Waterman’s team in Dublin is providing civil and structural engineering design services for the scheme, working alongside the architect, Henry J Lyons, to maximise the potential of the redevelopment whilst preserving the historic building for future generations to enjoy. The design includes the careful removal of multiple layers of historic shop fit-out and modifications to allow the original structure to be revealed. Working closely with the demolition contractor, we helped develop a demolition phasing and temporary works scheme which ensures the stability and structure of the historic building will be maintained and protected throughout the development.
A mixed-use development across three buildings comprising five diverse elements
Developed by Oakmount in partnership with Europa Capital and Core Capital, the mixed-use development is spread across three buildings and comprises five diverse elements. The 60,000 ft² historic department store, Block A, is currently being redeveloped and incorporates the addition of Clery’s rooftop bar and restaurant above, complete with breath-taking cityscape views including the world’s tallest sculpture – The Spire – which soars into the Dublin skyline from its home nearby on O’Connell Street. Elsewhere, a new 176-bedroom boutique hotel named The Clery will be added, and 92,000 ft² of premium Grade A office space will be created at The Earl Building, with 8,500 ft² of new food and beverage amenities at Earl Place Market completing the scheme.
Revealing the original structure
With demolition and strip-out commencing in summer 2019, all blocks have now been stripped-back and demolition of both the 1970’s North Earl Street structure and Clery’s warehouse building on Earl Place is complete. Within the original 1922 building, intricate demolition has steadily progressed, stripping away the 1940’s and 1970’s interventions. This includes the removal of the atrium infill structures, the roof structure, and the upper floors behind the original Portland stone colonnaded façade. Waterman Moylan’s efficient temporary works scheme, developed in coordination with the main contractor, has been implemented to allow demolition to proceed unimpeded, whilst protecting the existing structure.
Careful planning and phasing
Temporary works, piling, demolition and construction have all been carefully planned to happen in tandem, allowing great progress to be made with the scheme moving forward in different sections of the development. The new construction elements of the scheme have now begun, seeing all new reinforced concrete cores within the atrium and perimeter of the Clery’s building, up to the new third floor level, now in place. These cores tie into the existing structure, supporting the new steel framing of the upper levels with a series of bespoke steel cast-in plates which will carry the efficient long-span cellular composite beams supporting the new floors.
Vertical steel frame within the original building
Within the original Clery’s building, erection of vertical steel frame elements has now commenced, with approximately 50% of the new steel columns now installed up to level three. These steel columns will support new floors at level three and above, while the existing 1920’s columns and floors are retained below. The new columns have been located to respect the structural grid of the protected lower floors and are aligned to minimise their impact on the retained floor plates.
In order to maintain the continuity of the existing ‘Hennebique’ concrete floor beams, and to prevent harmful effects of differential settlement of the new frame relative to the existing, the new steel columns are intricately detailed to bridge the existing floor beam structures with bespoke stiffened splice plates at the floor levels. These two disparate structures, new and existing, will be tied together only after the new superstructure has been completed, allowing any settlement of the new structure to occur without transferring any stresses to the existing 1920’s frame. Steel beam and composite decking installation has begun both in the atrium and along the existing façade, and this will complete the new façade restraint system installation, allowing for final the elements of demolition to take place.
Micropiles
These new superstructures within both the Clery’s building and the Earl Building are supported on super-slim reinforced concrete pad and raft footings. Foundation depth has been minimised to maintain a formation level above the existing ground water level, mitigating the requirements for dewatering in gravel deposits adjacent to existing structures. The pile system used in the foundations is highly efficient and features methodically arranged micropiles, allowing for installation in reduced head height with relative speed, with a series of vertical and raked piles also installed to support the new structures.
Rapid pace
The Earl Building’s new basement is also progressing at rapid pace, with the foundations now fully installed and basement slabs, perimeter walls and vertical elements also nearing completion. This will allow the commencement of construction work on the building’s superstructure which will comprise a traditional reinforced concrete frame. Enabling works for the new Clery Hotel have also been completed, with contiguous piling utilised to enable the excavation for the new basement and temporary works to protect and monitor the surrounding structures now in place.
Waterman Moylan’s Lead Designer, Associate Anthony Byrne, said: “The Clery’s Quarter project represents a major step forward for the main street of the capital. It is a privilege to be involved in the restoration and retention of such an iconic building, and to compliment it with such an impressive development. The project has posed many technical challenges that we as a team have overcome with the best practices and principles of engineering.”
