Inworems2019 International Workshop on rehabilitation and retrofitting of Masonry structures
Lyon, France, 8-9 juillet 2019, http://inworems2019.univ-lyon1.fr/
Characterization of the dynamic behavior of structures by ambient seismic noise vibrations
Dominique Daudon1, Lucas Garino2, Pablo Burgos2, Mary Salivar3, Raphaelle Grousson-Troyes4 ,
Frederico3,
In situ non-destructive auscultation of buildings by ambient noise vibration (or seismic noise) is
used to study the actual state of behavior of civil engineering structures and to characterize their
degree of possible degradation (Dunand 2005, Hans et al. ., 2005) provided that the dynamic
characteristics of the structure can be monitored more or less regularly.
Widely used for large-scale concrete structures (Fujino et al 2010) or to determine seismic
amplification-type site effects (Guegen et al 2010), this technique is still little explored for raw earth
buildings (Bui et al. 2011). Nevertheless, it can perfectly well make it possible to diagnose a tipical
state at a given moment and to check the improvement through a repair, as soon as the structure is
tested before and after repair. The objective of the study is firstly to evaluate the capacity of this
type of experiment to characterize adobe (mud brick) raw earth constructions widely used in a large
part of the world but submitted to seismic solicitations and thus regularly degraded more or less
importantly. The study thus presents some cases of figures concerning: the dam of Punta Negra on
the Ruta 12, the earthen house of the Campus de Grenoble (BTC), a "finca" of the park el leoncito
(Argentina) (Adobe old and degraded), as well as 2 renovated buildings (old adobe Calingasta-and
museum Sarmiento San Juan-Argentina). The study conditions show disparities (characterization of
the structure and / or the seismic amplification due to the site effect), in particular in the
characteristic of the "available" seismic ambient noise: of casi "silence" for the finca "El leoncito"
to urban for buildings, and operating for the dam. The condition of the four buildings is also very
different, as the earthen house is considered as young (30 years old), and built with adobes enriched
in cement, while the other Argentinean buildings are about a hundred years old. The presented
experiments of project is part of the Rize GEO-RAMP project, cnrs program "peps green
engineering ", is a first exploration of the vibratory characteristics of raw earth constructions by
means of low-cost equipment, including only one velocimeter sensor 3axes. If the vibratory
properties of the structures can be captured, the elastic properties of the material itself would require
several simultaneous measurements to access the velocities of the waves, related to the elastic
parameters. Measurements were carried out on the 4 sites and the signals were processed on the free
software GEOPSY(http://geopsy.org/) developed by the laboratory ISTerre. For the mud house, a
finite elements elastic modeling (SALOME-MECA) was carried out, allowing to go back to
homogenized elastic properties. In perspective, a model discrete masonry elements would be
developed, for which, the elastic properties of the bricks could be identified subject to strong
assumptions regarding the joints.
The authors would like to thank the RISE-GEORAMP project as well as the PEPS engineering
green program of the CNRS, and the iDEX training of the UGA website, which contributed to the
funding of collaboration through the viatics, the acquisition of knowledge, and the experimental
equipments.
F. Dunand , 2005. Pertinence du bruit de fond sismique pour la caractérisation dynamique et l’aide
au diagnostic sismique des structures de génie civil. Géophysique. Grenoble : Université Joseph-
Fourier. 377 pages.
Y. Fujino, D.M. Siringoringo, T. Nagayama & D. Su, Control, simulation and monitoring of bridge
vibration – Japan’s recent development and practice ABSE-JSCE Joint Conference on Advances in
Bridge Engineering-II, August 8-10, 2010, Dhaka, Bangladesh. ISBN: 978-984-33-1893-0
Amin, Okui, Bhuiyan (eds.) www.iabse-bd.org