge (as the least impactful structure) as the major usefulness of the result. Any industry drive towards masonry bridges is, however, constrained by initial construction cost, span limitation and speed of completion. General findings from the study revealed that LCA incorporation into the design process will be a complex matter, as the design process is already intricate, and environmental concerns are not a major design criterion. The study therefore makes recommendations that can enhance the consideration of LCA, and consequently LCA of bridge maintenance actions, in the early design process. The thesis concludes by making detailed recommendations to policy makers, researchers, designers, and bridge owners.

• Thesis Type: Thesis
• Publicly Available Date: Jun 7, 2019
• Keywords: Life cycle assessment, bridge maintenance, bridge design, sustainability, environmental impact
• Public URL: https://uwe-repository.worktribe.com/output/860594
• Award Date: Sep 14, 2018