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The study, based on experiments and numerical modeling, discusses the behavior of masonry walls in the loading case of a uniform out of plane pressure. Engineering applications are multiple, for example the case of detached house built on mountain in blue area, where structures are liable to undergo an impact of snow avalanche type; or the case of masonry subjected to lateral pressure induced by accidental load such as an explosion in Seveso area or more generally in city following the explosion of a gas pipeline. Our study allows, first to quantify the bearing capacity in the case of uniform pressure in quasi-static loading case, and thus to highlight the associated modes of rupture, and secondly to estimate the improvements in terms of global behavior when the structure is reinforced by Carbon Fiber Reinforced Polymer (CFRP) layers. Then, discrete element method (DEM) is illustrated by applications to various masonry problems from simple to more complicated, where in plane loading, out of plane loading, or both, are considered. This modeling allows us to evaluate the pertinence and limitations of DEM in masonry structure. Finally we discuss the dynamic tests, with the case of impact, easier to manage in laboratory than the testing dynamic "blast type" that we will put into perspective., Cette contribution, en s’appuyant sur expérimentation et modélisation numérique, vise à une meilleure compréhension du comportement de structures en maçonnerie. Nous traitons tout d’abord le cas des murs soumis à un chargement hors plan de type pression uniforme. Les applications en ingénierie sont multiples, par exemple le cas de la maison individuelle construite en montagne en zone bleu, zone où les structures sont susceptibles de subir un impact de type avalanche de neige ; ou encore le cas de la maçonnerie soumise à une pression latérale induite par une charge accidentelle telle qu’une explosion dans une zone Seveso ou plus généralement en ville suite à l’explosion d’une conduite de gaz. Notre étude se confine au cas quasi-statique, l’objet étant une meilleure compréhension du comportement d’un mur en maçonnerie soumis à pression latérale uniforme. Nous avons aussi testé différentes configurations de renforcement par matériau composite. Puis nous évaluons pas à pas, les possibilités de la modélisation via la méthode des éléments discrets (DEM). Des essais judicieusement choisis, maçonnerie à joint sec ou mortier, nous permettent d’en évaluer les pertinences et les limites. Nous abordons ensuite sur maquettes, les essais sous charge ponctuelle hors plan en quasi-statique et le cas de l’impact en dynamique, puis nous traitons des essais vibratoires et des sollicitations dynamiques harmoniques. La modélisation DEM est aussi évaluée dans certains cas tels que les vibrations et les sollicitations modales, voir l’application d’une sollicitation sismique unidirectionnelle. L’étude des sollicitations dynamiques est limitée à la vibration et l’impact, plus facile à gérer en laboratoire que les essais dynamiques de « type souffle », non ici abordés mais que nous mettons en perspective.

This paper addresses the construction of probabilistic models for time or space dependent natural hazards. The proposed method uses Karhunen-Loève expansion in order to construct an empirical model matching the non-stationarity and the randomness of natural phenomena such as earthquakes or other complex environmental processes. The terms of the Karhunen-Loève expansion are identified directly from measured data. The approach is illustrated and its performance assessed through two academic examples. It is then applied to seismic ground motion modelling using recorded data.

The study, based on experiments and numerical modeling, discusses the behavior of masonry walls in the loading case of a uniform out of plane pressure. Engineering applications are multiple, for example the case of detached house built on mountain in blue area, where structures are liable to undergo an impact of snow avalanche type; or the case of masonry subjected to lateral pressure induced by accidental load such as an explosion in Seveso area or more generally in city following the explosion of a gas pipeline. Our study allows, first to quantify the bearing capacity in the case of uniform pressure in quasi-static loading case, and thus to highlight the associated modes of rupture, and secondly to estimate the improvements in terms of global behavior when the structure is reinforced by Carbon Fiber Reinforced Polymer (CFRP) layers. Then, discrete element method (DEM) is illustrated by applications to various masonry problems from simple to more complicated, where in plane loading, out of plane loading, or both, are considered. This modeling allows us to evaluate the pertinence and limitations of DEM in masonry structure. Finally we discuss the dynamic tests, with the case of impact, easier to manage in laboratory than the testing dynamic "blast type" that we will put into perspective., Cette contribution, en s’appuyant sur expérimentation et modélisation numérique, vise à une meilleure compréhension du comportement de structures en maçonnerie. Nous traitons tout d’abord le cas des murs soumis à un chargement hors plan de type pression uniforme. Les applications en ingénierie sont multiples, par exemple le cas de la maison individuelle construite en montagne en zone bleu, zone où les structures sont susceptibles de subir un impact de type avalanche de neige ; ou encore le cas de la maçonnerie soumise à une pression latérale induite par une charge accidentelle telle qu’une explosion dans une zone Seveso ou plus généralement en ville suite à l’explosion d’une conduite de gaz. Notre étude se confine au cas quasi-statique, l’objet étant une meilleure compréhension du comportement d’un mur en maçonnerie soumis à pression latérale uniforme. Nous avons aussi testé différentes configurations de renforcement par matériau composite. Puis nous évaluons pas à pas, les possibilités de la modélisation via la méthode des éléments discrets (DEM). Des essais judicieusement choisis, maçonnerie à joint sec ou mortier, nous permettent d’en évaluer les pertinences et les limites. Nous abordons ensuite sur maquettes, les essais sous charge ponctuelle hors plan en quasi-statique et le cas de l’impact en dynamique, puis nous traitons des essais vibratoires et des sollicitations dynamiques harmoniques. La modélisation DEM est aussi évaluée dans certains cas tels que les vibrations et les sollicitations modales, voir l’application d’une sollicitation sismique unidirectionnelle. L’étude des sollicitations dynamiques est limitée à la vibration et l’impact, plus facile à gérer en laboratoire que les essais dynamiques de « type souffle », non ici abordés mais que nous mettons en perspective.

