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Dans l’histoire de l’industrialisation, la coutellerie est le plus souvent décrite en termes d’échec dans l’adoption des formes modernes de production. Le but de cet article est de discuter les raisons et les circonstances de ce soi-disant « échec ». Selon l’interprétation traditionnelle, les ouvriers et les patrons dans la coutellerie et la métallurgie légère ont été trop conservateurs pour adopter les techniques de la production de masse quand elles furent introduites au xixe siècle. Si cela fournit une explication, ce n’est qu’un pan de l’histoire. Dans ce texte, le développement historique de deux secteurs différents est abordé : les industries de la coutellerie et de la métallurgie légère de Sheffield au Royaume Uni, celles du duché de Berg en Allemagne (Solingen et Remscheid). On insistera sur les facteurs exacts qui ont déterminé la voie suivie dans chaque site et la logique qui sous-tend ce que beaucoup considèrent comme une simple dépendance du sentier ou un conservatisme. On montrera que des facteurs comme l’extrême division du travail, le système domestique et la séparation entre producteurs et marchands sont cruciaux pour expliquer « l’échec » de la coutellerie dans ces villes et ses problèmes à adopter les nouvelles méthodes et techniques de production. In the history of industrialization the cutlery industry is most often depicted as a failure to adopt to modern forms of production. In this paper the aim is to discuss the reasons and circumstances for this alleged “failure”. According to the traditional interpretation the workers and managers in the cutlery and light-metal trades were too conservative to adapt to the new mass production technologies when they were introduced in the end of the 19th century. While this provides a partial explanation it does not present the whole story. In this paper the historical development of two different cases is discussed: the cutlery and light-metal industries of Sheffield in the Unites Kingdom as well as in Bergische land in Germany (Solingen and Remscheid). The focus is more exactly on the factors which determined the path taken in each locale as well as the logic behind what many have seen as the result of mere path dependency or conservatism. It is shown that factors such as an extreme division of labour, the putting-out system and the division between producer and seller were pivotal for the “failure” of the cutlery industry in these localities and its problems to adapt to new production methods and technologies.

Elastic guided waves are of interest for the non-destructive evaluation of cables. Such structures are usually helical, multiwired and highly prestressed, which greatly complicates the understanding of wave propagation from a theoretical point of view. A remarkable feature is the occurrence of a missing frequency band in experimental time–frequency diagrams, sometimes referred to as notch frequency in the literature. The central frequency of this band increases under tensile loads. Recently, a numerical model has been proposed to compute the dispersion curves of prestressed helical seven-wire waveguides. Results have shown that the notch frequency indeed corresponds to a curve veering phenomenon between two longitudinal-like modes and that the increase of the notch under tensile loads is mainly due to interwire contact mechanisms. The main goal of this paper is to highlight the origin of this curve veering phenomenon, which is still unexplained up to the author׳s knowledge. This paper also provides further results which allow us to clarify the accuracy of numerical solutions as well as the influence of contact assumptions. First, the static part of the model, necessary to compute the prestress state including contact effects, is checked from reference analytical solutions. Owing to the importance of contact, the accuracy of results is discussed both in statics and in dynamics. The influence of slip contact conditions is outlined. Then, some numerical tests are conducted by varying the Poisson coefficient and the helix lay angle. These tests allows us to find out that the radial displacement constraint imposed on peripheral wires by the central one in the contact regions constitutes the main source of curve veering. More precisely, it is shown that a similar curve veering does occur for an uncoupled single peripheral wire when constrained by a radially blocked motion localized in its contact zone. Indeed, such a localized boundary condition completely breaks the circular symmetry of the wire cross-section, yielding coupling between longitudinal, flexural and torsional motion together with curve veering phenomena.

