Étude numérique d'une connexion boulonnée aveugle entre un tablier en aluminium sur poutres en acier

L'utilisation de l’aluminium dans les ponts au Canada n'est pas nouvelle, mais elle est moins répandue que celle des matériaux plus traditionnels comme l'acier, le béton ou le bois, et ce, même si l'aluminium possède plusieurs propriétés qui rendent son utilisation intéressante. L'aluminium présente plusieurs caractéristiques qui favorisent son utilisation, telles que : sa très bonne résistance à la corrosion, sa légèreté, ainsi qu'une bonne formabilité. Pour ces raisons, l'aluminium est envisagé pour la production de tabliers de ponts fabriqués à partir d'extrusions multicellulaires. Néanmoins, ces tabliers doivent être reliés à des poutres en acier par un assemblage rapide et facile qui pourra en même temps répondre à critères techniques. Compte tenu de la difficulté d'accéder à l'intérieur des cellules extrudées, l’utilisation d'un boulon à haute résistance n'était pas possible, d'où l'idée d'étudier numériquement l'utilisation de deux boulons aveugles Ajax ONESIDE et BOM. Il a été déterminé, par des simulations numériques avec la méthode des éléments finis, que ces deux boulons ont la capacité de permettre la libre expansion / contraction de l'aluminium, en maintenant une action composite avec et sans la présence du freinage, ainsi qu'en générant une usure de quelques micromètres à la surface de contact, sans aucun risque d’initiation de fissure. Une étude comparative avec un boulon à haute résistance a été réalisée afin de classer ces boulons par comportement, et il a été montré que le boulon à haute résistance offre une meilleure résistance au freinage quel que soit l'effet thermique sur l'assemblage. En revanche, en analysant son comportement vis-à-vis le phénomène du fretting, on constate qu'une apparition probable de fissures associée à une usure mineure peut se produire au niveau de la zone de contact tête boulon/ platelage.This research project revolves around the innovative use of aluminum in bridges. The use of aluminum in highway bridges has received special attention in recent years. This material offers several qualities compared to traditional materials such as concrete or steel, an aluminum bridge solution offers enormous potential for the construction of modern road bridges.The optimization of a new aluminum bridge solution and the design application still remains a difficult task. One of the most optimized solutions is the use of a multicellular extrusion profile. However, this solution presents a unique challenge in connecting the bridge deck to the girders using the traditional assembly method, given the difficulty of access to the interior of the extruded cells. The objective of this project is to establish a methodology to analyze two types of blind bolts as an alternative assembly solution using numerical simulation. Through this project, it was determined numerically that these two bolts (Ajax ONESIDE and BOM) have the ability to allow thermal expansion and contraction of aluminum in case of temperature fluctuation, given that the coefficient of thermal expansion of aluminum is twice that of steel. The possibility to minimize the sliding that may occur during the thermal loading was also studied, the two blind bolts offer good resistance with and without the presence of braking. Which allows a possible transfer of this force to the foundations. A special numerical model was prepared for the prediction of the fretting, showed a very good consistency with analytical and literature results. This model was used to analyze the fretting for each bolt at the surface of contact between the bolt head and the aluminum plate. Following the results found, we have observed that the blind bolts will undergo a few micrometers of wear, while for the standard bolt a probable appearance of cracks associated with minor wear may occur at the contact area

Occurrence of common pollutants and pharmaceuticals in hospital effluents

This chapter summarizes the current knowledge on the occurrence of common pollutants and pharmaceuticals in hospital effluents. These common pollutants include a myriad of biological, inorganic and organic pollutants. Daily and weekly concentration variability is presented for many of the covered pollutants. Particular attention is given to heavy metals (gadolinium and platinum) and pharmaceuticals commonly used in hospitals. For pharmaceuticals, the prevalent therapeutic categories are presented and are found to be dependent on the type of healthcare facility â\u80\u93 general hospital, specialized hospitals, wards, and units

New Insights into the Occurrence of Micropollutants and the Management and Treatment of Hospital Effluent

This chapter deals with investigations carried out over the last five years on hospital effluent in terms of the occurrence of micropollutants; new and promising technologies tested to improve the removal of key compounds (including emerging contaminants); the environmental and health risk assessments of pharmaceuticals residues and pathogens; and, finally, some of the strategies adopted in hospital effluent management and treatments through the discussion of some case studies. It emerges that the occurrence and treatment of hospital effluent are becoming issues of increasing concern also for countries such as Morocco, Tunisia, Iran and Colombia, whose research groups had not actively participated in the worldwide debate thus far. Their interest in these topics highlights the shared, global awareness of the need to adopt safe, economic and technically feasible technologies for the treatment of hospital effluent to reduce the impact on the aquatic environment of hazardous substances typically administered or used in healthcare facilities. The experiences reported and discussed herein demonstrate the worldwide efforts that have been made and are still ongoing with the aim of reaching Sustainable Millennium Goal number 6 “Improve Clean Water and Sanitation” by 2030, as defined by the World Health Organization