HomeInfrastructureIn case you missed it - Broken bridge at Barrow

In case you missed it – Broken bridge at Barrow

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Barrow-upon-Soar railway station, nine miles north of Leicester on the Midland main line, was opened by the Midland Counties Railway in 1840. Thereafter, it changed its name a couple of times, from Barrow (1840) to Barrow-upon-Soar (1871) and then Barrow-upon-Soar and Quorn (1899). The station closed in 1968 and, despite the fact that much of its original Midland Counties architecture was still intact, it was completely demolished.

A new station, a simple couple of platforms, opened in 1994. It was a few hundred metres from the original location and accessed down steps from the bridge approach at Grove Lane. This bridge consists of two arch spans over four tracks, one arch for the two Fast lines and the other over the two Slows.

So it was a major problem in many respects when, on 1 August 2016, the southern parapet wall and spandrel of the Down Fast line arch of the bridge collapsed, together with the adjacent wing wall. (right) A significant quantity of debris fell onto the adjacent embankment and Fast Lines below, but fortunately rail traffic was stopped in time to prevent a train running into this.

Swift action

A short while earlier, a depression had appeared in the footway of the road above the Fast line arch. This had been seen and reported, with the result that investigatory works were under way on site at the time of the collapse. Nobody was hurt and the prompt actions of those on site enabled rail and road traffic to be protected.

The south footway was lost with the collapse of the structure, along with some of the fill beneath, and a water main and other utilities were left without adequate support.

Steps were taken by Network Rail and its contractors to make matters safe by closing the road to vehicular and foot traffic, and arranging for the affected utilities to be shut off. AMCO’s Asset Management Minor Works team came in at once to assist with this and to begin to clear up the debris. AMCO brought in the Derby office of consultant engineers Donaldson Associates to assist them at this stage. At the same time, Amey undertook checks on the bridge to ensure that the remaining structure was safe and not liable to further collapse.

As a result of these rapid actions, it was possible to reopen the Slow lines on the following day, with the Fasts being reopened 24 hours later. Some 200 tonnes of debris had to be collected and removed to permit this. The road over the structure remained shut to vehicles and pedestrians at this stage, however, and the utilities could not be reinstated either.

Permanent repairs

The next stage in the repair process involved the development and implementation of a suitable permanent scheme. The first priority had to be the reopening of the bridge to foot traffic and the restoration of the water and gas mains and the other utilities. Consultant HPBW was engaged by AMCO to design the permanent works to achieve these ends.

The work began with the stabilisation of the remaining structure of the Fast line span and of the fill above it. The fill that had not fallen had been left unsupported by the disappearance of the brick walls that had collapsed. It was at a fairly steep angle of repose and liable to possible further movement if, for example, there had been heavy rainfall.

To eliminate this risk, two measures were taken. Firstly, tie bars were installed by drilling right through the structure from the north spandrel parallel to the railway, to emerge at the failure surface on the south side.

Secondly, (right) sprayed concrete was applied to the exposed fill, to strengthen it and protect it from rainfall. The tie bars were secured using sprayed concrete, but in the final works they will be extended by the addition of further lengths of bar to bring them out through the rebuilt spandrel wall. Pattress plates have been fitted to the tie bars on the north spandrel face, and will be fitted similarly to the bars’ southern ends when the new spandrel is complete. In all some 20 tie bars have been installed in this way.

The drilling for the tie bars was demanding work since the holes had to pass through mudstone between the south and north sides of the bridge as well as through the remaining brickwork.

These works were completed, allowing pedestrian traffic across the bridge to resume three weeks after the original incident.

At the time that AMCO’s project manager Shaun Trickett and Network Rail’s scheme project manager Gary Matenga spoke to Rail Engineer, it was thought that the final structure was likely to be built in reinforced concrete and faced with bricks to match the existing work. Reconstruction entirely in brick would be feasible, but would take longer to reach a point where the restoration of utilities and vehicular traffic would be safely allowed. Given the priority attached to these restorations, the reinforced concrete with brick facing option is expected to be adopted.

Network Rail and AMCO have been at some pains to avoid unnecessary inconvenience and disruption to neighbours in Barrow. They held a public meeting in the village early on to explain what was happening and to consult with local people. They obtained the use of the local Scout hut for this meeting, and intend to thank the Scouts by carrying out some works for them in return.

Plans are afoot to avoid further works on Grove Lane bridge for the Midland main line electrification in the immediate future by doing these concurrently with the present repairs.

In particular, the parapets of the bridge need to be raised and modified to comply with electrification requirements. If this work is carried out now it will avoid the need for further noise, dust and road closures, minimising future inconvenience to local people.

Written by Chris Parker

This article was first published in November 2016.

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