No description available.

Les grands groupes de l'industrie de la construction souhaitent intégrer le concept de prévention au sein de leurs organisations en recherchant des améliorations techniques et organisationnelles et en déployant des méthodes tantôt coercitives, tantôt participatives visant une maîtrise du facteur humain. L'objectif de cette industrie est de contrôler les risques inhérents aux chantiers dont il est possible de déterminer plusieurs classifications. Le point commun de ces dernières est leur finalité, c'est-à-dire établir une liste exhaustive d'un ensemble infini selon des critères variables. Après avoir analysé les différents facteurs influençant sur la genèse des risques dans un environnement aussi particulier qu'est celui des chantiers de bâtiment, nous proposons un modèle dynamique d'appréhension des risques et d'aide à la décision reposant sur la mobilisation de la TNI et de la théorie des représentations sociales. Plus spécifiquement, en considérant les propriétés des risques « émergents » actuels, nous nous interrogeons sur la pertinence des moyens mis en œuvre par l'organisation pour permettre leur intégration. / The major companies of the construction industry wish to integrate the concept of prevention within their organizations by seeking technical and organizational improvements and by implementing coercive or participatory methods whose goal is to deal with the human factor. This industry aims at controlling the risks inherent to the construction sites of which several classifications can be determined. Those classifications have in common their purpose, which is to draw up an exhaustive list from an infinite set according to variable criteria. After analyzing the different factors that influence the genesis of the risks in such a specific environment as the building sites, we propose a dynamic model for risk understanding and decision-making, based on the mobilization of the TNI and the Theory of social representations More specifically, considering the characteristics of the current emerging risks, we wonder about the relevance of the means implemented by the organization towards their integration.

Made available in DSpace on 2014-08-20T14:25:45Z (GMT). No. of bitstreams: 1 dissertacao_catia_cristina_braga_rodrigues.pdf: 1202246 bytes, checksum: 0067166e90de2215d4ec858dba3e1ba5 (MD5) Previous issue date: 2012-04-18 / The periods of large variations in rainfall in the Mato Grosso do Sul State (centralwest region, Brazil), in particular the great floods or droughts, generate large economic losses to the state. The summer drought may further compromise the winter period, which often short rains occur. The main objective of this research is to verify bimonthly rainfall variation in the state of Mato Grosso do Sul during the summer (maximum variation) and the winter (minor variations) and their relationships with the bimonthly SST anomalies combined of the South Pacific and South Atlantic oceans. The combined anomalies were represented by Principal Oscillation Patterns (POPs), which represent the predominant patterns of ocean circulation. Monthly precipitation data from January to December (from 1981 to 2009) and monthly data of Sea Surface Temperature (SST) were used. From the rainfall climatology of the marking periods were selected two periods: December/January (rainier) and July/August (dry season). Homogeneous regions were generated by the K-means Method, three for December/January period and two for the July/August period. The regional accumulated rainfall presented no significant trend at 5% probability. The regional accumulated precipitation anomalies of two-month periods showed no significant correlations with SST anomalies in the Central Pacific (Niño 3.4) along the studied period. During the two months December/January, the largest excess precipitation in the region occurred with a predominance of strong El Nino events and droughts in major events La Niña and neutral. In regions 2 and 3 there is not a predominant sign of some events. During the July/ August period, the greatest excesses of precipitation occurred in the region with a predominance of La Niña events, with less relation respect region 2, both regions in a coherent signal (Neutral and La Niña). In cases of severe dry period, both regions have low relation with the events signals. The settings of multiple regressions of bi-monthly precipitation accumulated in homogeneous regions with the scores of the first six patterns of SST showed significant increase in both studied marking periods. The correlation coefficient between the bimonthly observed accumulated precipitation and regional estimates were significant at 1% probability in all regions. This occur especially in the region that represents the northwest quarter of the state in December/January and in the region that represents the major portion of Mato Grosso do Sul State in the July/August