After a definition of technical innovation in the Middle Ages and it’s relationship to industry, this paper explores it’s characteristics in the fi eld of iron and silver (silver-bearing lead and copper) metallurgy from the 13th to the 15th centuries in the western Mediterranean area. The exploration opens with a synthesis of the circulation of iron and steel products, with special care taken over the definition of their respective qualities, in particular the distinction between iron and steel; the exploration continues with an introduction to specific technical territories related to industrial “districts”, which allows the author to present the study of the circulation of technical knowledge. The paper concludes with a study of notables (Catalan in particular) as rural entrepreneurs who invested in the technical innovation of their time.[fr] Après avoir défi ni l’innovation technique au Moyen Âge et ses rapports à l’industrie, cet article en étudie les caractéristiques dans les domaines de la métallurgie du fer et de l’argent (plomb et cuivre argentifères) du XIIIe au XVe siècle, en Méditerranée occidentale. Cet examen s’ouvre par un tableau de la circulation des produits sidérurgiques, attentif à la définition de leurs qualités respectives, en particulier à la distinction fer-acier; il se poursuit par la présentation des territoires techniques spécifiques associés à des districts industriels, ce qui permet à l’auteur d’aborder l’étude des circulations des savoirs techniques. L’article se conclut par une étude des notables (en particulier catalans), entrepreneurs ruraux, qui ont investi dans l’innovation technique.

In the framework of sustainable development policies, it is essential that infrastructure owners can rely on effective repair or strengthening solutions, designed and tested in relevance to actual service conditions. In the case of steel structures, fatigue damage is a major concern that can significantly affect the lifespan of the structure, and so far, there are very few operational methods capable of preventing fatigue cracks in the field. Adhesively bonded carbon fiber reinforced polymer (CFRP) composites are being successfully applied to the rehabilitation of concrete structures for more than two decades, and they are currently receiving much interest for the strengthening of steel elements, but mainly for curative purpose after severe damage has occurred. In the present study, which is part of a European project called FASSTbridge, a specific CFRP system has been developed as a preventive method against fatigue damage of steel structures. The proposed system consists of a commercially available ultra-high modulus (UHM) CFRP composite plate compatible with the stiffness of the host steel structures, which is bonded to the steel support using a novel hybrid epoxy/polyurethane adhesive. A first part of the paper presents the main specifications that should be adopted in the design of CFRP strengthening systems applied to steel structures, and that were identified from an extensive literature survey. These specifications have guided the development of the polymer adhesive and the choice of a peculiar commercial CFRP plate in the preliminary phase of the project. Experimental characterizations were then conducted (i) on the formulated hybrid polymer adhesive to optimize its curing schedule and check the previous specifications are fulfilled, and (ii) on CFRP reinforced steel specimens in order to verify the effectiveness of the proposed strengthening system. This experimental program involved both short term and durability tests that were performed by different laboratories. Such an inter-laboratory study made it possible to verify the performances of the developed strengthening system and to assess the influence of installation parameters and environmental conditions. The authors wish to acknowledge Epsilon Composite Company for supporting the study. This work is part of the FASSTBRIDGE project. This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 31109806.0008. FASSTbridge is co-funded by Funding Partners of The ERA-NET Plus Infravation and the European Commission. The Funding Partners of the Infravation 2014 Call are: MINISTERIE VAN INFRASTRUCTUUR EN MILIEU, RIJKSWATERSTAAT, BUNDESMINISTERIUM FÜR VERKEHR, BAU UND STADTENTWICKLUNG, DANISH ROAD DIRECTORATE, STATENS VEGVESEN VEGDIREKTORATET, TRAFIKVERKET – TRV, VEGAGERÐIN, MINISTERE DE L'ECOLOGIE, DU DEVELOPPEMENT DURABLE ET DE L'ENERGIE, CENTRO PARA EL DESARROLLO TECNOLOGICO INDUSTRIAL, ANAS S.p.A., NETIVEI, ISRAEL - NATIONAL TRANSPORT INFRASTRUCTURE COMPANY LTD, FEDERAL HIGHWAY ADMINISTRATION USDOT

