On an island site next to London's Tate Modern, two 1960s office blocks were demolished to make way for a landmark development. The three buildings of Bankside 123 provide 70,000 sq m of high specification office space, with retail and leisure facilities at ground floor level. Bankside 1, the first to be completed, is the largest, providing approximately half the development's total indoor area.
Our involvement from the earliest stages of feasibility planning helped de-risk the project and maximize commercial viability. We used 3D modelling to map out a forest of existing mini-piles that congest the site. This informed a successful foundation design which incorporates 52m deep piles and a waterproof basement wall that doubles as support for the superstructure. Plunge columns were sunk directly into the piles to facilitate top-down construction. This shaved two months off the construction programme, delivering potential extra rental income of £2 million.
We ensured that the scheme design could accommodate a steel frame or flat slab construction, increasing the scope of competition at tender stage. The concrete frame chosen was the best value solution.
fire & safety
At Bankside 1 — the first of three new buildings in a major riverside office and retail development — the two top floors are suspended from the steel roof support structure. This massive steel system must be fire resistant for up to 120 minutes as specified in Approved Document B.
Working to the recommendations of code B57974, our engineers calculated fire temperatures under actual conditions in the building and were able to show that the hot smoke temperature at truss level will remain less than 550 degrees centigrade — the temperature of steel collapse — for two hours. The authorities were satisfied that the structure is inherently resistant to the standard required and therefore needs no additional protection, such as intumescent paint. This saved three weeks' construction time and £50,000, and the same process was used to increase construction efficiency at Bankside 2 and Bankside 3.
As part of a bespoke fire strategy, fire engineers were also able to provide for the evacuation of ground floor retail spaces without affecting office workers on the floors above.
Bankside 123 incorporates three new buildings that house 70,000 sq m of high specification office space, with retail and leisure facilities at ground floor level. Bankside 1, the first of the buildings to be completed, is the largest and is provided with a three storey basement.
Two 1960s office blocks formerly occupied the island site next to London's Tate Modern. An early survey revealed that the site was congested with hundreds of mini-piles, obstructing foundations for the new development.
We developed a strategy that combines the use of very large piles — up to 52m deep and 2.5m in diameter — that support internal columns and walls, and a 200m long secant pile wall along the basement perimeter of Bankside 1. Existing foundations were removed only where these clash with the new scheme, and a combination of surveying techniques and 3D modelling enabled us to predict clashes with 100% accuracy.