LTM 1750-9.1 dismantles huge suspended scaffold

The Bergheim heavy load logisticians Wasel impress with a tough crane job at the Cologne Cathedral. A giant suspended scaffold on the north tower of the Cathedral is dismantled at a height of around 100 metres.

Logistical and structural challenges

Suspended erection of the more than 90 metre long lattice boom jib

Suspended erection of the more than 90 metre long lattice boom jib

Backbreaking work by night: Restricted spaces make the set-up work a challenge.

The aluminium scaffold has to be removed from the tower of the cathedral not only at 100 metres above sea level, but also with an almost identical outreach in three parts. A Liebherr LTM 1750-9.1 mobile crane is in operation, at its maximum hook height of 154 metres.

The crane site above an underground station provides major obstacles to the planning team. But with meticulous preparation and planning phase which lasted two years in total, Wasel GmbH masters the crane job, which is not lacking in logistical and structural challenges.

Challenges and solutions in action

Very little space for set-up work

Very little space for set-up work

The meticulous project preparation pays off. Less than eight hours after the positioning of the crane vehicle, the basic unit was equipped with supports, Y-suspension and telescopic boom extension including pivot section and ballast.

The LTM 1750-9.1 is mounted on the station forecourt. The underground railway station below the area where the crane is to be erected requires a complicated search for points where the concrete foundations for the large crane's supports can be poured. In addition, the vast crowds outside the station must be considered.

"The construction has already given us headaches in advance," admits Jürgen Oprée, Technical Director at Wasel. "We had to consider station evacuation plans in our assembly schedules and also had to keep the escape and rescue routes free at all times. We also have a very tight time frame allocated for the set-up work."

Cologne Central Station is extremely busy. The forecourt areas required to assemble the boom are blocked off during night-time hours only. In addition, the allocated area is much too small to assemble the lattice boom to its full length flat on the ground. The boom must be assembled in a suspended position. The parts required must each be delivered at exactly the right time.

From 10pm, the area is cordoned off for suspended mounting of the lattice jib. Assembly of the lattice section with a Liebherr LTM 1095-5.1 requires full deployment and the intense concentration of the Wasel team the whole night through. In the early hours of the morning, the boom finally extends close to the cathedral towers in the Cologne sky.

Even when setting up, the dimensions of the mobile crane are clear.

Even when setting up, the dimensions of the mobile crane are clear.

The first of three scaffolding parts hangs on the LTM 1750-9.1 hook.

The first of three scaffolding parts hangs on the LTM 1750-9.1 hook.

Many crane fans from all over Germany and the Netherlands made the special pilgrimage to the Rhine metropolis to be able to observe the operation.

Under the watchful eyes of a large audience the largest crane in the history of Cologne cathedral starts up. The fastening of the elements to the special cross beam and the release of the respective scaffold parts from the basic structure turned out to be the most tedious part of the action.

So slowly as to be almost imperceptible, the gigantic aluminium elements are set in motion. Through the precise interplay of crane operators and advisers on the tower, the some 7 metres wide and 33 metres high lattice is guided cautiously past centuries-old chapters and weathered angel figures.

"When removing the rear scaffold, we had in some cases only 15 centimetres of space between the load and the cathedral," says Jürgen Oprée, Technical Director at Wasel, of the difficult space conditions of the lift. The Liebherr crane manoeuvred the bulky load forward between the towers, over the north aisle and the past the tower, before finally laying it down in front of the main entrance using an LTM 1070-4.2.

Satisfied team after successful execution

Prominent construction site: Cologne Cathedral, the Ludwig Museum and Central Station

Prominent construction site: Cologne Cathedral, the Ludwig Museum and Central Station

The work has been completed much earlier than planned. The actual crane job had taken just about four hours.

The Wasel team coordinator Jürgen Oprée is satisfied with the smooth running. "Just a few years ago a job like this wouldn't have been possible in this manner," explains Oprée. "From a technical aspect, maybe, but certainly not within these short times. And probably another crane would have also caused problems in terms of the support pressure. The LTM1750-9.1 was ideal for this job on the cathedral."

Video

A tricky crane job in detail: Set-up work in a constricted space, a suspended erection of the lattice jib and crane movements with millimetre precision. An LTM 1750-9.1 dismantles a suspended scaffold on Cologne Cathedral.

A tricky crane job in detail: Set-up work in a constricted space, suspended erection of the lattice jib and crane movements with millimetre precision. An LTM 1750-9.1 dismantles a suspended scaffold on Cologne Cathedral. Open video

A tricky crane job in detail: Set-up work in a constricted space, a suspended erection of the lattice jib and crane movements with millimetre precision. An LTM 1750-9.1 dismantles a suspended scaffold on Cologne Cathedral.

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