period. / Os períodos de grandes variações da precipitação no Mato Grosso do Sul, em especial as grandes cheias ou grandes estiagens, trazem grandes prejuízos financeiros ao Estado. As estiagens de verão podem comprometer ainda mais o período de inverno, no qual já é normal ocorrer poucas chuvas. Esta pesquisa tem por proposta principal verificar as variações bimensais da precipitação no estado de Mato Grosso do Sul nos períodos de verão (variações máximas) e inverno (variações mínimas) e suas relações com as anomalias bimensais de TSM combinadas dos oceanos Pacífico Sul e Atlântico Sul. As anomalias combinadas foram representadas pelos Padrões de Oscilação Principal (POP), os quais representam os padrões predominantes de circulação oceânica. Foram usados dados de precipitação mensal de janeiro a dezembro, período de 1981 a 2009 e dados médios mensais de Temperatura na Superfície do Mar (TSM). A partir da climatologia da precipitação foi selecionado os bimestres dezembro/janeiro (mais chuvoso) e julho/agosto (menos chuvoso) e geradas pelo método K-means regiões homogêneas, sendo três para o bimestre dezembro/janeiro e duas para o bimestre julho/agosto. As precipitações acumuladas regionais não apresentaram tendência temporal significativas a 5% de probabilidade. As anomalias de precipitação acumulada regionais dos bimestres não apresentaram correlações significativas com as anomalias de TSM na região do Pacífico Central (Niño 3.4) ao longo do período estudado, mas durante o bimestre dezembro/janeiro, os maiores excessos de precipitação da região 1 ocorreram com forte predomínio de eventos El Niño fortes e a maiores estiagens em Eventos La Niña e Neutros. Nas regiões 2 e 3 não existem um sinal predominante de alguns dos eventos. Durante o bimestre julho/agosto, os maiores excessos de precipitação ocorreram na região 1 com predomínio de eventos La Niña, com menor relação na região 2, mas ambas regiões com coerência do sinal (Neutro e La Niña). Nos casos de fortes estiagens, ambas as regiões apresentam baixa relação com os sinais dos eventos. Os ajustes das regressões múltiplas das precipitações acumuladas bimestrais nas regiões homogêneas com os escores dos seis primeiros padrões de TSM apresentaram aumento de significância em ambos bimestres estudados. O coeficiente de correlação entre as precipitações acumuladas regionais bimestrais observadas e estimadas foram significativas a 1% de probabilidade em todas as regiões, especialmente na região que representa o noroeste do Estado no bimestre dezembro/janeiro e a região que representa a maior parte do estado do Mato Grosso do Sul no bimestre julho/agosto.

No description available.

In this thesis we examine intra-seasonal oscillations (ISO) in the aqua-planet setup of the Community Atmospheric Model (CAM) version 5.1, mainly based on July and January climatological sea surface temperature (SST). We investigate mainly two questions -what should be the SST distribution for the existence of (a) northward moving ISO in summer, and (b) eastward moving MJO-like modes in winter. In the first part of the thesis we discuss the northward propagation. A series of experiments were performed with zonally symmetric and asymmetric SST distributions. The basic lower boundary condition is specified from zonally averaged observed July and January SST. The zonally symmetric July SST experiment produced an inter tropical convergence zone (ITCZ) on both sides of the equator. Poleward movement is not clear, and it is confined to the region between the double ITCZ. In July, the Bay of Bengal (BOB) and West Pacific SST is high compared to the rest of the northern tropics. When we impose a zonally asymmetric SST structure with warm SST spanning about 80 of longitude, the model shows a monsoon-like circulation, and some northward propagating convective events. Analysis of these events shows that two adjacent cells with cyclonic and anticyclonic vorticity are created over the warm SST anomaly and to the west. The propagation occurs due to the convective region drawn north in the convergence zone between these vortices. Zonally propagating Madden-Julian oscillations (MJO) are discussed in the second part of the thesis. All the experiments in this part are based on the zonally symmetric SST. The zonally symmetric January SST configuration gives an MJO-like mode, with zonal wave number 1 and a period of 40-90 days. The SST structure has a nearly meridionally symmetric structure, with local SST maxima on either side of the equator, and a small dip in the equatorial region. If we replace this dip with an SST maximum, the time-scale of MJO becomes significantly smaller (20-40 days). The implication is that an SST maximum in the equatorial region reduces the strength of MJO, and a flat SST profile in the equatorial region is required for more energetic of MJO. This result was tested and found to be valid in a series of further experiments.

