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Contractors World - UK & Ireland Vol 2 No 8
Heavy traffic means constant
highway surface maintenance
A t e n d e r wa s awa r d e d t o R a y n e swa y
Construction in February 2012 to carry out a trial
replacement of a limited number of the deck
joints on the main and side spans.
The trial will determine whether or not an
alternative half joint detail can help to minimise
the issues that are caused by the original detail.
These include a large amount of maintenance
time spent repairing the existing joints using
overnight carriageway closures and occasional
emergency daytime temporary closures; the
secondary effects of the dynamic loading on
some truss members and surfacing, and the ride quality
experienced by users.
Work commenced on site in August 2012 and following
extensive engineering design work by Fairhurst, the
engineers for the project, a further revision to the detail
and method of installation has allowed the trial to go
ahead without requiring daytime weekend closures.
All the required carriageway closures will be now be
carried out overnight which will minimise disruption to
users.
As in all cases involving working overnight on the
bridge, noise and other environmental issues
will follow guidance set by both Fife and the City
of Edinburgh Council. However, there is the potential that works overnight involving
steelwork modifications, whilst within acceptable noise levels, can still cause disturbance to some local residents
especially on calm evenings.
Bridge bearings successfully replaced
Balfour Beatty commenced work on site on the Viaduct Bearing Replacement contract on 17 May 2010 and the
project was substantially completed by September 2012.
No disruption to daytime traffic has been caused as a result of this project. It was expected that some overnight
restrictions might be necessary to ensure that the jacking and lowering of the bridge deck could be sufficiently
controlled, however this did not prove necessary.
A major project to replace the bearings on the Forth Road Bridge’s north and south approach viaducts began in
May 2010. The project was scheduled for completion by the end of 2012.
The approach viaducts sit at either end of the bridge on each shore, connecting the A90 with the main body of
the suspension bridge. Unlike the middle of the bridge, which is suspended from the main cables, the approach
viaducts are supported by
reinforced concrete piers. Steel
bearings sit on top of these
piers, allowing the deck to
move as required by changes in
temperature and traffic loading.
The project involved jacking
up the deck to allow removal
of the existing bearings. The
steel box girders that support
t h e c o n c r e t e d e c k we r e
strengthened at the jacking
©2012
Video and images courtesy of Forth
Estuary Transport Authority