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La stabilité des infrastructures est un souci majeur pour différentes raisons économiques, écologiques ou, plus important, la sécuritédes batiment. Ceci peut se faire par différentes techniques, mécanique, chimique ou les deux à la fois, afin d’améliorer les propriétésgéotechniques des sols instables. Les techniques utilisées sont les ajouts, dont les plus courants sont la chaux et le ciment. Cette étude a pour objet de déterminer l’évolution des propriétés géotechniques d’un sol schisteux du pôle universitaire d’El-Aouana dans la wilaya de Jijel (Algérie). L’échantillon prélevé sur site a été modifié avec des proportions d’additifs avec 0, 1 %, 3 % et 7 % du remplacement du ciment et de la chaux en poids sec afin de tester les différents proprietées de la patte fraiche du sol argileux.On conclut que l’addition d’un liant (Ciment ou chaux) au sol schisteux provoque une réduction de la plasticité, une amélioration des caractéristiques de compactage au Proctor, une augmentation rapide de l’indice de portance immédiat en fonction du traitement et une augmentation de la cohésion et de l’angle de frottement.

The stability of infrastructure is a major concern for various economic, ecological or, more importantly, the security of buildings. This can be done by different techniques, mechanical, chemical or both, to improve the geotechnical properties of unstable soils. The techniques used are the additions, of which, the most common are lime and cement.. The purpose of this study is to determine the evolution of the geotechnical properties of a shale soil of the university center of El-Aouana in the wilaya of Jijel (Algeria). The sample taken on site was modified with additives proportions, 0, 1 %, 3% and 7% of the replacement of cement and lime in dry weight in order to test the different properties of the fresh paw of clay soil. Finally, on conclude that the addition of a binder (Cement or lime) to shale soil causes a reduction in plasticity, an improvement in compaction characteristics with Proctor, a rapid increase in the immediate lift index depending on the treatment. and an increase in cohesion and the angle of friction. [ABSTRACT FROM AUTHOR]

The transverse shear behavior of the composite beams can be critical and must therefore be properly represented by the various models of structures normally used to predict their behavior or to identify their properties. We propose in this work, a warpage analysis in short laminated beams using a simple analytical approach based on the theories of higher order.

Les géosynthétiques sont devenus des matériaux majeurs dans tous les domaines du génie civil pour assurer l'étanchéité, le drainage, la filtration ou bien la protection des ouvrages. La qualité, la performance et la durabilité des produits sont donc essentielles. Aussi, dans le souci de mieux caractériser les produits pour optimiser leur conception tout en assurant leur fiabilité, les industriels du secteur travaillent avec les chercheurs à l'élaboration d'essais et de normes. À partir d'une méthode de mesurage d'un géocomposite spécifique, il est question ici d'établir une norme d'essai permettant de mesurer la résistance au cisaillement interne d'un produit géosynthétique pour assurer sa stabilité et optimiser sa conception.

This paper discusses the shear and torsion induced in low-rise and medium-rise buildings, according to wind load specifications provided in NBCC 2015. Results from experimental studies, carried out in wind tunnels were compared with corresponding NBCC 2015 provisions under different upstream roughness conditions. These comparisons demonstrated notable discrepancies for the case of torsion in low-rise buildings. Further, comparisons between the wind load specifications given in NBCC 2015 and ASCE/SEI 7-10 standard were carried out. Following both sets of provisions, wind-induced shear and torsion were computed and compared for five low-rise and medium-rise buildings with the same horizontal dimensions but different heights. Emphasis was directed towards the cases that create maximum shear forces and (or) maximum torsions to reflect critical design conditions. For low-rise buildings, the ASCE/SEI-7-10 and NBCC-2015 yield similar shear coefficients but quite different torsional coefficients; while for medium-rise buildings, clear agreement was found, for both shear and torsion. The diversity of the results is discussed and some suggestions for improvement of code provisions are made. A definition for medium-rise buildings was provided. [ABSTRACT FROM AUTHOR]

