Vulcan Mill

Specialist offsite design and build contractor PCE Ltd has been engaged to deliver a newbuild seven-storey apartment block with basement as part of the final phase of development at the Vulcan Mill site in Ancoats, in central Manchester. Main contractor Russells Construction appointed PCE after an initial design development phase where PCE worked alongside MPSL Architects and Healey Consulting to develop a DfMA delivery strategy for the scheme.

The new block will house a mixture of one and two-bed apartments creating 101 new homes with both off-street and basement car parking facilities. The site, which is surrounded by residential properties, is sandwiched between the original Victorian Vulcan Mill, previously converted into residential units in 2007, and the Albion Works building thus making the site logistics particularly challenging.

The DfMA solution is a combination of hybrid concrete construction and conventional precast construction with the ground floor slab also being constructed in precast. Beneath the ground floor slab is a 4.0m deep basement box formed by a contiguous piled wall with an in-situ capping beam. The structure internally within the basement is a series of precast concrete blade columns supporting shallow composite Deltabeams which align with the party walls between apartments above. The ground floor slab is a composite slab formed from a long span pre-stressed hollow core plank spanning between Deltabeams and a structural topping. This arrangement of blade columns creates a flexible layout which has allowed the creation of 42 car parking spaces at basement level.

At the front of the building, the blade column arrangement extends through to the first-floor level and allows the creation of undercroft parking and plant rooms. The rear of the building has apartments commencing from ground floor with the complete floor from Level 1 to roof being the apartment layout. The Deltabeams have been designed to carry the line loads from the apartment superstructure above with the ground floor slab transferring lateral loads back into the basement wall via diaphragm action.

The superstructure is being delivered as a precast cross wall solution with main party walls between apartments being 180mm thick precast concrete shear walls which carry long span 260mm thick pre-stressed hollowcore floor units. The inner leaf of the external wall is also precast concrete, formed from a series of 150mm thick panels with preformed openings for windows and balcony doors. This approach creates a flexible and efficient cellular, the structural arrangement of rooms which range from 7.5 x 6.5m to 10.2m x 6.5m. The 'concrete box' which forms each apartment creates a fire compartment with 90 minutes resistance which will then have conventional stud partitions constructed on site to form the internal rooms within the apartment. The precast walls are being supplied with a high-quality, smooth finish and integrated electrical containment, external precast walls are being manufactured with integrated brickwork support channels and balcony connections to allow ease of façade and fenestration connections onsite.

Key to the delivery of the scheme was the craneage and logistics strategy with PCE utilising a Crawler Crane to one long elevation with offloading of delivery vehicles being from the opposite long elevation. The crane has had to be positioned between the existing Mill building and the new structure and will be derigged on the road outside site once complete. This approach has negated the need for using tower cranes which would have created a number of oversailing issues with neighbouring properties.

The complete structure includes in excess of 1800 pre-engineered structural components, manufactured offsite and delivered on a just-in-time basis. For more information visit: www.pceltd.co.uk