Sustainability Comparison of a Geosynthetic-Reinforced Soil Abutment and a Traditionally-Founded Abutment: A Case History

A sustainability comparison was performed for two design alternatives considered for the replacement of an existing culvert bridge southeast of Dupuyer, MT. The first alternative supported the bridge on deep foundation elements and the second alternative employed a geosynthetic reinforced soil integrated bridge system (GRS-IBS). The sustainability comparison focuses primarily on the predicted embodied energy and carbon dioxide emissions for each alternative. Construction costs and some social aspects are also considered. The embodied energy and carbon dioxide emissions estimates were made using the streamlined energy and emissions assessment model, which is a streamlined life cycle analysis methodology specific to geotechnical works. Based on the available data and our assumptions, there is little difference in the embodied energy between alternatives. However, the GRS-IBS alternative resulted in lower carbon dioxide emissions and lower construction costs, suggesting it is more sustainable than the structure supported by deep foundation elements. A sensitivity study suggests these findings are reasonable for the assumptions made in the analyses. One limitation to this study is the uncertainty in the long term performance and reliability of GRS abutment systems compared to that of traditional pile supported structures.