The objective of this study is to develop a shear deformable hybrid finite element formulation for the flexural buckling analysis of fiber-reinforced laminate composite columns with doubly symmetric cross sections. The hybrid finite element formulation is developed by using the Hellinger-Reissner functional which is obtained by introducing the conditions of compatibility as auxiliary conditions to the potential energy functional. The shear deformation effects due to bending are included by equilibrating shear stress. In comparison to the displacement-based formulations the current hybrid formulation has the advantage of incorporating the shear deformation effects easily by using the strain energy of the shear stress field without modifying the basic kinematic assumptions of the beam theory. The agreement with Engesser formulation for flexural buckling analysis of columns with shear-weak cross sections shows the applicability and accuracy of the current hybrid finite element method for composite structural elements. The applicability of the developed method herein to sandwich and built-up columns are also illustrated. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The knowledge and understanding of soil mechanical properties is essential for designing agricultural machines. However, little information is available regarding shear properties of agricultural soil. In this study, triaxial compression tests were performed to measure shear properties of a sandy loam soil at three moisture levels: low (10.5±0.5%), medium (19±1.0%), and high (28±1.0%), and three confining pressures of 50, 100, and 150 kPa. A discrete element model was developed to simulate the triaxial compression tests. The test results showed a linear increase in soil shear strength at a decreased soil moisture level and an increased confining pressure. The effect of moisture level on the modulus of elasticity changed with the confining pressure. The highest modulus of elasticity was observed for the low moisture level with 150 kPa confining pressure. The model results showed that the particle friction coefficient was the most influential model micro-parameter to the simulated soil shear strength. This model micro-parameter was calibrated with the triaxial test data. The calibrated particle friction coefficients varied from 0.2 to 1.0, depending on the soil moisture content and confining pressure. As compared to the test data, the simulated soil shear strengths had relative errors ranging from 0 to 6%. Keywords: Calibration, confining pressure, moisture, PFC3D, shear, soil, strength, triaxial test. [ABSTRACT FROM AUTHOR]

Light frame wood shear walls resist lateral loads primarily through the individual nailed connections between the sheathing and framing. The most common arrangement for such shear walls is to have sheathing on one side and gypsum board on the other. In various situations it can be desirable to increase the capacity of this type of walls by fastening a layer of sheathing overtop of the drywall. This study considered the effect that an intermediate layer of gypsum has on the strength of nailed connections in shear walls, while maintaining code-defined minimum nail penetrations. Results show that intermediate gypsum placed between the sheathing and framing resulted in significantly reduced capacity and stiffness. Analytical modelling showed good correlation with experimental results. The implications of the experimental testing and modelling are that code provisions allowing the use of intermediate gypsum wallboard should not be relied upon. [ABSTRACT FROM AUTHOR]

Clays exhibit creep in compression and shear. In one-dimensional compression, creep is commonly known as 'secondary compression' even though it is also a significant component of deformations resulting from shear straining. It reflects viscous behaviour in clays and therefore depends on load duration, stress level, the ratio of shear stress to compression stress, strain rate, and temperature. Research described in the paper partitions strains into elastic (recoverable) and plastic (nonrecoverable) components. The plastic component includes viscous strains defined by a creep rate coefficient ψ that varies with plasticity index and temperature ( T), but not with stress level or overconsolidation ratio (OCR). Earlier elastic-viscoplastic (EVP) models have been modified so that ψ = ψ( T) in a new elastic-thermoviscoplastic (ETVP) model. The paper provides a sensitivity analysis of simulated results from undrained (CIŪ) triaxial compression tests for normally consolidated and lightly overconsolidated clays. Axial strain rates range from 0.15%/day to 15%/day, and temperatures from 28 to 100 °C. [ABSTRACT FROM AUTHOR]

Tests were carried out on softwood structural glued-laminated-timber (glulam) members to calibrate a linear elastic fracture mechanics design method for bending members having tension-side end notches. Fifty-eight specimens with depths up to 646 mm represented 11 combinations of member size, notch depth, member geometry, loading arrangement, and glulam type. Specimens were loaded until they sustained significant damage at or near notch locations, but none of them failed as bending members. Notch damage started with creation of short stable cracks parallel to the laminations and ended with episodically crack growth. Typically, crack initiation is at about half the load level associated with episodic crack growth. Contrary to current design practice loads positioned close to notched end supports were found to influence strengths of members significantly, and their effects should be taken into account. The findings have been implemented in the 2014 edition of CAN/CSA Standard 086 'Engineering Design in Wood'. [ABSTRACT FROM AUTHOR]

