Dissertations / Theses on the topic 'Snow loads'

A well structured computer program has been developed to perform geometrically nonlinear finite element analysis of space trusses and to study the sensitivity of parallel lamella dome under wind and snow loads. The modified Riks/Wempner method is used to perform the prebuckling and postbuckling analysis. The European Convention for Constructional Steelwork (ECCS code) is used as the code of practice for design wind pressures on domes. Failures of domes have occurred during snow storms and have attributed to heavy local snow concentrations. Most codes of practice do not provide design wind and snow loads for domes, and a few international codes do show significant differences in the distributions of design wind pressure for domes. Moreover, current design practices for domes do not reflect the possibility of heavy local snow concentrations. Since wind load data is widely varied among the codes, and specific information on local snow concentrations is not available, the study of the behavior of a full-size lamella dome under different wind pressures and various snow distributions will be carried out with the finite element analysis, and critical load combinations will be obtained with the aid of stability boundary. The proposed study is expected to provide guidelines for the determination of critical wind and snow load conditions.
M.S.

A computer program for the analysis of loads on buildings is developed. The program determines wind loads, earthquake loads, and snow loads according to the ASCE 7-93 Standard Minimum Design Loads for Buildings and Other Structures (ASCE 7-93). The program is developed using the object-oriented programming methodology and runs on the Microsoft Windows 95 graphical environment. It is a valuable and useful tool for determining loads on buildings.
Master of Engineering

A structure comprised of two arches that lean against each other at the apex is considered. The arches are thin shells with internal pressure. This type of structure with solid arches has been used in bridges, such as the Gateway Arch Bridge in Columbus, Indiana, U.S.A., the Monongahela River Bridge in Pittsburgh, Pennsylvania, U.S.A., and a pedestrian bridge at the Pacific Tower in Paris, France. A series of leaning arches was incorporated in the frame of the Museum of the Moving Image, a temporary structure in London, England, during 1992-1994. Pressurized arch-shells made of a flexible material have been utilized as part of the framework for some transportable tent-like structures.

The behavior of a pair of pressurized leaning arch-shells with various tilt angles, boundary conditions, and loads is investigated numerically. Several types of loads are considered, including uniformly-distributed vertical loads applied over all or half of the structure (representing snow), and wind loads on the structure. The arches are pinned or fixed to the ground. Deflections, vibrations, and stability of the structures are investigated using the finite element method. The effect of the tilt angle on the response is examined, and buckling may occur for some tilt angles under vertical loading. This type of structure has not been used widely, but may be effective for various applications.
Master of Science

Purpose: When introducing new construction standards arises some uncertainties due to overlapping with the old construction standards. Because of these uncertainties’ roofs have collapsed due to excessive snow loads. To ensure a safe workplace for companies responsible for snow removal, accepted means in connection with snow removal and the work environment will be studied. The final goal is to find and study new methods to make the work safer and more efficient. Method: The work contains both qualitative and quantitative data. The method is a case study with the data collection techniques measurement, observation, personal communication and document and literature study. All of these are necessary to be able to answer the questions and achieve the goal. Findings: The techniques used today regarding snow removal give a good result, but the majority are very time-consuming and risky for the employers who perform the work on the roofs. Several new techniques and means have been described that would be able to perform the same work in a more efficient and sustainable way seen from a work environment point of view. Implications: To limit the time spent on the roof would contribute to a safer workplace. Today there are several means and techniques that after being installed, can operate, and remove snow on its own. This would be safe and efficient. The only danger for the staff is when installing and maintenance. Limitations: The report is limited by the fact that not all types of roofs have been examined. The study focuses on roofs that are within a snow zone of 2.5 kN/m2 or lower. Keywords: Snow removal, working environment, low-sloping roofs, handle snow loads.
Syfte: Överlappningar när nya konstruktionsregler tagits fram har skapat osäkerhet kring dimensioneringar och tyvärr lett till att takras uppstår på grund av allt för stora snölaster. För att skapa en tryggare arbetsplats för företag som ansvarar för snöröjning kommer vedertagna hjälpmedel och tekniker i samband med snöröjning och hur arbetsmiljön ser ut vid pågående arbete studeras. Slutligen är målet att studera nya metoder som bidrar till ett effektivare och säkrare arbete. Metod: Arbetet består av både kvalitativa och kvantitativa data. Metoden som användas är fallstudie med datainsamlingsteknikerna mätning, observation, personlig kommunikation och litteraturstudie. Alla datainsamlingsteknikerna är nödvändiga för att kunna besvara frågeställningarna och uppnå målet. Resultat: Teknikerna som är vedertagna idag gällande snöröjning ger ett bra resultat men majoriteten är mycket tidskrävande och riskfyllda för personer som utför arbetet. Främst när det gäller arbetsmomenten som utförs uppe på tak. Flera nya tekniker och hjälpmedel har redovisats som skulle bidra till att företag kan utföra samma arbete på ett sätt som anses betydligt effektivare och mer hållbart ur arbetsmiljösynpunkt. Konsekvenser: Ett minskat arbete på tak skulle bidra till en säkrare arbetsplats. Det finns flertalet tekniker och hjälpmedel ute på marknaden som efter viss installation skulle kunna utföra snöröjningen på egen hand, vilket innebär en effektivisering. Detta innebär också att den enda risken som finns för personal är vid installation och underhåll och därmed är arbetsmiljön så säker som är möjligt. Begränsningar: Rapporten begränsas av att inte alla typer av tak undersökts. Studien fokuserar på tak som finns inom snözon 2,5 kN/m2 eller lägre. Nyckelord: Snöröjning, arbetsmiljö, låglutande tak, hantering snölaster.

