In the Irish construction market new-build has long been the preferred approach of Clients and Public Bodies. However, in recent years the industry has begun to recognise the benefits of adaptive re-use and refurbishment. At DBFL we frequently work on conservation and heritage projects, so it was a privilege to be given the opportunity by our Client Hines, to work on the refurbishment, re-purposing, and re-use of one of Dublin’s most recognised landmark buildings, One Central Plaza.
One Central Plaza is a dramatic building that commands the skyline in Dublin. Originally designed by Sam Stephenson, the 1970’s structure was eight storeys high, uniquely suspended from an innovative roof structure using twelve sets of Macalloy tension bars. The building has a double basement over the entire site. The project involved the complete repurposing & structural refurbishment of all building levels, including the repurposing of the roof area, previously housing plant, to deliver a glass-topped hospitality space affording panoramic views over the city. The building & surrounding plaza was re-designed & extended to house new retail, leisure, and dining spaces.
DBFL’s engineering team was engaged to work with our client Hines to successfully deliver the structural, civil and transportation designs for this complex and challenging project from initial pre-purchase due diligence of the campus through scheme design, planning application, detailed design, tender, construction and handover.
The construction industry is responsible for almost 40% of greenhouse gas emissions globally. At DBFL we want to reduce our impact. Embracing adaptive re-use and refurbishment offers a sustainable approach to construction. In line with Hines’ vision for minimising environmental impact and preserving the architectural heritage of the city, DBFL have had a uni que opportunity to breathe a new extended life into an iconic building in the heart of the city. Through the reinstatement of key building elements and the protection of a unique structure with modern materials and procedures, One Central Plaza has maintained almost the entire original structure and facade.
Circular economy principles were implemented throughout our investigation, assessment, refurbishment, and protecting of the critical hanging tension rods and principle nodes at each level. Plant risers, lift shafts, stairs and staff facilities housed within the cores were completely modified to deliver the needs of a modern office. To preserve the character of the building and to maintain office floor space, the existing cores were retained with interventions kept to a minimum. At roof level, new hospitality levels provide a panoramic space for socialising with maximum daylight and amenity.
The result is a saving of approximately 10,000 tonnes of embodied carbon.
The re-design of the public plaza, along with new retail, leisure and dining spaces engages the public and re-establishes the building in its urban context. The positive impact of the new design at street level and the surrounding area is profound.
Undertaking structural interventions on core walls required that the remaining walls could at all times continue to support the point loads from the massive umbrella trusses at the top of the building. DBFL ensured effective support was maintained through constant modelling of the cores’ load paths, the definition of works sequences / phases, the redistribution of loading through strategic jacking and the embedment of new structural steelwork within the cores. At roof level, the introduction of new mezzanine levels and change of use required full structural analysis of the load-bearing tension structure back to foundations. The ability to safely support modern office loading was also verified through analysis, and vibration modelling carried out.
Retaining the existing building fabric to reduce time, cost and environmental impact was central to DBFL’s design philosophy. A full assessment and refurbishment of the building’s hanging truss and bars system was performed to extend their design life. The two-storey basement car park was partly repurposed to house building plant previously located in the roof space, with the remainder concealed in strategic locations at high level. Some car parking now accessed by car-lift was redesigned at the lower basement.
Collaboration between the Design Team, Contractors and Specialist Service providers has successfully resulted in a modern Grade A building, proudly achieving LEED Gold status. At DBFL, innovative thinking and a detailed understanding of the challenges and complexities of the project allowed us to contribute to reducing the environmental impact of One Central Plaza, and expand our experience in forward-thinking adaptive re-use and refurbishment of the built environment.
Project Director