Apr 01 2020, by Fleetwood Urban (Marketing)

NESCIOBRUG - Nescio Bridge

Suspension bridges are nothing especially new. Unless you happen to be in the Netherlands, that is, where the ground is notoriously soft, a natural phenomenon that presents all sorts of engineering challenges. At almost 800 metres long, the Nesciobrug, or Nescio Bridge, spanning the Amsterdam Rhine Canal was officially opened to cyclists and pedestrians back in 2006. The single-cable self-anchored structure still stands as a multi-award winning beacon for the power of collaboration to solve even the most complex of community access problems.

“There are no other suspension bridges in Holland for the very good reason that the ground is very soft and therefore it is difficult to anchor the cables.”
Angus Lowe, Project Leader, ARUP

The Team
Commissioned by the City of Amsterdam, the Nesciobrug project drew together some of Europe’s brightest and most creative minds. The project team included globally-acclaimed London architects Wilkinson Eyre, together with engineering firms on both sides of the English Channel, the UK-based ARUP and Dutch-based Grontmij.

The Brief
The Netherlands is a country well versed in travelling by foot and bike, and has long been considered a world leader when it comes to Access infrastructure. In the instance of the Nesciobrug, the City of Amsterdam identified the critical need to deliver a new pedestrian and cycle bridge over the Amsterdam-Rhine Canal – one of the busiest inland shipping routes in Europe. In difficult terrain, the brief was to design and construct a vital Access link for the residents of IJburg, a newly-reclaimed suburb in Amsterdam’s north, allowing them to easily connect to the wider city on the ‘mainland’. At the same time, the new bridge was also needed to deliver safe and direct access in the opposite direction, allowing the people of Amsterdam to more easily enjoy an expansive 90-hectare green space opened in 2004, known as Diemerpark.

The Nesciobrug is named after the late Dutch novelist, Jan Hendrik Frederik Grönloh, who used to walk along the former dike where the bridge now touches down. His works were published under the pseudonym ‘Nescio’.

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Kerry Doss - Deputy Director, General Planning Group at Queensland’s Department of State Development, Manufacturing, Infrastructure and Planning

The Challenge
Despite being completed at a cost of almost €10 million, the budget for such a large and complex undertaking was actually very tight. Suspension bridges are also rare in the Netherlands; the notoriously soft earth makes it difficult to adequately anchor the main cables. On the Nesciobrug project, this was solved by anchoring the cables to the bridge itself at the ends of the deck, rather than to the ground via large anchorages. Beyond this, the design also needed to ensure sufficient clearance was maintained to allow unrestricted commercial shipping access to the Amsterdam Rhine Canal below. The potential for high winds was another factor requiring careful consideration, with wind tunnel testing conducted prior to final approval, while a series of tuned mass dampers was also specified to prevent the bridge from wobbling as people walked across it.

The construction phase presented yet more challenges, both due to the unprecedented size of the structures and their proximity to such an important shipping route. In a strategy frequently used here at Fleetwood Urban, it was determined the main 180-metre span should be constructed off-site as a single steel structure. In order to minimise disruption to shipping, the span was then hoisted into place in less than 12 hours. Weighing almost 510 tonnes this was a major and hugely impressive undertaking.

The Design
The award-winning design of the Nesciobrug stands out for many reasons. But the feature that continues to draw the greatest acclaim is its use of a single, self-anchored cable. When completed in 2006, the curved, steel structure was the first suspension bridge in the Netherlands to carry only pedestrians and bicycles. Stretching 10m above the canal and almost 800 metres in length, it was also the longest single cable suspension bridge anywhere in the Netherlands. The curved steel box girder deck follows an elegant natural route in the middle sections of the bridge, however the design then forks at each end to create safe and separated access for cyclists and pedestrians. Both sections follow a gentle slope to maximise access and inclusivity. From an aesthetic perspective, the bridge possesses a fluid form, with its cross-section changing from a deep triangular section at mid-span (for optimum stiffness) to shallower end sections that merge into the sweeping concrete approaches.

Awards
IstructE Pedestrian Bridges Award (UK) 2007
Arthur G. Hayden Medal (USA) 2007
Nationale Staalprijs (Netherlands) 2006