A Savonius wind turbine is a self-starting vertical axis rotor. It can be designed to be compact in size and also produces less noise which makes it suitable to integrate into urban spaces such as rooftops and sign-poles. These characteristics make it interesting from a sustainability point of view, especially when aiming to increase the decentralization of electricity production. This thesis aimed to investigate the aerodynamic performance of different two-bladed Savonius profiles by varying the blade arc angle and the overlap ratio. For evaluation, the dimensionless power coefficient and torque coefficient were investigated over different tip speed ratios. The study was conducted numerically with 2D simulations in Ansys Fluent. The partial differential equations describing the characteristics of the flow, including the flow turbulence effects, were solved with the Reynolds-average Navier Stokes in combination with the k-omega SST model. A validation was performed by comparing data from simulated and experimental tests of a semi-circular profile and a Benesh profile. The investigation of the blade arc angle and overlap ratio was performed on a Modified Bach profile. The profile with a blade arc angle of 130 degrees and an overlap ratio of 0.56 generated a maximal power coefficient of 0.267 at a tip speed ratio of 0.9. This blade configuration generated the best performance of all conducted simulations in this project. However, this project contained uncertainties since simulations can never be an exact description of reality. The project was also limited by the computational power available. Nevertheless, according to the conducted simulations, it was observed that a higher blade arc angle and a larger overlap ratio seem to generate higher efficiency. / En Savonius vindturbin är en självstartande vertikalaxlad rotor som kan utformas i en kompakt design samtidigt som den producerar mindre oljud än horisontalaxlade vindkraftverk. Dagens hållbarhetssträvan i kombination med Savonius turbinens karakteristiska egenskaper gör den till ett potentiellt starkt vertyg för vindenergi. Då den kan placeras på exempelvis hustak eller skyltstolpar, utan att störa närliggande omgivning, finns det många möjliga sätt att implementera och integrera den i samhällets infrastruktur. Målet med detta projekt var att undersöka den aerodynamiska prestationen för Savoniusturbiner med två blad genom att variera bladvinkeln och överlappningsförhållandet. För att jämföra de olika profilerna användes den dimensionslösa effektkoefficienten och momentkoefficienten. Dessa koefficienter beräknades i förhållande till löptalet. Studien utfördes numeriskt med 2D-simuleringar i Ansys Fluent. De partiella differentialekvationerna som beskriver flödets egenskaper, inkluderat turbulenseffekterna, löstes med Reynolds-average Navier Stokes i kombination med k-ω SST modellen. En validering utfördes genom att jämföra data med simulerade och experimentella värden av en Semi-circular profil och en Benesh profil. Studien av bladvinkel och överlappningsförhållandet utgick från en Modified Bach profil. Den mest effektiva profilen hade en bladvinkel av 130 grader och ett överlappsförhållande på 0,56. Den genererade en maximal effektkoefficient av 0,267 vid löptal 0,9. Projektet innehöll en del osäkerheter då simuleringar aldrig kan beskriva verkligheten till fullo. Den tillgängliga beräkningskapaciteten begränsade även projektet ytterligare. Trots vissa begränsningar, visar ändå utförda simuleringar att ökad bladvinkel och ökat överlappningsförhållande genererar högre effekt. / <p>This project was conducted within Stand up for wind and Stand up for energy.</p>

