Earthquake resistance for the hospital ward towers at the Centre Hospitalier Louis Domergue,

The Centre Hospitalier Louis Domergue in Trinité was built in 1974. At that time it was not mandatory to apply the so-called PS 69 earthquake resistance rules. The “tower” of the hospital comprises 3 blocks: (a) one block B, R+7, (b) a second block C, R+8, also a hospital ward block, (c) a third block A, located to the side of the other two and comprising elevators, staircases and the freight elevator. Since it was built, the building has suffered two earthquakes: June 1999 (M = 5.4) and 29 November 2007 (M = 7.3). To implement earthquake protection at a reasonable cost and after analysing how towers B and C were used, it was decided to remove, i.e. to “plane” off the top 4 storeys while continuing activities on the lower floors and ensuring maximum safety conditions. Several reinforcement solutions were studied. Even though they had not been calculated with earthquake protection in mind, blocks B and C behaved well during the earthquakes of 8 June 1999 and 29 November 2007. Since the decision was taken to reinforce towers B and C, joint reflections with hospital management helped identify the various reinforcement possibilities: reduction of the mass by removing three levels and implementing a combined structure (trellis made from a metal framework) with vertical pre-stressing at the location of the transversal shear walls. The studies were carried out under the direction of Professor Victor Davidovici.