Because of the new introduced snow loads a higher demand is applied on buildings in Jonkoping area. The reason that the value has increased is partly because new load combinations that is applied on dimension equations but also because of the intensified precipitation. Additional reasons to the updated standards are that several roofs with large spans have in recent years collapsed in Sweden. When using design equations on existing constructions, new standards must be applied, whether if the structure is further back designed with older standards. Due to the case, the new standards result in an increased dimension value; therefore strategic considerations must be done in case of reconstruction. The purpose of the report is to highlight the differences that occur when calculating loads and design. In case of reconstruction of an old construction, basically two options can be done. Either carry through the reconstruction and possibly enhance the strength of the construction at large costs or choose not to perform the extension. If the latter option is made it may result in; annual costs of clearing snow of roofs, the risk of roof collapse or even denied access rights to all, or parts of the building. These options must be analysed with consideration to strength and costs to result in a good solution.

One critical consideration in the design of buildings constructed in the western United States is the weight of settled snow on the roof of the structure. Engineers are tasked with selecting a design snow load that ensures that the building is safe and reliable, without making the construction overly expensive. Western states use historical snow records at weather stations scattered throughout the region to estimate appropriate design snow loads. Various mapping techniques are then used to predict design snow loads between the weather stations. Each state uses different mapping techniques to create their snow load requirements, yet these different techniques have never been compared. In addition, none of the current mapping techniques can account for the uncertainty in the design snow load estimates. We address both issues by formally comparing the existing mapping techniques, as well as creating a new mapping technique that allows the estimated design snow loads to be represented as an interval of values, rather than a single value. In the process, we have improved upon existing methods for creating design snow load requirements and have produced a new tool capable of handling uncertain climate data.

A pressurized arch-shell structural component made of flexible material is considered. The component is inflated with high internal pressure. The behavior of similar types of structures, such as a pair of leaning pressurized arches and pressurized arch-supported membrane shelters, has been investigated in the past. More recently, several types of pressurized structures have been incorporated as part of the framework for a variety of structural systems. Particularly, the U.S. Army has been investigating the use of large lightweight and transportable pressurized arch-shell structures to be used as maintenance shelters for vehicles, helicopters, and airplanes. The formulated equations using thin shell theory are applied to a pressurized arch-shell component. A numerical investigation based on the Rayleigh-Ritz method is utilized to determine the behavior of arch-shells under various types of loading. The types of loading include a uniformly distributed vertical load representing snow, a wind load, and a horizontal side load distributed along the arc length. Deflections, stress resultants, and moments at various locations are computed for two types of shapes: circular and non-circular arch-shells.
Master of Science

