North Hospital of Grenoble, Construction of a helipad on the roof

As the previous helipad of the Hospital Center could not be exploited any more because of its too steep situation, the request was focused on a new equipment to be built on the terrace of the New Technical Platform in project. Important equipment because in addition to a landing/takeoff area, it was also necessary to foresee 2 parking areas in connection with a hangar for the night parking of the helicopter of the SAMU and a peripheral corridor in recessed for the use of the firemen.

By its dimensions, 80m length / 30m width, the surface of the helipad exceeds appreciably that of the part of the building on which it is posed. The choice of a metal structure was then imposed to treat the needs of cantilever in both directions, longitudinal (16m) and transverse (10m), for reasons of weight and coherence with the metal decking itself made of an assembly of aluminum caissons of 15m long by 45cm wide.

The metal frame of the helipad is supported on the reinforced concrete framework by means of supports forming shock absorbers. It is mainly constituted by two primary beams welded profiles supporting cantilevered transverse beams on both sides on which rests the joisting. Horizontal and vertical locking stops are provided for each support device. These blocking stops are intended to limit the displacement of the deck in relation to its supports under earthquake conditions while leaving the displacement free in service.

In this proposal, there is a search for an effective relationship between the effort of crossing and the effect felt by the object in its landscape. Each component of the metal framework has a mechanical and static function that it resolves and exceeds to fit more globally within a global device. If functionality is the primary objective of such a facility, the result must be supported by the surrounding landscape to become one of its incubators.

Pascal Beau, Architect and Jean-Marc Weill, Structural Engineer