The main objective of this research project was to develop a new methodology for the assessment of wrought iron structures using a more informed knowledge of the material.A database of tensile test data for wrought iron across the range of all types of structural elements was compiled and analysed to establish the characteristic yield strength for comparison with the value of 220N/mm2 quoted by the UK Highway Standard BD21. It was found that the characteristic yield strength of bar iron is 151N/mm2 and that of plate iron is 187N/mm2.Bending tests of wrought iron beams were conducted to investigate the potential for brittle fracture under static loads, which was observed, and further investigated by conducting Charpy impact tests, where it was found the that ductile to brittle transition temperature of the metal lies in the range 20 to 80oC, whereas that of mild steel, is typically in the range -30 to 10 oC.A new assessment method was proposed that incorporates a 'quality factor' and a 'component significance factor' into the definition of design yield strength. Comparative studies using the proposed method and the existing method were conducted on a trussed highway bridge, a long span iron roof to a railway station and the Clifton Suspension Bridge. The newly obtained lower values of characteristic yield strength tend to dominate the final design strength value of a component, but this may be improved by the expansion of the database. Furthermore, the inclusion of the quality and significance factors offset this effect and their inclusion was validated by proving that a safe yet not overly conservative design yield strength may be established by application of the proposed method.

Historic truss bridges are examined in this thesis through material characterization of wrought iron and structural evaluation of an early 20th century pony truss bridge. The mechanical properties of wrought iron from six 19th century truss bridges were evaluated through mechanical testing that includes hardness and tension tests. The main findings of this work are: 1) That hardness is a poor predictor of yield and ultimate stress but has some ability in screening iron for iron with low ductility, 2) there is a statistically significant difference in the distribution of yield and ultimate stresses between material samples from different bridges, and 3) that a size effect is present in the material that results in lower yield and ultimate stresses for larger members. Load tests were conducted on an early 20th century pony truss bridge where member axial strains and truss deflections are measured, which were then simulated in computer models. The key observations are: 1) that connection type between truss members has little effect on computer model results, 2) that a significant difference was observed between measured axial forces and those predicted in the computer models for certain members, and 3) that although the bridge response is best modeled with a pin-roller support condition, compressive forces measured in the bottom chord members from temperature change indicate the supports have some lateral resistance, thus are not a true pin-roller.

No description available.

L’art de la Serrurerie en Bretagne aux XVIIe et XVIIIe siècles met en lumière l’art du fer forgé, un domaine des arts décoratifs aux confluents de ceux de l’architecture, du mobilier et de l’ornement, devenu, au fil du temps, la « Cendrillon des arts ». Les recherches en archives et les enquêtes sur le terrain inédites ont été menées sur les cinq diocèses (Finistère, Côtes-d’Armor, Morbihan, Ille-et-Vilaine et Loire-Atlantique) qui composent la province de Bretagne avant la Révolution et ont donné lieu à une synthèse historique et artistique développée sur trois axes. La première partie analyse le cadre d’origine et l’évolution des communautés de serruriers en Bretagne à partir de l’étude des chartes et des statuts et de leur application. La deuxième partie s’intéresse à la connaissance de l’individu-serrurier dans son environnement socio-familial, mais également à travers sa formation artisanale et les étapes marquantes de sa vie professionnelle (apprentissage, compagnonnage et maîtrise). La troisième partie examine les commanditaires, le processus de la commande et la production des œuvres – clef, serrure, grille, heurtoir, balcon, rampe…- depuis l’atelier jusqu’aux édifices bretons où certaines d’entre elles demeurent encore. Le catalogue des œuvres ainsi que le dictionnaire biographique (1200 notices) illustrent et proposent des outils documentaires complémentaires à l’étude sociale et culturelle ainsi qu’à l’histoire du goût afin de contribuer à la redécouverte des serruriers bretons tout autant que de leurs œuvres pendant une période considérée, en France, comme l’âge d’or du fer forgé. / The Art of Locksmithery in Britany in the 17th and 18th centuries highlights the art of iron forged – a section of the decorative arts in between architecture, furniture design and ornament that has become the “Cinderella of arts” over the ages.Records based research and on-site investigations were conducted in five dioceses - Finistère, Côtes-d’Armor, Morbihan, Ille-et-Vilaine and Loire-Atlantique, which Britany included before the French Revolution- and resulted in a synthetic essay about history and art. The first part analyses the original background and the evolution of the community of locksmiths in Britany from the study of charters, statuses and their application. The second part presents individual locksmiths in their social and family environment as well as through their training as craftsmen with the main steps of their professional life – apprenticeship, companionship and mastering. The third part deals with the contractors, the ordering process and the creation of pieces of work - key, lock, knocker, grille, balcony, bracket, lectern... - from the workshop to the Breton buildings, a few of which still feature some of those creations.The works catalogue and the biographical dictionary (1200 entries) illustrate and offer other documenting tools for further social and cultural studies and knowledge of design history in order to contribute to the rediscovery of Breton locksmiths and their works over a period regarded as the French golden age of ironwork.

