The Schöck Isokorb structural thermal break for concrete-to-steel connectivity has been widely incorporated into the Islington Wharf project in Manchester. This landmark residential scheme, designed by Ryder Architecture, lies adjacent to the attractive waterside setting of the Ashton canal and is the third phase of an established residential development. The project includes 220 new build dwelling units, comprising a mix of town houses together with one, two and three bedroom apartments. They are all built around a central mews-style courtyard – each with a balcony.
An Isokorb hollowcore combination
To minimise any risk of thermal bridging at the balcony connections, Schöck Isokorb structural thermal breaks are incorporated throughout. Block A is a conventional recessed balcony installation; but Block B had different requirements. The Schöck Regional Sales Manager responsible for the project, Ashley Houlton, explains: “One of the UK’s largest manufacturers of prestressed hollowcore, Acheson & Glover, supplied the flooring and the core diameter allowed many of the Isokorbs to be cast easily inside. This involved casting in-lap reinforcement bars at AG’s manufacturing facility and on site, breaking out the cores to suit the balcony steelwork and introducing lap splice reinforcement within the hollow cores. The Isokorb products were installed using a template for accurate spacing, the broken out cores then filled with insitu concrete. Where the balcony span was perpendicular to the Precast Planks, AG offered an unpropped composite PlateSpan system. This allowed a fast, flexible solution to accommodate the Isokorb units within an insitu topping”.
Eliminating undesirable vibration
Another factor though was the relatively large cantilever depth, which can easily influence the natural frequency and therefore the vibration behaviour of the steel balconies. To assess how prone to vibration the balconies might be, Schöck has a software package available which uses geometric and material variables. This calculates the Natural Frequency of the steel balconies and by adopting a limit frequency of 7.5Hz for steel balconies it not only eliminates the possibility of undesirable vibration, it also enables the design of cost efficient structures. With Islington Wharf, the balcony geometry, cantilever length and spacing between the connections was critical and by using the ‘Natural Frequency’ software it was possible to optimise the overall number of connectors required.
Verifiable performance
In addition to concrete-to-steel capability, Schöck also provides solutions for concrete-to-concrete and steel-to-steel. The range meets full compliance with the relevant UK building regulations, has NHBC approval, LABC Registration and independent BBA Certification.
For a free copy of the Schöck Thermal Bridging Guide and / or the Thermal Bridging Solutions brochure contact the company on 01865 290 890 or visit www.schoeck.co.uk The website also features an extensive range of downloadable software. .