Traditionally unreinforced tension-side notches at supports of glued-laminated-timber (glulam) bending members have been designed in Canada assuming shear capacity is reduced in proportion to the square of the residual depth ratio. The origin of that practice lies in World War II era studies in the USA on solid wood members. More recent research in Canada, US, and Europe has focussed on application of linear elastic fracture mechanics (LEFM) methods to such problems, reflecting that such approaches can account for effects of variables other than notch depth ratio. Canadian wood design code CSA Standard 086 'Engineering Design in Wood' first capitalized on availability of LEFM approaches in 1994 by adopting such a method for design of sawn lumber members with tension-side notches at supports. The same was not done then for glulam members because of paucity of supporting test data. That gap has now been filled and the 2014 edition of CSA Standard 086 employs consistent LEFM based design approaches for both sawn lumber and glulam members with tension-side notches. New provisions for glulam recognize influences that notch length and shape, and how laminations in members are fabricated have on member capacities. Discussion here addresses the logic that underpins the new glulam provisions and how application of those provisions impacts design solutions. Overall impact of the new design provisions is to discourage use of relatively large tension-side notches at supports of larger glulam bending members, while not discouraging use of notches in smaller glulam members. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The results of five experimental test series on masonry walls supported by reinforced concrete beams or slabs are reported and compared to theoretical predictions of the load bearing capacity. The experiments were performed on deep masonry beams built with respectively calcium silicate and clay brick. Investigated parameters were: position of the supports, concrete beam-masonry interface, concrete beam stiffness, type of loading, and height of masonry wall and concrete beam. Based on literature, the method proposed by Davies and Ahmed as well as the method according to Eurocode 6 were used to estimate the load bearing capacity of the tested masonry walls supported by concrete beams. The method of Davies and Ahmed allows for the determination of the stresses and stress resultants in the masonry. The analysis shows that near the support an inclined compressive force acts at the bed joint, which means that a shear-compression stress state exists in the bed joint. Strength evaluation has been carried out using the Mann-Müller criterion that is adopted in Eurocode 6. Based on the test results, it may be concluded that both methods yield conservative values of the load bearing capacity, as could be expected. Before cracking a linear elastic behavior was observed, while after cracking a strut-and-tie model may be applied. To develop more accurate design models, it is recommended to investigate the post-cracking behavior in more detail. [ABSTRACT FROM AUTHOR]

Un diagnostic des usures des semelles en matériaux composites Carbone/Carbone de freins de Wagons SNTF est dressé à partir d'une analyse du contact acier/composite sur un trajet de 425 Km. L'identification et la classification des usures est mise en évidence à l'aide de l'étude du comportement en ligne des sabots en cours d'exploitation ce qui a permis de cerner celles les plus fréquemment observées. La modélisation paramétrique du phénomène pour chaque rame et pour chaque période a été établie à la base de la quantification des différentes usures constatées sur chaque sabot. Des tests de résistance du sabot en matériau composite au cisaillement et à la flexion ont été mis en place ce qui a conduit à définir sa conformité par rapport aux normes. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess wind-induced torsional loads on low- and medium-rise buildings determined in accordance with the National Building Code of Canada (NBCC 2010). Two building models with the same horizontal dimensions but different gabled-roof angles (0° and 45°) were tested at different full-scale equivalent eave heights (6, 12, 20, 30, 40, 50, and 60 m) in open terrain exposure for several wind directions (every 15°). Wind-induced measured pressures were numerically integrated over all building surfaces and results were obtained for along-wind force, across-wind force, and torsional moment. Torsion load case (i.e., maximum torsion and corresponding shear) and shear load case (i.e., maximum shear and corresponding torsion) were evaluated to reflect the maximum actual wind load effects in the two horizontal directions (i.e., transverse and longitudinal). The evaluated torsion and shear load cases were also compared with the current torsion- and shear-related provisions in the NBCC 2010. The results demonstrated significant discrepancies between NBCC 2010 and the wind tunnel measurements regarding the evaluation of torsional wind loads on low- and medium-rise buildings. Finally, shear and torsion load cases were suggested for evaluating wind loads in the design of low- and medium-rise rectangular buildings. [ABSTRACT FROM AUTHOR]

