The Swedish Transport Administration needed to replace two bridges on the E4 highway, at one of Swedenâ€™s busiest junctions â€“ RotebroÂ â€“ as the technical lifespan of the bridges had been reached. Rotebro is in the municipality of Sollentuna, halfway between Stockholm and Arlanda airport. Approximately 70,000 vehicles cross the bridges daily.
Under the bridges, there are municipal streets with approximately 25,000 vehicles. Here the railway â€śOstkustbananâ€ť also crosses with around 600 trains per day where the fastest trains to Arlanda airport have been able to pass at a speed of 200 km/h through the construction site. The train traffic is active all day onÂ every day of the year, meaning that this is a complicated project, in a very busy traffic setting.
In the beginning of July 2015, a 325 meter long and 6,360 ton heavy bridge was carefully pushed into position. The lateral move was 22 meters and was performed using beams and lift jacks. The new bridges will stand for 120 years.
The unique aspect of this project is that we have used new technology which makes it possible to perform virtually all work without influencing the existing traffic. We are building a permanent bridge in a temporary position which is then pushed into place. Thanks to the new technique we reduced the disturbance to traffic as wellÂ as time and costs.
A calculation of carbon dioxide emission savings, using the chosen technique has been made, and has been calculated at 122 tons of CO2. That corresponds to 91,000 km of car driving, or 60 flightsÂ between Stockholm and London. This reduction is due only two bridges beingÂ necessary in the solution from NCC instead of five bridges in the original proposal. The calculation does not include the absence of emissions from lines of cars, which would have been the case in the original proposal.
Safety and accessibility are the most prioritised goals of the project. Because of this, a key focus of the project was the identification of risks and the management over the courseÂ of the project. This increases the possibility to proactively prevent risks. Over 300 million journeys have passed through the site without being affected, and the accessibility has been one of the main challenges of the construction. The challenge in safety and accessibility has not only focused on train and car traffic, but also on cyclists and pedestrians. Since the construction site has been adjacent to a commuter train station it has been important to always keep pedestrians informed about how to get to the station. Another challenge was to demolish the old bridges without affecting the train traffic under the bridges.
The project was procured as a turn-key contract. That means the Swedish Transport Administration leaves a greater responsibility to the contractor, who in addition to the realisation of the project also is responsible forÂ material choicesÂ â€“ giving NCC a greater freedom. For the Swedish Transport Administration it meant that more time could be spent on planning and on focusing on the function. NCC proposed a solutionÂ to the Swedish Transport Administration where the accessibility during the construction phase was very good at the same time as the price for the contract was around 25 percent lower than the original estimate from the Swedish Transport Administration.
The project has received a lot of attention. At the Concrete Gala in 2013 it won the environmental prize with the motivation that the rebuilding of the Rotebro bridges is Swedenâ€™s first environmentally certified infrastructure project. In 2016, the bridges were one of the second place prizewinners in the Construction of the Year. The Swedish Transport Administrationâ€™s new procurement strategy, was opened up for new thinking by the contractor NCC and enabled a cheaper, more efficient and environmentally friendly solution when rebuilding the bridges. NCC built a permanent bridge in a temporary position, and then pushed it into place laterally. The judgement was that it was a brilliantly smart solution, both cheaper and less disturbing for traffic.
The Highway E4 Rotebro project was chosen as a pilot for certification throughÂ CEEQUAL. The work has been done in cooperation with the contractor NCC. The project was the first Whole Team Award with Interim to be performed in Sweden, and included the planning, design and construction phase. Our British verifier Catherine Arotsky has been a very pleasant acquaintance who quickly got into Swedish conditions and was very keen and helpful.
As a side effect of the project, the slings used for reinforcement steel have got a new life. The slings can for work safety reasons only be used once. Waste studies have shown that slings make up around 15% of the combustible waste. A collaboration on design and reuse was started between NCC and Eskilstuna folk high-school. Some examples of what the slings can be used for is as room dividers, seats of chairs, baskets, carpets and dresses.
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