Capital Square
Capital Square is a 122,500 sqft Cat A, office development located on Morrison Street adjacent to the Edinburgh International Conference Centre. The project involved the demolition of the previous Sky Park building which was replaced with the new 3 level concrete basement and 7 office levels above ground.
Location: Edinburgh
Client: BAM Properties, in conjunction with Hermes Investment Management and Parlison Properties
Cost: £40m
Completion: May 2021
Capital Square is located on the site of the Sky Park building, also designed by Blyth & Blyth as part of the original Edinburgh One office development. The Sky Park was demolished to make way for this new development.
The project comprises a 3 level concrete basement which provides onsite parking and provision for plant space. The basement has been constructed in close proximity to the surrounding structures. Excavations adjacent to Edinburgh One were enabled through the use of large diameter Contiguous Piles.
The 122,500 sqft of office accommodation is provided over levels 00 – 07. Level 00 is a suspended concrete flat slab construction accommodating the main, double volume entrance and external landscaped gardens for the tenants. The superstructure above ground floor is steel frame construction comprising cellular steel beams with composite concrete decks.
Lateral Stability is provided by two vertical stair and lift cores located on the North and South of the building.
The completed project is built to a very high specification, including spa level facilities for cyclists and runners. The building also has a private garden usable by occupiers, whilst rooftop terraces on the top 2 floors have spectacular views of Edinburgh Castle and Firth of Forth.
Key challenges
The demolition and construction of the multi-level basement was a key challenge for this project. The basement construction was located directly adjacent to Edinburgh One. This required the use of a contiguous piled wall located, constructed at the interface, to provide lateral support to the excavation of the basement and the installation of the North Core Foundations.
The excavation of the basement was achieved with king post walls on three boundaries. The King Post walls were propped at mid height by flying shores spanning the width of the basement to enable the construction of the foundations, ground slab and the first suspended slab. The temporary flying shores were removed once the suspended slab linked the North and South Cores.
The perimeter concrete walls and ground slab of the basement are constructed with a waterproofing additive, Pudlo, to limit the time required for external tanking allowing the contractor to cast the single sided walls against the temporary king post wall.
Site access was constrained on all sides and construction requires careful coordination and consideration for access and the adjacent land owners and users.
Results
A collaborative approach between client, contractor and design team has enabled construction to overcome the key challenges and constraints posed by the site location.
The end result is the delivery of a high quality office building with iconic views within Edinburgh.