This paper presents the findings of an experimental research project that was conducted in two phases to study the behavior of glass fiber reinforced polymer (GFRP) sandwich panels with reinforced cores under in-plane loading conditions. The tested panels consisted of two GFRP face skins separated by a polymeric foam core. The foam core was reinforced with different configurations of through-thickness fiber insertions and through-thickness GFRP web skins. In the first phase the performance of three different types of structural connections was tested - namely, bolted, bonded, and so-called enhanced bolted connections. The findings indicate that bolted connections to thinner and more flexible panels exhibited lower strength and a higher degree of nonlinear behavior compared with the bonded connections to the same panels. In contrast, the bolted connections to thicker and stiffer panels were generally stronger and stiffer than their bonded counterparts. The findings further indicate that the ultimate strength of the connections can be increased by up to 26% by bonding a steel reinforcing plate to the face skins of the panel prior to bolting. In the second phase three full-scale sandwich panels (1400 mm × 1400 mm) with different panel configurations were tested under proportional, biaxial, in-plane loading. The applied loads were selected to simulate the in-plane loading conditions in sandwich panels that are subjected primarily to in-plane loads, such as webs of deep beams and shear walls in lightweight structures. The full-field strains and displacements of the panels were measured using a digital image correlation-based (DIC) non-contact measurement system. The findings indicate that the through-thickness core reinforcements effectively prevented localized buckling, debonding, and separation of the panels' face skins. The findings also demonstrated that slender panels exhibit shear-compression buckling failures, whereas less slender panels exhibit shear-tension rupture failures. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Changes to CSA A23.3-04 (R2010) are proposed to correct errors and ensure safety relevant to the shear and the bending moment induced by the transfer of moments at slab–column connections. The corrections were considered non-persuasive in 2009; the CSA A23.3 Committee does not publish submittals of the public or the responses to them. The present note is a public submittal for improving the code. [ABSTRACT FROM AUTHOR]

Abstract: This Note proposes an extension to composite section of the non-uniform (out-of-plane) warping beam theory recently established for homogeneous and isotropic beam by R. El Fatmi (C. R. Mecanique 335 (2007) 467–474). For the present work, which constitutes a first step of this extension, the cross-section is assumed to be symmetric and made by orthotropic materials; however, Poisson''s effects (called here in-plane warping) are also taken into account. Closed form results are given for the structural behavior of the composite beam and for the expressions of the 3D stresses; these ones, easy to compare with 3D Saint Venant stresses, make clear the additional contribution of the new internal forces induced by the non-uniformity of the (in and out) warpings. As first numerical applications, results on torsion and shear-bending of a cantilever sandwich beam are presented. [Copyright &y& Elsevier]

This paper reports experimental data on the structural performance of disturbed regions in reinforced concrete beams with corrosion damage to the embedded steel stirrups. A total of 15 reinforced concrete beams were constructed and tested. The test beams were 350 mm deep, 125 mm wide, and 1850 mm long. The beams were tested in three-point bending under a simply supported span of 1500 mm. Nine beams had the embedded stirrups subjected to accelerated corrosion. The test variables were the corrosion damage level and the shear span-to-depth ratio. The test results indicated that the corroded beams exhibited reduced shear strength in comparison to the uncorroded control specimens. The shear strength reduction was up to 53%. Furthermore, the reduction in shear strength due to the corrosion was found to be greater at smaller shear span-to-depth ratios. [ABSTRACT FROM AUTHOR]

This paper evaluates the performance of carbon and glass fibre-reinforced polymer (FRP) stirrups and the accuracy of the shear design provisions incorporated in the currently available design codes and guidelines. A total of seven large-scale T-beams were constructed and tested: three reinforced with carbon fibre-reinforced polymer (CFRP) stirrups, three reinforced with glass fibre-reinforced polymer (GFRP) stirrups, and one reinforced with a steel stirrup for comparison, when applicable. The test results revealed that the design strength of the tested beams is not affected by the reduced strength of FRP stirrups at bend locations. Also, the recent CAN/CSA-S6 update is capable of adequately predicting the shear strength of the beam specimens reinforced with FRP stirrups. The software, Response-2000, which is based on the modified compression field theory (MCFT), predicted well the shear strength and the average strain in the stirrups of the tested beams; however, it overestimated the shear crack width. [ABSTRACT FROM AUTHOR]

