A number of major concrete road bridges throughout the Netherlands probably need to be reinforced to cope with present day traffic levels, the transport ministry confirmed on Wednesday.

The news follows last week’s surprise closure of the bridge on the A6 motorway between the A1 and Almere to all lorries because of the risk of craters suddenly appearing on the bridge’s surface.
The closure of the bridge, used by between 2,000 and 6,000 lorries a day, was described by local business leaders as ‘unacceptable and incomprehensible’.
The ministry said on Wednesday that inspectors are currently compiling a report into the condition of all concrete bridges built before 1975 because of concerns about their safety.
In today’s Telegraaf, Delft university professor Leo Wagemans says engineers made serious mistakes in their calculations when the bridges were built.
Lorries not only carry heavier loads than 30 years ago, but the amount of traffic on Holland’s roads has also gone up sharply, developments which civil engineers failed to include when designing the bridges.
Today, bridge surfaces are becoming pulverised and there is a risk of dangerous holes in the road suddenly appearing, he said.
Wagemans told the paper that the situation is so serious that hundreds of bridges needed surface repairs.
The transport lobby groups EVO and TLN say the closure of the A6 bridge over the Gooimeer lake will cost the industry €17m if it remains closed for six months.