Snow deposited in urban areas is exposed to pollutants originating from traffic, wet and dry atmospheric deposition, de-icing chemicals and traction materials. The conventional pollutants found in urban snow include solids (TSS), metals (Zn, Cu, Cd, Pb, etc.), Polycyclic Aromatic Hydrocarbons (PAHs), and chlorides. Microplastics (MPs) are emerging pollutants of interest and their presence in urban snow was reported only recently. The pollutants accumulate in snow deposits over time and may be released when snow melts, and the resulting snowmelt may carry pollutants to the receiving waters. Understanding the concentrations and mass loads of pollutants in snow and pollutant behaviour during snowmelt is helpful for planning and developing site-specific snow management practices. The overall aim of this thesis was to evaluate the quality of snow in urban areas, with respect to: (i) quantity of metals, PAHs and MPs in urban snow storage piles and roadside snowbanks, (ii) compare the quality of snow collected in the same catchment during repeated sampling campaigns and evaluate the effect of the sampling design on estimation of pollutant loads in snow piles, and (iii) investigate the pollutant release patterns and temporal variations in their concentrations in water leaving the melting snow piles (in laboratory). For such studies, snow samples were collected from snow storage piles in Frihamnen (a port facility in Stockholm, Sweden) and roadside snowbanks in Luleå and Umeå cities in Northern Sweden. The quality of snow collected in the three study areas varied considerably, because of differences in such area characteristics as the annual precipitation and snowfall, the population, average daily traffic, land use activities, and snow management activities. The average values of major parameters in analysed snow samples were as follows: TSS - 1500 mg/L, conductivity- 2.1 mS/cm, Zn – 870 µg/L, Cu – 240 µg/L, Cd – 0.48 µg/L, Cr – 120 µg/L, Pb – 50 µg/L and the sum of 16 PAHs – 3.5 µg/L. Microplastics were abundant in urban snow samples, with the following descending order of concentrations: black road wear particles, consisting of bitumen and tire wear particles,  mean = 19300 ± 47400 particles/L; road marking paints with the mean of 430 ± 998 particles /L; and, plastics particles, mean 33 ± 34 particles /L. No correlations were found between the numbers of MP particles and the site-specific parameters. Comparison of snow pile sampling designs revealed that systematic 1-m square grid sampling yielded the best estimates of mass loads (BEML) of pollutants, compared to single snow cores, or horizontally composed core samples. The mass loads estimated from composite or single snow column sampling deviated up to 50 and 400%, respectively, from BEML. Results of the laboratory snow melting indicated that PAHs in the snow samples were mostly attached to the particles; only 10% of the total PAHs burden was contributed by the meltwater and the rest stayed on the ground with the sediment residue. The dissolved concentrations of PAHs were below the detection limit (0.010 µg/L) in all the analysed samples except for Fluoranthene and Pyrene with concentrations ranging between 0.01 and 0.02 µg/L. PAHs displayed a delayed release from snow piles, which was similar to that of TSS. Truly dissolved fractions (<3000 MWCO, Molecular Weight Cutoff) of Zn, Cu and Cd represented 71-90% of dissolved fractions in the snow samples collected in Luleå (snow without road salt) and 74-98% in those from Umeå (snow with added road salt). Both dissolved and truly dissolved metals showed advanced releases from all the snow piles. The influence of road salt on releases of metals and PAHs from laboratory snow piles was hard to discern, because of great differences in snow quality characteristics at both locations.

In today's society, companies are trying to find ways to utilize all the data they have, which considers valuable information and insights to make better decisions. This includes data used to keeping track of timber that flows between forest and industry. The growth of Artificial Intelligence (AI) and Machine Learning (ML) has enabled the development of ML modes to automate the measurements of timber on timber trucks, based on images. However, to improve the results there is a need to be able to get information from unlabeled images in order to decide weather and lighting conditions. The objective of this study is to perform an extensive for classifying unlabeled images in the categories, daylight, darkness, and snow on the load. A comparative study between partitional clustering and competitive learning is conducted to investigate which method gives the best results in terms of different clustering performance metrics. It also examines how dimensionality reduction affects the outcome. The algorithms K-means and Kohonen Self-Organizing Map (SOM) are selected for the clustering. Each model is investigated according to the number of clusters, size of dataset, clustering time, clustering performance, and manual samples from each cluster. The results indicate a noticeable clustering performance discrepancy between the algorithms concerning the number of clusters, dataset size, and manual samples. The use of dimensionality reduction led to shorter clustering time but slightly worse clustering performance. The evaluation results further show that the clustering time of Kohonen SOM is significantly higher than that of K-means.

