MOVE BIG THINGS under 225,000 Volt high voltage: SENNEBOGEN 120 t telescopic crawler crane is the only crane to meet the requirements of a Parisian construction site

Sefi-Intrafor, the main contractor for special civil engineering work at three other underground stations, has decided to rent a 120 t SENNEBOGEN 6113 E crawler crane from the ENCO fleet for work on the extension of line 14 south of the Paris underground to Chevilly-Larue. The work, carried out under RATP project management with the Systra-Setec Group as prime contractor, is both highly complex and restrictive in nature:

High complex and restrictive construction site below 225,000 volts

The main difficulty of the project is due to the presence of the Réseau de Transport d’Electricité (RTE) high voltage line over half of the right-of-way of the future Porte de Thiais metro station at Chevilly-Larue. This is a very high voltage line (225,000 Volts) that provides power to the Orly airport platform. "The particular nature of this section is that it is one of the only ones in the grid that the utility company cannot divert.

As a result, the entire setup of the site is based on this very particular situation," explains Frédéric Roche, Construction Manager at Sefi-Intrafor.

"Working near a very high voltage line creates huge safety issues. Well before the start of construction we considered the most appropriate practical solution to address the specific nature of the site and the one that would provide the safest environment for us to work in". This solution was found with the SENNEBOGEN 6113 E telescopic crawler crane.

A unique configuration for special demands

After consulting RTE regarding height measurements for the cables and determining the specific on-site lifting requirements for installing 1.2 meter to 1.5 meter thick diaphragm walls up to 36 meters deep, the contractor traced out the work envelope in which lifting operations would be carried out. "We are working within a template, setting a ‚virtual‘ ceiling above which we cannot use lifting resources, so as to avoid risking electrical arcing from getting too close to high voltage wires," states Frédéric Roche, "this safety limit was set at 9 meters“. Not much space to place and weld the 5 m long steel cages.

The 120 t telescopic crawler crane from SENNEBOGEN enables optimum operation under these safety conditions and at the same time meet the requirements for lifting heavy loads. In fact, the working height / load capacity ratio and the issues of compactness and reach were determining factors in arriving at the choice of equipment. With a maximum load capacity of up to 120 t and a maximum reach of up to 40.2 m, the full-power boom of the SENNEBOGEN 6113 shows its strengths. Particularly where space is at a premium, the width of the crawler tracks can be varied and set between 6.30 m support width and 3.9 m. The SENNEBOGEN 6113's Full-Power Boom is the perfect choice for this application.

Virtuell Wall for maximum safety

But that's not all: the SENNEBOGEN 6113 E is the only one that not only meets the load requirements of the customer, but can also be equipped with a "Virtual Wall". Thanks to this function, the system blocks as soon as the boom is extended to a height of 9 metres. A screen in the cabin shows the position of the boom in relation to the power lines. As the crane works in a confined space next to several other machines, the operator's constant attention is required. A camera mounted on the side covers the blind spot on the right side of the cabin, the crawler crane also has a rear view camera and a camera on the winches.

"I had misgivings about this job because of the high voltage power line. I was reassured by the fact that I could adjust the machine's work area myself in relation to the requirements of the site and the height limit. This function is reassuring because once the telescopic boom extends to 9 meters in height, the system blocks further movement, preventing me from going further. This is what keeps the work safe.“ Antonio De Sousa, Crane Operator with ENCO.