The effect of masonry infill walls on the reinforced concrete frames behavior under lateral load

The reinforced concrete structures with masonry infill walls are widely used to construct buildings in Algeria, as in many parts of the world. According to earthquake analysis, this type of construction can undergo serious damage under seismic load. The interaction between the infill wall and the surrounding reinforced concrete structure is considered a key parameter, which could trigger damage and even collapse in self-stable frame buildings. To study the behavior of this type of structures and the wall–frame interaction, four half-scale single-storey, single-bay reinforced concrete unfilled and unfilled frames were constructed and tested under in-plane lateral load. Furthermore, the experimental results were analyzed using the Digital Image Correlation (DIC) technique giving a detailed analysis of displacement and strain fields. The wall–frame interaction was evaluated in terms of displacement field evolution and interface slip in the contact contour. The masonry infill wall demonstrated a significant influence on the in-plane lateral response of this type of structure. The analysis of the results of the experiment are discussed in this paper

PRELIMINARY DISCRETE MODELLING OF LANDFILLS CLAY BARRIER

International audienceSUMMARY: The Discrete Element Method is used to investigate the tensile behaviour and cracks mechanisms of a clay material submitted to bending loading. It is the case of compacted clay liners in landfill cap cover application. Such as the soil tested in this study is plastic clay, the distinct elements model was calibrated with previous data results by taking into account cohesive properties. Various contact and cohesion laws are tested to show that the numerical model is able to reproduce the failure mechanism. Numerical results are extending to simulate a landfill cap cover

The effect of masonry infill walls on the reinforced concrete frames behavior under lateral load

The reinforced concrete structures with masonry infill walls are widely used to construct buildings in Algeria, as in many parts of the world. According to earthquake analysis, this type of construction can undergo serious damage under seismic load. The interaction between the infill wall and the surrounding reinforced concrete structure is considered a key parameter, which could trigger damage and even collapse in self-stable frame buildings. To study the behavior of this type of structures and the wall–frame interaction, four half-scale single-storey, single-bay reinforced concrete unfilled and unfilled frames were constructed and tested under in-plane lateral load. Furthermore, the experimental results were analyzed using the Digital Image Correlation (DIC) technique giving a detailed analysis of displacement and strain fields. The wall–frame interaction was evaluated in terms of displacement field evolution and interface slip in the contact contour. The masonry infill wall demonstrated a significant influence on the in-plane lateral response of this type of structure. The analysis of the results of the experiment are discussed in this paper

Behaviour of the clay cover of a site for storing nuclear waste of verylow activity submitted to differential settlement of underlying waste:laboratory and field bending tests

International audienceThe behaviour of the cover barrier of a site for storing nuclear waste of very low activity isstudied. The risk of a bending of the clay layer in case of differential settlements within underlying waste isparticularly studied. Laboratory and field bending tests are performed. Influence of the water content on themechanical behaviour of the clay is examined. Initialization and propagation of cracks are studied. The limitvalue of the extension strain of the clay layer without cracking is characterized. Results of field and laboratorybending tests are presented. The main aim is to optimize the use of clay as landfill cover, in terms ofconditions of implementation (water content, compaction energy)

Seismic Assessment of Rammed Earth Walls Using Pushover Tests

AbstractRammed earth (RE) construction is attracting renewed interest throughout the world thanks to its sustainable characteristics: a very low embodied energy, an advantageous living comfort due to a substantial thermal inertia, good natural moisture buffering, and an attractive appearance. This is why several studies have been carried out recently to investigate RE. However, there have not yet been sufficient studies on the seismic performance of RE buildings.This paper presents an experimental study on the static nonlinear pushover method and its application on the seismic performance of RE structures. Several walls with two height/length ratios were built and tested to obtain the nonlinear “shear force–displacement” curves. By transposing to the “acceleration-displacement” system and by using the standard spectra presented in Eurocode 8, the performance points could be determined which enabled to assess the seismic performance of the studied walls in different conditions (seismicity zones and soil types)

Development of a fibre optic-based patch sensor for monitoring structures

The number of accidents involving the collapse of civil engineering structures, in addition to the cost of maintenance in the construction industry, has drawn the attention of researchers and builders over the last few years. Therefore, much attention is given to the importance of improving periodic measurements, analysis, and diagnostics of operating structures’ integrity, frequently referred to as structural health monitoring (SHM). These monitoring activities were first operated by visual inspections. These methodologies have evolved with the emergence of new tools and devices that are leading SHM towards techniques of remote monitoring based on data transmission networks featuring alarming systems. Nowadays, fiber optic sensors represent a promising solution over existing sensors because of their unique features, such as the versatility for installation and to measure different parameters as well as their immunity to electromagnetic interference. In this project, part of the SENTMI Region project (PSPC Region 2020), an innovative 2D patch carrying weaved optical fibers is being developed in a partnership made by Leon Grosse, Inouid, Brochier Technologies, and the laboratory LOCIE from the University “Savoie Mont Blanc”. Each of these partners adds up essential know-how in structural diagnostics in buildings and the construction of civil engineering structures, sensor devices, and optical fibers. The technology is being tested in concrete structures at the laboratory level using methods that include 2D digital image correlation (DIC). The preliminary main results are presented in this paper. Its performance has raised significant prospects over the possibilities for detecting the presence of water, temperature change, and cracks in structures. The potential applications at the real scale and their respective challenges are also discussed with the goal of pushing the limits of structural health monitoring

