The Cube is a 24-storey mixed-use development in the centre of Birmingham, England. Designed by Ken Shuttleworth of Make Architects, it contains 135 flats, of offices, shops, a hotel and a 'skyline' restaurant. It is the final phase of The Mailbox development.
The site is enclosed by The Mailbox complex, Commercial Street, Washington Wharf apartment complex and the Worcester & Birmingham Canal.
History
Planning history
As the final stage of The Mailbox development, Birmingham Development Company Ltd. decided to organise a design competition for a building on the site. The winning design was submitted by Birmingham-born architect Ken Shuttleworth of Make Architects.
Plans for The Cube were first submitted to Birmingham City Council's Planning Department on 31 August 2005 for outline planning permission. A six-week public consultation stage was implemented immediately, and the planning application received outline planning permission from the Planning Committee on 7 February 2006.
On 17 May 2006, a reserved matters planning application was submitted to Birmingham City Council, the submission of reserved matters for design, external appearance and landscaping relating to the erection of two buildings. One in the form of a cube incorporating a mix of uses to include car parking, retail, restaurant, office, residential, boutique hotel and skyline restaurant, and one plant building in accordance with the application. Full planning permission was granted by the Planning Committee on 7 August 2006.
The project was originally scheduled to be completed in 2008, but has been delayed. Construction company, Taylor Woodrow had won the project from Sir Robert McAlpine and Miller Construction, but had been unable to agree a final price, with the developer, BDC. Due to other contractors being deterred by the complexity of the design, BDC decided to establish their own subsidiary contractor, BuildAbility. This led Building magazine to dub the project 'Britain's biggest DIY job'. Employees of Build Ability are being offered a 60% share of the profits of The Cube as an incentive to encourage recruitment.
Construction
Preparation for construction commenced in 2007 with the clearance of all structures on site and reconfiguration of a pedestrian bridge towards The Mailbox. Bachy Soletanche Limited (BSL), led by Project Manager Oliver Cooper, then set to work creating a perimeter retaining wall around the site to prevent ground movement whilst the foundations were being constructed. A large diameter auger piling technique was used to install 226, diameter piles at spacings and to depths of . BSL skipped three piles – after installing the first pile – to avoid concrete flowing into the next borehole and therefore damaging the original pile. Due to the presence of groundwater when the piles were bored, a Tremie pipe was used which displaced water to the surface as the bore hole was filled with concrete. At the southwest corner of the site, where the automated car stacking system was to be installed, BSL removed the large diameter auger piles and replaced them with 24Nr, diameter minipiles bored to a depth of . Along the western boundary of the site, a further 54 minipiles were installed to a depth of to provide further support Washington Wharf, an adjacent apartment building. BSL then constructed 30 king post piles to provide the foundation for a temporary ramp which was required for future building works. Each king post pile was formed in a diameter pile, with a square steel column concreted into the toe of the pile. These piles ran in two parallel rows down the centre of the site from Commercial Street.
With all the initial piling works complete, excavation commenced on site by local firm O'Donnell, who had to test various ramp gradients at one of their sites before starting work at the Cube. The optimum gradient for lorries transporting earth from a hill start was recreated at the site, with the surface of the temporary ramp up to Commercial Street being maintained in a coarse condition to give sufficient grip for vehicles entering and leaving the site. A total of of earth and sandstone was removed from the site. Once this had been completed, BSL returned to construct 12 temporary anchors to hold back the retaining piles on the east side of the site. BSL completed the piling project at the end of 2007.