Slim floor beams, high quality steel

The steel structure of the new building for RIVM/CBG was delivered by Ferross Staalbouw. In total, Ferross delivered 220 tons of steel: SFB girders for the floor floors and supporting elements, just-in-time, for the first through fifteenth floors. Consortium MEET designs, builds, finances, maintains and operates the new building for the duration of 25 years in PPP. The design achieved the highest score for sustainability (BREEAM 'Outstanding').

The new building for RIVM/CBG will be completed in the fall of 2021. Ferross is supplier of all structural and structural steel, commissioned by precast concrete builder Byldis. "An excellent collaboration, which is project-transcending," says Ferross project manager Johan Langendonk. "We supply for this project, in addition to supporting components, all steel beams for the floor floors, a just-in-time delivery that is taken over by Byldis in the assembly phase. The latter is slightly more labor intensive than using our own assemblers, but in this project logistically the best choice."

The steel fabricator provides detail engineering within an elaborate structural design, using slim floor beams in conjunction with precast concrete floors. The abbreviation SFB stands for "Slim Floor Beam. These beams are easier to fabricate than hat or cap beams. One forms them by welding a wide strip of steel under a standard hot-rolled profile. The heads of the channel plates close laterally against the flanges of the profile, and the hollow spaces on either side in the profile can be filled with concrete.

Custom

SFB girders are often chosen for their light structural weight (important under the BREEAM system) and construction speed. "The welded steel plate provides sufficient structural strength. Because a high quality steel is used here, S355, it is possible to achieve the right spans. A just-in-time delivery of materials in a project of this size is only possible if the cooperation goes well. The cooperation between Ferross and Byldis was excellent. This is of great importance: the coordination of such a project, even when it comes to final changes, remains in our own hands, which allows for quick switching without one party having to wait for the other. We noticed during the floor construction that the repetitive nature ensured speed."

RIVM/CBG was extensively reviewed by the client. This involved the submission of a CE mark for the products. "Although for us this is a delivery without assembly based on an elaborate structural design, it is indeed customization based on detail engineering and assembly method, obviously in cooperation with Byldis. For a hybrid construction like this, that's an excellent form of cooperation."