The main contractor, Dandara, working with MPA Precast member, Creagh Concrete, to design and construct the structural frames using an innovative offsite fast track modular precast concrete build system, called ‘Rapidres’.
The total frame solution comprises structural walls and solid or hollowcore flooring, and construction speed is greater than alternative systems with significant programme savings. The build was manufactured offsite and took 40 weeks to complete consisting of precast panels, columns, transfer beams, hollowcore flooring, internal cross walls, lift shafts, stair flights and landings.
Benefits of the hollowcore flooring and stair flights used in the offsite build system include:
• Acoustic separation is minimised due to the density of the units
• Inherent thermal mass
• Reduced heating and maintenance costs
• Reduced site co-ordination as many follow-on wet trades are eliminated
• Reduced preliminary costs due to reduced programme times
• Improved health and safety - precast floors and stairs provide an early, secure and broad platform from which subsequent site activities can be undertaken
• Excellent fire protection
For this scheme Creagh Concrete used 250mm deep prestressed hollowcore concrete floor planks for the upper floors. A typical span for a two-bedroom apartment is 10.15 m with no requirement for a structural topping. The floor slabs were designed with a fire rating of 90 minutes.
Each staircore housed two flights and two landings. The stairs were supplied ready for direct decoration with no requirement for plasterboard or suspended ceilings.
Dandara was so impressed with the modular precast concrete system on the successful build at Forbes Place, that it is now using the system on another residential development.
MPA Precast is part of the Mineral Products Association, the trade association for the aggregates, asphalt, cement, concrete, dimension stone, lime, mortar and industrial sand industries. www.mineralproducts.org
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