The Chainbridge at Kemeys Commander will be subject to a new weight restriction as a result of the special monitoring measures which have been in operation for several years.
Monmouthshire County Council have maintained the 44T rating for the structure over that time. This was achieved by introducing traffic lights to reduce the bridge to one loaded lane and by strengthening a number of the hanger rods which connect the bridge deck to the main arch.
The hanger rods are one of the main issues on the bridge, especially where they connect into the bridge deck. The rods are monitored regularly, and intervention levels are outlined, which the council says must be acted upon when they are reached.
One of these rods had deteriorated since the previous inspection, which has resulted in the need to impose a 7.5T weight restriction.
The council carried out a further inspection a few weeks ago and says it is using the information gathered to reassess the structural integrity of the bridge to see if this imposed weight restriction can be safely improved. The reassessment is underway. It says the bridge is a complicated structure to analyse and will take time to complete. The results are expected by October.
As well as the reassessment the council says it will also actively be looking into the refurbishment options to assess what is required to bring this structure back up to unrestricted status.
It is also looking into what can be done on the surrounding lanes and roads to see what improvements or modifications can be made to help alleviate some of the issues caused by introducing the weight restriction on the bridge. Hedges will be cut back as much as possible and the tree canopy cut back to improve height clearances. It says it will widen the road where verges have overgrown the carriageway, and existing passing bays will be improved as much as practicable.
The council says it is also looking to improve the height restriction on B4598 Porthycarne Street disused rail bridge. By funnelling vehicles down the centre of the bridge, guided by suitable white lining and signing, it believes this can be improved from 11’6” currently to 13’9”.
