Sustainability assessment of sheet pile materials: concrete vs steel in retaining wall construction

The construction industry plays a pivotal role in global carbon emissions, prompting a critical need for sustainable infrastructure-development practices. Retaining walls, which are essential for stabilising earth and water pressure in civil engineering projects, represent a significant opportunity to mitigate environmental impacts through material optimisation. This study investigated the design efficiency and embodied carbon and cost implications of cantilever retaining walls constructed with concrete and steel sheet piles. This study employs a thorough methodology that incorporates quantitative studies of the cost and embodied carbon at varying retaining wall heights. The environmental effects and financial viability of the concrete and steel sheet piles were assessed using standardised procedures and local market data. The results indicate that in every height category, concrete sheet piles show consistently reduced total costs and embodied carbon when compared to their steel equivalents. Superior environmental sustainability is demonstrated by concrete, where the embodied carbon levels gradually increase as the wall height increases. On the other hand, steel provides better load-bearing capability, but at a higher cost to the environment and economy, which is especially noticeable in taller structures. This study offers significant perspectives for engineers and other relevant parties to enhance design results that harmonise ecological responsibility with cost-effectiveness in building methods.