Contribution à l'étude de l'endommagement de la glace columnaire S2 en compression uniaxiale

This work is based on the study of the nucleation of micro cracks in polycrystalline ice. A large part of it consisted in designing a process to grow artificial "model" columnar ice. This structure controlled ice is very close to a two-dimensional material and could be used to connect experimental studies and theoretical analysis. Brick shaped specimens of "model" and "regular" columnar ice have been tested under uniaxial compression (constant load between -1 and -0.5 MPa). The largest face of the specimen was filmed continuously to localise each nucleation site in relation with the local microstructure. By following this experimental procedure, we have obtained a set of data on the number of cracks, their length and orientation together with strain measurements. The comparison between experimental results and theoretical analyses allows a better understanding of the mechanical behaviour of columnar S2- ice which experiences microcracking. Finally, by using the Eshelby's inclusion model in the case of a Newtonian viscoplastic material, which describes the microstructural stress concentrations, we have developed a model of crack initiation based on the stress intensity factor in mode 1.Ce travail est centré sur l'étude de la nucléation de fissures dans la glace. Une partie importante de l'étude a été consacrée à la mise au point d'une glace artificielle qui fournit un matériau bidimensionnel idéal pour un couplage d'études expérimentales et théoriques. Notre démarche a consisté à conduire une série d'expériences de fluage sur ce type de matériau et sur le type de glace couramment utilisé par la communauté des glaciologues. Selon le niveau de contrainte (entre -1 et -0,5 MPa) le fluage de la glace était accompagné ou non par de l'endommagement. La partie la plus originale de l'étude expérimentale réside dans l'analyse des images vidéo qui permettait l'enregistrement de l'apparition des fissures dans le tiers central des échantillons. Nous avons ainsi obtenu une base de données importante sur la taille des fissures, leur orientation et leur localisation et sur les déformations de la glace. La confrontation des résultats expérimentaux et des analyses théoriques nous a permis de renforcer nos connaissances sur les mécanismes physiques qui sont à l'origine des processus de déformation et de germination de fissures dans la glace de lac. Enfin, en utilisant le modèle de l'inclusion d'Eshelby, dans le cadre d'un comportement viscoplastique newtonien, nous discutons un critère de nucléation basé sur le facteur d'intensité de contrainte en mode 1

CONTRIBUTION A L'ETUDE DE L'ENDOMMAGEMENT DES GEOMATERIAUX : APPLICATIONS INDUSTRIELLES

The research topics developed in this report refer to the study of the damage of the geomaterials. They always associate experiments and modelling to answer industrial requirements. The first part will be related to the study of the behaviour of the fibre reinforced concrete (BFUHP). This research, realized at several scales, focuses on the impact of a local heterogeneity on the total behaviour of a concrete structure. The second part aims to the study of the behaviour of the argillaceous barriers for cap cover application. This research focuses, particularly, on to define for clay a criterion of inflection without cracking which takes into account conditions of implementation. For these two researches, the scientific step selected led to the development of specific experiments. Moreover, this work uses specific numerical simulations in which the characteristics relating to the problems arising were integrated. In both cases the objective was to control the implementation and the behaviour until the damage of materials in order to optimize their mechanical characteristics.Les thèmes de recherche développés dans le mémoire d'HdR se rapportent à l'étude de l'endommagement des géomatériaux. Ils associent toujours des expériences et des modélisations pour répondre à des exigences industrielles. La première partie de l'exposé portera sur l'étude du comportement des bétons de fibres à ultra haute performance (BFUHP). Ce travail de recherche, réalisé à plusieurs échelles, a mis en évidence l'impact d'une hétérogénéité locale sur le comportement global d'une structure en béton. La deuxième partie a pour objet l'étude du comportement des barrières argileuses des centres de stockage de déchets industriels spéciaux. Ce travail de recherche a permis, entre autre, de définir pour l'argile un critère de flexion sans fissuration qui tient compte des conditions de mise en œuvre. Pour ces deux travaux de recherche, la démarche scientifique retenue, a conduit au développement d'expériences spécifiques souvent uniques et non-conventionnelles pour les matériaux étudiés (bitraction sur le béton et flexion sur l'argile). De plus, ce travail a utilisé des modélisations non usuelles dans lesquelles ont été intégrées les particularités relatives aux problèmes posés (couplages modèles d'inclusion et éléments finis, modélisations discrètes et matériaux cohérents). Dans les deux cas l'objectif était de maîtriser la mise en œuvre et le comportement jusqu'à la ruine des matériaux afin d'optimiser leurs performances mécaniques

IN-PLACE DETERMINATION OF TOPSOIL SHEAR PROPERTIES FOR OFF-ROAD VEHICLE TRAFFIC

International audienceThe study of the off-road mobility for a vehicle consists in the study of its drawbar pull on a given sol and can be calculated by models such the Janosi-Hanamoto's model which depend on the soils mechanic parameters like the angle of friction and the cohesion. These parameters result generally from shear tests. The annular shear test is often used to estimate the soil shearing for mobility studies. Other shear test is the translation shear test which consists in the translation at a constant speed of a loaded plate with a smooth interface or with grousers. This article aims to present the validation of the translation shear test for the study of the shearing of the granular surface soils and the methodology to apply to link this operational test to the efforts measured during full-scale tests. An experimental device was developed to perform superficial translation shear tests of a loaded plate at slow speed or fast speed to obtain the shearing forces

Preparation and Preliminary Study of Structure-Controlled S2 Columnar Ice

International audienc