Il ne subsiste aucun vestige direct des charpentes grecques et, bien souvent, l’état de conservation des blocs constitutifs des parties hautes des édifices est lacunaire. Ce constat conduit souvent à la reproduction du cadre interprétatif des charpentes antiques établi à la fin du XIXe siècle, opposant charpente grecque à empilement d’une part, et charpente romaine à ferme d’autre part. L’enjeu de cette thèse consiste à reconsidérer cette opposition binaire entre deux types de charpente. Afin de pallier le manque de vestiges archéologiques, d’autres pistes sont explorées. Les techniques utilisées dans la réalisation des charpentes ne sont pas toutes spécifiques à cet artisanat. Aussi, élargir le champ d’investigation à des activités connexes relevant de l’artisanat du bois comme, par exemple, la construction navale, permet de définir les contours d’un environnement technique dans lequel s’inscrit la charpente. Plusieurs traits caractéristiques de cet environnement technique ont été dégagés, parmi lesquels la maîtrise d’assemblages permettant la reprise d’efforts de traction, le recours à la triangulation des structures et un grand savoir-faire dans la taille des pièces de bois. À la suite de ce réexamen des connaissances pratiques et techniques des charpentiers grecs, une série d’études de cas est proposée, incluant l’arsenal du Pirée, les temples doriques de Sicile, le Parthénon, ainsi que le temple en calcaire et le temple d’Apollon du IVe siècle à Delphes. Les comptes de construction de ce dernier édifice, très riche concernant le matériau bois, font par ailleurs l’objet d’une analyse systématique. Enfin, sur le plan méthodologique, cette thèse aborde la question de la restitution des parties hautes. Le recours à la modélisation 3d et au calcul de structure permet de formuler des hypothèses neuves et d’en évaluer la pertinence dans un mouvement de va-et-vient entre les vestiges, les techniques et le comportement mécanique des charpentes. Les principaux résultats de cette thèse concernent la caractérisation de l’environnement technique dans lequel évoluent les charpentiers grecs des VIe et Ve siècle et conduisent à considérer comme pertinente l’hypothèse de l’existence de charpentes triangulées. / There are no direct remains of Greek roof structures and, in many cases, the state of conservation of the constituent blocks of the upper parts is incomplete. This observation often leads to the reproduction of the interpretative framework of antique roof frameworks established at the end of the 19th century, opposing Greek prop-and-lintel on the one hand, and Roman truss on the other. The challenge of this thesis is to reconsider this binary opposition between two types of framework. In order to compensate for the lack of archaeological remains, other avenues are being explored. The techniques used in the construction of the roof structures are not all specific to this craft. Also, extending the scope of investigation to related activities in the field of woodworking such as, for example, shipbuilding, makes it possible to define the contours of a technical environment in which the framework is embedded. Several characteristics of this technical environment were identified, including the use of assemblages that allow the recovery of tensile forces, the use of triangulation of structures and a great deal of know-how in the preparation of wooden beams. Following this review of the practical and technical knowledge of Greek carpenters, a series of case studies are proposed, including the Piraeus Arsenal, the Doric temples of Sicily, the Parthenon, as well as the so-called “limestone temple” and the fourth century BC Apollo templein Delphi. The construction accounts of this last building, which is very rich in wood materials, are also systematically analysed. Finally, from a methodological point of view, this thesis addresses the question of the restitution of the upper parts. The use of 3d modelling and structural calculation makes it possible to formulate new hypotheses and evaluate their relevance in a back and forth movement between the remains, techniques and the mechanical behaviour of the structures. The main results of this PhD dissertation concern the characterization of the technical environment in which Greek carpenters of the sixth and fifth centuries BC evolve and lead to consider as relevant the hypothesis of the existence of triangulated roof structures.

The following project work studies trusses and roof structures and their performance during a fire in terms of rules and requirements that needs to be considered. Determination of how resistant truss or roof construction is still heavily dependent on the subjective experience and assessment of professional. It means that nowadays stages of this defining of fire resistance of roof/truss are still in need of clarification. The load combination for accidental load is compared to the ultimate limit state during the fire and it was showed that the loads were lower. The strength of timber during the fire was calculated by the two methods. Calculations by both methods revealed that timber used in construction can withstand fire by 0 minutes. However, fire resistance of the wooden materials can be improved by different techniques that were described in this study. The biggest improvement of fire resistance can be achieved with the help of covering - gypsum boards and rockwool, or even with wooden covering if lower protection is needed. As well, many fire-retardant treatments were developed that can improve wood performance during fire by slowing down the spread of fire, by limiting the building up of smoke and other volatiles. Instead of fire-retardant treatment fire retardant paints can be used too. This study showed stages of establishing fire requirements of wooden roof structures by two examples. In this study, two calculations were performed for two different house types, a family house, and an apartment building, to compare the difference between normal load dimensioning and fire load dimensioning. In the fire load dimensioning method, two different times were considered - R30 and R60 load capacity. When calculating the normal load dimensioning, it has been shown that an unprotected truss has no fire resistance, and that the truss has a fire resistance, with respect to bearing capacity, which corresponds to R0, which means that it must be protected for the required time. / Samhällsbyggnad / Husbyggnad / Konstruktion

