Anderson Construction, a reinforced concrete frame specialist, has overcome severe winter weather to complete the structural frames on a new urban regeneration project on schedule.
In a development for Bellway at Tower Hamlets, they used the Bamtec system for the concrete floor slab reinforcement from Hy-Ten to sustain the programme momentum and complete the framework on-time.
Space One in Christian Street is a multi level development mixing affordable housing and high specification apartments, duplexes and penthouses. Augered concrete piles and ground beams were required because of ground conditions to support the reinforced concrete frame structure. Each floor plate was approximately 1000 square metres.
The precise manual placement of reinforcement bars according to the structural engineer’s plan is required in conventional floor construction. This process is labour intensive, slow and especially susceptible to delays due to bad weather. Bamtec reinforcement overcomes many of these difficulties by the use of off-site manufactured carpets of reinforcement.
Adrian Gibbs, group contracts manager for Anderson’s explained, “During September through to February we had some foul weather on this job with many wet and windy days. Using the Bamtec system we were able to make the most of the available fine weather windows to progress the reinforcement installation. Each concrete floor slab was finished in two weeks so the frame could be completed to schedule and without holding up the following trades.”
The Bamtec reinforcement carpet design was based on the specifications of structural engineers SDP in St Albans. Hy-Ten has the largest range of re-bar sizes available in the UK, allowing greater precision when specifying reinforcement. The original specifications were reinterpreted by Hy-Ten’s design team, taking into account their wider range of reinforcement bar sizes.
Hy-ten’s manufacturing process takes design information directly from the CAD system so that reinforcement bars of the correct length and diameter are spot welded onto steel tapes by automated machines in precise sequence. The carpet of reinforcement is taped and tagged with colour coding to indicate its position within the floor for the correct installation. Less skilled labour is required for installation, an important benefit given the high cost and scarcity of skilled operatives in central London.
Once formwork is in place, the first layer of reinforcement carpets is rolled out over Tric Trac spacer, in accordance with the plan. A second layer of reinforcement at 90 degrees to this is then rolled out to complete the lower layer. Prefabricated chairs are positioned over the base layer to create the required depth before the final layers of reinforcement are installed. Other reinforcement detailing such as the manual placement of supplementary bars in areas of greater stress and the installation of sheer bars is then completed before concrete pouring.
“Richard Webster, a director at Hy-Ten explained, “We can address several issues that are crucial for the construction industry such as overcoming skilled labour shortages and project delivery in a more timely way. Given how weather, unexpected site conditions and a host of other problems can set back construction projects, having a system to speed frame construction provides contractors with a vital opportunity to recover time and pull programmes back on schedule.”