On-site welding work up to execution class 4

To realize the underpass on the Oosterengweg in Hilversum, Lasbedrijf De Rooij B.V. is supporting BAM Infra Nederland's efforts in the HOV in 't Gooi project. "We are equipped in such a way that we can weld structures in the field up to the highest execution class in accordance with NEN 1090 execution class 4," says director Mario de Rooij. "The underpass in Hilversum involves several outrigger structures, two of which we have sunk."

Welding company De Rooij prefabricated the outrigger structures as much as possible in the workshop. "That is, we provided the required HEB beams and outriggers (tubes) with end plates, baffles and suspension points," explains De Rooij. "The assembly to the final structure itself was done on site. That is mostly common in our branch, in which we distinguish ourselves by being able to offer welding work in accordance with the highest execution class NEN 1090 execution class 4 and go up to a steel quality X70. This is quite unique. Initially, we assembled two outrigger structures that we sunk 3.5 meters and 6.5 meters underwater, respectively. In the process, the structures were attached to special suspension points and suspended in steel cables."

Sinking was quite a precision job, according to De Rooij. "For example, the design took into account the limited space to maneuver the struts between the existing structure. Once the underwater concrete is poured and sufficiently cured, the final concrete construction can be started and the struts are dismantled by us in phases. These are then modified by us and deployed again for the realization of the next outrigger frame." Welding company De Rooij is mainly active in infrastructure and works throughout the Netherlands and (far) beyond. "We regularly roam all over Europe."