The new legal regulations derived from climate change dictate that hydraulic structures must be designed to handle flood events associated with return periods up to 10,000 years. This obviously involves adapting the existing infrastructure to meet such requirements. In order to avoid risks in the restitution of the flow discharged to rivers, such as bank overflows or streambed erosion and scour processes, hydraulic design must be supported by reliable tools capable of reproducing the behavior of hydraulic structures. In the work presented herein, a fully three-dimensional CFD model to reproduce the behavior of different types of air-water flow in hydraulic structures is presented. The flow is assumed to be turbulent, isotropic and incompressible. Several RANS turbulence models are tested and structured rectangular meshes are employed to discretize the analyzed domain. The presence of two fluids is modeled using different VOF approaches and simulations are run using the PIMPLE algorithm. The model is implemented using the open-source platform OpenFOAM and its performance is compared to the commercial code FLOW-3D. The analysis is conducted separately on two different parts of hydraulic structures, namely: the spillway and the stilling basin. Additionally, a case of practical application, where the model reproduces the flow of a real-life case, is also presented in order to prove the suitability of the model to actual design cases. Mesh independence and model validation using experimental data are checked in the results of all the case studies. The sensitivity of the presented model to certain parameters is extensively discussed using different indicator variables. Among these parameters are turbulence closure, discretization scheme, surface tracking approach, CFD code or boundary conditions. Pros and contras of each of them are addressed. The analyzed turbulence models are the Standard k ¿ ¿, the Realizable k ¿ ¿, the RNG k ¿ ¿, and the SST k ¿ ¿. The discretization schemes under study are: a first-order upwind method, the second-order limited Van Leer method, and a second-order limited central difference method. The VOF approaches analyzed are the Partial VOF, as implemented in OpenFOAM, and the TruVOF, as implemented in FLOW-3D. In most cases, the Standard k ¿ ¿ model provides the most accurate estimations of water free surface profiles, although the rest of variables, with few exceptions, are better predicted by the RNG k ¿ ¿. The latter model generally requires slightly longer computation times. The SST k ¿ ¿ reproduces correctly the phenomena under study, although it generally turned out to be less accurate than its k ¿ ¿ counterparts. As regards the comparison among VOF approaches and codes, it is impossible to determine which one performs best. E.g. OpenFOAM, using the Partial VOF, managed to reproduce the in- ternal hydraulic jump structure and all derived variables better than FLOW-3D, using the TruVOF, although the latter seems to capture better the momentum transfer and so all derived variables. In the case of flow in stepped spillways, OpenFOAM captures better the velocity profiles, although FLOW-3D is more accurate when estimating the water free surface profile. It is worth remark- ing that not even their response to certain model parameters is comparable. E.g. FLOW-3D is significantly less sensitive to mesh refinement than OpenFOAM. Given the result accuracy achieved in all cases, the proposed model is fully applicable to more complex design cases, where stilling basins, stepped spillways and hydraulic structures in general must be investigated. / Las nuevas disposiciones legales derivadas del cambio climático dictaminan que las estructuras hidráulicas sean capaces de funcionar correctamente con eventos de inundación asociados a periodos de retorno de hasta 10,000 años. Esto, obviamente, implica adaptar la infraestructura existente para satisfacer dichos requerimientos. A fin de evitar riesgos en la restitución de los caudales vertidos al río, como desbordamientos o procesos erosivos y de socavación, el diseño hidráulico ha de sustentarse en herramientas fiables capaces de reproducir el comportamiento de las estructuras hidráulicas. En este trabajo, se presenta un modelo numérico CFD completamente tridimensional para reproducir el comportamiento de diferentes tipos de flujo aire-agua en estructuras hidráulicas. Se asume que el flujo es turbulento, isotrópico e incompresible. Diversos modelos de turbulencia RANS son contrastados y se emplean mallas estructuradas rectanuglares para discretizar el dominio analizado. La presencia de