PART 2: PRECAST PANELLING EMBELLISHES NEW HQ BUILDING FAÇADE IN PAARL

Panel installation required a high degree of accuracy in casting and placement.

Written by David Beer on behalf of Concrete Manufacturers Association, this is Part 2 of a two-part series.

Using steel shuttering, the casting was done horizontally on a tilt-up table which was adjusted to an 80° angle after 18 hours, by which time the panels had reached a strength of 20MPa. They were then lifted and stored vertically before being transported to site on A-shaped steel frames mounted on flat-bed trucks.

The upper-level façade panels were cast with a support-beam section at the top of each panel. They extend 185mm from the inner panel face and provide an inverted ledge from which the panels were hung when lowered onto the supporting in-situ beam.

Galvanised steel brackets were used to ensure that the panels were permanently affixed to the in-situ beam. The right-angled brackets were first attached to the support-beams with bolts threaded into fixing anchors, which Cape Concrete had cast into the beams. Then, once the panels were accurately aligned, holes were drilled into the in-situ beam and knock-in anchors, similar to rawl bolts, were hammered through the bracket bolt holes into the in-situ beam and tightened with a spanner.

The panels were also secured at the bottom ends for added stability by galvanised angle brackets which were pre-fixed to the upper-level floor deck and two galvanised steel pockets which were cast into the bottom of each panel. As the panels were lowered into position the galvanised angle brackets were slotted into the pockets and grouted after the alignment process had been completed.

The panels were cast with window sections as well as pockets for the attachment of timber-screened pergolas. The pergolas shade the west-facing windows from the direct sunlight during office hours. They were supported by steel I-beams, which were attached to the superstructure through panel pockets.

After being lowered into position, the ground-floor panels were temporarily supported by push-pull props while they were permanently secured to a steel I-beam along the top ends with cast-in fixing anchors and galvanised steel pockets at the bottom ends.

Cape Concrete director, Johan Nel, said that some of the panels had to be cast with mitered ends for corner installations and that one of the panels was cast with an embedded Delecta logo which required the fabrication of special moulding.

“The project required great accuracy during casting to ensure the required level of precision in the installation of the panels. Extensive planning had to be undertaken to make sure that the installation was trouble-free and the installers spent a day using as-build lines and levels to set out the placement of each panel. This enabled accurate first-time placements which only took small adjustments to achieve perfect alignments. This meant that instead of taking the planned two days to complete the installation it was done in one day,” concluded Nel.

PROJECT TEAM

Client                                              Delecta Fruit (Pty) Ltd

Architects                                      Malherbe Rust Architects

Developer                                     Beston Group

Consulting Engineers                Nortje & De Villiers Consulting Engineers

Main Contractor                         Isipani Construction

Quantity Surveyors                    Best Africa Consulting

Precast Panel Supplier              Cape Concrete

Panel installers                            CPI