Interviews

Ramping up the work on Reading Viaduct

Kevin Brown, Network Rail’s civil engineering project manager on Reading, and William Smith, project director at Balfour Beatty, talk to RTM about the latest developments on the £45m Reading Viaduct. David Stevenson and Alexandra Clarke report.

Work on the £45m Reading Viaduct has reached a major milestone, with principal contractor Balfour Beatty handing over the viaduct to Network Rail ready for track installation on the structure.

The viaduct, which forms part of Network Rail’s £895m redevelopment of the railway in and around Reading, is expected to cut delays caused by congestion on the tracks to the west of the station. When it opens in 2015, it will create enough capacity for an additional four passenger trains per hour as well as more freight trains.

In July, Her Majesty the Queen officially opened the redeveloped Reading station, which has been transformed in the last five years by Network Rail, and marked a major milestone in the overall Reading project.

The refurbished station – completed a year ahead of schedule and within budget – now has two entrances, 15 platforms including five new platforms, new retail facilities and a new passenger bridge three times the size of the original footbridge.

Although the station is the most visible aspect of the project for the travelling public, in many ways the viaduct that allows the grade separation of the lines is a more important development. 

Work on the viaduct has recently passed a number of key stages, with the third of five sectional schemes being delivered by the principal contractor to Network Rail. Between now and when the viaduct is expected to open in 2015, Balfour Beatty is to complete the work on the Feeder Line, to be delivered in October 2014, and the Festival Line, due for completion in January 2015. 

Discussing the handover of the viaduct, Kevin Brown, Network Rail’s civil engineering project manager on Reading, told RTM: “We have handed over the full trackbed to the track team. That whole piece of structure is essentially complete. All the beams are in, and all the piers are there, so that key part of the structure, which is the majority of it, is actually complete.”

Carillion is the contractor for the track works on top of the viaduct, while Balfour Beatty has been handling the civils element.

William Smith, project director at Balfour Beatty, who started on the project in January 2014, has overseen a number of key civils works in order to get to the current handover stage.

He told us that following the harsh winter weather, the on-site team was working 24/7 for at least six months to ensure the construction of the bridge piers, box structures and culverts were completed on time.

Getting the foundations right

However, before any of this work could be completed, the teams had to ensure that the ground was ready and stabilised for the flyover’s construction.

This included the completion of the piling phase for the viaduct, which started in May 2013. The £3.8m foundation package also included the installation of 980 continuous flight auger piles to support the viaduct structure.

During the ground improvement phase, the team also had to install 1,685 vibro concrete columns, to support the ramps at the eastern and western ends.

Brown said the teams have filled approximately 21,500 linear metres of board piles. “If you put all of our piles end-to-end they would add up to 21,500m. We’ve also done 10,500m of other concrete piling; shallower concrete piling for ground improvements,” he said.

Working together

Although the viaduct contract was not based on an alliance structure, it was a target-cost contract. Balfour Beatty and Network Rail have worked “hand in glove”, according to Smith, who recently celebrated his 25th anniversary working for Balfour Beatty.

“However, in all that time I have never felt closer and more connected on a project,” he said.

As mentioned earlier, the wet winter weather caused some problems in the production and construction phases.

But, while working in these extreme conditions, it also highlighted the collaborative nature of the teams not just at Network Rail and Balfour Beatty, but also further down the supply chain.

Brown told us that at one stage the concrete sub-contractor, Sword Contracts, had its batching plant flooded. The project partners were informed that because of this it would be shut down for about two weeks.

“We could have just sat back and said ‘well, that’s a problem for that supplier’ – but we couldn’t just stop work,” he said. “At that time we were pouring 500m³ of concrete a day, which is quite a significant amount, and if we’d lost a week or two in production we couldn’t regain that in the programme.”

So, Network Rail and Balfour Beatty took a truly hands-on approach: they sent workers down to the flooded unit with pumps and within a couple of days the site was back online.

Smith said that for a long time “you couldn’t tell who worked for who”. Even without a formal alliance-type contract in place, such collaborative working still became the mindset of the site team.

Balancing beams

At the project’s peak, more than 400 people worked on it. And in November 2013, the first of the Shay Murtagh constructed concrete bridge beams and precast concrete culverts started to be shipped over from Ireland to Reading.

However, lifting the beams into place – each weighs about 40 tonnes and is 23m long –required some innovative engineering. This took the form of tandem lifts.

“Ordinarily you wouldn’t plan to do tandem beam lifts, but because of the geography we couldn’t get close enough with a regular crane,” said Smith. “We had to plan to allow a tandem lift, in which you pick up one end of the beam with each crane to place them. One crane would not have been enough to cope with the reach to land them.”

Network Rail told us that there are only a few companies, Balfour Beatty being one of them, with the expertise to carry out this type of work. In fact, Kevin Brown said tandem lifting is “an art in itself”. He also stated that this work was done without disrupting services.

“We made impact briefs, and talked to the train drivers on the line, because what you don’t want to do when you’re driving a 125mph train is come hurtling round a corner and see [because Reading is actually on a very big curve of the track] a beam in the air, which could look like it’s over the track because of the curvature,” he said.

But, during the production of the 2km viaduct, because of this “informative” work Network Rail has received no complaints from any of the train drivers.

Brown noted that, despite tight access to the site, the civil engineering has been fairly basic. “It’s concrete works and earth works,” he said. “What’s been difficult is the logistics.

“It’s a very small site. The site, essentially, isn’t much wider than the actual bridge itself, so it’s the logistics of being able to do that much work in what’s not much more than a year that’s the challenge really.

“We’ve done nothing particularly complex in terms of novel engineering: that’s why we kept it simple, because we had a lot to do in a short time.”

Feeder line box

In May, Balfour Beatty completed the concrete pours for a Feeder Line box, which will provide a route for the freight lines from Southampton and the south to run beneath the east-west main line railway passing over the new viaduct.

The box required six 900mm-thick reinforced concrete decks, using 3,030m³ of concrete, and was completed by June. And now, as part of Balfour Beatty’s remaining work, it will return to the Feeder Line.

By October it is expected to deliver the Feeder Line underbridge, and the embankment that carries the railway from Reading heading south.

In early 2015, the Festival Line viaduct will be the last remaining elevated structure to be completed. “This involves the construction of a reinforced earth ramp and a viaduct bridge, which has six spans,” said Smith. “That carries the Festival Line, which goes through the previously constructed Festival Line box/Reading West Curve box.”

Once the tracks are in use over the viaduct, Network Rail will be able to complete the widening of Cow Lane from one lane to two, removing a major bottleneck on the road network. At this point, motorists as well as rail passengers will feel the full benefit of the project.

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