My diploma theisis is focused on design and assessment of structural systém of industrial building in tended for livestock farming. The design is processed in two options. Both oft hem has the same dimensions but cross sections of the supporting elements are changed. Floor plan of the first part is a rectangular shape, dimension is 29,28 m x 24,8 m. Floor plan of the second part is a rectangular shape, dimension is 161,18 m x 46,8 m. Slope of saddle roof is 18°.

The goal of my thesis is the design of a multipurpose sport hall in Litoměřice locality made in two separate variants. Objects ground plan dimensions are 38x38 meters and the height of the object is 16 meters. Used material is S235 steel and C20/25 concrete. The periphery and roof casing of the object is realized from sandwich panels. The carrying construction of the object is made from cross truss, oblong truss and from pillars. Thesis consists of assessing the carrying elements of the construction, selected details and drawing documentation.

It is of interest to investigate extended usability of Saab’s Deployable Aircraft Maintenance facility(DAM) with respect to Eurocode standards. One of the features of the deployable hangar is that it shouldcomply with the structural strength standards for permanent buildings which requires compliance withEurocodes.Eurocodes are European standards which deals with the development of building and structural design.Compliance with Eurocodes works as a proof of requirement for mechanical strength, stability andsafety of structures. The Eurocodes were created by the European Committee for Standardization withthe intent to simplify technical obstacles and enable trade within Europe and elsewhere.The thesis has resulted in the creation of a Finite Element Model (FE-Model) of the deployable hangar,for which different loading combinations have been applied. From the FE-results, trade-off curves havebeen generated that show the effect that the different loading conditions have on the differentcomponents of the hangar. This is done for the current configuration of the hangar and for differentproduct variants. The analysis includes the effects of increased load levels.From the trade-off curves it is possible to see to what extent the hangar can withstand increased load.This is being measured with a Eurocode ratio. It has been found that the Eurocode ratio is directlydependent on increase of loads i.e. increased loads give a linear increase in Eurocode ratio for most ofthe components studied. The product variants consists of different lengths of the hangar. From the studyit has been found that adding or removing sections does not have a substantial effect on the strength ofthe hangar and the Eurocode ratio mostly remains constant. In addition the most critical componentshave been found and design suggestions have been proposed to improve the strength of the hangarwithin compliance with Eurocodes.

The content of the bachelor thesis is static verification and the desing of two options of a roofing of the winter stadium in Olomouc. The object has a rectangular plan of dimension 68 x 100 m, the minimum clearance is given by requirements of the operation of winter sports. Steel construction is made of steel strength class S355. The calculations are made according to valid norms ČSN EN.

Examensarbetet kom som en förfrågan från företaget Northpower stålhallar AB som var i behov av en beräkningsmall för vind- och snölast. Beräkningsmallen utformas i Microsoft Excel och den ska möta de önskemål och krav som tillkommer vid projektering av en hallbyggnad. Beräkningsmallen grundas på en litteraturstudie av vind- och snölast kapitlen i Eurokoderna som inleder den teoretiska delen av rapporten. För att se skillnader mellan stomstabiliseringssystem som vanligen används i hallbyggnader, utfördes en litteraturstudie på vanligt förekommande systemen. En kraftanalys vid olika placeringar av företagets nuvarande stomstabiliseringssystem gjordes med hjälp av den tillverkade beräkningsmallen. Litteraturstudien och analysen sammanställdes till jämförelse av de olika stomstabiliseringssystemen.
The subject of this bachelor thesis was a query from Northpower stålhallar AB that was in need of a calculation model for wind- and snow loads. The Calculation model was created in Microsoft Excel and shall satisfy the requirements for the design of an industrial building. The calculation model is founded on a literature study of Eurocodes wind- and snow load chapters, which initializes the theoretical part of the report. To gain a better understanding of the differences between the different types of bracing systems that is normally used in industrial buildings, we performed a literature study on a selection of the usual systems.  Using the calculation model, a force analysis on different placing’s of the current lateral stability system the company use was carried out. The thesis ends with a comparison of the study and analysis of the different lateral stability systems that’s been studied.

The thesis deals with the design and review of the supporting structure of the exhibition pavilion in the suburb of Brno. The design is shaped dome built over the octagonal floor plan with eight lateral niches. The pavilion is 30m wide and 8 meters tall.

