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Due to the efficiency, sustainability, and advances in firefighting technologies, the allowable height for wood buildings was increased from 4 to 6 storeys in 2015 and will be further increased to 12 storeys in the 2020 edition of the National Building Code of Canada, as a result of the advent and application of mass timber products. To match the development in the industry and the increasing need in the market for highly skilled timber engineers, structural timber design curricula at the university level must evolve to train the next generation of practitioners. At most Canadian universities, structural timber design courses are mainly provided in civil engineering departments. In this study, 31 accredited civil engineering programs in Canada were reviewed for structural wood design content at undergraduate and graduate levels based on two surveys conducted in 2018 and 2020. In the 2018 survey, the percentage of structural timber design content was estimated and compared with other engineering materials (e.g., steel, concrete, and masonry), and a similar survey was repeated in 2020 to determine if any significant changes had occurred. In early 2021, two complementary questionnaires were sent to the instructors of timber-related courses across the country to collect quantitative information, including enrollment statistics, percentage dedicated to timber design in combined material courses, and potential topics deemed critical to support the design of modern timber structures. Based on the responses provided, and also on the availability of resources and the research ongoing, the content for five advanced-level courses is proposed to address the needs of the timber design community. The findings presented in this paper will assist the timber industry, government agencies, and educational institutions in effecting potential changes to university curricula to educate the next generation of timber design professionals who will possess the necessary skills and knowledge to meet the challenges in designing modern mass timber structures.

This paper proposes an innovative hybrid timber beam-to-steel column connection for seismic design of multistory buildings. This innovative connection consists of a set of two U-shaped steel fuses connecting a glulam beam to a steel column. U-shaped fuses are designed to dissipate seismic-induced energy and can be replaced after a moderate or potentially strong seismic event. Eight full-scale experiments were conducted, involving four glulam beam specimens with varying thicknesses and eight pairs of fuses with two U-shaped plate configurations (open-fuse and closed-fuse). The key connection performance metrics, including the flexural stiffness and strength, hysteresis response, ductility, and energy dissipation capacity, were investigated using the test results. A set of mechanics-based equations is proposed to estimate flexural stiffness and strength of the connection. The results of the experimental program confirmed that the proposed hybrid connection exhibits a stable hysteresis response without noticeable strength degradation and possesses excellent ductility and energy dissipation capacities. Furthermore, the proposed mechanics-based equations can predict the moment capacity of the connection with sufficient accuracy. [ABSTRACT FROM AUTHOR]

Steel shear connections are mainly designed to sustain shear forces. There is limited research assessing the axial response of shear connections, which is important in the evaluation of robustness of steel structures. Structural collapse can be arrested following localized damage if an alternative load path with sufficient capacity is available. In this study, the formation of compressive arching action followed by tensile catenary action is investigated. It is shown that in a column loss scenario, connections may develop significant axial compressive force before catenary action begins; this phenomenon has often been neglected in assessments of connection robustness in the sense that axial force is reported as a tensile action only. The presence of arching action has been confirmed in two experimental programs, and one set is selected for further study using a numerical approach. A simplified analytical model is then presented and compared with the observed axial response of these connections. It is concluded that vertical eccentricity between the centres of rotation of the connections at the two ends of a beam is the principal factor causing the development of a compressive arching force. Another influential parameter that affects the formation of arching action is the stiffness of the surrounding structure. Key words: finite element method, disproportionate collapse, column removal scenario, shear connection, compressive arching action, tensile catenary action. Les entretoises de cisaillement en acier sont principalement concues pour supporter l'effort tranchant. Il existe peu de recherches evaluant la reponse axiale d'entretoises de cisaillement, ce qui est important pour l'evaluation de la robustesse des structures en acier. L'effondrement de la structure peut etre arrete a la suite de dommages localises si une autre voie de contrainte avec une capacite suffisante est disponible. Dans cette etude, la formation d'action de voute de compression suivie d'une action de catenaire en traction est etudiee. Il est montre que dans un contexte de perte de colonne, les entretoises peuvent developper une force de compression axiale significative avant le debut de l'action de catenaire; ce phenomene a souvent ete neglige dans les evaluations de la robustesse des entretoises en ce sens que la force axiale n'est signalee que comme une action en traction. La presence de l'action de voute a ete confirmee dans deux programmes experimentaux et un ensemble est choisi pour une etude plus approfondie en utilisant une approche numerique. Un modele analytique simplifie est ensuite presente et compare a la reponse axiale observee de ces entretoises. On en conclut que l'excentricite verticale entre les centres de rotation des entretoises aux deux extremites d'une poutre est le principal facteur provoquant le developpement d'une force de voute de compression. Un autre parametre qui influe sur la formation de l'action de voute est la rigidite de la structure environnante. [Traduit par la Redaction] Mots-cles : methode des elements finis, effondrement disproportionne, scenario d'enlevement de colonne, entretoise de cisaillement, action de voute de compression, action de la catenaire en traction., 1. Introduction The potential for disproportionate collapse is an important issue in building failure characterization. It is generally accepted that a column removal scenario can be used to assess the [...]