In many developing countries the most common alternative for dwelling construction is building with earth because the material is abundant and cheap. The quality of most traditional earthen construction is very low, because it is done informally, with little or no technical assistance. In seismic areas where earthen construction is common, every time an earthquake occurs, many dwellings collapse, causing considerable economic losses and tragic injuries and deaths. The professional and academic communities in some seismic countries have not remained indifferent to this important problem. Researchers at the Catholic University of Peru (PUCP) have been investigating on the construction of earthen buildings in seismic areas for about 40 years and have obtained invaluable results. This article describes the evolution of the knowledge generated at PUCP of reinforced earth, a material composed of earth and compatible reinforcements, with which it is possible to build seismic-resistant constructions., En muchos países en vías de desarrollo la alternativa de vivienda más común es la construcción con tierra, pues el material es abundante y barato. La construcción tradicional de viviendas de tierra se realiza informalmente, sin asesoría técnica. Por ello, la calidad de estas construcciones es generalmente muy baja. En zonas sísmicas donde se construye con tierra, cada vez que ocurre un terremoto colapsan muchas construcciones de este material, causando considerables pérdidas económicas y lamentables pérdidas de vidas. Las comunidades académicas y profesionales de algunos países sísmicos no han permanecido impasibles frente a esta grave situación. En el Perú, investigadores de la Pontificia Universidad Católica del Perú (PUCP) han venido investigando la construcción con tierra en áreas sísmicas desde hace cerca 40 años y han obtenido invalorables resultados. Este artículo describe la evolución del conocimiento generado en la PUCP del material tierra armada, compuesto por tierra y refuerzos compatibles, que permite lograr construcciones sismorresistentes.

In many developing countries the most common alternative for dwelling construction is building with earth because the material is abundant and cheap. The quality of most traditional earthen construction is very low, because it is done informally, with little or no technical assistance. In seismic areas where earthen construction is common, every time an earthquake occurs, many dwellings collapse, causing considerable economic losses and tragic injuries and deaths. The professional and academic communities in some seismic countries have not remained indifferent to this important problem. Researchers at the Catholic University of Peru (PUCP) have been investigating on the construction of earthen buildings in seismic areas for about 40 years and have obtained invaluable results. This article describes the evolution of the knowledge generated at PUCP of reinforced earth, a material composed of earth and compatible reinforcements, with which it is possible to build seismic-resistant constructions. En muchos países en vías de desarrollo la alternativa de vivienda más común es la construcción con tierra, pues el material es abundante y barato. La construcción tradicional de viviendas de tierra se realiza informalmente, sin asesoría técnica. Por ello, la calidad de estas construcciones es generalmente muy baja. En zonas sísmicas donde se construye con tierra, cada vez que ocurre un terremoto colapsan muchas construcciones de este material, causando considerables pérdidas económicas y lamentables pérdidas de vidas. Las comunidades académicas y profesionales de algunos países sísmicos no han permanecido impasibles frente a esta grave situación. En el Perú, investigadores de la Pontificia Universidad Católica del Perú (PUCP) han venido investigando la construcción con tierra en áreas sísmicas desde hace cerca 40 años y han obtenido invalorables resultados. Este artículo describe la evolución del conocimiento generado en la PUCP del material tierra armada, compuesto por tierra y refuerzos compatibles, que permite lograr construcciones sismorresistentes.

Catastrophes and risks have had a great influence on the evolution of human development. We analyze behaviors in front of risks, then we consider some basic principles that have guided private and public behaviors. Managing risks has become a specialty for finance and insurance, but they are not the only institutions that allow to confront them. We conclude on an example of how public funds, private insurance and reinsurance companies can work together and use financial markets in order to cover financial risks due to seisms.

