Life Cycle Assessment of Drilled Shafts-Article

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The paper demonstrates how life cycle assessment (LCA) can be used to evaluate the environmental impacts of drilled-shaft foundations and support more sustainable geotechnical design. LCA tracks resource and energy use, emissions, and environmental impacts across a product’s life cycle. The study explains the four main LCA stages—goal and scope definition, life cycle inventory, impact assessment, and interpretation—and provides example calculations.<br /><br />The authors designed 22 drilled shafts for two homogeneous sandy soil profiles, considering both bearing capacity and settlement requirements. The assessment used cradle-to-site boundaries, covering raw-material extraction and processing, concrete and steel production, transportation, and construction. It evaluated nine impact categories, including global warming, acidification, eutrophication, particulate formation, and toxicity. The analysis relied on established databases, with some processes—such as bentonite slurry—estimated using substitute data or excluded where their contribution was judged small.<br /><br />Results show that global warming, marine eutrophication, and photochemical oxidant formation are the most significant impacts. Concrete and reinforcing-steel production, including raw-material extraction, account for most impacts; transportation and construction activities contribute comparatively little. Larger shaft diameters generally increase impacts because they require more concrete and steel. Longer shafts can sometimes reduce impacts when their design allows a smaller diameter and lower total material volume. Impacts also vary with soil conditions and the resulting shaft dimensions.<br /><br />The study’s results are illustrative rather than universal: they depend on design assumptions, databases, and site conditions. More accurate estimates would benefit from current, location-specific data and measured equipment fuel use. The authors conclude that LCA can help engineers compare design alternatives and account for environmental performance alongside cost and safety, while noting the need for better data and geotechnical-specific guidance.

Keywords

life cycle assessment

drilled-shaft foundations

geotechnical design

environmental impacts

global warming

concrete production

reinforcing steel

sustainable engineering

impact assessment

soil profiles