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T

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

13

Contractors World International