Delivering each of the transformers on two separate occasions, Collett mobilised their 250-tonne capacity Goldhofer girder bridge in modular form, arriving in Stafford to configure the trailer and load the first of the cargoes.
Once loaded, the transformer and girder bridge combination featured a 65.8 metre overall length, with a rigid length of 41.6 metres. This required extensive surveying and route planning ahead of the first leg of the project, transporting the cargo from Stafford to Ellesmere Port.
Having undertaken route access surveys, visual route inspections and numerous swept path analysis reports, the Collett team identified several modifications and traffic management procedures to allow the cargo to safely navigate the route from the point of origin to the port. This included extensive street furniture removal (including electrical elements), tree trimming, parking restrictions and designated hold points to allow the continual flow of traffic.
Departing from the Stafford facility, Collett travelled 70 miles over two days, with a total of 11 hours travelling time. Undertaking contraflow manoeuvres at several highlighted pinch points along the way, the Collett team travelled from Stafford, via Stoke-on-Trent and Congleton, before heading west towards Chester and final onward arrival at Ellesmere Port.
Waiting at the port was a Leibherr LG1550 mobile crane. Here, working under CPA Contract Lift Conditions, the Collett team unloaded the 215-tonne super grid transformer from the girder bridge.Having undertaken all the ship’s chartering operations, the transformer was loaded directly to a coaster vessel for onward shipment to the Port of Aberdeen. With the cargo safely lashed and secured on board the vessel, the coaster set sail for Aberdeen while Collett dismantled the girder bridge trailer. Then, travelling once again in modular form, the Collett team transported the trailer via road to greet the incoming vessel and transformer at the Port of Aberdeen.
Arriving three days later in Scotland, the transformer was discharged from the vessel by a 600-tonne strut crane directly to the girder bridge trailer for the final leg of the journey. With the final 14 miles having also been extensively surveyed in the planning stages of the project, all street furniture and route modifications had already been completed.
This included the relocation of a post box and the widening of site access roads to enable the 4.2 metre-wide load to gain entry to the site. With all this in place, the loaded girder bridge arrived on site at the 400kV substation extension site at Leylodge, Kintore.
Once unloaded on site, and having undertaken detailed ground bearing and pressure calculations, the Collett team began jacking and skidding operations to position the cargo.
Utilising its specialist hydraulic equipment, the team were able to jack and skid the super grid transformer, accurately monitoring force and pressure during the operation, including forces on the jacks, on each skid shoe and maximum ground pressures throughout.
All this combined allowed Collett to safely and successfully deliver the first of the two transformers, returning to GE Stafford’s facility in the following weeks to begin the operation to deliver the second transformer. Following the same procedure, the Collett team loaded, transported, shipped and positioned the second of the transformers, completing the Kintore substation extension project.
View the accompanying video here: https://bit.ly/3lJ0Uoe