Waterfront South Central: Urban geotechnics for the deepest basement and highest building in Ireland

Waterfront South Central represents a groundbreaking development as Dublin’s first carbon-positive campus. This docklands development by Ronan Real Estate encompasses three residential towers and four commercial buildings, setting a new standard for sustainability in the city. Notably, it will showcase Europe’s largest living wall, alongside three remarkable residential towers soaring up to 45 stories and four exemplary commercial office buildings. Following a bulk excavation of 75,000 cubic metres, the basement has three levels and is 15.8 meters deep, supported by a secant pile wall and tie-back anchors designed by our Geo Team. Currently, construction has completed the first phase of all basement levels, with the Lower Ground Floor also nearing completion.

Employed by the contractor PJ Hegarty & Sons and foundations experts, PJ Edwards & Sons, our role is to provide in-depth geotechnical expertise. We’ve been responsible for designing the secant pile wall and implementing tie-back anchors. This contribution is crucial to ensuring the structural stability and longevity of the 3-level basement, one of the deepest in Dublin city.

Eliminating risk

Ayesa has provided expertise in geotechnical engineering, foundation design, and piling, with the primary aim of ensuring the stability, safety, and durability of the basement throughout its lifespan. Ayesa addressed engineering challenges to prevent settlement, structural problems, and potential risks associated with the significant depth of the basement, nearly 16 meters below ground. Ayesa also implemented temporary soil nailing to help prevent soil movement and collapse of the excavation site. Our team has also provided the tower crane base design which is a key part of such high-rise structures including structural design, adherence to safety standards, and ongoing monitoring to ensure the crane operates safely and efficiently in the construction phase.

Geotechnical Considerations

Ayesa has been involved in multiple major underground spaces within Dublin and has a reputation for its technical expertise, practicality, and safety. A key aspect of Ayesa’s involvement was to design the secant pile wall and temporary tie-back anchors to counter soil and water pressures. The Geo Team conducted extensive Finite Element Modeling to assess ground movements and ensure they remain within acceptable limits. Additionally, Ayesa considered the future extension of the excavation near the Luas line and conducted thorough modeling to prevent excessive settlement.

Site Investigations and Mitigation

The team has conducted extra site investigations to understand and mitigate ground risks, ensuring that the proposed construction methods are feasible for the deep basement construction.

Temporary Works and Stability Checks

We were appointed as the temporary works designers for the main contractor, PJ Hegarty & Sons. Our responsibilities include conducting slope stability assessments considering factors such as basement excavation, dewatering, and soil conditions across the site. Regular inspections on the temporary slope’s stability will be conducted during basement construction.

In summary, our involvement in the Waterfront South Central project is characterised by pragmatic geotechnical expertise and meticulous planning. Our contributions ensure the project’s foundation remains solid, and its execution aligns with safety and resilience.

Expertise/Services:

• Foundation Design.
• Crane base design.
• Deep basement.
• Finite Element Modelling.
• Site investigation and Monitoring.
• Temporary Works.
• Stability Checks.
• Slope Stability Assessments.
• Groundwater.