Annuaire des thèses
Horizontal seismic band in masonry wall: characterisation, behaviour and modelisation to improve housing resilience to earthquake Yannick Sieffert
Date de début :
Date de fin :
*Main objectives of the thesis This PhD stands on the foundation of multidisciplinary knowledge, experience, and skill developed by the 3SR and AE&CC research unit over the last decade, in the areas of prevention, risk management and reconstruction, through the promotion of local building cultures and development dynamics, in particular in Haiti and Nepal. The main objective of this PhD is to improve the knowledge on the traditional stone masonry building culture using seismic resistant solution through the inclusion of horizontal shear bands in a final goal to give useful and relevant scientific recommendations for reconstruction guidelines. Use of shear bands is very common in seismic prone areas all around the world and are present in different kind of typology. Due to a lack of scientific knowledge, the use of shear bands in masonry construction is often forgotten and even not allowed in some guidelines with the consequence of this knowledge and technical skills fading away quickly. However it could a very efficient and relevant option for construction in seismic areas meeting social and cultural needs as well, being accessible to communities and local population, improving their resilience and reconstruction capacities. The scientific impact of shear bands in masonry is not known as it requires specific tools which has not so common or easily accessible in the world. The main challenges are both the dimension of a full scale building to take into account local damage/dissipation (shear band, masonry and mortar) with the global structural effect and the dynamical loading that requires a large number of time steps discretization (i.e. small time step). These challenges are present both in numerical modeling and experimental aspect. For numerical, a specific modelization should be developed to represent the local dissipation with a limited number of elements to describe the building in line with the time consuming with seismic loading. For the experimental aspect, different apparatus should be made available to test a structure at the full scale with seismic loading. Fortunately, the 3SR laboratory is developing high level numerical modeling with macro-element in Atlas platform (F.E.M.) or brick element in Yade plateform (D.E.M.) coupled to a shake table with adequate capacity. In addition, the full scale experimental capacity is actually under development thanks to a shear wall apparatus with a quasi-static cyclic loading and at the building scale the global behavior with a pseudo-dynamic with sub-structuration technical. Then 3SR laboratory is well positioned to answer to the hight challenges of increasing resilience and development strategies for vernacular construction re-appropriation. One of the goals of this PhD will be to compare different methods to give recommendation for future work in evaluation of structural vulnerability. The shear wall apparatus is well dimensioned for a parametric study as the sample could be at a small dimension, i.e. a representative part of the wall (which needs a preliminary investigation but should be near 1m by 1m). This parametric study will be on the material used for shear band, masonry and mortar. The impact of build quality in the real project of reconstruction will be also analyzed in the laboratory. At this first art of the PhD, the local dissipation between shear bands and masonry will be investigate in relation with the propagation and the opening of cracks in masonry. The displacement at the interface and the opening of cracks will be calculated by a Digital Image Correlation process with a handmade 3SR software (Tracker). Numerical investigation will be made with Finite or Distinct Element Method. For increasing efficiency, a post-doctoral position will be added to this PhD for the modeling development. Then, a multi-criteria analysis will be used to take into account the mechanical results, the cost of materials, the gap between propriation by local population and government. At the end of this first stage, two kinds of typologies will be choosen. Then, the wall scale will be investigated (3m by 2m) with an earthquake solicitation for both cases of shear wall and out-of-planbending wall direction. A real wall will be tested on the new sake table of the 3SR laboratory for two main advantages for numerical modeling: first to estimate the real damping ratio, second to evaluate predictive capability of the model. The last scale during the PhD will be the building scale with the structural dimensions (opening, storey, roof). A pseudo-dynamic method with sub-structuration will be develop for this scale in order to used real constitutive law coming for the wall scale and numerical model to represent storey and roof impact (mass and stiffness). The last step of the PhD will be to give recommendations to improve guidelines and also knowledge in the field. Two kind of movie medias will be edited with the experimental tests and numerical visualization. One will be for civil engineers who work for government agencies of reconstruction. The second for masons, carpenters and people who work in the field. Then the PhD will be “feed” of information coming on the field and at the end, the PhD will be give the results of his work accessible to the field. The geographic area concerned is Nepal as cooperative work on reconstruction project is on going with various partners (local stockholders, construction companies and peoples, humanitarian association). *Multidisciplinary The PhD which is presented here is built on an existing core team of researchers who have already collaborated within a variety of activities (research projects, master level training) following the spirit of mutual enrichment through interdisciplinary between STI and SHS. The PhD student will meet every weeks its directors who come from STI and SHS. Then he will have many opportunities to interact in a multidisciplinary approach with them. He will also have the opportunity to join evaluation mission or construction site visit on the field with them. The PhD student will join the “doctoral days of the CDP Risk@UGA” and if relevant he will participate to the organization of a conference on topic of prevention, risk management and reconstruction, through the promotion of local building cultures and development dynamics. *Deliverables - at least 2 articles in WoS - at least 2 internationals conferences - at least 2 kind of movies for communication/dissemination in the field - recommendations to improve guidelines *5 references to support the topic: Caimi, A., Vieux-Champagne, F., Garnier, P., Guillaud, P., Moles O., Grange, S., Sieffert, Y., Daudeville, L. 2013. Harnessing traditional and scientific knowledge to reduce the vulnerability of the rural habitat to natural hazards in Haiti. Field Actions Science Reports FACTS, 10 p. Sieffert, Y., Vieux-Champagne, F., Grange, S., Garnier, P., Daudeville, L. 2016. Full-field measurement with a digital image correlation analysis of a shake table test on a timber-framed structure filled with stones and earth. Engineering&Structures. 123, 451-472. Sieffert, Y., Huygen, J.-M., Daudon, D., 2014. Sustainable construction with repurposed materials in the context of a civil engineering-architecture collaboration. Journal of Cleaner Production. 67, 125–138. Vieux-Champagne, F., Sieffert, Y., Grange, S., Belinga Nko’o, C., Bertrand, E., Duccini, J.- C., Faye, C., Daudeville, L., 2017. Experimental analysis of a shake table test of a timber-framed structures with stone and earth infill. Earthquake Spectra, DOI:10.1193/010516EQS002M. Vieux-Champagne, F., Sieffert, Y., Grange, S., Daudeville, L., Polastrib, A., Ceccotti, A. 2014. Experimental analysis of seismic resistance of a filled wood structure, Engineering&Structures. vol. 69. pp 102-115.
Type de financement :
Autre financement public national
3sr - Laboratoire Sols Solides Structures Risques
Entreprise(s) partenaire(s) :
École doctorale :
Ingénierie Matériaux Mécanique Environnement Energétique Procédés Production
Cette thèse est en cours.
- Dynamique des structures