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Last but not least

Contract 102 was the biggest and by far the most complex on the job. Antony Oliver talks to the guys in charge.

JLE senior supervising engineer for Westminster, Mike Jenkins is confident that Westminster Station, the last to be opened on the JLE will be ready to hand over to London Underground by the end of November.

Despite the abundance of problems, Jenkins is happy that the team will have done a good job on the ultra-difficult Contract 102. For him, Westminster Station winning the Institution of Civil Engineers' special merit Award last year was the icing on the cake, giving recognition to everyone on the job of their phenomenal achievement.

He also points out that problems such as the knock-on effect of the Heathrow Express collapse - a completely separate BAA/Railtrack project - had a bigger effect than was perhaps realised. 'It was a massive distraction of management attention away from the work that they should have been doing.'

Industrial problems during the fit out stages of the job have been a continuous hindrance to progress but Jenkins is confident that the right deals have now been struck to see the job through to completion. 'I always measure Drake & Scull's performance as a contractor rather than looking at the outputs of individuals,' he explains. 'Current performance is better but it still gives us concern.'

He also believes that at Westminster it was always ambitious to try to reconstruct the existing District and Circle Line station within the same contract as building the new JLE station. Having to do all the work in night-time engineering hours meant that two years into the contract little new construction for the JLE had been achieved. This work would certainly, he believes, have been better let as an advance works contract.

That said, he is confident that even the Railway Inspectorate's notoriously fine tooth comb approach to approving the station as ready for use in a few weeks time will not add too much to his programme. 'We have looked at the things that have been raised elsewhere on the project and made changes already,' he explains. 'Of course there may be other things they pick up but we believe we have met the majority.'

Jenkins admits that working in such a high profile area has had its difficulties. Being under the gaze of MPs in the House of Commons and at the heart of one of the busiest tourist attractions in the capital, required a certain amount of politics and humour. In particular he says, he enjoyed reading press coverage of the Westminster project, which has commanded significant attention. Learning that Big Ben was about to topple over from an article in The Times, he points out, certainly warmed up the phone in his office.

Balfour Beatty-Amec project director Clive Pollard was similarly amused but is conscious that the coverage results from the public perception of the project as a failure. 'Technically the project has been a success,' he insists.

With hindsight he doubts whether in reality it was ever possible to meet the original deadline. 'Certainly, as a contractor, we have scored no own goals here. Our original programme at tender said it was possible but relied on everything clicking into place.'

The first problem to hit the contract was not of the project's own making. When shotcrete tunnels collapsed at Heathrow Airport similar work on the JLE also stopped, delaying the project by up to a year and causing the entire programme to be turned upside down. Tunnels designed to be built using sprayed concrete were redesigned in cast iron. Areas that had to be built using sprayed concrete methods had to be proved safe to construct. Monitoring of ground movements was put under the microscope.

But those solutions to these problems, and the cash to resolve them, was found and agreed back in August 1995. Since then a great deal more water has flowed under the bridge, cutting heavily into the ultra-tight programme.

The revised programme for Contract 102 relied on time being saved during the excavation of the huge Westminster box by leaving out one level of propping during the top down construction. However, as work progressed the Parliamentary Works Department, entrusted with the safety of the Big Ben clock tower and Houses of Parliament, called a stop to work and insisted that the props be reinstated as it felt the resulting ground movements were too high.

'It was a massive blow, but we simply could not take a chance with something like Big Ben,' explains Pollard. 'We agreed the situation with the client and that the consequences to the programme were not at our risk.'

Months were added to the programme as large temporary props were installed at one level and permanent floors constructed, which would affect the construction logistics until completion. But more delay was to come. The complex geogrid topslab of the new station forms the structural base for the New Parliamentary Building and it soon became apparent that any differential settlement while the station was excavated below would overstress this delicate structure. A £1.2M jacking system had to be designed and installed by sawcutting through each of the pile supports so that the base slab could be adjusted continuously to keep it precisely level.

With such a tight programme and so many extremely difficult operations, not to mention the effects of tunnelling delays outside the project's control, Contract 102 will be the last to finish and when complete will have seen the original £157M price rise by well over £200M and still rising. But Pollard admits he will be proud when it is finally completed.

'There were times when I felt I was beating my head against a wall but there are just as many time when it has been a marvellous experience,' he says. 'What grieves me as a civil engineer is that the public will get no real appreciation of the incredible engineering necessary to build these stations and tunnels.'

With such complex work going on at Westminster, it is easy to forget that the contract also included the difficult tunnelling work to construct Waterloo Station and the twin 4.35m diameter tunnels driven to Green Park. The compensation grouting used to ensure that none of the historic and highly sensitive buildings moved vertically more than around 15mm pushed the boundaries of what was previously possible.

Pollard is also particularly pleased with the four huge junction connections that had to be made with the 10m diameter concourse tunnel to link the new line with Waterloo Station. These, in his view were civil engineering on a scale that the public using the station will simply never appreciate.

'The design of Waterloo Station is a work of art,' says Pollard. 'To fit the new construction into the existing infrastructure requires phenomenal vision.'

Pollard chooses his words carefully when asked if problems could have been avoided on the contract. 'For me it comes down to the strength of the client's management team. The job was set up to have a very strong team, but I really do not think JLEP realised how important this was.'

But Pollard accepts that JLEP must take credit for the excellent safety record on the whole project. Throughout the five years of construction no one has been killed, due mainly to the client's continuous focus on safety.

'JLE did a tremendous job,' says Pollard. 'This contract has changed our attitudes towards safety and had a huge impact on the way we work. We have just notched up 1.6M man hours with only one reportable injury. The JLE Safety Award Scheme achieved a lot in terms of safety awareness in construction.'

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