Tandem lift over a cellar: Haslach sets 98-tonne concrete trusses

The problem: a roof to build over a basement

At the Getzner textile factory in Bludenz, Austria, ten prestressed concrete trusses weighing 98 tonnes each had to be installed in the roof of a new hall. The complication was underneath: the hall floor sits over a full cellar with a limited permissible support load, the working area was tight, and deliveries to the factory had to continue throughout.

Kranverleih Haslach GmbH of Wertach, southern Germany, solved it by strengthening the structure rather than avoiding it.

“After extensive planning and many detailed calculations, we were able to come up with a solution for the installation work in conjunction with the other companies involved. We stabilised the cellar ceiling from underneath with ceiling supports in order to achieve the support strength required to allow our LTM 1300-6.3 to work on this cellar ceiling.”

— Tobias Haslach, owner, Kranverleih Haslach GmbH

With the ceiling propped, not only the six-axle crane but also the special transport carrying the 98-tonne truss was able to drive onto the slab.

The second crane, behind a wall

An LTM 1230-5.1 formed the other half of the tandem. It had to be set up outside the hall on a purpose-built embankment, and its position behind a concrete wall meant the crew had no line of sight to the lift.

“We set up the 5-axle vehicle on a specially filled embankment outside the hall. Due to the positioning behind a concrete wall, we were only able to coordinate with the work team via radiotelephony. The truss also had to be guided around the LTM 1300-6.3.”

— Tobias Haslach, owner, Kranverleih Haslach GmbH

Lifting each truss from the trailer put both cranes at maximum capacity, carrying 51 tonnes apiece at radii of 13 and 15 metres respectively. The transport itself was 47.3 metres long and weighed 148 tonnes all up, requiring a special permit and night-time running only.

Two a day, then reposition

Two trusses were installed per day. After each pair, both cranes were relocated complete with equipment and ballast and set up again for the next lifts – a cycle that turned the rigging arrangement into as much of a planning exercise as the lifts themselves. Production at the Getzner plant continued almost without interruption.

Kranverleih Haslach is a family business running nine mobile cranes, all supplied by Liebherr.