Bersche-Rolt was among those recognised at The Historic Bridge & Infrastructure Awards (HIBA) at the Institute of Structural Engineers (ICE) headquarters in London in Nov 2004 for our part in the strengthening of the Hungerford Canal Bridge, Berkshire.

The awards are sponsored by ICE’s Panel for Historical Engineering Works (PHEW), English Heritage, Network Rail, British Waterways and the County Surveyors’ Society.

Roland Paxton, chairman of HBIA, commented: “Competition for this year’s awards was very strong indeed. The Awards are important because they recognise and encourage excellence and innovation in historic civilengineering.”

The Hungerford Canal Bridge was built around 1800 and carries the high street over the Kennet & Avon canal. In 2001 its load-carrying capacity was assessed by West Berkshire Council as 3 tonnes.

A feasibility study carried out by Jacobs Babtie (formerly Babtie Group Ltd), the council’s consultants, concluded that the technique of “retro-reinforcement” of the arch ring was the most advantageous strengthening solution in terms of cost, safety, traffic disruption, and inconvenience caused to nearby residents.

Bersche – Rolt engineers prepared a design and stainless steel reinforcement was inserted in holes drilled below the

surface of the intrados, to form a mesh of strengthening reinforcement across the arch barrel, which left the appearance of the brickwork unaltered.

Services located below the road surface were not disturbed and the works were extended to include the repair and strengthening of the retaining walls and parapets.

Judges’ comments: “The concept is a clear innovation. Strengthening created a bridge capable of carrying unrestricted traffic and there is a sheet of calculations to prove the high load capacity”.

Our Engineers provide a full design service supported by information obtained through testing and research work carried out at Bradford University.

Hungerford Canal Bridge prior to refurbishment

Bersche-Rolt received a commendation at the Historic Bridge & Infrastructure Award in March 2010 for their part in the refurbishment and strengthening of St. Helena Bridge in Bolton.

The Bridge is a single-span stone and brick arch with masonry abutments and retaining walls and it is thought to have been constructed before 1875. The bridge has a 55˚ Skew and a span of approximately 13.4 metres and an almost semi-circular arch profile. The bridge carries the busy Marsden Road A676 and spans St. Helena Road.

The bridge was suffering from cracking to the arch barrel to the North abutment indicating spandrel wall separation thought to be caused by water ingress and possibly local settlement of the north eastern corner.

All work was carried out from below the arch allowing the carriageway above to remain fully open throughout the contract and services in the road were undisturbed.

The design by Garrity Associates following discussions with Bersche-Rolt engineers involved core drilling 7-8m long transverse holes through ornate voussoirs from both sides of the arch and installing B-R stainless steel reinforcing bars with fixed locating spacers to tie across the longitudinal cracks.

The reinforcement was bonded in place with B-R bonding mortar and cores from the drilling were retained and refixed to restore the appearance of the stonework. Radial ties were also installed in pre-drilled holes to resist arch ring separation.

Cleaning and re-pointing of the arch barrel in a sympathetic mortar was also carried out by others once the strengthening scheme was complete.

Bersche-Rolt Engineers provide a full survey and design service including detailed proposals and method statements, supported by information obtained through testing and research carried out at Bradford University.

Bersche-Rolt LimitedStream House, Heron’s GhyllUckfield, East SussexTN22 4BY

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