Falls continue to be a major problem in the residential construction industry and account for a large number of injuries and fatalities each year (US Department of Labor, 2012).  The effects of a fall are catastrophic to the workers and their families as well as the construction company and surrounding community.  Prevention of these incidents has been the primary focus of organizations such as the Occupational Safety and Health Administration (OSHA).  To reduce the number of falls on residential construction sites, OSHA has put forth several standards that require the use of fall protection.  Although guidelines have been provided, there have been concerns and complaints regarding the standards as well as methods and materials that should be used. The goal of this research was to measure the behavior of a five truss roof system with various anchor points and bracing configurations loaded by a horizontal force.  A lab built roof system was used to test three different anchor types with three forms of temporary bracing.  The materials and methodology used in this testing were based on common materials and practices currently used in the residential construction industry. The results of this research show that anchors must engage multiple trusses to spread the applied load throughout the roof system.  Several forms of temporary bracing such as lateral, diagonal, and sway bracing, are also required to strengthen the roof system allowing it to withstand an applied load. / Master of Science

Under the direction of the Federal Highway Administration the Long Term Bridge Performance Program (LTBP) selected Minnesota Bridge number 5718 as a pilot bridge for evaluation. This program focuses on the monitoring of bridges for a 20-year period to understand the structural behavior over time due to the various loads and weathering. In monitoring this bridge a better understanding can be acquired for the maintenance issues related to the nation's deteriorating bridge infrastructure. Bridge Number 5718, which is located just outside of Sandstone Minnesota, is a steel truss bridge that spans the Kettle River. Constant monitoring of the bridge along with periodic testing of the bridge will allow for the collection of data over a 20-year period. The focus of this work is to establish a baseline for the bridges characteristics through nondestructive dynamic testing. Later tests will be compared to these results and changes can then be tracked. In order to perform the required testing, two electromagnetic shakers were used to produce the excitation. The bridge was also outfitted with an array of velocity transducers to allow for the response to be recorded. The data was then used to extract the resonant frequencies, mode shapes, and damping ratios. A modal assurance criterion was also performed to solidify the findings. These parameters define the structural identity of the bridge. Through performing these tests the database that is being collected under the Long Term Bridge Performance Program will be used to better the overall health and safety of the nation's bridges.

The aim of the diploma thesis is a design and an assessment of steel structure of Sports hall. The load-bearing structure consists of arched truss girders. Model dimensions are 55 x 45 m. The arched girders are simply supported to the foundation. The girders are connected with the purlins and the girts. The stability of the structure is provided by lateral and longitudinal bracings.

This thesis deals with design and static assessment of steel structures buildings for storage purposes. The work contains a static calculation performed by software Scia Engineer, manual examination of selected bars and drawings proposed design solution.

Diploma thesis describes the design of roofing for the monastery Rosa Coeli. The initial thought to perform the revitalization of this complex via this way was formed after an exhausting research. At its current state, the Rosa Coeli is sought after and is very popular among tourists; however, as an object, it has a fairly limited impact to everyday life of residents of the city Dolní Kounice. The roofing will, understandably, change the character of the building. As such, it will be usable during the entire course of the year – not only for one-off events. The construction of the timber roof truss consists from solid features, where the chief endeavor was to preserve the unique genius loci.

No description available.

In single storey industrial buildings, the most common material used for the load-bearingsystem is steel. The load bearing system can be designed in different ways. The two mostcommon load-bearing systems of steel industrial buildings are portal frame and thetruss/pillar-system. The benefit of using these systems is the possibility of having largespan structures. These systems have also a high load capacity in function of its weight.Geometrical parameters like width, height, length, and roof slope of the building effectsthe design and the selection of which load-bearing system will be more suitable.The purpose of this thesis is to compare the two systems in terms of weight of steel, priceand global warming potential (GWP) and to see how the load-bearing systems differ. Tofulfil the purpose, it is necessary to find the geometrical parameters to design an optimalportal frame system and use the same parameters in order to design the truss/pillarsystem. By using the same geometrical parameters, the two systems can be comparable.The results of this thesis show that the truss/pillar system has less weight, lower price andlower global warming potential than the portal frame.As conclusions of this parametrical study, it was seen that the truss/pillar system isperforming better than the portal frame system. In general, it is not possible to say that thetruss/pillar-system is better. This is because this thesis work did not consider amongstithers the bracing system, foundation, connections, mounting or fabrication. But it ispossible to say that the differences between the two systems are not major.

This document will outline the findings of three separate and independent studies: Study 1: In or around 1972, an experimental building was constructed. One of the intents of the construction project was to demonstrate advancements in wood building construction design. It was value-engineered throughout. That is, its materials and systems were intended to function at or near design capacity. In 2019, part of the roof of the structure collapsed. This case study investigates two potential factors that led to the failure: stress concentration in excess of the 12 allowable stress for 2 × 4 web members and insufficient plywood sheathing to support live loads 13 caused by large rain events. Study 2: As a building material, cross laminated timber (CLT) has exponentially grown in popularity recently. Although performing superior to numerous other popular building materials, a consistent issue presented in wood construction is the effect of moisture on performance. This study looks to investigate the effect of moisture content on the performance of a 2-way dowel type fastener system loaded in shear perpendicular to the major strength axis. It was found that the peak load capacity of the specimens was not affected by the moisture content of the CLT. However, yield strength increased as the moisture content decreased. Lastly it was found that the failure mode changed from ductile to brittle as specimens became drier than 12% moisture content by mass. Study 3: Inherently, the weak point of any structure is the connection system. This phenomenon is particularly apparent in wooden structures as dowel type fasteners place tremendous amounts of stress perpendicular to the grain of the wood, as well as shear stress under the bolt. In hopes of mitigating this behavior, fiberglass reinforcement of these samples is examined to see if both failure mode as well as overall performance of these fasteners could be improved with reinforcement. It was found that fiberglass significantly reduced the standard deviation of failure strength of fasteners, significantly increased the overall strength of the fasteners, increased the efficiency of the fasteners, and finally increased the probability of bearing failure opposed to block shear failure.