HGVs are to be allowed to cross the Forth Road Bridge from this evening in a phased introduction.
The vehicles will be allowed limited night time access, when traffic volumes are lower. The structural monitoring installed at the truss end links have showed that the bridge could allow up to 600 northbound vehicles to cross between 11pm and 4am nightly.
There will be a dedicated HGV lane and stacking area, and traffic signals will release HGVs onto the bridge at a rate of one every 30 seconds. The release rate has been calculated by engineers as the optimum rate to maximise the number of vehicles able to cross whilst minimising the impact on the structure.
However, monitoring has shown that the second phase of the repair work to strengthen the bridge’s main span must be completed to the main span before the bridge can fully reopen to HGVs. High winds and wet weather have limited the opportunities to carry out this work.
Amey account director for the Forth Road Bridge Mark Arndt said: “During the recent storms, the bridge has been closed to traffic, at times, because wind speeds have been so high and it wouldn’t be safe to have people out working in those conditions. Our teams are working flat out to complete the work necessary to fully reopen the bridge, but our timetable is highly dependent on the weather and our priority has to be on safety.”
It is now anticipated that the bridge will not fully reopen to HGVs until mid-March.
Transport minister Derek Mackay said: “This is a phased reintroduction of HGVs to the Forth Road Bridge which aims to provide access to the bridge at the earliest available opportunity. Allowing limited access to the bridge when traffic is lighter will hopefully provide some relief to local hauliers while repair work continues.
“Ninety per cent of traffic returned to the Forth Road Bridge in December and while we recognise that around 600 HGVs crossing the bridge each night does not get us to 100%, it is a step in the right direction – with full reopening expected in mid-March. We will of course continue to explore every option to see if we can increase access as the trial develops.
“The information from the monitoring equipment is providing a detailed picture of how the bridge is behaving to inform our decision making and modelling. We will not take any decision which could risk damaging the bridge or compromising safety, so we have taken the decision to push back the reopening of the bridge to HGVs to allow time for phase two of the repair work to be complete, with additional time added as contingency due to the effects of the weather.
“The expert engineering advice we have received, indicates that, with phase two of the works complete, the bridge will have sufficient strength to cope with normal loading of HGVs alongside other traffic.
“Every effort is being made to carry out the repair work as quickly as is possible. When the phase two strengthening works are complete the bridge will re-open to HGVs with no restrictions.”