Antal installerade solcellsanläggningar har ökat drastiskt de senaste åren i Sverige, och utsikten för ökad mängd solel i Sverige är mycket god, med prognoser på kraftig tillväxt av installerade solcellsanläggningar de kommande åren. Detta med bakgrund att utvecklingen av solcellspaneler har gjort att priset har sjunkit, samt politiska beslut har gjort det lönsamt att investera i solcellsanläggningar i Sverige. Dessa förutsättningar har lagt grunden för en ny växande bransch, solcellsinstallationer. Risken vid en ny och snabbt växande bransch är att kunskapen inom ämnet för de som är verksamma inom branschen kan vara bristfällig samt oseriösa företag kan lockas av att tjäna snabba pengar på en lukrativ marknad. Efter en omfattande litteraturstudie visades att någon större kvalitésundersökning av solcellsinstallationer i Sverige, med avseende på hållfasthet ej har gjorts tidigare. Detta motiverade att denna undersökning var av hög relevans. Syftet med denna studie var att ta reda på om solcellsanläggningar monteras tillräckligt hållfast i Gävle-Dalaregionen med avseende på snö- och vindlast. Fjorton anläggningar har besökts för att samla in data. Data har sedan utvärderats i tre kategorier per anläggning. För att en anläggning skall bedömas som en godkänd skall alla dessa tre kategorier vara godkända. Bedömningen av solcellsanläggningarna gjordes i de tre kategorierna: 1. montagesystemets antal infästningar, 2. mått mellan infästningarna, 3. placering av solcellspanelerna i förhållande till montagesystemet. Resultatet visade att ingen av dessa anläggningar var godkända i samtliga tre kategorier. Vissa anläggningar var godkända i två av tre kategorier, medan två anläggningar var ej godkänd i någon kategori. Vid en summering av bedömningsresultatet för alla anläggningar i de tre montagekategorierna, visades att ca 20% ej gick att fastställa (pga. bristande information) ca 40% var godkända och ca 40% var ej godkända. Bedömningar har gjorts utifrån beräkningsprogram och anvisningar tillhandahållna av tillverkarna av de montagesystem och solcellspaneler som har använts i anläggningarna. Att ingen anläggning var godkänd i samtliga tre kategorier som undersöktes indikerar att solcellsmontage på tegeltak byggs ej tillräckligt hållfast i Gävle-Dalaregionen. Detta kan dock inte generaliseras för solcellsanläggningar på tegeltak i hela Sverige då mängden undersökta anläggningar var relativt liten och endast fördelade på två län i landet. Då det antas att installatörer avser att bygga korrekta anläggningar visar denna studie att kunskap om solcellsmontage med avseende på hållfasthet är bristfällig. Detta kan vara en följd av den stora efterfrågan på solcellsinstallationer, som kan medföra att stort fokus ligger på att installera anläggningar snabbt, och inhämtning av kunskap ej blir prioriterat.
The number of installed PV-systems (Photovoltaic systems) has increased rapidly in Sweden the last years, and the forecast for even more installations shows an increase for the coming years. Due to the price for PV-panels har dropped and political decisions for subventions of PV-systems has made it more profitable to invest in PV-installations in Sweden. These reasons have paved the road for a new growing branch, PV-installations. The risk of a new profitable, fast growing branch is that there might be short of knowledge for new installers, and the possibility that dishonest companies just want to take the advantage of the situation to make quick money, which can lead to installations poorly made.   After a search of published literature in strength of mounting for PV-panels there the result was that this is a rather unexplored subject, which motivated this investigation.   The aim of this study was to find out if PV-panels on tiled roofs were installed correct due to the snow load and wind load in the region Dalarna and Gävleborg in Sweden.   Fourteen PV-systems has been studied and evaluated. When the evaluation of the PV-systems were made the following criteria were considered: number of fixing attached to the roof of the mounting, distance between mounting fixings and how the PV-panels were installed relative the construction of the mounting. A PV-system had to be installed correctly for all three criterias to be considered approved. The result of this work shows that none of the evaluated systems were installed correctly. Some systems were approved in two of the criteria, while two systems were not approved in any of the criteria. The evaluation was made due to calculation programs and instructions from the manufacturers of mounting and PV-panels.   The fact that none of the PV-systems were approved for all three criteria implies that the installations of PV-systems are not made strong enough. This result is not stated for all installations in Sweden because the number of studied PV-systems were not big enough, and the area of the studied installations were rather small. Basis of snow load and wind load variates quite much in Sweden depending on region. It is assumed that designers and constructors attempt to install PV-systems correct, therefor shows this work that there’s a lack of knowledge for construct installations strong enough. This may be a result of the fast increase of PV-installations, where the priority lays in installing many PV-systems, not in education and search of knowledge.

