Casting aesthetically-pleasing architectural shapes is no easy task – it requires a close collaboration between the formwork supplier, architect, engineer and contractor in terms of devising the most optimal and cost-effective engineering solution.
The biggest challenge with difficult architectural shapes is not only how to form them quickly and cost-effectively, but also how to maintain the necessary consistency during construction, highlights PERI South Africa technical manager Riaan Brits and senior project engineer Andrew Rowe. It is for this reason that PERI has developed innovative solutions such as RUNDFLEX, its flagship product for circular and curved formwork, notes Brits and Rowe.
They explain that RUNDFLEX consists of pre-assembled standard panels for curved walls that can be adjusted to suit the required radius, with no modification work on the panel. An additional advantage includes less installation effort due to the pre-assembled units.
Adjustment is quick and easy by means of a template and spindles with self-cleaning hexagonal threads. In addition, the flexible adjustment of wall internal radii of 1m and larger means that RUNDLFEX is a highly variable solution for a range of architectural requirements and features.
Panel connections and compensations up to 10cm are possible with the BFD alignment coupler. Other features are determined tie points, horizontal extensions up to 7.80m panel heights and the availability of components for working and concreting scaffolding, as well as for providing support.
WBHO Construction selected RUNDFLEX when it was appointed in 2015 to transform the derelict Silo Building at the Victoria & Alfred Waterfront in Cape Town into the Zeitz Museum of Contemporary Art Africa (Zeitz MOCAA).
Here the main construction challenge for the formwork supplier was the fact that the existing silos had to be re-sleeved with a 350-mm-thick concrete layer, to a very small radius of under 2.5m, with an average silo height of 33m. The concrete sleeving also had to incorporate various splays.
RUNDFLEX is ideal for the continuous adjustment of the tight inner radii needed as the silo re-sleeving progresses vertically. This has to be carried out in conjunction with an integrated PERI BR platform system to allow for the safe installation of the RUNDFLEX panels by crane. Each silo was built up in 2.5m high vertical forming sections.
The day after each circular wall section was cast, the RUNDFLEX system was removed from the silo in question and placed on a cleaning deck, where the formwork was cleaned and serviced prior to it being deployed again.