Academic literature on the topic 'Abaques normatifs'

This article presents the results of testing a prototype of a bar jumper for deflection in the conditions of a test center and using the ABAQUS CAE computer program. The results of both tests showed the suitability of the proposed technology for manufacturing bar jumpers. The deflection value at the maximum load application of 50 kN is 1.48 mm, which does not exceed the normative permissible value of 2.2 mm.

En Ecuador la mayoría de viviendas unifamiliares construidas con estructuras de acero, son conformadas mediante perfiles tubulares. No existe una unión precalificada según la normativa AISC para esta tipología por lo que esta investigación se enfoca en modelar y analizar la capacidad de rotación de la conexión viga-columna. Se ha generado un modelo con elementos finitos en el software ABAQUS, a partir del cual se ha obtenido el diagrama de momento curvatura y la capacidad de rotación de la conexión. Se ha encontrado que el momento flector aplicado en la cara de la columna es menor al 80% del momento plástico de la viga, la capacidad de rotación es de 0.002 rad y se determinó que la cara de la columna en contacto con la viga se plastifica lo que impide que la viga desarrolle su momento plástico, por lo que la conexión presenta un bajo desempeño ante condiciones sísmicas.

Abstract Reinforced concrete short corbels are components characterized to represent typical conditions of geometrical and static discontinuity. In general, the classical bending theory is not valid for their design. With the strut and tie method, a model of a self-balanced truss, a strategy of representation of the principal stress flow appears as a representation of the trajectories of the main stresses in these components. Within the context of obtaining the strut and tie models, topology optimization is an indicated technique for an automated process. Combined with a numerical analysis based on finite elements, the SIMP (Solid Isotropic Material with Penalization) method formulation, which is defined with the criterion of minimum strain energy restricted by the volumetric fraction, is used for the development of the models with the ABAQUS® v. 6.14.1 software. Therefore, with the material distribution posterior to the optimization and the validation based on normative codes, it is demonstrated that the tool is effective in the development of strut and tie models.

abstract: Innovative composite structures have been intensively studied towards meeting the demands of civil construction. An example of such structures is slim floor, comprised of concrete or composite slabs positioned at the height of steel beams, reducing the total height of the floor. In Brazil, studies on this system are still in early stages, and due to the lack of both experience and national normative codes, it is hardly used in civil construction. Given the possible combinations between concrete slabs and steel beams, the system exhibits different typologies. This article reports a numerical investigation on two typologies of slim floor, namely Asymmetric Slimflor Beam (ASB), composed of an asymmetric I beam, and Composite Slim-Floor Beam (CoSFB), comprised of an asymmetric beam with small openings at the top of its web. Nonlinear numerical models of ASB and CoSFB typologies were developed by Finite Element-based software ABAQUS®. The models were calibrated with the use of experimental studies from the literature, and showed high accuracy and good results. After calibration, the materials properties and geometric dimensions of the models, such as height and thickness, were standardized for a comparison of the typologies. The comparative analysis showed the particular characteristics of CoSFB promoted higher stiffness and flexural capacity compared to ASB, and a parametric analysis evaluated the influence of steel and concrete parameters on the flexural behavior of the typologies. The parametric study revealed the steel parameters exerted a more substantial influence on the slim floors behavior than the concrete ones.

