The story of the Velser Tunnel
The story of the Velser Tunnel
Speaker: Stephan van der Horst (civil engineering project leader at Rijkswaterstaat)
The Velser Tunnel may not be the oldest tunnel in the Netherlands - that honour goes to the Maastunnel in Rotterdam - but it is the oldest motorway tunnel. Construction of the tunnel began during the Second World War. Work started in 1952 and by 1957 the tunnel could open, connecting the north and south. The Velser Tunnel is famous for its monumental ventilation towers, popularly known as 'the hyacinths'.
From mid-April 2016, the Velser Tunnel underwent a major renovation. The tunnel was completely closed for nine months. Rijkswaterstaat increased the clearance height, modernised the escape routes and renewed almost all tunnel technical installations. In a lecture, Stephan van der Horst, civil engineering project leader at Rijkswaterstaat, will tell you more about the significance of the tunnel in the region, its construction in the 1950s and the renovation of the oldest motorway tunnel to today's modern requirements.
History
There were plans for a single tunnel tube before World WarII. Work started in 1941, but had to stop in 1942 due to war and lack of materials. In 1952, work started on the double tube and rail tunnel, and on 28 September 1957 the tunnel was officially opened by Queen Juliana. Nice photos were shown, including of the construction. Immediately after the opening, there were huge traffic jams as a large crowd wanted to drive back and forth through the tunnel.
The construction method was also special. No drilling or sinking of sections, but building in an open construction pit. The North Sea Canal was much narrower then, so half the width of today could be used for an open construction pit. When that half was ready, the North Sea Canal was extended there and a construction pit was created on the other side.
Ventilation
As a switch is made from vertical to horizontal ventilation, the old ventilation towers become redundant. But after the opening of the tunnel (16 January 2017), they will be refurbished and given another function. Ventilation for other rooms. Since 2014, the 'hyacinths' have been a national monument. The new ventilation consists of 21 fans at the exit of the tube. These blow smoke out in the direction of travel. To make way for the ventilation tubes, the light grilles at the entrances will be converted and partially removed.
Clearance height
Although the legal height for trucks is a maximum of 4 metres, there were still an awful lot too high. Clearance height 4.23 m. This has all kinds of causes: excessive load, flapping tarpaulins, unadjusted suspension after unloading, etc. Now the clearance height will be 12 cm more, so 4.35m. Also, an additional tunnel guard will be made for the entrance, lower than the lowest clearance height, to prevent ceiling damage and jamming. This is achieved by a new ceiling and thinner asphalt and concrete on bottom.
Escape routes
The current escape routes go up with stairs. Now there will be a number of large escape rooms in the middle shaft. Each room can hold as many passengers as a large double-decker bus can hold. The (sliding) doors can always open, except on the side where there are still cars in case of an incident. These can open when the other carriageway is empty after 2 minutes (that is the empty driving time). The escape route is then via the other tunnel tube. At an incident, light signals and sound indicate what to do: out of car, to designated escape room. This point generated a lot of discussion. Because unfortunately, it is only possible to minimise the risk of misery. 100% safe is impossible.
Miscellaneous
Of course, much more has been improved. The controls from De Wijde Blik have been completely updated to the current state of digital technology. The lighting has also been renewed, taking into account greater headroom and all cabling. The construction and dismantling of turning loops and calamity curves was briefly discussed as well as the additional safety measures at the Wijkertunnel.
Description
The Velser Tunnel may not be the oldest tunnel in the Netherlands - that honour goes to the Maastunnel in Rotterdam - but it is the oldest highway tunnel. Construction of the tunnel began during the Second World War. In 1957, the tunnel was able to open, connecting the north and south. The Velser Tunnel is famous for its monumental ventilation towers, popularly known as 'the hyacinths'.
From mid-April 2016, the Velser Tunnel will undergo a major renovation. The tunnel will be completely closed for nine months. Rijkswaterstaat will increase the clearance height, modernise the escape routes and renew almost all tunnel technical installations. In a lecture, Stephan van der Horst, civil engineering project leader at Rijkswaterstaat, will tell you more about the significance of the tunnel in the region, its construction in the 1950s and the renovation of the oldest motorway tunnel to today's modern requirements.
Speaker(s)
Stephan van der Horst, civil engineering project leader at Rijkswaterstaat
Location
Organiser
Region North-Holland
Name and contact details for information
Region North-Holland