dos fluidos es modelada utilizando diferentes enfoques VOF y las simulaciones son ejecutadas empleando el algoritmo PIMPLE. El modelo es implementado mediante la plataforma de código abierto OpenFOAM y su respuesta es comparada con la del modelo comercial FLOW-3D. El análisis se lleva a cabo sobre dos partes diferentes de una estructura hidráulica, a saber, el aliviadero y el cuenco amortiguador, de forma separada. Además, un caso de aplicación práctica, donde el modelo reproduce el flujo en una estructura real, es presentado también a fin de probar la adecuación del modelo a casos de diseño aplicado. Se comprueban la independencia de la malla y la validación con datos experimentales de los resultados de todos los casos de estudio. La sensibilidad del modelo presentado a ciertos parámetros es analizada de forma exhaustiva empleando diferentes variables indicadoras. Los pros y contras de cada uno de éstos son planteados. Los modelos de turbulencia analizados son el Standard k-epsilon, el Realizable k-epsilon, el RNG k-epsilon y el SST k-omega. Los esquemas de discretización estudiados son: un método de primer orden upwind, uno de Van Leer de segundo orden y un esquema de segundo orden limitado de diferencias centradas. Los enfoques VOF analizados son el Partial VOF, implementado en OpenFOAM, y el TruVOF, implementado en FLOW-3D. En la mayoría de casos, el modelo k-epsilon aporta las estimaciones más precisas de perfiles de lámina libre de agua, pese a que el resto de variables, con alguna excepción, son mejor predichas por el RNG k-epsilon. Este modelo generalmente requiere mayores tiempos de cálculo. El k-omega reproduce correctamente los fenómenos bajo estudio, pese a que su precisión es generalmente más baja que la de los modelos k-epsilon. En lo que respecta a la comparación entre enfoques VOF y códigos, es imposible determinar cuál es el mejor. Por ejemplo, OpenFOAM, empleando el Partial VOF, logra reproducir la estructura interna del resalto hidráulico y todas las variables derivadas mejor que FLOW-3D, empleando el TruVOF, a pesar de que este último parece capturar mejor la transferencia de cantidad de movimiento y, por tanto, todas las variables derivadas. En el caso del flujo en aliviaderos escalonados, OpenFOAM captura mejor los perfiles de velocidad, pese a que FLOW-3D es más preciso en la estimación de los perfiles de lámina libre de agua. Conviene recalcar que ni tan sólo su respuesta a ciertos parámetros del modelo es comparable. Por ejemplo, FLOW-3D es significativamente menos sensible al refinado de malla que OpenFOAM. A la luz de la precisión de los resultados obtenidos en todos los casos, el modelo propuesto es completamente aplicable a casos de diseño más complejos, donde cuencos amortiguadores, aliviaderos escalonados y estructuras hidráulicas en general han de ser investigadas. / Les noves disposicions legals derivades del canvi climàtic dictaminen que cal que les estructures hidràuliques siguen capaces de funcionar correctament amb esdeveniments d'inundació associats a períodes de retorn de fins a 10,000 anys. Això, òbviament, implica adaptar la infraestrctura existent per satisfer aquests requeriments. A fi d'evitar riscs en la restitució dels cabals vessats al riu, com desbordaments o processos erosius i de socavació, el disseny hidràulic ha de recolzar-se en ferramentes fiables capaces de reproduir el comportament de les estructures hidràuliques. En aquest treball, es prsenta un model numèric CFD completament tridimensional per a reproduir el comportament de diferents tipus de flux aire-aigua en estructures hidràuliques. S'assumeix que el flux és turbulent, isotròpic i incompressible. Diferents models de turbulència RANS són contrastats i s'empren malles estructurades rectangulars per discretitzar el domini analitzat. La presència de dos fluids és modelada utilitzant diferents enfocaments VOF i les simulacions són executades emprant l'algorisme PIMPLE. El model és implementat mitjançant la plataforma de codi obert OpenFOAM i la seua resposta és comparada amb la del codi comercial FLOW-3D. L'anàlisi es du a terme sobre les diferents parts d'una estructura