Live today, November 30, 2020

Dominique Daudon, Yannick Sieffert and Santosh Yadav offer an exceptional commented sequence of tests in progress this week : "I would try to make a "noisy top" to each interesting part during the live. You will see the test of  50%, 100%, 150%, 300% of the Guadeloupe earthquake amplified and contracted due to the change of scale. It elapses approximately 1 hour between each test", explain Dominique Daudon from 3SR.
to be found here https://youtu.be/iHoNirNFaE8

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Modelling mechanical behavior of seismic bands

If seismic bands have existed for several millennia and their effectiveness is clearly proven, their mechanical behavior is difficult to model, preventing reliable structural design under earthquake conditions. This is due to the virtual absence of scientific studies to characterize their impacts.

Characterize the behavior of buildings with or without seismic bands

Santosh Yadav's PhD, supported by the CDP Risk, aims to characterize their mechanical behavior experimentally. Thus, three houses have just been built at scale 1/2 at the FCBA of Bordeaux. Built in masonry of mud brick, they will allow a comparison of three models (timelaps here):

. the first house has no seismic band,
. the second has wooden seismic bands
. the third has reinforced concrete seismic bands.

Through the use of similarity law, the seismic resistance that will be characterized by the application of seismic signals using the ABF vibrating table, the behaviour of these houses at full scale will be determined.

Identify and promote the best technique

In the field, the use of concrete seismic strips has become widespread. However, so far, it has not been proven that concrete seismic strips are really an optimal solution compared to the wooden solution, especially since knowledge and materials are often not readily available in the areas that were impacted by the last earthquakes.
The next tests will provide an answer and influence the reconstruction projects in progress as well as the construction rules in the future.
Finally, the aim of this work is to promote this type of construction in natural materials, adapted to the capacities of the local populations (financial and know-how), to their cultural identity, having moreover a very low environmental impact.
 

Special Guests

Combining usefulness with pedagogy

5 students of the M2 GC of PhITEM (UE construction in bio-sourced materials) sacrificed their autumn vacations to take part in a large-scale scientific experiment consisting in building 3 houses in raw earth masonry on a scale of 1/2, which will be tested on the vibrating table of the FCBA of Bordeaux; the vibrating table of the 3SR laboratory is no longer operational since the fire of February 2020.  The students are also participating in the creation of educational resources on the earthquake-resistant behavior of sustainable earthen constructions.This pedagogical activity allows to make the link between higher education and research but also between the theoretical courses given at PhITEM and the practice of a real construction site. Humanly speaking, the experience was very beneficial to the students who were able to train in masonry construction thanks to two architects specialized in earth construction in connection with the CRAterre laboratory and the AE&CC labex: Majid Hajmirbaba and Luis Arleo. The latter are the guarantors of good practices and traditional know-how. They organize, throughout the world, training camps on model houses.

Photos: Mustafa/Text: Yannick Sieffert & Philippe Garnier/ Edition: Sylvie Perrier