Abstract: Under certain synthetic conditions vanadium oxide gels are made of nanoribbons subunits. Due to this textural specificity it is possible to align the ribbons while employing an extrusion process, generating thereby vanadium oxide macroscopic fibers. In this process V2O5 gel is extruded through a syringe within a PVA (1% wt) solution rotating beaker. A composite fiber can be then extracted from the beaker. These as-synthesized fibers are bearing outstanding mechanical properties (20GPa of Young modulus) addressed with transversal flexibility that alloys macroscopic knot formation. Furthermore, they appear to be excellent alcohol sensors, enable to detect 0.1ppm of ethanol within 16s at 40°C, sensitivity being associated with a good selectivity. Subsequently, we were able to tune the fibers’ sensing and mechanical properties by varying the shear rate addressed to the vanadium oxide extruded gel. In order to better appreciate the correlation between fibers’ porosity, nanoribbons subunits alignment and the addressed properties (mechanical and sensing) we tuned the porosity making the use of latex nanoparticles inclusion followed by their calcinations while varying still the imposed sheer rate during the extrusion. Finally synthesis of hybrid PANI–V2O5 allowed reaching enhanced tenacity 12Jg−1, concomitant with a loss of sensitivity. We show that all the parameters involved within the mechanical and sensing performances are acting within a strong partitioning mode rather than a cooperative one. Overall, these iterative synthetic approaches demonstrate once more the importance of the correlation between structures and properties, approaches where the integrative chemistry is appearing, via its versatility, as an essential tool of chemical science to conceive rationally functional architectures bearing enhanced properties. [Copyright &y& Elsevier]

Abstract: Late-Hercynian, high temperature (HT) shear deformation affected the zone straddling the contact between the Sila Massif batholith (above) and the host migmatitic paragneisses (below). A segment of the regional HT shear zone was investigated close to the town of Mesoraca, where a natural section allows one to analyse the solidus deformation of syn-tectonic granitoids. Shearing favoured the formation of polycrystalline quartz ribbons in deformed granodiorite and tonalite. Two main c-axis fabrics were found in the quartz-ribbons, different from each other by opening angles around Z between strong point maxima, in accordance with deformation under granulite to amphibolite facies conditions. These fabrics, along with microstructural observations, suggest that temperature of deformation played a key role and that ribboning was accompanied by the activation of (i) prism [c] slip and prism [c]+prism slips, under granulite facies conditions, followed by (ii) basal and prism slips under amphibolite facies conditions. [Copyright &y& Elsevier]

Common transverse reinforcement of reinforced concrete members with circular cross section consists of round ties or spirals. Its purpose in members that are not subjected to significant shear loading is to provide proper confinement for concrete, and eliminate buckling of the longitudinal reinforcement bars. If spirals are to be used as both a shear resister and confining enabler for reinforced concrete beams, then under combined action of moment and shear, spirals will be required to provide or contribute to proper shear resistance. Hence a proper assessment for spiral shear contribution is required. [ABSTRACT FROM AUTHOR]

