Description:
This project was for the supply and installation of a feature link bridge
between the new head office and existing offices for O2 in Slough Berkshire,
with the head offices remaining operational for O2 throughout the onsite works.
The initial design was for simple "V" support CHS columns to the bridge deck,
following design team meetings the final design comprised of complex "tree"
CHS columns the majority with double branches whilst the main two at the east
end having 4 branches, none of the columns are vertical the angles in both
directions differ for each set of columns. The 4 branch columns ending up
weighing 9t as an assembled unit.
The design and selection of the column CHS sections was made harder by the use
of smaller CHS sections for the lower portion and larger CHS sections for the
upper sections of the columns. The aim and criteria here was that the end
product onsite for the columns had feature shapes to their lower sections
whilst looking the same diameter up to the upper side of the bridge.
The head of every column had very large moments and in order to accommodate
these GWS designed sections of the main bridge floor beams as plate girders to
allow the connections of incoming members as the 914UB's designed by the
engineer failed at the connection points, these were fabricated as part of the
upper CHS column. This made for challenging detailing and fabrication to
ensure the geometry was correct to allow onsite erection. This issue was made
harder with the design constraints set by the architect as all steels needed
to stay within the timber cladding zones which were very tight to the steel
lines.
Along with the link bridge GWS were contracted to supply and install a housing
frame that enclosed the bridge from the new head office to the existing head
office. This comprised of 15m long CHS columns with 18m long 914UB roof beams.
On the outside of each of the CHS column machined support brackets were site
welded in order to take the specialist glazing system. GWS undertook the
engineering of these with the Glazing supplier as these had to be within 2mm
in each direction in each location.
The contract comprised of 270t steelwork with some 1,300 members.
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