It can almost be called a sky ride. After the completion of a huge new cycle viaduct last Thursday in ʼs-Hertogenbosch, you can now cycle over a motorway, a new canal and a new turbo-roundabout – completely uninterrupted – at a height of 4 to 7 metres above ground level for a distance of 1.2 kilometres. If there is one thing the Dutch are good at, it’s seizing an opportunity when it arises. Sometimes that means combining the replacement of pipes and cables and a new street design, but in this case it was the construction of a new canal that was taken as an incentive to reconstruct the entire road and cycleway network at the east side of the city.
This video shows the new cycle viaduct over the turbo-roundabout betweenʼs-Hertogenbosch and Rosmalen.
A few weeks ago I showed you how the cycleway alongside the new Máximakanaal in ʼs-Hertogenbosch looks. But a new canal is also a new barrier. Roads that ran through fields before now need tall bridges, at a height of over 7 metres, to cross this new canal. That led to long new access ramps, that in turn meant several roads and intersections had to be relocated. So why not do it entirely right then, and update those roads and intersections to the latest design standards? One huge intersection at the entrance of Rosmalen (a former town now belonging to the municipality of ʼs-Hertogenbosch) was changed from a large signalised four arm crossroads into a modern turbo-roundabout that does not require traffic lights. Turbo-roundabouts and cycling do not go together well, unless the cycleways pass the turbo-roundabout grade-separated. The proximity of the tall new bridge over the new canal was taken as an opportunity to have people cycling only go up that height once and to make it possible for them to pass over the canal and the new turbo-roundabout in one go. There already was an overpass over the motorway A2, so all three are now combined. That means that if you cycle you don’t get back to ground level for 1,200 metres. This turned three possible barriers into one easy ‘sky ride’.
The bridge over the canal and the new turbo-roundabout are not precisely at the original location of the road and the crossroads. That made construction easier. The construction had started with ground works next to the original road in June 2013. Concrete pillars were put in position and the concrete viaduct was constructed on site. Only after the new turbo-roundabout and the cycle viaduct above it were finished and partly opened in November 2014, the original road and intersection were removed. That made constructing the third and final leg and access ramp for the cycle viaduct possible. The viaduct was completely opened last Thursday, 9 April 2015. All that happened was that construction workers simply removed the fences. There was no fanfare, there were no officials. This is just another piece of infrastructure. The cycle viaduct doesn’t even get a name.
Video showing several stages of the construction works.
The information leaflet of the construction company gives a hint as to why that might be. This viaduct is not meant to be a landmark. On the contrary, it has to blend into the new park alongside the entire length of the canal. So it was made as thin as possible to make it optically less intrusive. At the same time that emphasises the long horizontal lines. Because there are three access ramps, the viaduct has a rounded bottom and there is a curve, it has no distinct direction. Therefore the architect felt that the pillars had to be completely round as well, so they do not have a direction either. The 9 pillars are almost identical, they only vary in height. That meant only 4 castings were needed to construct them all.
The viaduct consists of a curved west-south connection with 8 spans with a length between 21.6 and 26.8 metres. The connected north-arm has two spans with a total length of 49.8 metres. With the access ramps on dams the total length of the viaduct is 279.7 metres and its width is 5.14 metres. The cycleway deck that people ride on is 3.7 metres wide from kerb to kerb. (Nice, but I think that should have been 4 metres considering the amount of cycle traffic.) The height of the viaduct is 5.8 metres and the gradient of the access ramps is only 3%.
The cycle viaduct over the turbo-roundabout is an asset to the already great and award-winning cycling network in ʼs-Hertogenbosch, but there was one thing that didn’t quite work out as planned. The new infrastructure has come awfully close to an existing farm-house. Initially it was believed that the new turbo-roundabout and the cycle viaduct would be at an acceptable distance, but while construction progressed it became increasingly clear that the end-result is not acceptable at all. Motor vehicles drive almost in the front garden and the cycle viaduct almost touches the roof of one of the stables. This will also make future maintenance more difficult. Rijkswaterstaat (the service of the Ministry of Transport in charge of the canal/road construction project) and the municipality of ʼs-Hertogenbosch have now come to an agreement with the owner of that farm-house. She is a single elderly woman who had already stopped farming. She only keeps horses as a hobby and she does not want to give that up. Her land was reduced in size drastically because of the construction of the canal, but it is still of a considerable size. It proved possible to build a new farm-house with stables for her hobby horses at the other side of her own land. The bulk of the costs for the removal of the old farm-house and building the new farm-house with stables will be reimbursed by the Ministry of Transport.
The new cycle viaduct makes cycling from ʼs-Hertogenbosch to Rosmalen and back again very convenient and safe. Lots of school children will use this route, but also other people wanting to cycle the short distance between these two parts of the municipality can easily do it. The construction of the canal bypass could have meant an extra barrier for cycling. Instead it has made cycling easier and quicker and thus a viable alternative to taking the car.
Ride 1 (the red line)
Ride 2 (the green line)