Unbalanced moments, transferred between concrete flat plates and columns due to earthquakes, produce shear stresses that increase the vulnerability to brittle punching failure. Appropriate design and detailing of the slab-column joints are essential to prevent such failure. Because of the high flexibility of flat plate structures, lateral-force-resisting systems, e.g., bracings, frames or shear walls, are necessary to limit the interstorey drift ratio to specified values. The slab-column joints must have the strength and the ductility to undergo, without punching failure, the lateral displacement of the structure. In the 2004 version of the Canadian standard, CSA A23.3-04, clause 21.12.3 is added, specifying the punching shear design of slab-column connections subjected to earthquakes. The provisions of the clause are critically reviewed using a design example. It is shown that the new clause permits absence of shear reinforcement in cases that lack strength and when it requires shear reinforcement, it specifies excessive amount. Changes to the standard are proposed. Lors de séismes, les moments non balancés transférés entre les planchers-dalles en béton et les colonnes produisent des contraintes de cisaillement qui augmentent la vulnérabilité à la rupture fragile par poinçonnement. Une conception et un dimensionnement appropriés des joints dalles-colonnes sont essentiels pour prévenir une telle rupture. En raison de la grande flexibilité des structures à planchers-dalles, il est nécessaire d’avoir des systèmes de résistance aux forces latérales, p. ex. des contreventements, des murs à ossature ou des murs de cisaillement, afin de limiter le rapport de glissement entre les étages à des valeurs spécifiques. Les joints dalles-colonnes doivent avoir la résistance et la ductilité nécessaires pour subir le déplacement latéral de la structure sans rupture fragile par poinçonnement. L’article 21.12.3 a été ajouté à la version 2004 de la norme canadienne A23.3-04 : il définit la conception de la résistance par poinçonnement des connexions dalles-colonnes soumises à des séismes. Les dispositions de l’article sont examinées en détail en utilisant un exemple de conception. Il est démontré que le nouvel article permet l’absence de renforcement en cisaillement dans les cas manquant de résistance et lorsqu’un renforcement en cisaillement est nécessaire, il en spécifie une quantité excessive. Des changements à la norme sont proposés. [ABSTRACT FROM AUTHOR]

The Canadian highway bridge design code (CHBDC) contains provisions for designing concrete members with fiber-reinforced polymer (FRP) reinforcement. In the second edition of the code, new shear design procedures for FRP-reinforced sections are provided. These procedures are consistent with those for steel-reinforced members in the code, in consideration of some modifications that account for the substantial differences between FRP and steel reinforcement. The shear approach adopted in the CHBDC follows the traditional approach of Vc + Vs for shear design. This paper presents an evaluation of this approach by comparing it with experimental shear strengths of available test data on beams longitudinally reinforced with FRP bars and with or without FRP stirrups. In addition, the CHBDC approach was compared with the FRP shear design provisions currently in effect in North America using the available test results. The comparison shows that the CHBDC method significantly underestimates the shear strength of FRP-reinforced concrete beams. A proposed modification to this method is presented and verified against available test results. Le Code canadien sur le calcul des ponts routiers (CCCPR) contient des dispositions pour la conception de membres de béton avec armature en polymères renforcés de fibres (PRF). Dans la 2e édition du code, de nouvelles procédures pour la conception de cisaillement pour les sections armées de PRF sont fournies. Ces procédures sont compatibles dans le code avec celles des membres armés d'acier en considérant certaines modifications pour tenir compte des différences substantielles entre les armatures en PRF et en acier. L'approche du cisaillement adoptée dans le CCCPR suit l'approche traditionnelle de Vc + Vs pour la conception du cisaillement. Cet article présente une évaluation de cette approche en la comparant à des forces de cisaillement expérimentales dans des données de test disponibles sur des poutres armées longitudinalement de barres de PRF, et sans ou avec étriers de PRF. En outre, l'approche du CCCPR a été comparée aux dispositions de conception de cisaillement PRF actuellement en vigueur en Amérique du Nord en utilisant les résultats de tests disponibles. La comparaison montre que la méthode du CCCPR sous-estime significativement la résistance au cisaillement des poutres armées en PRF. Une proposition de modification de cette méthode est présentée et vérifiée par rapport aux résultats des essais disponibles. [ABSTRACT FROM AUTHOR]

Recent literature emphasized the scarcity of information on the shear behavior of fiber-reinforced polymer (FRP) reinforced concrete short beams and the need to develop sufficient experimental data in this area. The present study responds to this need by conducting shear force testing on eight concrete short beams reinforced with carbon-fiber-reinforced polymer (CFRP) and four control concrete beams reinforced with steel. To ensure a shear failure, all tested beams were reinforced with only bottom longitudinal reinforcement and no web reinforcement was provided. The crack pattern, reinforcement strain, mode of failure, and shear strength and deflection of tested beams were studied. The influence of the shear span to effective depth ratio, a/d, beam effective depth, d, longitudinal reinforcement ratio, ρ, and concrete compressive strength, f ′c on the shear behavior of CFRP-reinforced concrete short beams was examined. It was observed that the experimental parameters investigated had a significant effect on the shear strength and deflection of tested beams. It was also found that the strut-and-tie method more accurately predicts the shear strength of steel-reinforced concrete short beams than it does for similar CFRP-reinforced beams and, thus, needs to be modified to be applicable for reinforced concrete beams with FRP reinforcement. [ABSTRACT FROM AUTHOR]

