T
Main Pic
The largest of the ribs
measuring 96 meters
in length and weighing
nearly 86 tonnes, was
installed using a 750
tonne crawler crane
he £44 million project
undertaken by Network Rail
to redevelop and transform
Manchester Victoria station
includes a state-of-the-art roof which
has been constructed around 15 curved
steel ribs, all of which are unique in
both size and curvature. The task of
producing the curved structure for this
project was awarded to expert tube
and metal profile bending company
Barnshaws, which conveniently has
one of its production facilities located
in the city.
The new £16 million roof will provide a
modern and bright feeling to the new
concourse, which has been designed to
be sympathetic with the original Grade
II listed building and also to provide
sufficient capacity for future expansion.
For the main contractor tasked with
delivering the project, precision and
timing were key to the overall success
of the refurbishment.
From the start, the design of the
new roof was going to pose some
tough challenges for the fabricators,
Severfield (UK). Each rib has a unique
design, not only in length but also
in width, depth and curvature, so
the actual manufacturing of the ribs
required a high level of precision. In
addition, the ribs had to be made in
sections up to 20 meters in length and
then transported to the site before final
assembly and installation.
Established in 1969,
Barnshaws has grown
to become the world’s
premier specialist
profile bending
company; supplying
market sectors such
as construction,
power generation,
mining, transport and
general
manufacturing with
shaped beams, tubes,
plate and other profile
section materials.
From the outset the engineers from
Severfield (UK) consulted with
Barnshaws to discuss the best way of
creating and manufacturing the design
so that it could be installed in the most
efficient manner. As it turned out this
would involve two of the largest cranes
in the country and some millimetreperfect construction as well as precise
timing.
Greg North, Commercial Director for
Barnshaws, comments: “We have
worked with Severfields on a large
number of projects in the past and we
understand each other’s capabilities
and strengths. For one particular part
of the project we were able to provide
350mm square hollow section (SHS)
steel that was curved to a 7000mm
radius at certain points with no
distortion to the section, thanks to our
specialised methods of bending.”
In fact, all of the SHS steel required 3
or 4 different radii within each length
but this is all within the capability
of Barnshaws and the engineering
team, who were able to deliver these
components, on time, to Severfield’s.
The second part of the project required
steel plate measuring up to 550mm
wide by 50mm thick to be curved to
various radii in order to make the
larger sections of each rib.
Each plate section has been curved to
a specific set of dimensions to allow it
to be assembled into a curved boxsection by Severfield (UK). These are
then transported to the station site
where they are welded together to
create the complete rib which is then
carefully positioned and installed.
Each of these unique ribs has required
considerable precision and tight
tolerances to ensure the installation
process went smoothly.
Most of the curved beams were
installed using the UK’s largest
telescopic crane, a 1,200 tonne
behemoth, while rib 9, the largest of
the ribs measuring 96 meters in length
and weighing nearly 86 tonnes, was
installed using a 750 tonne crawler
crane, which is one of Europe’s largest
of its type.
This in itself created complications
due to the live tracks that run beneath
the new roof structure and the whole
installation process required close
cooperation with Network Rail. In this
way, the short periods during which
the tracks can be made safe could
be utilised as efficiently as possible,
ensuring the roof structure was
installed on schedule.
With the main ribs installed, the
smaller subsections 6