Broadway bridge strike repair

On 27th February 2017 bridge 1 at Broadway suffered a relatively violent strike by the steel arm of an excavator being carried on a trailer along the road. It has taken almost 12 months for the railway to be in a position to commence repairs, these (mostly) being paid for by the insurance of the company involved.

On 3rd January station road was closed off to traffic for the repairs to begin. Below is a photograph of the works, and a progess report on the repair so far.

Bridge I at Broadway under repair - again.

The railway runs roughly due north from Cheltenham Racecourse, and Broadway station is immediately north of this bridge.

The bridge is a steel plate deck supported by a grillage of steel girders, as per picture below. 

This is a portion of a drawing prepared by our Consultants – Halcrow. This shows the layout of the “grillage” and also a cross section through the bridge. It basically comprises 3 large main girders tied together with a series of cross girders. Running between them are the track bearers and at right angles plate stiffening angles. This drawing was produced, after a detailed inspection had been done, to illustrate the 14 areas where damage had been caused to the structure.

When the bridge was built in 1903, it was entirely riveted. 

A 2014 photograph, taken prior to the first refurbishment. Note the large plate bolted across the front, from an earlier repair in 1975.

In repairs to subsequent damage by bridge strikes many parts were bolted together instead. In the 2014 repairs we used high strength torsion control bolts which have a domed head, with a hexagon nut, to replace many rivets.

Sadly we have to report that since the moderately serious strike on 27^th February 2017, which is the reason that these repairs were needed, a further strike has taken place on an unknown date. Incredibly, the damage resulting was in virtually the same locations.  However this has caused extra damage to the central main girder putting a localised but large kink in the 3-plate thick bottom flange 

 The steelworkers have now managed to just about straighten the steel again (see photo below).

Centre buckle

Centre buckle repaired

The repair work involves first weakening the steelwork in some places, and so no trains or any traffic could be permitted until the repairs are completed. The most important repair is to the upside, east track bearer, which has been displaced towards the east and badly buckled. 

 

Buckled track bearer.

During repair

After repair.

We had to remove the original rivets by grinding off the heads, then drilling out the shafts. The two bent bottom angles were then removed and the buckled vertical web plate straightened. Next new angles, site drilled to ensure that the holes lined up, were fitted and the 3 pieces were then bolted together. (see photos, before, during and after the repair was completed). Other sheared off bolts and rivet heads have to be replaced and then all repaired areas will be painted.

Buckled plates removed.

It has also caused extra damage to the east main outer girder, but fortunately, when we did the enormous repair work in 2014, the girder was re-built using bolts. Consequently this new repair was much easier and involved unbolting splice plates (see photo of the removed plates above) and making new longer ones. Similarly the damage to the west main girder has been simplified due to the bolted arrangements. See completed photos of both main girders.

Unfortunately the damage extended to the worst repair needed, that to the east upside track bearer, was across the westbound lane. Consequently we have had to close the entire road, causing inconvenience to all users of this road and especially to the garage and shop, right next to the bridge. Diversions are in place, and though the problem is not of our making and costs a lot of money and time organising the work, we extend our apologies to everyone affected.

At the beginning of this blog post there is a photograph showing the closed road, which has to include Heras fencing to stop people straying into the working area, and even crash barriers to stop vehicles running into the Heras fencing at night. Within the working area we have built a fully scaffolded section on which the men will work. This bridges the public footpath to provide a protected pedestrian walkway right through the site. You can also see an area enclosed with plastic sheeting. This helps to contain sparks, dust, etc from the operations and also provides an area which can be lit and heated to improve the working conditions, in the poor winter conditions, and to enable painting to be done, which otherwise cannot be done below 5 Degrees C.

It is really disheartening to have to suffer more and more strikes after the bridge was refurbished. There may have been more than a dozen now. A number of vehicles involved in the strikes did stop and do the honourable thing, but many did not and could only be observed from the damage suffered, and debris such as sheared off rivets found in the road. As a minimum the damage needs to be inspected and an assessment made after each strike, during which period no trains can run. In a worst case scenario the whole bridge could be displaced, thus closing the railway at Broadway for a considerable time. This could have serious financial consequences for us, now that the extension to Broadway is about to open. The provision of crash protection beams for the bridge, and a system of video camera surveillance, is therefore now being studied in depth.