UC San Diego

Sustainability is increasingly becoming a major concern in construction and development of the built infrastructure. Systematic inclusion of environmental impact and cost as metrics in performance-based engineering frameworks is a primary objective of this research. In this study, this objective is addressed within the context of ground improvement in seismic regions, as a geotechnical application of major economic and environmental consequence. For a representative lightweight structure such as a residential house built on potentially liquefiable ground, three cases are considered. In the first case, the structure is built, and potential settlement damage resulting from seismic activity is repaired thereafter (by re-leveling the structure). The other two cases include a ground improvement countermeasure before construction of the structure, to mitigate such potential settlement damage. Based on a corresponding specific seismically-induced settlement scenario, this study aims to develop a pilot framework for assessment of cost and carbon emissions associated with these three cases. For the stakeholder, the initial as well as potential post-earthquake cost and carbon emissions are assumed to be factors of interest. As such, the framework is presented along with the necessary underlying computations and outcomes. Carbon emissions are computed via two life cycle assessment (LCA) approaches : (i) process-based (P-LCA) and, (ii) a hybrid approach which uses P-LCA and economic input-output LCA. The a priori ground improvement technique considered for this study is vibro stone columns and the method for post- earthquake re-leveling of the residence is compaction grouting. Potential benefits and shortcomings in terms of cost and carbon emissions are contrasted, as a primary element of an overall decision-support process