The heavy lifting capacity of modern mobile cranes is revolutionising industrial project roll-out, with complete structures now being moved and lifted. Gaining full benefit from this trend, however, needs careful and early planning, warns Johnson Crane Hire national sales executive Peter Yaman.
“Taking advantage of today’s advanced lifting and moving technology needs a thorough assessment of lifting options, and this needs to be done as early in the project life cycle as possible,” says Yaman. “For this reason, Johnson Crane Hire offers customers our ‘upfront engineering’ service to fully explore which solution will be safest, quickest and most cost effective for the specific project.”
He notes that South Africa did not historically have much capacity to deal with abnormally wide, high or heavy items, and many of the country’s road routes were not conducive to transporting them.
“Our whole construction methodology was therefore aimed at much smaller components, which could be more easily transported, and then lifted by smaller cranes,” he says. “The downside, of course, is that the ‘stick-build’ required on site brought a range of risks and costs. Working at height is always hazardous, for example, and assembly on site generally takes much longer than in a purpose-designed manufacturing facility.”
Yaman notes that it is usually preferable to build an engineered structure or component in a factory environment where manufacturing conditions are more controlled. Here, there are better quality controls, and testing can be conducted before the item leaves the facility for site.
“This is generally a lower risk option than fabricating the item on site, especially where factors like adverse weather conditions, limited availability of specialised equipment and working at height can make the process more challenging,” he says.
Where customers are not fully aware of all the lifting and moving options available to them, they may make assumptions about the most practical route to take. The benefit of Johnson Crane Hire’s upfront engineering is to go beyond these assumptions to set out the alternatives now available, in the light of the project’s priorities.
“As the largest mobile crane hirer in South Africa, we have a wide range of crane sizes and types that each excel in their own applications,” he says. “We are therefore not limited in applying the most suitable technology to the customer’s specific project demands.”
Yaman highlights some of the alternative technologies that can be brought into play when project options are examined at an early stage. In a recent proposal, the company was able to apply jacking and sliding techniques to moving 3,000 tonne concrete units. The sheer weight and size of the units made normal lifting by large mobile cranes impractical but lent itself to the use of a jack-and-slide method to get the loads from the casting area to the location where they were to be installed.
“This was only one element of the solution, however, as gantry systems and strand jacking could then be considered for the lifting requirements of these structures during installation,” he says. “A key benefit of alternative systems like jack-and-slide or strand jacking is their modularity. This means their capacity can be cumulatively increased to match the demands of the items to be moved or lifted.”
The same applies to self-propelled modular trailers (SPMTs), where almost any combination of axle lines can be built into a trailer configuration to suit the load. This suits very long loads, allowing extra axles to be added to extend the trailer’s lifting stability and transporting capacity.
“At Johnson Crane Hire, we have strengthened our capacity to systematically conduct these upfront engineering studies – to safely and cost effectively move their loads from factory to foundation,” concludes Yaman.