A Multicriteria Based Quantitative Framework for Assessing Sustainability of Pile Foundations
Open Access Open Access
Civil Engineering is the major instrument of anthropocentric development over centuries through ever expanding infrastructure, cities and facilities. Civil engineering processes are both resource and fuel intensive. The building industry alone, during the construction stage, uses about 30-40% of the total resources used in the industrialized countries. There is a growing consensus that delivering a sustainable built environment starts with incorporating sustainability thoughts at the planning and design stages of a project. Geotechnical engineering is most resource intensive although this intensive consumption of energy goes unnoticed mainly because of the indirect nature of the energy used in the form of materials and natural resources (e.g., concrete, steel and land use). Hence, geotechnical engineering warrants a sustainability study to balance the environmental effectiveness, technological feasibility and economic profitability in any civil engineering project.
In this thesis, a quantitative, multi-criteria based sustainability indicator for pile foundations is developed that will aid the design and decision making processes of pile foundation projects. Specifically two types of pile foundations, namely, the driven concrete pile and the drilled shaft, are considered. The impacts these two types of piles create on the environment are investigated from the viewpoints of both resource consumption and process emissions. A life cycle analysis (LCA), which incorporates environmental impact assessment (EIA), is performed to develop sustainability metrics for pile foundations considering resource use, process emissions and waste generation. Other environmental impacts like change in land use pattern, noise pollution, compaction and vibration have been qualitatively considered in the study. Resources utilized in the process are accounted for by the thermodynamics-based accounting methods of exergy, emergy, and embodied energy. An economic cost-benefit analysis is performed to ensure that the framework is not skewed towards environmental sustainability alone. The performance of the individual pile types in the categories of resource use, environmental impact and cost benefit analysis is quantified as scores in their respective categories, and these scores represent the impact indicators. The impact indicators are then incorporated into a multi-criteria analysis with chosen weights for each category and a sustainability index is obtained. Thus, a new holistic approach to incorporate sustainability in geotechnical design and planning is introduced in this thesis.