Steelwork Pontsteiger latticework

A prestige project with a long breath: residential project Pontsteiger in the Amsterdam IJ is now typically one of those structures that finally got off the ground thanks to perseverance and hard work. Over nine hundred tons of steelwork went into it, including eighty-ton trusses.

Even a layman can see it: Pontsteiger Amsterdam will be a building with, euphemistically speaking, a challenging construction. Not surprisingly, therefore, Buiting Machinebouw en Staalconstructie from Broekland was particularly pleased with the order for the steelwork of this new 'gateway' to the NDSM site of Amsterdam North. "Complex constructions are our driving force," says Dennis Frankot, project manager at Buiting. "You won't often see us for the construction of an industrial hall. This project is beautiful for several reasons: it is an imposing and above all well-known structure, so interesting to work on. In addition, the enormous loads, combined with a diversity of special profiles, make for complex (welding) connections. Finally, the transport and assembly process is, to put it mildly, challenging."

Buiting is supplying and assembling a total of over nine hundred tons of steel for the building, spread throughout. By far the most attention deserves the partly steel truss bridge construction that connects both residential towers. With weights of eighty tons each, partly constructed with HD girders specially manufactured for this work, special elements, says Frankot: "The choice of HD girders stems from the architect's desire to make the trusses and braces as slender as possible. The trusses are made in one piece, the largest of which is 48 meters long and 9 meters high. Several mobile cranes will be used to assemble the trusses." The alternative of prefabri-cation - assembly on the job - immediately fell out for mainly (structural) safety reasons. There are too many risks associated with that, according to Frankot.

While the girders are imposing enough on their own, the logistical plan is much more of a headache. There is really only one way to go, and that is by water. And that is how it is done, from the production site in Almelo. Frankot: "The most difficult part is the two-kilometer stretch over land, with bends, trees and lampposts along the way. For this we use a transport system with loose turntables that was specially developed for large material. The whole route from our factory, via the loading/unloading quay across the water to the construction site, will have to be tuned very precisely. But I am convinced that it will succeed." Right now, Buiting is still working on production. Frankot expects to start the approximately three-calendar-month assembly work in January 2017.

Buiting became involved in the work in 2014. This happened immediately after it became clear that the project - thanks in part to a change in construction - could still go ahead. Frankot applauds being at the table quickly. Because it allows the company to get rid of expertise that would otherwise go unused. "Work like this is always an interplay between structural engineer, architect and the executing parties. We are broadly organized, and in this way we can express our knowledge well. Pontsteiger is by no means an easy job, but that is exactly what we like. There has to be something special in it."