Carbon Footprint of Common Quay StructuresÂ-Paper

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The study compares the embodied carbon of three common quay structures for a container terminal: concrete caissons, steel sheet-pile combi-walls, and open-piled suspended decks. Using a Life Cycle Assessment (LCA) approach, it evaluates emissions from material production (A1–A3), transport (A4), and construction (A5) for designs with a 50-year service life. Use and end-of-life stages are excluded.<br /><br />The steel combi-wall has the lowest baseline carbon footprint, followed by the caisson; the open-piled deck has the highest. Material production accounts for approximately 80–90% of emissions, while transport and construction activities contribute substantially less. The open-piled deck’s high footprint is attributed largely to its concrete and steel quantities.<br /><br />A sensitivity analysis examined options including higher recycled-steel content, alternative concrete binders with fly ash or ground-granulated blast-furnace slag, reduced caisson reinforcement, and shorter tubular piles. Combined optimisations could reduce emissions by roughly 30% for caissons, 26–32% for combi-walls, and 40% for open-piled decks. The combi-wall remains the lowest-carbon option after these changes.<br /><br />The authors note that achieving very high recycled-steel content may be constrained by limited scrap supply, and that alternative binders can affect concrete strength development and construction schedules. They recommend further study of construction-equipment emissions and the carbon benefits of recovering and recycling steel at the end of a structure’s life.

Keywords

embodied carbon

life cycle assessment

quay structures

container terminal

concrete caissons

steel sheet-pile combi-walls

open-piled suspended decks

material production emissions

recycled steel

alternative concrete binders