What’s causing ripples on the Victoria Bridge

The Victoria suspension bridge.

The Victoria suspension bridge.

The entire surface of the newly refurbished and historic Victoria suspension bridge across Bath’s section of the River Avon is going to have to be replaced.

The bridge only officially completely re-opened three months ago after a multi-million pound restoration.

B&NES has erected prominent notices explains the problems they have had with the anti-slip coating which started lifting soon after it was laid.

A notice explaining the problems with the decking

A notice explaining the problems with the decking

Seems the need for speed may in the end result in additional costs – as the notice explains:

‘The surface of the bridge deck is an anti-slip coating, applied to ‘planks’ of glass reinforced plastic, (GRP) which in turn have been glued and screwed to the timber deck planks beneath.

The rippling effect on the bridge decking.

The rippling effect on the bridge decking.

The system was chosen particularly to give an efficient means of securing the anti-slip surface to the deck during the tight time-frame in November 2014 when the route across the bridge was closed to the pubic for the removal of the temporary truss and finishing of the bridge deck.’

It seems the plastic planks have been expanding and contracting with temperature changes and the movement has broken the glue bond with the timber below which has caused ‘ the GRP to lift between screw-points resulting in the ripple effect that can be seen particularly during warm periods.’

Another view of the problem decking.

Another view of the problem decking.

The amount of movement has been ‘much greater than predicted’ and it could also be that doing the job during a cold November meant the glue didn’t bond properly. A calculated risk the Council took to finish the job on time!

If you go down and make a careful crossing you will see a trial patch of what will probably be an alternative surface which ‘involves gluing a fine aggregate to the timber planks without the use of the GRP’ which will be stripped off.

B&NES say they aim to keep the bridge open during the laying of the new surface. The notice says it will happen ‘Spring 2015’ so they had better get a move on.

A section of the new decking which has been on trial.

A section of the new decking which has been on trial.

The bridge – a Grade 11 listed 19th century suspended footbridge – formally opened this January after a four-year refurbishment project costing £3.4 million pounds.

The bridge was built in 1836 as the prototype demonstration of James Dredge’s patented taper chain principle.

Over 50 further bridges were built throughout Britain, Ireland, India and Jamaica using the same principle.

Bath’s Victoria Bridge is the eldest of a small number of the survivors.