hidràulica, a saber, sobreeixidors esgraonats i vas esmorteïdor, de forma separada. A més, un cas d'aplicació pràctica, on el model reprodueix el flux a una estructura real, és presentat també a fi de provar l'adequació del model a casos de disseny aplicat. Es comproven la independència de la malla i la validació amb dades experimentals dels resultats de tots els casos d'estudi. La sensibilitat del model presentat a certs paràmetres és analitzada de forma exhaustiva emprant diferents variables indicadores. Els pros i contres de cadascun d'aquests són plantejats. Els models de turbulència analitzats són l'Standard k-epsilon, el Realizable k-epsilon, el RNG k-epsilon i l'SST k-omega. Els esquemes de discretització estudiats són: un mètode de primer ordre upwind, un de Van Leer de segon ordre i un esquema de segon ordre limitat de diferències centrades. Els enfocaments VOF analitzats són el Partial VOF, implementat en OpenFOAM, i el TruVOF, implementat en FLOW-3D. En la majoria de casos, el model Standard k-epsilon aporta les estimacions més precises de perfils de làmina lliure d'aigua, tot i que la resta de variables, amb alguna excepció, són millor predites pel RNG k-epsilon. Aquest model generalment requereix majors temps de càlcul. El k-omega reprodueix correctament els fenòmens sota estudi, tot i que la seua precisió és generalment més baixa que la dels models k-epsilon. Pel que fa la comparació entre enfocaments VOF i codis, és impossible determinar quin és el millor. Per exemple, OpenFOAM, emprant el Partial VOF, aconsegueix reproduir l'estructura interna del ressalt hidràulic i totes les variables derivades millor que FLOW-3D, emprant el TruVOF, tot i que aquest últim pareix capturar millor la transferència de quantitat de moviment i, per tant, totes les variables derivades. En el cas del flux en sobreeixidors esgraonats, OpenFOAM captura millor els perfils de velocitat, tot i que FLOW-3D és més precís en estimar els perfils de làmina lliure d'aigua. Cal deixar palès que ni tan sols la seua resposta a certs paràmetres del model és comparable. Per exemple, FLOW-3D és significativament menys sensible al refinament de malla que OpenFOAM. En base a la precisió dels resultats obtinguts en tots els casos, el model proposat és completament aplicable a casos de disseny més complexos, on vassos esmorteïdors, sobreeixidors esgraonats i estructures hidràuliques en general han de ser investigades. / Bayón Barrachina, A. (2017). Numerical analysis of air-water flows in hydraulic structures using computational fluid dynamics (CFD) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90440 / TESIS

Hlavním cílem této práce je seznámit se s požadavky specifické procesní aplikace a návrhem výměníku tepla s křížovým tokem pracovních látek a zhodnotit návrh předmětného výměníku pomocí simulačního softwaru. Nejprve jsou v práci prozkoumány provozní podmínky rekuperace odpadního tepla a obecné možnosti návrhu a jsou uvedeny základní rovnice pro tepelný a hydraulický výpočet. Hlavní část práce se zaměřuje na modulární trubkový výměník tepla s křížovým tokem pracovních látek navržený pro experimentální výzkum rekuperace tepla a zanášení ze znečištěných spalin produkovaných spalováním alternativních paliv na VUT v Brně (VUT) na Ústavu procesního inženýrství (UPI). Nejprve je stručně představena situace v testovací laboratoři. Poté je popsán postup návrhu předmětného tepelného výměníku pomocí softwaru HTRI a výsledky jsou shrnuty a porovnány s cílovými požadavky. Následně je analyzována distribuce toku vody v trubkovém prostoru uvnitř jednoho ze čtyř identických modulů výměníku tepla užitím softwaru CDF pomocí tří různých simulačních přístupů. Jsou popsány dva přístupy využívající model turbulence k--SST a jeden přístup využívající model turbulence k--Realizable turbulence. Nakonec jsou diskutovány rozdíly mezi přístupy a výsledky simulací distribuce toku.

Purpose of this thesis is to check influence of turbulent model used for simulation of flow close to primary elementi inserted into piping. The goal is to check if results computed by these models are equal and how precise is their prediction.