Les déformations rachidiennes de l’adulte sont des pathologies fréquentes, mais leur traitement chirurgical est associé à un taux de complications mécaniques important. Les objectifs de cette thèse par articles étaient d’identifier de nouveaux paramètres anatomiques associés à l’alignement postural et de redéfinir des valeurs de référence des paramètres d’alignement utilisés en pratique clinique à l’aide de la stéréoradiographie et de la barycentremétrie. Une cohorte de 879 sujets sains avec radiographies bi-planaires corps entier a été constituée. Le but sera ensuite d’appliquer ces conclusions à une population de patients opérés d’une déformation rachidienne de l’adulte et d’en évaluer l’impact sur les complications mécaniques.La première étude a mis en évidence une corrélation entre l’angle des côtes supérieures et le rachis thoracique ainsi qu’entre les côtes inférieures et le rachis lombaire. Une plus grande cyphose thoracique était associée à un diamètre antéro-postérieur de la cage thoracique plus grand, et une moins forte pénétration du rachis, et ainsi un plus grand volume de la cage thoracique. De façon plus intéressante en ce qui concerne l’alignement global, il a été retrouvé une augmentation compensatoire de la version pelvienne en association avec une augmentation de la largeur de la cage thoracique dans le plan sagittal.La deuxième étude a mis en évidence une corrélation significative entre l’angle de version du col fémoral et la version pelvienne. Cette relation n’était pas linéaire, puisque la version du col était comparable dans les groupes de faiblesse faible et moyenne VP, tandis que le groupe avec la plus forte version pelvienne, présentait une version du col fémoral significativement plus importante. Les conclusions de cette étude pourraient suggérer d’adapter l’orientation des implants dans la chirurgie prothétique de la hanche en fonction de la version pelvienne des patients. Par ailleurs, il avait été démontré une association entre l’augmentation de la version fémorale et le risque de coxarthrose ainsi que de conflit ischio-fémoral.De nombreux paramètres d’alignement (version pelvienne, TPA, SFA, SSA) sont corrélés à l’âge de façon physiologique, et à l’incidence pelvienne (IP) du fait de leurs définitions anatomiques. Il est proposé dans la troisième étude des formules pour estimer ces quatre paramètres en fonction de l’âge et de l’IP. La cohorte globale a été divisée en cinq groupes selon l’IP, permettant de fournir des valeurs de référence pour tous les paramètres d’alignement pour chaque groupe. Cette étude a également permis de constater que la cyphose thoracique et la courbure cervicale n’étaient pas significativement corrélées à l’IP. Ces résultats permettent une étude plus précise de l’alignement postural, en prenant en compte les spécificités individuelles du patient, pour une correction plus adaptée aux patients et amener ainsi une diminution des risques de complications mécaniques postopératoires dans les chirurgies de déformation rachidienne de l’adulte.L’étude barycentremétrique a mis en évidence qu’une plus forte lordose lombaire était associée à une translation postérieure du centre de masse corporel au-dessus de l’apex de la cyphose thoracique. L’analyse des centres de masse a également permis de valider le rôle des membres inférieurs dans l’alignement postural. Ainsi, de plus grandes extensions de hanche, versions pelviennes et flexions de genou étaient associées à une translation postérieure du centre de masse du corps entier. La forte corrélation de l’ODHA avec les différents centres de masse en fait un bon paramètre de substitution pour estimer la ligne de gravité corporelle. Une association significative a été mise en évidence entre l’alignement postural et la distance entre le rachis et l’enveloppe corporelle au niveau de la lordose lombaire : une distance plus importante était associée à une rétroversion pelvienne, ainsi qu’une majoration de la lordose cervicale
Adult spinal deformities are common pathologies, but their surgical treatment is associated with a high rate of mechanical complications. The aims of this article-based thesis were to identify new anatomical parameters associated with postural alignment, and to redefine reference values for alignment parameters used in clinical practice using stereoradiography and barycentremetry. A cohort of 879 healthy subjects with bi-planar whole-body radiographs was set up. The aim will then be to apply these findings to a population of patients undergoing surgery for adult spinal deformity, and to assess their impact on mechanical complications.The first study showed a correlation between the angle of the upper ribs and the thoracic spine, and between the lower ribs and the lumbar spine. Greater thoracic kyphosis was associated with a greater anteroposterior diameter of the rib cage, and less penetration of the spine, resulting in greater rib cage volume. More interestingly, with regard to global alignment, a compensatory increase in pelvic tilt was found in association with an increase in ribcage width in the sagittal plane.The second study showed a significant correlation between femoral neck version angle and pelvic tilt. This relationship was non-linear, as neck version was comparable in the low and medium pelvic tilt groups, while the group with the highest pelvic tilt had a significantly greater femoral neck version. The findings of this study may suggest that implant orientation in hip replacement surgery should be adapted to the patient's pelvic tilt. Moreover, an association was previously demonstrated between increased femoral version and the risk of hip osteoarthritis and ischiofemoral impingement.Many alignment parameters (pelvic tilt, TPA, SFA, SSA) are physiologically correlated with age, and with pelvic incidence (PI) due to their anatomical definitions. The third study proposes formulas for estimating these four parameters as a function of age and PI. The overall cohort was divided into five groups according to PI, making it possible to provide reference values for all alignment parameters for each group. This study also found that thoracic kyphosis and cervical curvature were not significantly correlated with PI. These results enable a more precise study of postural alignment, taking into account individual patient specificities, for a more patient-specific correction and thus bring a reduction in the risk of postoperative mechanical complications in adult spinal deformity surgery.The barycentremetric study showed that a higher lumbar lordosis was associated with a posterior translation of the body's center of mass above the apex of the thoracic kyphosis. Center of mass analysis also validated the role of the lower limbs in postural alignment. Greater hip extension, pelvic tilt and knee flexion were associated with a posterior translation of the whole-body center of mass. The strong correlation of ODHA with the different centers of mass makes it a good surrogate parameter for estimating the body's line of gravity. A significant association was found between postural alignment and the distance between the spine and the body envelope at the level of lumbar lordosis: a greater distance was associated with pelvic retroversion, as well as an increase in cervical lordosis

AbstractThe paper investigates the response of the pavement of a road sector analyzed to the traffic load that was determined numerically by using Abaqus numerical modelling software. This tool offers advanced analysis options in comparison with the normative road structure dimensioning tool. Thus, in contrast to the current use road structure dimensioning program, the FEM software allows the definition of the interfaces between layers and switch loads from static load to moving load, based on the determination of the resilient stresses and deformations in road structures by using the classical linear elastic multilayer model. The aim of this study was to determine whether the road pavement with deficiencies of adhesion between asphalt layers can take over the calculated traffic load considered in the study, or the proportion of design traffic load that can be taken over. That would allow an assessment of the service operation life of the road pavement and, implicitly, of the possibility of its yielding before the end of the perspective period considered.