Abstract: This Note proposes a non-uniform warping beam theory including the effects of torsion and shear forces. Based on a displacement model using three warping parameters associated to three St Venant warping functions corresponding to torsion and shear forces, this theory is free from the classical assumptions on the warpings or on the shears, and is valid for any kind of homogeneous elastic and isotropic cross-section. The result on the structural behavior of the beam specifies the effect of the non-symmetry of the cross-section, and the closed form results obtained for the stresses show the contribution of each internal force. Comparison with St Venant beam theory highlights the additional effects due to the non-uniformity of the warping. To cite this article: R. El Fatmi, C. R. Mecanique 335 (2007). [Copyright &y& Elsevier]

Abstract: The evolution of a stably stratified homogeneous turbulence (SSHT) with mean shear is studied according to two nondimensional parameters: the Richardson number Ri and Prandtl number Pr. A linear analysis in spectral space gives access to the evolution of various physical characteristics of such turbulence (Reynolds stress, kinetic energy, potential energy, turbulent heat fluxes). More precisely, the dependence of transition Richardson number on Prandtl number is given in the interval and results in a power law decrease. To cite this article: M. El Hattay, T. Lili, C. R. Mecanique 335 (2007). [Copyright &y& Elsevier]

This paper describes the development of the 2004 Canadian Standards Association (CSA) A23.3 shear design provisions for reinforced and prestressed concrete structures. These methods are similar to the 1994 standard in providing a simplified and general shear design method. They differ from previous standards by providing a direct link between these two methods and simple equations for the calculation of β and θ used in the general method rather than providing these values in a table. The paper explains the basic assumptions behind the new shear provisions, provides a derivation of the new equations, and compares designs made with the new equations to designs obtained from previous standards. In general, the new shear provisions require slightly less shear reinforcement than that required by the previous standard. The new general method is significantly easier to use, particularly with spreadsheets. [ABSTRACT FROM AUTHOR]

An investigation into the behaviour of simple beam-to-column connections subjected to combined shear and tension was carried out by testing 108 full-scale specimens, including header angle, knife angle, single angle, and shear tab configurations. Specimens were rotated 0.03 rad, and a prescribed shear between zero and the design shear resistance was held constant while the specimens were loaded in tension to failure. Results showed significant differences in serviceability, ductility, interactions, and ultimate tension strength. Ductility was provided through yielding in bearing at bolt holes, bending of angle legs, and shear yielding of the gross section of connection elements. Tension and shear load versus displacement plots were acquired for all tests because of ductility and serviceability considerations in design. Existing methods of determining connection resistance, including bolt shear, net section shear, and bearing resistance, were used to compare predicted capacity with test results. The findings of the test program indicate that most simple connections can sustain significant amounts of tension in combination with design shear capacity. [ABSTRACT FROM AUTHOR]

The seismic forces and deformations obtained from the equivalent static force procedure and the dynamic analysis method proposed for the 2005 National Building Code of Canada are compared for 4-, 8-, 12-, and 16-storey buildings with structural mass irregularity. Setbacks resulting in 200% and 300% mass discontinuities located at 25%, 50%, or 75% of the building height were considered. The buildings are located in Vancouver and Montréal, and lateral loads are resisted by concentrically braced steel frames. The storey shear forces, overturning moments, and storey drifts obtained from static analysis were found to exceed the values determined from dynamic analysis for all irregular structures except at the base of "podium-type" buildings located at the Vancouver site. [ABSTRACT FROM AUTHOR]

