Assembly of the Liebherr Container Cranes (LCC) by Sarens South Africa is complete in Durban and Port Elizabeth, and is partially complete in Cape Town and at the Coega port.
A 500-t crawler crane, the Demag CC2500, was bought for about R50-million by The Sarens Group for the LCC construction projects at ports around the country.
The second of the two cranes being used for the project, the 250-t Demag CC1100, was already owned by the group and only needed to be transported to South Africa.
The logistics of transporting the cranes to South Africa and then around the country to the different ports is a complex project, Sarens South Africa COO Peter Yaman tells Engineering News. “The biggest challenge is logistics, the planning side – once you have a crane on site and working, it is relatively easy.”
The range of transport logistics that needs to be considered is extensive. The cranes were first transported by road in Holland from their previous locations to a port where they were loaded onto separate ships. Upon arrival at the Durban harbour, they were offloaded from the ships and then had to be transported by road once again from the port to the first construction site at Durban harbour.
The shipping of cranes presents a number of difficulties for project planners. Sarens South Africa MD Martin Verzijl explains that finding an available ship to meet the project timeframe, bad weather and longer port stays, which delay deliveries, is one of the challenges that accompany the importing of cranes like the CC2500 and the CC1100.
Road-transporting the cranes to the different ports requires that they are first stripped down into a number of separate parts and loaded onto trucks. The entourage for the CC2500 alone consists of about 20 vehicles. The main crane component of the CC2500, which is transported on one of the 20 trucks, weighs 65 t.
The same two cranes are being used for the LCC assem- blies at the Durban, Cape Town and Coega developments. The Irish-manufactured LCCs are bigger than previous container cranes used for loading and offloading ships and, therefore, require cranes with a significant lifting capacity for assembly.
Once the crawler cranes have reached the relevant harbour, the container cranes are assembled off-site so as not to interrupt normal harbour activity. When the assembly is complete, Sarens South Africa uses a hydraulic jacking system to lift the LCC up onto a sliding system, which moves the crane into position at the quay. The cranes can be moved distances of up to 400 m. The sliding system can be run continuously for 12 hours a day and it can take several days to move a 1 200-t LCC into position.
The safety systems in place for big equipment like the crawler cranes need to be reliable, says Verzijl. The crawler cranes that Sarens South Africa uses have built-in safety systems that calculate the relationship between the radius of the working area, the height of the crane and the weight of the components being lifted and will not allow objects to be lifted if these elements do not fit into the safety margins. Owing to the nature of the work, and the risk associated with lifting heavy items, the safe load indicator system is an extremely important component on the crane, explains Yaman. The cranes also have wind measurement technologies and the wind speed is factored into safety calculations. This is particularly relevant for work in the Port Elizabeth and Cape Town regions, where there are high wind speeds, says Yaman.
Using cranes in coastal areas also requires operators and managers to be aware of the effect of weather on equipment. Corrosion is one of the main things to be aware of, explains Yaman. Booms are lowered and greased in order to reduce the effect of corrosion.
When assembling the LCCs, Sarens South Africa employs on-site supervisors that are qualified either as riggers or lifting machi- nery inspectors to ensure that safety standards are maintained.
The assembly of the LCCs in Durban is complete. Several of the Cape Town cranes have also been assembled and Sarens South Africa is currently working at Coega ahead of a break in the project. After the break, the crawler cranes will be moved back to Cape Town towards the end of 2010 to complete the LCC assemblies there, says Yaman.