The aim of this thesis was to develop assessments of existing supporting structure of a rectangular object and design of new options for rectangular and cylindrical object administrative center in the Jihomoravská plynárenská, a.s. in Brno. According to the task have been recalculated construction and design of new structures in accordance with applicable standards. New design of both buildings (rectangular and cylindrical) came from several studies.

Structural design of buildings and infrastructures is significantly influenced by the definition of climatic actions (snow, wind and thermal loads) that the structure shall withstand during its life, which could be significantly greater than the design service life. Therefore, the impact of climate change on climatic actions could significantly affect, in the mid-term future, the design of new structures as well as the reliability of existing ones designed in accordance to the provisions of present and past codes, which are based on the assumption of stationary climate conditions. In this work, a general methodology to derive future trends of snow load on structures is presented aiming to study the influence of climate change at European scale in view of the definition of updated snow maps for the new generation of structural Eurocodes. First, a general algorithm based, on Monte Carlo simulations, is defined to estimate ground snow loads maxima considering daily outputs of the climate models, in terms of maximum and minimum air temperatures and precipitation, supplemented by local information of snowfall and snow melting conditions derived from the elaboration of real measurements of actual meteorological events. Once validated the procedure, reproducing observed data series of yearly maximum ground snow loads, future trends in characteristic values of the load are investigated. Analysing different climate models and scenarios, the relevant issue of uncertainty assessment of climate projections is deeply investigated. In particular, the three main sources of uncertainty affecting climate projections: model uncertainty, scenarios uncertainty and internal variability, are assessed also implementing an innovative ad hoc developed weather generator, able to generate future weather series directly from climate model outputs. Factor of change confidence maps are finally derived combining all the presented results and providing guidance for potential amendments of the current version of snow load maps given in structural Codes.

