climbed until it reached a final height of
As well as the land-based crane, this crane
needed four ties to the pylon to ensure
that it could work without a problem at
such impressive height.
The work of the cranes, both with max-
imum load capacity of 18 tonnes, consisted
in the lifting of all the pylons’ steel struc-
tures and concrete, and afterwards, the
lifting of the cables that support the deck
of the bridge.
The 110 kW hoisting engines allowed
the cranes to work at a great speed and
efficiency during these 8 years.
During the works, a change in the design of the metal
anchors that attach the cables to the pylons forced
Linden Comansa’s engineering team to quickly find a
solution to an important although unexpected
The anchors, which initially had to weigh less than
18 tonnes to be elevated and fit into place by the cranes,
became pieces of more than 23 tonnes.
Dragados used a very large mobile crane for placing
the anchors on the pylon located ashore, something that
was impossible for the pylon located in the sea.
In this instance, so that the crane could load these
anchors, Linden Comansa’s R & D department had to
review and reinforce the crane’s kinematics (pulleys,
trolley/hook set, hoisting cable, etc.) and counterweights.
This enabled the 21LC400 to lift this "extra" load in a
timely manner and under the supervision of technicians
from Eleva Grúas Torre.
Disassembly, the greatest challenge
Once the Linden Comansa tower cranes ended their
tasks in the summer of 2015, the Eleva Grúas Torre team
had to face the removal. While both cranes had been
erected with the same configuration, different setbacks
appeared in their take-downs.
The crane in the middle of the bay was the first to
be removed once the most important works on the
bridge were completed.
The crane had four ties to the pylon, with the highest
one a weight of 10 tonnes and a length of 23 metres.
Removing it with a mobile crane was impossible due the
height and the presence of the bridge cables, so the
tower crane itself had to take care of this manoeuvre.
The crane had already been jacked down some tower
sections and when it was time to slew, an interference
arose between the boom of the crane and pylon, so it
was necessary to remove several jib sections.
An articulating crane, located at the top of the pylon
for future bridge maintenance tasks, was used for such
This crane removed jib sections and counterweights
in a sequential way and placed them at the top of the
pylon so that the tower crane could lower them down
to the deck of the bridge.
Thus, it was possible to reduce the jib from 50 to 20
metres, and with this reach the tower crane was able to
rotate freely and remove the bracing by itself.
The crane installed on land was erected closer to the
pylon in comparison to the one in the middle of the
When it came to remove the jib sections of the tower
crane, the articulating crane located at the top of the
pylon was not able to reach the jib-end.
It was necessary to use a jib section dismantling
device, designed by Linden Comansa’s engineering team,
to reduce the jib length of the 21LC400 from 50 to 30
metres (two sections).
With this new configuration, the articulating crane
was able to dismantle the last jib section and leave the
crane with a reach of 20 metres.
However, to achieve this jib-length reduction, it was
necessary to study a new disassembly sequence, move
the trolley winch 20 metres through the boom, and
change the jib end.
Finally, the 21LC400 was able to remove the ties 4
and 3, leaving the lowest two to a mobile crane, which
had to remove them by placing its boom between the
cables of the bridge.
According to Rodrigo García, head of Eleva Gruas
Torre’s erection team, the removal of both cranes was
complicated, but was done very efficiently:
"We jacked down and dismantled the crane
installed in the middle of the bay in just 21
working days of work, when we had raised
possibilities of more than 30 days.
" In the case of the 21LC400 located inland,
it took just 17 days, even though we had several
days in which the weather hindered our work".
Contractors World International
Contractors World International Vol 7 No 1