he emergency works has been completed to
repair the cracked member through the instal-
lation of a steel splint, as planned. This splint
repair is intended to be interim in order to allow the
bridge to be safely re-opened to traffic pending a per-
manent repair being carried out.
Since completion of the interim repair, the member
in question has been thoroughly load tested, monitored,
and results gathered through the use of strain gauges.
These sophisticated devices have been installed for the
first time on the bridge and provide live and accurate
data on strains, stresses and rotations within this area
of the bridge.
The results from this monitoring
show the bridge could be safely reo-
pened to all traffic, except HGVs and
abnormal loads. This meant that the
bridge was open to over 90 per cent
of the traffic that uses it.
Independent engineering experts
have analysed the findings and agree
with Amey’s assessment that loading
the bridge with HGVs could result in
stress to the truss end link. They agree
the best way to mitigate against this
risk is to exclude HGVs from using the bridge until the
permanent repair is in place.
This should take around six weeks to complete and,
subject to favourable weather conditions and no further
defects being identified, the bridge should reopen to
HGVs in mid-February.
In addition to repairing the defect, Amey is taking
preventative action on another seven similar locations
on the bridge to prevent any issues from occurring and
structural monitoring systems are also being installed
at these locations.
For the first time, strain gauges have
been fitted to the Forth Road Bridge
following cracking of steel members.
Engineers from Amey responded rapidly to survey and
implement temporary repairs after a crack was found
in one of the structural members (left) forcing closure
of the Forth Road Bridge
Contractors World International Vol 7 No 1
Contractors World International