e-mosty September 2018 Vessels and Equipment Used for Bridge Construction | Page 39

Lifting operation was divided in two phases depending
on span position.
During the first phase Uglen used the so called high
lifting boom configuration of the crane lifting mast
with total height of 140 meters. In this phase, the
floating crane was operating in the middle of main
span and above the level of main cables.
Operation was especially dangerous as the crane hook
was lowered in between the two main cables down to
the transport vessel with the stored steel deck
segments.
Once the deck segment was attached to the hook the
floating crane movements were extremely restricted
and any strong wind gusts hitting the hanging load in
that time could lead to potential disaster.
The bridge deck elements weighed upto 243 tons,
and altogether the HLV Uglen lifted about 7300 tons
of steel bridge elements onto the bridge cables.
Another challenge were the strong winds in the fjord
area. Calculated maximum wind speed for the safe
operation was 10-12 m/s.
During the operation period there were many days
with constant wind speed over 20 m/s and gusting
winds up to 28 m/s which delayed erection works for
certain period.
The lifting operation itself took 30 days, excluding the
days lost when the wind was too high for safe
working.
In the second phase the floating crane was operating
closer to the pylons and below the main cables. The
lifting mast configuration was changed to use a
normal lifting boom with a height of 80 m.
A particular challenge was to ensure proper anchoring
of the floating crane and transport vessels while
operating inside Rombaksfjord. Due to an overall
water depth of 340 metres conventional anchoring
was not possible. Therefore a special mooring system
with 6 different mooring points had to be
established.
Cooperation on this article:
Per Gunnar Gundersen
Senior Operation Manager
UGLAND CONSTRUCTION AS
http://www.jjuc.no/
e-mosty June 2017:
The Hålogaland Bridge: Design and Construction. Drawings. Photo and Video Gallery.
3/2018