The main objective of this study was to develop an analytical model for predicting the diaphragm deflection and the induced shear force at the panel joints when the applied load is perpendicular to the panel length. An equivalent finite-element model was developed to capture the elastic behavior of the diaphragm made from the panels and the connections in between. The analytical model's predictions were compared with predictions from finite-element models. The results of an experimental test were used to partially validate the analytical and numerical models in the absence of full-scale diaphragm test data. A sensitivity analysis was carried out with the aim of finding the most influential parameters in the behavior of the cross-laminated timber (CLT) diaphragm. The connection's stiffness and diaphragm size were varied. The difference in diaphragm deflection was investigated, and it was found that under realistic material properties and geometry, the diaphragm deflection was not strongly related to the connection's stiffness. However, the floor's geometry was the key influencing parameter. A parametric study was performed, and the contribution of each deflection component was quantified for each specific case. It was observed that the floor's flexibility was dominated mainly by the shear deflection of the cross-laminated timber panels as well as the slip in the panel joints as the length of the diaphragm increased. This study proposes a method that designers may use to estimate the in-plane displacement of the cross-laminated timber diaphragm when it is loaded perpendicular to the panel's length. [ABSTRACT FROM AUTHOR]

Introduction and Aims: Socioeconomic Status (SES) is considered as one of the important factors associated with use of various drugs. The present study aimed to investigate the effect of SES on cigarette smoking, alcohol use, drug use, and passive exposure to opium and cigarette smoke. Design and Methods: In this study, which is part of a multicenter case-control study, the research hypothesis was checked among controls who had referred to hospitals. Data were collected through a questionnaire and laboratory tests to determine the actual consumers of opium and other illicit drugs. Then, the data were analyzed using STATA 13. Result: This study was performed on 364 individuals within the age range of 30 to 75 years. More than 55% of the participants had a history of life-time consumption of cigarettes and hookah as well as alcohol and drugs. The results revealed an inverse relationship between SES and life-time consumption of hookah and alcohol. Furthermore, individuals with higher SES were more likely to deny their drug use. Discussion and Conclusions: The results revealed little robust evidence supporting the assumption that SES level can have an important effect on illicit drug use. On the other hand, the participants' characteristics could have a prominent effect on precise evaluation of the relationship between SES and drug use. Further multicenter studies are needed with samples diversified in terms of age and ethnicity to identify these confounding relationships. [ABSTRACT FROM AUTHOR]

Background/aim: Thirty male BALB/c mice were equally divided into three groups: control, L. acidophilus, and B. bifidum for the assessment of the probiotics' stability in the gut microflora. Materials and methods: First, the gut microflora of the mice was checked every 3 days (days 3, 6, 9, and 12) without probiotic consumption, and then the mice were daily given orally 1.5 g of probiotics in 30 cc of drinking water. The consumption of probiotics was then stopped for recovery and then the consumption continued for 5 months. Results: On day 9 after the consumption of the probiotics, L. acidophilus and B. bifidum were significantly increased from 4% to 83% and from 1% to 61%, respectively. L. acidophilus count showed no significant decrease at the end of 5 months compared to day 9 of probiotic consumption (74%), but B. bifidum count was dramatically decreased to 45% and 36% at the end of 1 and 5 months, respectively. Conclusion: Our results revealed that, unlike B. bifidum, the amount of L. acidophilus remained almost unchanged in the long term, indicating more stability of L. acidophilus than B. bifidum in the gut microflora. [ABSTRACT FROM AUTHOR]

Procalcitonin (PCT) is a prohormone that has been used as a marker for the diagnosis of bacterial infections. The aim of this study was to survey PCT levels in patients with cirrhosis. Sixty-four patients with hepatic cirrhosis and 32 healthy blood donors were enrolled in this study. Serum PCT levels was detected using immunoluminometric assay. The rate of positive PCT was higher in patients with hepatitis C cirrhosis (92.8%) than the other groups. Among other cirrhotic patients, positive PCT levels were 77% for hepatitis B, 70% for cancer and 53.3% for unknown groups respectively. Serum procalcitonin levels were significantly higher in cirrhotic patients with bacterial infection (2.65±1.11 ng/ml) than those without infection (0.59±0.16 ng/ml, P=0.0001). PCT assay in cirrhotic patients may help diagnosis of sepsis and reduce unnecessary antibiotic use. [ABSTRACT FROM AUTHOR]