DAM IMPRESSIVE

adVanCed SuPPoRt foR long bRidgeS
So how on earth does a 45-metre-high, 2.67-km-long
bridge get built? The work could be done with a support
structure built from the ground up. ‘However, this
solution is only viable for bridges up to 250 metres long.
That type of scaffold would have to be taken down and reassembled
continually,’ points out Rene Kirsch, ALPINE’s
appointed construction manager. For bridges this long
you need a formwork carriage. ‘This is a structure that
allows the pre-assembled formwork of a deck section to be
moved forward step by step. Then that section of the bridge
can be built there on-site,’ says Kirsch. In this case it is a
71-metre-long, 770-ton structure which makes its way
bit by bit – that is, section by section – through the
valley.
a total of 46 deck
sections are
gradually assembled.
The formwork carriage was supplied by the specialist
Norwegian company Strukturas AS. They were able to
adapt the product to the requirements of the construction
project. The carriage was then purchased by AL-
PINE – a rented formwork carriage would never have
stood up to the challenge. The formwork carriage arrived
unassembled, neatly packed into its 20 containers.
‘After six weeks we had managed to put the steel puzzle
together,’ recounts Lohmann with a laugh. They then
hauled the beast into place using cranes.
PReStReSSed ConCRete boX-giRdeR bRidge
PRaCtiCe makeS PeRfeCt
With this construction method the bridge deck is not a slab or beam but
rather a hollow box (see cross section). This design is used particularly for
long spans and curved routes. It is characterised by considerable flexural
and torsional rigidity, which makes it particularly stable and allows for a slim
bridge profile.
The formwork carriage helps progress enormously. By
constantly repeating the same operation, the team is
steadily becoming more efficient. ‘With every section of
concreting we are confronted with the same lengths, loads
and requirements,’ says Kirsch. ‘A routine is developed. In
the beginning we needed three weeks to complete each deck
section, now we can do it in 14 days.’ After completing a
58-metre section the experts move the formwork carriage
one stretch along. This hydraulic process moves at
a speed of ten metres per hour. Rollers are used in order
to minimise resistance and damage. According to
Kirsch, ‘the material wear would be too great using conventional
Teflon plates.’
Section by section this gigantic bridge makes its way
from west to east, extending a spectacular arc across
the Unstrut valley. Passengers will be able to appreciate
the view from up high from 2015 onwards, after the
entire new VDE 8.2 Erfurt-Leipzig/Halle line has been
completed. //
39
Through a
process of
repetition, the
formwork
carriage allows
for greater
efficiency.