A Liebherr MK 88-4.1 mobile construction crane from the Ponticelli group of companies repaired a historic Paris bridge and reinstalled a damaged artwork on it. Working on the Pont-Neuf, the crane restored parts of 'La Caverne du Pont-Neuf,' an installation by French artist JR.
The temporary artwork was created as a tribute to the wrapping of the Pont-Neuf by artists Christo and Jeanne-Claude, first installed in 1985. The inflatable structure is approximately 120 metres long. In early June, violent gusts of wind and hail damaged parts of its outer shell.
A rapid response
Ponticelli, a French lifting and industrial services company, said it mobilised quickly. 'We were on site just a few hours after the damage occurred to work out the best technical solution together with the client,' said Louis-Arthur de Quatrebarbes, head of the handling and lifting agency at Ponticelli. He said that in addition to repairing the tarpaulin, the team had to carry out a lifting operation safely in almost constant wind and under considerable time pressure.
Choosing the crane
As the oldest bridge in Paris, the Pont-Neuf offers limited space for work and welcomes a large number of daily visitors. Load-distribution plates were used to reduce ground pressure, while safety and traffic management measures supported a safe operation.
The team originally planned to use a larger Liebherr mobile crane, but because of the tight conditions it deployed the MK 88-4.1 instead. Its 45-metre-long trolley jib reached all the damaged areas of the structure, and its four-axle design enabled easy relocation from one side of the bridge to the other, where there was also storm damage. Short set-up time and a compact outrigger system further facilitated the work.
Working at height, at night
The crane cab could move at working height, giving the operator a clear view of the roughly 18-metre-high structure and the rope access technicians. Boom-mounted spotlights ensured optimal illumination of the work area during night-time operations.
Four nights of repair
The repair work was carried out over four night shifts. Damaged fabric sections weighing between 200 and 400 kilograms were lifted and reattached in collaboration with rope access technicians. Because the construction site sits in a wind corridor along the River Seine, weather conditions were continuously monitored, and the crane operator and the rope access technicians communicated continuously by radio.
Before work began, the team carried out site inspections, load calculations and collision analyses of the surrounding buildings, and a 360-degree test confirmed the planned crane positioning.
A crane as part of the art
For Ponticelli, the project was more than a conventional lifting operation. 'We are proud to have been part of this work of art,' de Quatrebarbes said, quoting JR: 'The installation of the artwork is part of the artwork' — and so is the crane. 'The visually striking deployment of the MK crane created a magical moment.'
With its deployment on the Pont-Neuf, the Liebherr MK 88-4.1 demonstrated its strengths in demanding inner-city projects, where heritage conservation, confined spaces and a high level of precision come together, offering a combination of reach, compactness and flexibility.