Full Scale Dynamic Behaviour of an RC-Building under low to moderate seismic motions: 1-Year Recordings in Grenoble City Hall (France)

Clotaire Michel (1) , Philippe Guéguen (1, 2)

1 LGIT - Laboratoire de Géophysique Interne et Tectonophysique
2 LCPC - Laboratoire Central des Ponts et Chaussées

In countries with a moderate seismic hazard, the classical method developed for countries with strong earthquakes to estimate the behaviour and subsequent vulnerability of buildings during earthquakes are often inadequate and not financially realistic. An alternative method is proposed whereby the structural characteristics of the building are obtained by using experimental values of the modal parameters. This article describes the application of an advanced modal analysis technique (Frequency Domain Decomposition) to process ambient vibration recordings taken at the Grenoble City Hall building (France). The frequencies of ambient vibrations are compared with those of low-to-moderate earthquakes recorded by the permanent accelerometric network that was installed to monitor the building. The frequency variations of the building under moderate earthquakes are shown to be slight and therefore ambient vibration frequencies are relevant over the entire elastic domain of the building. The modal parameters extracted from ambient vibrations are then used to determine the lumped-mass model in order to reproduce the building motion under moderate earthquakes.

Mots clés: earthquake; ambient vibrations; monitoring; Grenoble; Vallorcine earthquake; frequency drop

Domaines: Géophysique [physics.geo-ph]; Géophysique [physics.geo-ph]; Mécanique des structures [physics.class-ph]; Mécanique des structures [physics.class-ph]; Vibrations [physics.class-ph]; Vibrations [physics.class-ph]

Clotaire Michel, Philippe Guéguen. Full Scale Dynamic Behaviour of an RC-Building under low to moderate seismic motions: 1-Year Recordings in Grenoble City Hall (France). 2007. ⟨hal-00177086v1⟩