June 16 - UK based heavy haulage and abnormal load engineering company JB Rawcliffe & Sons was contracted to come up with an innovative solution for the replacement of an old transformer, located in an 8 m deep substation underneath a car park in Hyde Par

With low permissible ground loading due to the substation below and limited space at ground level, providing a solution was no easy feat.

After working many engineered calculations, 3D drawings, swept path analyses, and testing, JB Rawcliffe engineered a solution, which involved using the company's hydraulic lift system and strand jack technology. The company explained that this combination produced a unique jacking system with an unlimited lifting capacity.

After civil contractors had opened up the underground space, the hydraulic lift system was constructed around the opening, with special bridging mats placed down to support the system over the hatches on the site's strong points.

Due to the time-sensitive nature of the project, JB Rawcliffe preassembled the strand jack frame so that it could be lifted directly from the delivery vehicle onto the site. This reduced rigging time on the site, said the company.

The redundant transformer, which weighed 40 tonnes and measured 5.3 m x 2.7 m x 3.8 m, was then lifted by the system from its position 8 m below ground to the surface and loaded directly onto one of JB Rawcliffe's trailers for onward transport.

In order to install the new transformer, which weighed 27 tonnes and had the dimensions 5.1 m x 2.5 m x 2.9 m, JB Rawcliffe used the same system in reverse.