BICYCLE DUTCH

All about cycling in the Netherlands

Wooden cycle bridge Grubbenvorst

New motorways often sever old connections, especially for people walking and cycling. It’s always good when those old routes are quickly reconnected, especially when that is done with a beautiful piece of infrastructure. The wooden cycle bridge at Grubbenvorst over the A73 motorway is a very nice example of such a reconnection.

The wooden cyclebridge at Grubbenvorst, crossing the A73 motorway from Venlo to Nijmegen.

The 20 year old wooden cycle bridge at Grubbenvorst, crossing the A73 motorway from Venlo to Nijmegen.

When the bridge was opened, now exactly 20 years ago and shortly after the motorway it crosses was opened, it was the country’s first wooden cycle bridge over a motorway. There is at least one other now, the wooden cycle bridge at Harderwijk, which I showed you earlier.

A drawing of the bridge.

A schematic of the bridge.

The cable stayed bridge was designed and built in 1995 by Rijkswaterstaat, the governmental body responsible for main roads (and waterways and flood control). The timber came from a company in Friesland, Groot Lemmer, experts in building high-tech wooden bridges.

Cable stayed bridges made from timber are suitable for larger spans up to 100 metres. In this case there are two pylons also made from timber. The entire bridge is kept as slender as possible. The type of wood that was chosen, azobe wood from Cameroon, is very homogenous. This means you can calculate the forces the bridge has to endure just like you could if it had been made of steel. Computer programs can help you get the optimum: a strong bridge using the least amount of material. The main span of the bridge is 45 metres, the total length is 154.1 metres. The construction height of the bridge is about 1 metre. The pylons lean outward and they stand almost 18 metres tall.

Clearly visible is that all the main parts of the bridge are made from azobe timber.

Clearly visible is that all the main parts of the bridge are made from azobe timber. Only the railings are made of steel.

Groot Lemmer imported the azobe timber from Cameroon. At the time there were already laws in effect in that country to protect its woods. The timber was grown and harvested in a sustainable way. Azobe wood is strong and resistant, making it useful for demanding constructions outdoor. It doesn’t need a coat of paint or any other treatment, so there is almost no maintenance necessary. The expected life span of the bridge is 80 years. That means the video shows the bridge at a quarter of its expected life.

grubbenvorst4

The wooden surface of the bridge is a coated with a sort of fine gravel to make it less slippery when wet. It also makes the wooden surface more durable.

The bridge was subject to severe vandalism in its very early days. Some old pallets were set on fire against the bridge, but the wood proved that it is very resilient and that it doesn’t burn easily. There were only some black spots, but no real damage. The heat of the fire did crack the concrete of the anchors, but that could be fixed easily.

road invisible

From the approach the motorway has become invisible because of the foliage. You can clearly hear it though. Very visible (especially when you look at the railings) is the ‘steplike’ incline. You see a sort of dents in the incline. These almost horizontal parts break up the incline, but they are very unpleasant if you ride at higher speeds.

A plaque states the opening date, the 4th of February 1996, and the bridge’s name: “De kortste waeg” meaning “the shortest way” in the local Limburg dialect. But if you look at the map, you see that it is hardly ever the shortest way for anyone. The main road crossing the motorway (Californischeweg) has excellent cycling facilities and is almost always shorter, especially if you go to the hamlet of Californië in the direction of America or even Siberië. These odd names for villages in the south of the Netherlands were given in the late 19th century, when peat was harvested in this area. To emphasise how remote these new workman’s settlements were, they were given names that imply ‘far away’ for people in The Netherlands.

A map to show the location of the bridge. Map from the Cyclists's Union's Routeplanner.

A map to show the location of the bridge. Map from the Cyclists’s Union’s Routeplanner.

That this cycle route is not a main route is clear from the fact that it is not lit at night. The bridge is also a bit on the narrow side by today’s standards. The inclines are quite steep and they are also not smooth. The grade of the access ramps is not constant, but varies at bit. That gives you the rather unpleasant feeling of riding on waves, going up and down.

recreation

Most people will only use the bridge on a recreational ride.

The bridge is part of the main recreational cycle network (the numbered junctions network) and when you cycle for recreation it is perfect to be away from motor traffic in the woods even when that means you take a small detour. This wooden cycle bridge has given people the opportunity to ride safely and in a pleasant way to the other side of the motorway for already 20 years now and it is still looking very good!

Cycle bridge in Grubbenvorst

Ride on the bridge

 

 

7 comments on “Wooden cycle bridge Grubbenvorst

  1. Kevin Love
    10 February 2016

    I notice that the railing has a perfectly sized snow gap at the bottom. Well done! That design prevents any accumulation of snow to build up.

    • bicycledutch
      10 February 2016

      Ah thanks I missed that detail. It is but a small gap, but enough for the amount of snow we get in this country. (Nothing this season so far). But the gap is most probably also useful against falling leaves getting trapped and building up in the autumn.

  2. Reid
    10 February 2016

    Excellent videos as always. Good to see you commemorate the 20th birthday of the old bridge.

    I had not heard of azobe wood. Very interesting properties and uses. A bridge in Wrocław Poland is made of azobe as well as the Arch Bridge in Kopenhagen.

    There is an azobe bridge in Belgium called the wrackhout. It was evidently installed overnight and provides safe passage for people to cross a busy highway to reach the beach.

    • bicycledutch
      10 February 2016

      As mentioned in the post, the bridge in Harderwijk is also azobe. Apparently a very attractive material in many aspects. Cost being one of them, that I forgot to mention in the post: a wooden bridge is cheaper than one in concrete and steel.

  3. meltdblog
    9 February 2016

    That approach looks quite steep, the cyclists wobble as they push hard. We too have these flat “landings” in steeper ramps, the official reason is they are for the elderly and disabled to stop and rest.

  4. midtoad
    9 February 2016

    as a cyclist, you may find those flat spots on the access ramp to be unpleasant. However, you noted that the ramps are rather steep. Pushing a manual wheelchair, you would be very happy to be able to take a little break at various points during your climb up to the top of the bridge. A little “unpleasantness” is surely a small price to pay.

    • bicycledutch
      10 February 2016

      Yes I know that is the reason. But more modern bridges don’t have those, because there is another solution to that: a longer ramp that is less steep. I also struggled to find something ‘negative’ to mention about this bridge.😉

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This entry was posted on 9 February 2016 by in Original posts and tagged , , .

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