Specialist heavy rigging and lifting company Vanguard reports that, during the transportation of three transformers from the Richards Bay harbour to the Zeus substation, in Secunda, at the end of last year, it initiated a new transport route that could in future also benefit other transport projects.
General trading company Sumitomo Corporation contracted the company to manage the transportation and rigging of the transformers for the second phase of the substation’s upgrade.
Vanguard was responsible for securing route and structural clearance, as well as organising police escorts for the trans- portation of the 260-t transformers, which are 9,9 m long, 5,25 m high and 4,75 m wide.
Owing to roadworks along the direct route, as well as the dimensions of the transformers, Vanguard decided to follow the Swaziland route, which it had suggested during the first phase of the substation upgrade project.
Vanguard says that it succeeded in motivating the inclusion of an abnormal vehicle gate at the upgraded Swaziland border post, which it believes will benefit many future projects.
“Further roadworks between Ermelo and Bethal forced us to explore alterna- tives for that stretch of road as well, and, as a result, we cleared a brand new route, which has never before seen loads this heavy,” says Vanguard engineer Roland Cumings. The route passes through Middelburg, Stoffberg, Groblersdal, Dennilton, Bronkhorstspruit and Bapsfontein and then joins up with the existing route. In total, the detours more than doubled the mileage to site.
Cumings notes that the company used its Goldhofer modular trailer, supple- mented by additional axles and a 4,5-m deck in the middle for this project.
Crossing a number of bridges along the way, Vanguard had to ensure the correct weight distribution of its trailer. A deck was included in the middle to give the trailer the extra length needed to ensure that the load would never completely be in between two bridge supports, which could result in structural damage.
With a total of 24 axles, the customised trailer configuration was 60 m in length with a width of 4,9 m. The trailer was pulled by two 8 × 4 prime movers and pushed by one 8 × 8 mover.
Another technical consideration was the sensitivity of the transformers. “To protect them from jolts, the trailer did not exceed a speed of 30 km/h and had to drive much slower over the bridges and rough terrain,” explains Cumings.
Throughout the transportation process, megger tests were performed on the transformers to make sure they did not sustain any damage. The megger test checks the state of the transformer by reading the G-force the internal structure has endured and indicates a level at which damage is likely.
“Once on site, we used our new 800-t gantries to offload the transformers, then safely turned them 90° with the help of our custom-designed and -built turntable, before sliding them into position on rails and fine-tuning the placement with jacks and metal slide plates,” notes Cumings.
All three transformers arrived in the Richards Bay harbour during September and October 2010.