Rapid high precision construction of city development

Doka Slipform solutions ensured the rapid, efficient construction of a high-rise concrete core that is integral to a standout redevelopment in London’s financial district.

The project involves the construction of 2 Aldermanbury Square, a 12 storey, grade A office building with market-leading sustainability credentials located in the City of London. The redevelopment will increase its lettable area significantly from 180,000 sq ft to 320,000 sq ft and incorporate public realm and amenity improvements designed to positively impact the local area.

Selected by specialist concrete sub-contractor Keltbray to construct the building’s 65-metre core, Doka took an innovative approach to the formwork specification and assembly in order to accommodate 12 lift shafts, two lobbies and two staircases within the core’s construction. Architectural demands led to the walls of the two cores being constructed using Doka’s Slipform system. The project’s size and scale demanded a solution that facilitated a safe build at rapid speed. Doka Slipform delivered on both counts. The system enabled the pouring of about 80m³ of concrete per working day on the vast concrete structure.

An additional benefit of Doka’s Slipform system was its easy maintenance and cleaning capability, enabling its readiness to begin effective operation during the strict council-allotted time provided. Up to 11 deliveries of ready mixed concrete per day were required in the construction process, resulting in Doka’s Slipform system exceeding the originally planned ‘climb’ target of 1.7 metres per day by an additional 0.3 metres.

Doka’s excellent working relationship with Keltbray was key to the concreting aspect’s success. Even before the commencement of site activities, the partnership began with Doka’s specialist Slipform supervisor overseeing pre-assembly works in Keltbray’s yard facilities, an alternative approach to Doka traditionally offering pre-assembly works and labour from its own yard.

With space severely restricted on-site, offsite assembly and delivery of the formwork was crucial in terms of operational safety, speed and efficiency. As part of its all-around customer service offering, Doka’s technical team attended the site to oversee the Slipform process and offer guidance when required.

Doka’s innovative incorporation of two concrete placing booms onto the rig via one concrete line was requested by the contractor and the move was instrumental in facilitating a smooth concreting process.

Unique to Doka’s Slipform equipment is its compatibility with a variety of Doka proprietary rental equipment. Potentially, this means customers can reuse equipment on a range of Slipform projects, which has long-term benefits in terms of cost and sustainability.

The Aldermanbury Square project offered further valuable proof of Doka’s ability to design and supply formwork solutions for projects ranging in profile and complexity. The team’s skill in meeting ad-hoc challenges throughout the programme ensured the core’s time-efficient, high-precision completion.