Le patrimoine ferroviaire français comporte de nombreux ponts métalliques, principalement construits au cours de la seconde moitié du XIXème siècle. Ces ouvrages d'art sont donc en service depuis plus d’un siècle et nécessitent une politique de maintenance adaptée. En collaboration avec SNCF Réseau, cette thèse de doctorat apporte des éléments de compréhension sur le comportement mécanique des assemblages rivetés à chaud sous sollicitations monotones et cycliques. Une stratégie expérimentale a été mise en oeuvre afin d'identifier les mécanismes de ruine des assemblages rivetés. Dans un premier temps, le matériau objet de cette étude, un fer puddlé, a été extrait d'éléments provenant du pont sur l'Adour à Bayonne (1864-2013). Ce matériau a été notamment caractérisé sous chargements monotones et cycliques ; sa fragilité, son anisotropie et son comportement dispersif ont été mis en évidence et analysés. Des outils numériques ont été développés pour l’étude microscopique de cette famille de matériaux. Des éprouvettes rivetées de type détail constructif ont par la suite été conçues, fabriquées et testées sous chargements monotones et cycliques. Un scénario précis du fonctionnement et de ruine d'un assemblage mono-rivet en double recouvrement a pu être identifié. Pour cela, les influences des caractéristiques matériau, des concentrations de contraintes, du cisaillement du rivet et de l'effort de serrage ont été étudiées. Les résultats de ce travail, comparés à ceux de la littérature et aux standards de dimensionnement des structures métalliques, montrent la complémentarité d'une étude à plusieurs échelles (comportement matériau et étude locale du fonctionnement des assemblages) dans le but de comprendre et estimer le comportement des structures rivetées anciennes. / Numerous metallic bridges can be found in the French railway heritage. Since a majority of these structures was built during the second half of the 19th century, they have been in service for over a hundred years and need an adapted maintenance policy.These doctoral thesis, done in collaboration with SNCF Réseau, improves the understanding of the mechanical behaviour of hot riveted assemblies under monotonic and cyclic loadings. An experimental strategy was proposed and carried out in order to identify the failure mechanisms of riveted assemblies. First, the studied material, a puddled iron, was obtained from recovered elements from the bridge over the Adour river in Bayonne (1864-2013). Mechanical testing and characterisation was performed under monotonic and cyclic loadings. Puddled iron’s brittle, anisotropic and scattered behaviour was observed and analysed. In-house software applications were developed in order to study this kind of material. Additionally, hot riveted specimens (constructional details) were designed, manufactured and tested under monotonic and cyclic loadings. A precise working (and failure) scenario of the double shear mono-rivet assembly was identified. The influence of the material’s behaviour, stress concentrators, shearing of the rivet and clamping force of the rivet were studied. The results obtained during these research works, compared to the ones found in academic literature as well as construction norms for metallic structures, showed the importance and complementarity of a multi-scale approach (material behaviour and local study of assemblies) in order to understand and assess the behaviour of ancient riveted structures.