Heavy-lift specialist Mammoet has begun an amphibious operation to replace five crucial bridge decks at Amsterdam’s main Centraal train station that have reached the end of their design life.
Working with Dutch engineering company Dura Vermeer for client ProRail, Mammoet will replace four steel bridges and one concrete one on its eastern approach (Oostertoegang), taking a year to replace each while the station remains open.
Because the station is surrounded by water, and to minimise city-centre traffic disruptions, the large, prefabricated bridge sections – three for each bridge – will be shipped to the site by barge.
The sections are between 24m and 28m long, and weigh between 173 and 275 tonnes each.
Five-day journey
Each section starts its journey from the yard of fabricator Hollandia Infra in the town of Krimpen aan de IJssel, east of Rotterdam.
It goes down the Nieuwe Maas River through Rotterdam to the North Sea, then north along the Dutch coast and into Amsterdam through the North Sea Canal, a five-day journey.
The first section departed Hollandia’s yard on Monday 18 November and arrived the following Friday to start replacing Oostertoegang’s northernmost concrete trough bridge.
Delicate lift
Once in place for installation, Mammoet’s Mega Jack 300 system lifts the section to a height of 4m on the barge deck, allowing enough space for a self-propelled modular transporter (SPMT) to drive underneath.
The SPMT then lifts and rotates the section 90 degrees to the correct orientation, then drives them over a ramp off the barge and onto the bridge support towers.
For each bridge, Mammoet will install the east side section first, then the west and finally the middle section, which will be lifted and installed over water from the deck of the barge.
Tight squeeze
Planners had to work out how to get the sections under a low footbridge near the Oostertoegang.
The solution was to partly submerge the main installation barge with copper pontoons weighted with water.
Mammoet has been planning and preparing for the operation since 2021.
“We came up with the approach to install the bridges on water to limit transport movements and disruption in the city centre,” said Mammoet project manager Leo de Vette.
“This makes it a complex operation because space is limited and there are many steps that must be carefully managed. Every change you make influences something else, and that is a major challenge for this project.”
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