Plusieurs types de givrages atmosphériques peuvent se déposer sur les lignes aériennes de transport d'énergie électrique incluant la neige collante lourde et adhérente, le givre dur, le givre mou et la glace à haute densité. Des dépôts de neige sur les structures exposées peuvent avoir un impact sur le fonctionnement, la sécurité et la fiabilité mécanique. Plus spécifiquement sur les lignes aériennes de transport d'énergie électrique, les charges de gravité résultant de Paccrétion de la neige lourde combinée aux charges du vent sur la neige peuvent causer des dommages structuraux, une rupture ou même en cascade des pylônes. La chute des dépôts de neige peut appliquer une charge dynamique sur la ligne de transport par les vibrations induites sur le câble et provoquer un effet déstabilisant entre les portées adjacentes couvertes et non couvertes. Ainsi pour protéger les lignes de transport contre les charges résultantes de l'accrétion de la neige sur la ligne et pour assurer la fiabilité des réseaux de distribution électriques, les processus du délestage de la neige doivent être compris et des techniques de prévention comme des méthodes d'antigivrage et de dégivrage doivent être utilisées. Cette étude porte sur l'analyse dynamique des lignes aériennes de transport d'énergie couvertes de neige et soumises à des charges périodiques. De telles charges peuvent être le résultat de l'effet d'une charge périodique externe appliquée pour enlever la neige accumulée sur les lignes ou le résultat d'effets naturels comme le vent ou des charges en déséquilibre conséquentes d'une chute de neige soudaine ou propagé d'une portée adjacente . L'objectif est de comprendre le phénomène du délestage de neige induite mécaniquement sur les portées des câbles aériens et de simuler les effets des charges périodiques sur la chute de la neige collante. Lors d'études précédentes, les réponses de la ligne de transmission aux chutes instantanées ont été modélisées alors que dans cette étude, on étudie la propagation de le délestage de la neige le long de la portée en réponse à une charge périodique. Plus particulièrement, la réponse dynamique des câbles couverts de neige aux charges périodiques est examinée par modélisation mathématique en utilisant une analyse d'éléments finis non linéaires et des études expérimentales en chambre froide. Le modèle numérique peut servir de base à l'étude de critères différents de rupture de la neige collante en ce qui concerne l'adhésion. Pour atteindre cet objectif, on a d'abord étudié expérimentalement l'adhésion en tension et en cisaillement à la surface des câbles. Ceci est essentiel pour mettre en corrélation la chute et la force d'adhésion entre la neige et le câble, puisque le délestage survient lorsque l'adhésion disparaît. Les mesures ont été obtenues en utilisant une machine à essayer le matériel et une centrifugeuse. Puis un critère de rupture de la neige collante a été déterminé et appliqué dans le modèle numérique. Ce modèle simule les vibrations du câble couvert de neige mouillée, par l'application d'une excitation périodique, celui que provoque du processus de chute de neige. L'excitation périodique est modélisée en utilisant une fonction temporelle de déplacement initial à une extrémité du câble, rendant la variation de la fréquence d'excitation possible. Le défi est de prédire si le dépôt va demeurer fixé au conducteur ou s'il va tomber suite à la vibration provoquée. Le modèle considère le délestage de la neige en retirant les éléments de la neige le long du câble, lorsque le critère de rupture est satisfait. Dans l'étude expérimentale, les manchons de neige collante ont été reproduits à échelle réduite en utilisant une technique développée précédemment. Les charges de neige de différentes épaisseurs ont été utilisées sur la portée et les charges périodiques ont été appliquées au point de suspension de façon à initier une vibration du câble et observer le mécanisme du délestage. La similitude des résultats du modèle numérique et ceux des simulations expérimentales à échelle réduite valide le modèle et assure sa fiabilité. Finalement le modèle de neige développé, avec un critère de rupture, est appliqué aux simulations numériques subséquentes des portées simples à échelle réelle soumis à des impacts périodiques. - Several types of atmospheric icing deposits may load overhead cables including heavy adherent wet snow, hard rime, large but lightweight soft rime and high-density glaze ice. Snow deposits on exposed structures can be the source of several serviceability, safety and mechanical reliability issues. On overhead power lines in particular, the gravity loads due to heavy snow accretion, coupled with wind-on-snow loads, may lead to structural damages, or failure and even cascading collapse of towers. The shedding of the snow deposit can apply dynamic loads on the line by the initiated cable vibration and results in unbalanced tension between shed and unshed adjacent spans. Therefore, in order to protect the line against loads resulting as a consequence of accreted snow on the line and to ensure the reliability of electrical power delivery networks, the processes of snow shedding have to be profoundly understood and countermeasures have to be taken, e.g., by applying anti-icing and de-icing methods. This study focuses on the dynamic analysis of snow-covered overhead transmission lines subjected to periodic loads. Such loads may result from the effect of an external periodic load intended to remove accreted snow from the cable, or from such natural effects as wind or load imbalances due to sudden or propagating snow shedding from an adjacent span. The objective is to understand the phenomenon of mechanically-induced snow shedding on overhead cable spans and to simulate the effects of periodic loads on wet snow shedding. In previous studies, the response of the line to instantaneous shedding was modeled, whereas in this research, the propagation of snow shedding along the span as response to a periodic load is studied. In particular, the dynamic response of snow-covered cables to periodic loads is examined by numerical modeling using nonlinear finite element analysis as well as experimentally in a cold chamber. The numerical model can serve as a basis to study various failure criteria of wet snow in terms of adhesion. In order to achieve this goal, first the tensile and shear adhesion of snow to cable surfaces were experimentally studied, which are essential to correlate shedding and the adhesive strength between cable and snow, since shedding occurs after adhesion vanishes. These measurements were carried out using material test machine and centrifuge machine. Then, a criterion of wet-snow failure was determined and applied in the numerical model, which simulates vibrations of the cable covered by wet snow due to application of periodic excitation resulting snow shedding process. The periodic excitation is modeled by an input displacement time function at one cable end, making the variation of excitation frequency possible. The challenge is to predict whether the deposit will remain attached to the conductor or fall off during the resulting vibration. The model considers snow shedding by removing snow elements along the cable where the failure criterion is satisfied. In the experimental study, wet snow sleeves were reproduced on a small-scale span by using a formerly developed technique. Snow loads of different thickness were thus created on this span and periodic loads were applied at the suspension point in order to initiate cable vibration and observe the resulting shedding mechanism. The coincidence of results of numerical model and those of small-scale experimental simulations validates the model and assures its reliability. Finally, the developed snow model with failure criterion is applied in further numerical simulations for real-scale single spans subjected to periodic impact.