Ce mémoire met en perspective plusieurs facteurs de risque en matière de santé et sécurité au travail (SST) qui sont importants pour les travailleurs, soit la formation SST (pas toujours adéquate, pertinente ou suffisante), le peu d’expérience des jeunes travailleurs, le fait de travailler dans de petites et moyennes entreprises du secteur de la construction et de la fabrication connexe, tout en tenant compte des impératifs imposés par la pandémie liée à la COVID-19. La recherche vise à identifier et à explorer les facilitateurs et les obstacles à la formation SST en entreprise dans ce contexte bien particulier. Pour ce faire, des entretiens ont été réalisés avec des jeunes travailleurs de ce secteur d’activité (n=6), des gestionnaires des ressources humaines (n=3) des trois entreprises participantes et un formateur (n=1) du cours Santé et sécurité générale sur les chantiers de construction. Les guides d’entrevues ont été développés pour discuter des facteurs individuels, organisationnels, liés à la formation et temporels jugés les plus pertinents dans des concepts théoriques et des modèles liés à la formation. En général, il semble que les jeunes travailleurs des secteurs de la construction sont sensibilisés aux enjeux et à la formation SST, et plus enclins à acquérir ces connaissances que les travailleurs plus expérimentés. Cependant, les jeunes travailleurs peuvent plus difficilement imaginer l'application concrète d'une nouvelle connaissance SST, et ainsi adopter un comportement sécuritaire en conséquence, en raison de leur expérience plus limitée et leur connaissance plus restreinte de la tâche. Dans l’ensemble, on constate que les travailleurs sont plus ou moins indifférents pour ce qui est de la SST et s’y conformeraient sans se poser de questions; ils auraient aussi la perception que la SST pourrait être améliorée, sans toutefois préciser la façon dont cela pourrait se faire. Cependant, ceux qui s’y intéressent auraient davantage tendance à mieux effectuer les tâches assignées de manière sécuritaire. Ceci soulève également l’importance de sensibiliser chaque travailleur à l’importance de sa tâche individuelle, qui se répercute sur l’ensemble des autres travailleurs et de l’organisation. Quant à l'application des mesures sanitaires liées à la COVID-19, à l’exception d’un répondant, tous les travailleurs participants ont jugé que la formation était pertinente et qu'ils savaient appliquer ces mesures dans leurs tâches quotidiennes et cela relativement facilement. / This master’s thesis puts into perspective several occupational health and safety (OHS) risk factors that are important to workers, namely OHS training (not always adequate, relevant or sufficient), the lack of experience of young workers, working in small and medium-sized companies in the construction and related manufacturing sector, while taking into account the imperatives imposed by the COVID-19 pandemic. The objective of the research is to identify and explore the facilitators and barriers to company-based OHS training in this particular context. To do this, interviews were conducted with young workers in this sector of activity (n=6), human resources managers (n=3) from the three participating companies, and a trainer (n=1) of the Santé et sécurité générale sur les chantiers de construction course (General Health and Safety on Construction Sites course). Interview guides were developed to discuss the individual, organisational, time-related and training-related factors identified as most relevant in theoretical concepts and models related to training. In general, it appears that young workers in the construction sectors are aware of OHS issues and training, and more willing to acquire this knowledge than more experienced workers. However, it is more difficult for young workers to imagine the concrete application of new OHS knowledge, and thus adopt safe behaviour accordingly, due to their more limited experience and knowledge of the task. Overall, workers were found to be more or less indifferent to OHS and would comply without question; they would also perceive that OHS could be improved, but would not specify how this could be done. However, those who were interested were more likely to do their assigned tasks in a better and safer manner. This also raises the importance of making each worker aware of the importance of his or her individual task, which has an impact on all other workers and the organisation. With regard to the application of health measures related to COVID-19, with the exception of one respondent, all participating workers felt that the training was relevant and that they knew how to apply these measures in their daily tasks relatively easily.