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Renovation of the Galecopperbridge

Client:
Rijkswaterstaat (Public Works Department and Water Management)

Engineering / construction:
BKB Infra

Products Cugla:

Most advanced structural engineering

The Galecopperbrug (bridge) near Utrecht, which was built in the 1970s, is starting to show signs of fatigue and must therefore be comprehensively renovated. And while you're renovating, why don't you raise the bridge by a couple of metres? Then ships of higher sailing classes can also pass under the bridge. Jos Kronemeijer, Sr. Specialist in Materials Technology at Volker InfraDesign, explains that by using Cugla he obtained a double benefit. 

Life-extending reconstruction

The Galecopperbrug is part of the A12 between Utrecht and The Hague and spans across the Amsterdam-Rhine Canal near Utrecht. Coping with more than 200,000 vehicles per day, the Galecopperbrug is the second busiest bridge of the Netherlands. The bridge has a steel road surface and an asphalt overlay. Kronemeijer: ‘Rijkswaterstaat commissioned an upgrade which summarily boils down to a life-extending reconstruction and an increase in the vertical clearance. An important contractual prerequisite was that the through-flow of traffic would be hindered as little as possible by the renovation activities, so closing the bridge for the road works was not an option. Then the right choice would be a clever traffic plan, a smart recovery method and a short reconstruction time.’

Bridge-strengthening effect

The life-extending reconstruction includes a replacement of the asphalt with a road surface of high-strength concrete which is reinforced with steel fibres. Kronemeijer: ‘This type of concrete is exceptionally durable in terms of abrasion resistance, de-icing salt and frost-resistance, and an extremely high cracking toughness. At the same time this concrete has a reinforcing as well as a stiffening effect, in the sense that driving comfort and the overall load bearing capacity of the bridge will increase. But because this concrete surface is also heavier than the former asphalt surface for the opted dimensions, the deadweight also increases. Moreover, the raising of the bridge also brings about slightly different force dynamics. You must be able to take up all those forces.’

Major reinforcement in the bearing position

‘The foundations, the pillars and the bearing position in the bridge all had to be strengthened’, Kronemeijer continues. ‘And supports had to be provided to enable the realisation of the raised height. Here, account also had to be kept of traffic thundering across the bridge at the time that the strengthening and raising had to be implemented. Rechecking our calculations for functionality, safety, reliability and durability raised concerned questions. There had to be a major reinforcement in the bearing position to cope with all those forces. Besides, there was barely any space to make them: it had to happen in a stooped position anyhow. All those matters called for a special type of concrete.’

Mock-up test

As a Specialist in Materials Technology, Kronemeijer discussed the required product specifications in consultation with structural engineers and implementation specialists. He consequently wrote a test programme in which not only the structural and durability properties would be guaranteed, but also the implementation aspects. Kronemeijer: ‘We then decided to do Mock-up tests. We built a 1-on-1 model of a supporting block in order to simulate the project as best as possible.’

 

Test at a height of twelve metres

‘Then we approached three renowned materials suppliers and presented our unique performance specifications’, says Kronemeijer. ‘To carry out a proper simulation, we also tested it at a height of twelve metres, the true height. We built a scaffolding and placed the formwork which contained the extremely complicated reinforcement on top of it. The grout mortar pump was placed at ground level because of the limited space between the supporting blocks and the bottom of the deck, so the mortar had to be pumped up over a length of more than eighteen metres through a flexible hose.’ 

Extensive list of technical specifications

‘To enable verification of all relevant performances, several sensors were suspended inside it’, Kronemeijer continues. ‘Aside from “makeability”, an essential filling rate, and a whole range of practical aspects in order to realise the planning, we also looked at long-term aspects such as durability in fifty years' time. I had drawn up an extensive list of performance attributes.’ 

Product specifications

Kronemeijer: ‘The most important special specifications of the concrete concerned the degree of self-compacting and to a certain degree also the self-levelling capability; after all, due to the extremely dense reinforcement configuration we couldn't just simply use any normal vibrating needles. Moreover, the mixture had to provide high resistance against plastic setting and hardening shrinkage, and drilling cores had to verify that a good reinforcement covering could be realised. After all, only if concrete is positioned homogeneously neatly around the reinforcement bars is it possible to have a good transfer of strength between both. Finally, the topmost layer had to have an additional steel fibre reinforcement to better control any possible shearing forces.’

Cugla wins the test

After the first Mock-up test it appears that the Cugla product required minimal adaptations to realise full compliance. Kronemeijer: ‘Only a slight improvement in the sedimentation resistance at low temperatures and a reduction of the hydration heat development still had to be improved. The Cugla experts accomplished that within a week. After the second Mock-up test their solution complied with all the performance attributes which I had mentioned. Well within the time allowed and in conformity with the design and implementation criteria. Then the choice was very easy.’

What if…

Kronemeijer and his colleagues are very satisfied with the outcome of the Mock-up tests. ‘To have to struggle within the assumed planning margins for another two weeks to find a suitable alternative was not a serious option. That meant that we sometimes have to “call on extra experts” to redo the calculations, to figure out other implementation methods, to readjust the planning where the implementation involved equipment and labour resources... And all this has to be approved by internal and external clients before the start of the project. Fortunately none of that was necessary because, within only three weeks, Cugla had come up with a solution to provide a special customised performance which complied with all the conditions. And then there was another new challenge: this time it was in logistics.’ 

Three weeks

‘Within three weeks after the second Mock-up test we had to start’, Kronemeijer continues. ‘For the project activities a total of about eighty cubic metres of mortar volume had to be produced. Cugla succeeded in this feat too. In total it concerns about fifty supporting blocks of various dimensions, of which the largest amounts to approximately four cubic metres. To be able to implement this by “X hour”, space still had to be cleared at the construction site so that the materials could arrive and be processed in frost-free circumstances for a just-in-time-delivery of the weekly production. Because of Cugla's logistics flexibility there were no delays and we could start on time. In the meanwhile all the bearing seats were realised to full satisfaction.’

Partner

Kronemeijer concludes: ‘Cugla is perhaps not the biggest mortar supplier in this country, but when it comes to their proactive approach, their excellent specific expertise and their flexibility, they seem to perceive very quickly some of the barely uttered desires which we sometimes have. They soon feel as if they're a partner in the contractor's technical issues; that works rather nicely.’

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You want more information about this project and the role of Cugla?

Please contact Frank Geerdink

Cugla BV | PO Box 3477, NL-4800 DL Breda Rudonk 11, NL-4824 AJ Breda Netherlands | +31 76 541 06 00 |