A new prestressed slab product has helped to deliver quality student accommodation at a West Country university within a tight deadline, reports George Tootell, special projects director at Buchan Concrete Solutions
The University of the West of England is soon to be the proud owner of a £77m student village and sports facility. This state-of-the-art facility, which draws on the latest best practice for accessibility, acoustics, security and sustainability, is being constructed in just 19 months, in order to be ready in time for the 2006 student intake.
If that weren’t enough of a challenge, the development, which is being undertaken by Carillion on the university’s Frenchay campus in Bristol, stands out because it is one of the first student accommodation schemes to be delivered under the new Building Regulations and Disability Discrimination Act requirements.
The accommodation consists of groups of self-contained apartment units, each with six en-suite study bedrooms and shared kitchen and lounge areas. Study-bedrooms have a shower pod and several flats have facilities for disabled students. The 24 terraced precast concrete-framed buildings of six and seven storeys are variously clad, and all rooms have prefabricated bathrooms.
A novel feature of the project is the use of the prestressed Wideslab system, developed by Buchan Concrete Solutions and used here for the first time to provide high-quality structural slabs and walls. The slabs are produced on a prestressing facility at Buchan’s Byley factory in Cheshire, which has a daily output of more than 300 m². At Bristol, more than 11,000 units were delivered to site in 39 weeks; at the peak of the work, six 100-tonne crawler cranes were erecting 400 tonnes of concrete a day.
The new prestressed slabs – ideal for multi-unit accommodation – have been introduced for spans up to 4 m and can be produced to a maximum width of 3.5 m.
They used concrete class C40/50, with a de-tensioning cube strength of 35 N/m², and are prestressed by 9.3 mm diameter standard strand on short spans and 12.9 mm diameter super strand on longer spans. The surfaces are power-floated to accept a resilient layer.
The slabs are recessed by 100 mm to accommodate prefabricated shower pods. For 3 m spans, the slabs are 200 mm thick, recessed to 100 mm, and the slabs spanning 4 m are 225 mm thick recessed to 125 mm. The pods for the Bristol project weigh 8 kN/m³, and slab sides are shear-keyed, with joints filled by small-aggregate concrete. Over the width of a building incorporating two rooms and a corridor – about 14 m – four 3.5 m slabs could be used.
Holes for services including the main service riser hole can be easily formed, and a further attraction is that electric conduits can be incorporated within the slab, together with any associated boxes. Slabs can incorporate cast-in pipework for under-floor heating.
All of which means that while this year’s A level students may be fretting about their grades, those who make it to the University of the West of England won’t need to worry about the quality of their accommodation.
New Concrete 2006
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