Schöck Bole prevents punching shear risk on major Manchester project

Sitting adjacent to Manchester Victoria station, the£185m New Victoria mixed development is a two-phase scheme which will initially provide two residential towers of 20 and 25 storeys comprising 520 one, two and three bed apartments. An eight-storey, 150,000ft² office block is scheduled for the second phase. The residential towers are solid in appearance, with the façades referencing the surrounding historic listed estate along Corporation Street. The layout of the two structures maximises the number of apartments with dual aspect views resulting in a central core with three wings. The façade concept is a ‘hooped envelope around a glass box’ with the ‘envelope’ consisting of vertical panels from the first floor to roof level in a mix of profiled and flat panels. These also wrap around the top of the buildings to provide shelter for the rooftop terraces.

Punching failure risk is a critical issue

The buildings are concrete frame, constructed using a slip-form method. An economical form of construction with benefits such as shuttering time minimisation, simplification of reinforcement work, ease of underslab work and importantly, the optimum use of space. However, with flat slab construction the risk of punching failure is always a critical issue. When increasing the loads in the stress areas, a great deal of consideration has to be given to variables such as the quality of the concrete, improving the reinforcement content and even enlarging the column heads. None of these options is necessarily time efficient or cost effective. They rarely solve the problem to an optimal performance level either. So the ideal solution to resolving any potential problems involving punching shear, needs to be cost-effective, easy-to-install and certainly dependable.

Greater resistance than a typical stirrup system

To prevent the risk of punching failure on the New Victoria development, the Schöck Bole reinforcement system has been installed. This trusted and popular solution consists of double-headed studs and anchors, with spacing bars, which enable installation after the bottom reinforcement and before the top layer. Two spacer bars are welded to the vertical studs, which ensure the correct distance between uprights; and the forged stud heads guarantee a perfect finishing bond with the concrete. As result, when compared with a typical stirrup reinforcement system, an increased shear force resistance of around 70% is achievable. Bole is a cost-effective, timesaving solution – and straightforward to install.

In addition to the standard Bole solution, Schöck has developed three other punching shear reinforcement variants. The type U, designed for installation before the lower mat; the type O for installation after the top reinforcement layer; and the type F for use in element slabs at prefabricating plants. The entire range is supplied ready for installation. There is downloadable user-friendly Schöck design software available too, which enables fast and simple dimensioning of the product to British Standards and the export of CAD drawings with dxf-format.

For further information on the Schöck Bole system contact the company on 01865 290 890 or visit www.schoeck.com