Catastrophes and risks have had a great influence on the evolution of human development. We analyze behaviors in front of risks, then we consider some basic principles that have guided private and public behaviors. Managing risks has become a specialty for finance and insurance, but they are not the only institutions that allow to confront them. We conclude on an example of how public funds, private insurance and reinsurance companies can work together and use financial markets in order to cover financial risks due to seisms.

In the Palaiologan period the Byzantines were confronted with a number of natural disasters (earthquakes, tsunamis, plague) which reinforced the idea that the world was approaching its end. Beyond the immediate perception and description of these catastrophes, the sources give us a glimpse of diverse explanations (natural, divine, demonic), interpretations (omens, warnings or punishments) and attitudes (ranging from political manipulation to conversion to despair). A special case was that of the tsunamis, on account of the belief that the submersion of Constantinople would be a sign of the end of the world., Sous les Paléologues, les Byzantins ont été confrontés à un grand nombre de catastrophes naturelles (séismes, tsunamis, peste), qui ont renforcé l’idée que la fin du monde était proche. Au-delà de la perception immédiate et de la description des catastrophes, les sources font entrevoir la diversité des explications (causalités naturelle, divine, démoniaque), des interprétations (présages, avertissements ou punitions) et des attitudes (de la manipulation politique au désespoir en passant par la conversion). Un sort particulier est fait aux tsunamis, en relation avec la croyance selon laquelle la submersion de Constantinople sera un des signes de la fin du monde., Congourdeau Marie-Hélène. Les Byzantins face aux catastrophes naturelles sous les Paléologues.. In: Revue des études byzantines, tome 67, 2009. pp. 151-163.

El proceso de reconstrucción después del sismo que afectó al Perú el 15 de agosto de 2007 resulta siendo profundamente desigual. En efecto, a más de un año del desastre, muy pocas familias están en capacidad de reconstruir sus viviendas. Están excluidos de la reconstrucción los más pobres y sobre todo aquellos que no pudieron apoyarse en buenas redes sociales y de poder. Es lo que revela una encuesta realizada dirigida a 1 703 familias damnificadas de la provincia de Chincha. La encuesta muestra también que la vulnerabilidad de la población, ya elevada antes del sismo, se ha incrementado desde entonces, en razón del aumento de la precariedad de las familias, del incremento de la vulnerabilidad de las construcciones y de una cohesión social debilitada. Le processus de reconstruction ayant fait suite au séisme qui a affecté le Pérou le 15 août 2007 s’avère profondément inégalitaire. En effet, très peu de familles sont en mesure de reconstruire plus d’un an après la catastrophe. Les plus pauvres et, surtout, ceux qui n’ont pas été en mesure de s’appuyer sur les bons réseaux sociaux et de pouvoir, se voient exclus du processus de reconstruction. C’est ce que révèle une enquête réalisée auprès de 1 703 familles sinistrées de la province de Chincha. L’enquête montre également que la vulnérabilité de la population, déjà élevée avant le séisme, s’est accrue depuis, en raison du renforcement de la précarité des familles, de l’accroissement de la vulnérabilité du bâti et d’une cohésion sociale remise en cause. The rebuilding process following the seismic event which affected Peru on August 15, 2007 was deeply inegalitarian. Indeed, very few families were able to rebuild even more than one year after the disaster. The poorest, especially the ones who were not able to rely on the support of the social and power networks, were excluded from the rebuilding process. A survey was carried out with 1703 disaster victim families of the Chincha province and it shows that the population vulnerability, which was already high before the earthquake, increased because of the reinforcement of family precariousness, of the increase in vulnerability of constructions, and the fact that the social cohesion has been weakened.

Approaches that are widely used to characterize propensity of soils to liquefaction are mainly of empirical type. The potential of liquefaction is assessed by using correlation formulas that are based on field tests such as the standard and the cone penetration tests. These correlations depend however on the site where they were derived. In order to adapt them to other sites where seismic case histories are not available, further investigation is required. In this work, a rigorous one-dimensional modelling of the soil dynamics yielding liquefaction phenomenon is considered. Field tests consisting of core sampling and cone penetration testing were performed. They provided the necessary data for numerical simulations performed by using DeepSoil software package. Using reliability analysis, the probability of liquefaction was estimated and the obtained results were used to adapt Juang method to the particular case of sandy soils located in Tangier.

Reinforced concrete structures play an important role in modern buildings, and common architectural designs often include RC frames strengthened with infill masonry panels. Due to their brittle nature, these components’ failure and collapse have been subject of studies which can lead to proper structural diagnose and design in order to decrease their risk to human lives during seismic activities. Digital image correlation was used in two of these studies, in order to validate its ability for large specimens monitoring and future structural health monitoring applications. It enabled spatial reconstruction of the wall movement, characterization of its rigid body motion and measurement of both displacements and strain fields in in-plane and out-of-plane load applications. Data post-processing allowed the identification of common in-plane damages in the wall such as corner crushing and separation between infill and resistant structure.