Concrete Magazine highlights resulting reduction of overall floor depth and structural dead load
The use of three-dimensional BIM techniques was critical during the tender period of the recently completed Avenue MSCP project and following the contract award, it enabled PCE Ltd to develop the car park element of the structure as an efficient precast hybrid concrete solution using its in-house designed-and-developed long-span GT flooring units.
The prestressed concrete GT units are designed to meet the required car park structural loading criteria without the need for the casting of any additional on-site reinforced structural concrete over their top surface, which gives a significant reduction in on-site activities and associated disruption, enabling following trades to progress more rapidly.
Two direction fall
Due to the car park deck being non-rectangular in plan and the development’s principal anchor stores, adjacent to either side of the car park, having differing floor levels, all of the decks were required to fall in two directions. In certain areas, this required design development of the GT flooring units to enable them to be splayed, cast with a 25mm fall across their top surfaces and the use of solid GT units to support reinforced concrete ‘cheese wedge’-shaped units. The longest unit was 17.8m by 1.5m wide which included a splayed end, while the solid slabs weighed 22 tonnes.
Compared to other off-site solutions of similar span, the GT floor units provide a reduced overall floor depth and structural dead load.
In certain areas, having a 25 mm fall across the width of the GT unit was insufficient to provide the transitions required, which resulted in the bearing corbels of the supporting beams and walls also having to be stepped. Prior to production commencing, two full-scale mock- ups were prepared to prove the structural geometry and adequacy of the non-standard GT units and supporting beams.
Compared to other off-site solutions of similar span, the GT floor units provide a reduced overall floor depth and structural dead load, which leads to a reduction in height and weight of the supporting precast concrete bearer beams, as well as a more efficient design of other structural frame components.
For the Avenue MSCP, a consistent high quality anti-slip brush finish was required for the surface of the car park floors. This was easily achieved with the GT units due to the high-quality control capabilities of factory-engineered concrete.
Extract and download courtesy of Concrete Magazine.
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