Jekko JF545.2 lifts MEWPs over the walls at Craigmillar Castle

The access problem

Craigmillar Castle is one of Scotland’s best-preserved medieval castles, begun in the 14th century and extended over the following centuries. Thick stone walls, narrow entrances and enclosed courtyards were the point of the design, and they are exactly what makes modern plant access difficult.

Historic Environment Scotland, working with Industrial Access Systems Ltd and Aurora Energy Services, needed to position specialist access equipment inside the walls so that inspection and maintenance could be carried out on the structure. The only route into the outer courtyard was a stone arch-gate wide enough for compact machinery and nothing more. Once inside, there was no second large opening to reach the areas where the lifts were needed.

Selecting the crane

The task was to lift and position tracked mobile elevating work platforms over sections of the castle walls. The lifting machine had to pass the gate, work inside a confined historic courtyard, deliver enough capacity and reach, stay light enough to limit ground pressure and be able to move around the site to serve more than one lifting position.

The team chose the JF545.2 articulated crawler crane. Its crawler undercarriage handles uneven and sensitive ground, while the articulated boom gives reach and positioning flexibility inside a restricted envelope. Crucially, it passed through the entrance gate and reached the internal yard — something the project team concluded no conventional crane could have done.

Protecting what is under the ground

Working on a scheduled monument meant considering the archaeology below the surface as well as the fabric above it. Ground protection matting was laid before the crane entered the working area.

“It was brought in as it was the only crane that would do the lift and fit through the front gate, which was very tight for the crane to get through. So from an access point of view it was great for that. The other condition we had to consider was the fact we had to account for archaeological matters under the ground, so the ground matting was laid to protect the ground.”

— Grant Black, HLM Programme Manager, Historic Environment Scotland

Two positions, one machine

After the first lift the crane was repositioned within the courtyard to place a second MEWP at another location. Being able to track between setup points inside the enclosed yard kept disruption down and avoided a second machine movement through the gate.

Source: Jekko — Photos: Jekko