Bespoke Spring Mount Bearings for Helipad, Stockholm Hospital – Sweden

Mason UK worked on the new Karolinska Hospital in Stockholm, Sweden where the roof serves as a landing pad for two helicopters. To prevent pulsations from the rotor blades affecting the sensitive equipment in this medical research facility the entire roof structure is isolated by our bespoke spring mounts.

The spring isolators were designed to provide a natural frequency of 2Hz, offering high isolation efficiency against the 24Hz rotor pulsations. The building features highly sensitive research equipment which would likely be affected by such energy, even following dissipation through the building structure.

Detailed Design

It was important to work closely with the structural engineering team on this project. The springs were integrated in the columns at the steelwork fabricator’s premises, meaning minimal interruption on the actual site. The column heads featured telescoping stanchions which bore the weight of the building during construction, providing a static platform.

When the construction was completed, Mason UK used the load transfer method to move weight from the stanchions to the spring mounts. This enabled precise control of spring compression and only negligible roof movement. This method significantly reduced the risk of isolating such a large structure. In addition to that, the Mason springs were designed to tolerate variation in the final weight. The spring compression was simply changed to suit the actual loading.

Successful Installation

The process of floating this large structure was complex but successful. Isolating the helipad rather than the sensitive equipment allowed for a much more flexible space and negated the need for large inertial blocks in each sensitive area.

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