Houses sink under ground

Houses sink under ground

15th September 2008, Comments 0 comments

Houses sink under ground. Amsterdam metro lives up to name.

Amsterdam Mayor Job Cohen has for the first time expressed doubts about Amsterdam's North-South Line, a new metro line scheduled for completion in 2015. "I realize the credibility of the project is suffering. It is a cause for concern." 

In June work on the underground tunnel was suspended for three months after water seeped through the enormous concrete slabs, causing four houses to subside. The municipal authorities said that "A responsible plan for renovation was undertaken and the work was carried out with optimal precision." On Monday the repairs were completed and work on the tunnel was resumed. On Wednesday evening residents of four 17th-century buildings which adjoin the construction site heard "remarkable noises". "A short time later pieces of grit began to fall, followed by plaster from the walls and pieces of ceiling." The 20 residents have been evacuated and may not be able to return to their homes for years to come. Three other houses have also been damaged.
Architect Wolbert Vroom, who owns three of the buildings, told de Volkskrant that there were "phenomenal" cracks in the walls, several centimetres wide and up to five metres in length. He says the buildings' foundations have sunk up to 24 centimetres. 
Photo right: Amsterdam Vijzelgracht buildings
subsided after tunnel work (NOS picture)
Lost confidence
The problem is that the construction workers have reached a depth of 15 metres and the deeper they go the greater the pressure. However the diggers are less than halfway, since the tunnel will be 40 metres deep. 

Mr Vroom, who specialises in the restoration of historic buildings, says it will take years to repair the damage to his properties. Previously he supported the construction of the North-South Line. 
"I have lost all confidence. I have the impression that a second-rate level [of bureaucrats] is responsible for the execution of the project and its supervision." 
Delays and costs
Work on the North-South Line began in 2003 and was originally scheduled for completion in 2012. The original costs were 1.5 billion euros. Now the projected date is 2015 and estimated costs are 2.2 billion, of which the city has to cough up around a billion. This is a far cry from 1997 projections: The metro was to have been completed in 2007 for 885 million euros, of which 40 million would be paid by Amsterdam.

In a 1997 referendum over the metro, 65% of those who voted opposed the project. However since the number of people who voted was under the electoral threshold, the city fathers and mothers decided to ignore the results. 

Untried technology
In 2003, opponents of the North-South Line argued that the technology used had never been tried before and predicted that the underground drilling in soggy ground next to historic buildings would lead to "unavoidable disasters". "In Amsterdam the removal of ground will have major consequences. Foundations of buildings supported by wooden stakes will subside or even collapse..."

According to an old Amsterdam rhyme:

Amsterdam, die grote stad, 
die is gebouwd op palen. 
Als die stad eens omme viel, 
wie zou dat betalen? 

That old town Amsterdam, 
It is built on stakes.
Should that town collapse,
Who will pay for the mistakes? 
Frank Scimone 
15 September 2008 
Radio Netherlands 

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