Construction World February 2017

Safety is the foundation of all tower crane erection at SA French. This photographs shows a rigger doing operation.

This photograph aptly illustrates a major advantage of a topless crane. It shows the jib foot being lifted with the trolley and hook block already pre-reeved.

the company’s projects going forward. “The purchase decision was based on the fact that we will be using it a great deal,” says Buck. “The market for high rise, urban residential projects is relatively active in Johannesburg, and we expect that it will continue to be put to frequent use.” Working alongside the busy Katherine Street is an added challenge, as concrete mixers and low bed trucks have only a slither of pavement to pull off onto and discharge their loads. “Careful planning combined with cooperation from our suppliers ensures that we have seldom had to request traffic disrupting lane closures,” says Simmonds. He says one of the advantages of the flat-top crane in this environment is that its jib can be assembled in-situ, rather than having to be done on the ground before lifting, which takes more space and lifting capacity, and invariably leads to greater congestion on the site. 

challenges during construction stage. “All these high rise sites are space constrained, as they tend to be in established suburbs where buildings are close to each other,” says Probuild contracts manager (buildings) Matthew Simmonds. “Logistics in this environment are quite demanding, as contractors have to deal with all the same volumes of material as any building construction, but with less space for storage, deliveries and moving material around.” He says this demands better planning and co-ordination to ensure an efficient sequence of operations, so that material is at the right place at the right time. In the case of Capital on the Park, says Simmonds, about 3,5 million bricks will need to be moved into place to construct the building; at 500 bricks per pallet, that means moving about 7 000 pallets to where the bricklayers are, and the bricklaying will go as fast as their material supply will allow. “This is the reason why we added another tower crane – a Potain flat top MCT85F5 model – to our on-site infrastructure in November to augment the larger Potain MD310B unit set up early in the contract,” he says. “While the primary crane is dedicated mainly to convey formwork, reinforcing and concrete, the second, smaller crane was brought on board to serve the wet trades – mainly brickwork and plaster. “Cranes are a substantial consideration when planning preliminary and general (P&G) costs for a project,” says Buck, “but we have learnt from experience on this kind of contract that there are times when logistics – moving material to where it is needed – can become a severe constraint to the work programme. Tower cranes facilitate rapid movement of materials, especially on space constrained sites, to help keep the work programme on track.” The Potain MD310B crane is on hire from SA French, while the flat-top crane was acquired by Probuild this year and is expected to be kept busy on a number of

5376 Balance of the counter weights being fitted.

Louw Smit, sales manager SA French, Kobus van der Merwe, site agent Probuild and Matthew Simmonds, contract manager Probuild.

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CONSTRUCTION WORLD FEBRUARY 2017