This paper presents results of an investigation on the shear strengthening of reinforced concrete (RC) beams with externally applied fibre reinforced polymer (FRP) composites. The first part of the study reviews and synthesizes the state of the art in the subject. Also, the requirements and recommendations specified in the Canadian CSA S806-02 standards, the American ACI-440 guidelines, as well as the European fib TG9.3 recommendations are compared with the test results reported in the literature so far. This part of the study indicates that the major parameters involved in the behaviour of RC beams strengthened in shear with FRP were not fully investigated. This can explain the observed discrepancies between the resistance values predicted by the codes and guidelines, and those obtained by tests. This has been the main impetus to carry out an experimental investigation, which is the subject of the second part of this paper. The objective of this experimental investigation was to study the influence of the following parameters on the performance of RC beams strengthened in shear with FRP composites: (i) the FRP ratio, (ii) the transverse steel reinforcement ratio, and (iii) the type of beam (deep versus slender). Results clearly showed the interaction between the FRP composite and the internal transverse steel reinforcement in the shear resistance mechanism. Results also showed the influence of the type of beam on the gain due to FRP on the carrying capacity of the beam. [ABSTRACT FROM AUTHOR]

The Cu ore of Ifri is a chalcopyrite stockwork hosted by Cambrian formations and was until now interpreted as a syngenetic massive sulphide deposit. Textural studies highlight two generations of pyrite early (Py I) and late (Py II) with respect to the regional deformation. The chalcopyrite stockwork overprinted Py II, outlining the epigenetic nature of the Cu mineralization. Regarding the origin of Cu-depositing fluids, the presence in the stockwork paragenesis of an U, W, Sn association and preliminary Pb/Pb dating of a brannerite belonging to this association suggest a contribution of the Tichka granite. To cite this article: L. Barbanson et al., C. R. Geoscience 335 (2003). [Copyright &y& Elsevier]

This paper presents results of an experimental investigation into the effect of flange geometry on the shear strength of point-loaded, reinforced concrete T-beams. A procedure to normalise the ultimate strength and calculate a concrete contribution is implemented. This is used to discuss the effect of varying the ratio of flange width to web width and the ratio of flange depth to effective depth on the shear strength of a reinforced concrete T-beam. An increase in the ratio of flange width to web width is shown to produce an accompanying increase in the ultimate strength of a reinforced concrete T-beam, providing the ratio of flange depth to effective depth is above a certain minimum value. This increase in shear resistance with an increase in the ratio of flange width to web width continues until the flange is wide enough to allow formation of a failure mechanism whereby the load point punches through the flange.Key words: shear, T-beams, flange, reinforcing, strength, failure mechanisms.Cet article présente les résultats d'une étude expérimentale sur l'effet de la géométrie de l'aile sur la résistance au cisaillement des poutres en T de béton armé chargées ponctuellement. Une procédure visant à normaliser la résistance ultime et à calculer une contribution concrète est mise en pratique. Ceci est utilisé afin de voir comment la résistance au cisaillement est affectée par un changement de rapport entre la largeur de l'aile et la largeur de l'âme et entre la profondeur de l'aile et la profondeur effective d'une poutre en T de béton armé sur la résistance au cisaillement. Une augmentation du rapport entre la largeur de l'aile et la largeur de l'âme est accompagnée par une augmentation de la résistance ultime des poutres en T de béton armé à condition que le rapport entre la profondeur de l'aile et la profondeur effective soit au-dessus d'une certaine valeur minimale. Cette augmentation de la résistance au cisaillement avec le rapport entre la largeur de l'aile et la largeur de l'âme continue jusqu'à ce que l'aile soit assez large pour qu'un mécanisme de rupture puisse prendre place là où la charge ponctuelle poinçonne l'aile.Mots clés : cisaillement, poutres en T, aile, renforcement, résistance, mécanismes de rupture. [Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

A study of the adhesion of two semi-crystalline polymers (EVOH and PEg (grafted polyethylene)) by peel has shown that local fracture energy, GA, is virtually independent of peel angle. Adopting the Dugdale model for energy expenditure, we obtain an estimate of GAD of the order of magnitude of GA. However, observation of fracture fronts suggests that supplementary energy losses occur after separation, due to shear stresses reorienting the fibrillar craze material. A simple model is proposed to estimate this shear contribution to fracture energy, GAS, suggesting the potential importance of shear effects in overall fracture energy. To cite this article: A. Guiu, M.E.R. Shanahan, C. R. Physique 3 (2002) 397–402. [ABSTRACT FROM AUTHOR]