Cet article présente les observations métallographiques effectuées sur 14 objets (12 couteaux, un couteau rétractable et une faux) trouvés dans le fort de Premyslid à Stará Boleslav (Bohème centrale). Seul un exemple de lame complètement aciérée a été trouvé. Elle a été réalisée à partir de la soudure de plusieurs pièces. Environ un quart des lames de Stará Boleslav sont en fer. Les trois quarts des lames sont réalisées à partir d’un assemblage fer-acier et les deux tiers présentent des tranchants trempés. Les assemblages fer-acier concernent également deux lames damassées, l’une d’elle avec des enrichissements locaux de nickel sur le dos de la lame. The paper deals with metallographic examinations of 14 iron objects (12 knives, one mortise knife and one sickle) found at the Premyslid stronghold in Stará Boleslav (Central Bohemia). Only one example of a steel blade was found, still welded together from several pieces. Roughly a quarter of the Stará Boleslav blades were made of iron. About three-quarters of the blades combine iron and steel, and two-thirds have quenched cutting edges. The assemblage also includes two pattern-welded knives, one of them with a nickel-enriched band in the back of its blade.

À l’époque moderne, dans la province de Brescia, l’acier était produit à partir de l’affinage de la fonte, en faibles quantités et au moyen de procédés dépassés. Toutefois, ce niveau de production était lié à une situation d’équilibre difficilement surmontable dans l’exploitation des ressources. L’époque napoléonienne provoqua une nouvelle accélération de la demande de fer et d’acier à des fins militaires, utilisant de manière considérable les appareils productifs locaux et sollicitant des tentatives expérimentales de production sidérurgique à grande échelle. Cette contribution présente, en particulier, l’histoire du métallurgiste Michele Scala et de ses expérimentations concernant la production à grande échelle de l’acier de cémentation. Les vicissitudes de Michele Scala sont exemplaires des efforts parfois contradictoires des autorités pour favoriser l’amélioration des techniques de production, de leur faible efficacité ainsi que des difficultés que l’action innovatrice rencontrait pour s’imposer et pour être sérieusement testée. In the Modern Age, in Brescia, steel was produced by refining the cast iron on a small scale and with low technologies. Such a production mode was the consequence of a particular equilibrium in the natural resource exploitation that was impossible to exceed at that time. On the contrary, during the Napoleonic age, the demand for iron and steel for military uses rose heavily. This implied an increasing exploitation of production machineries and some first progress towards large scale production. This paper reconstructs the story of the metallurgic technician Michele Scala and the experiments he conducted from 1779 to 1815 so as to be able to produce high quality case hardening steel. The lesson of this story allows emphasising both the inefficiency of public government in promoting technology innovation and the constraints posed by local production forces against any innovative action. The effect of these constraints has been the impossibility of putting technology innovation in concrete form, although this was really possible.

Cet article propose une synthèse sur les modes de fabrication et de commercialisation de l’acier en Grande-Bretagne au xviiie siècle. Au milieu du xviie siècle, la Grande-Bretagne occupait une place marginale dans la production d’acier en Europe ; ses fabricants étaient dépendants d’importations allemandes. Un siècle plus tard, la Grande-Bretagne était devenue le centre le plus dynamique de production d’acier en Europe. Ce texte se propose d’analyser ces changements. Deux transformations sont importantes : la diffusion des techniques de cémentation pour convertir le fer en « blister steel », dans les dernières années du xviie siècle, et le succès des marchands britanniques pour s’assurer le contrôle du fer suédois dit « Orground » – un ingrédient essentiel pour la cémentation – au tout début du xviiie siècle. Il nous semble donc que l’innovation la plus célèbre de l’acier britannique au xviiIe siècle, l’acier fondu de Benjamin Huntsman dans les années 1740, ait revêtu finalement une importance limitée. Les marchés spécifiques de l’acier fondu, distincts de ceux du « blister steel », restent en effet très limités avant le début du xixe siècle. In the mid seventeenth century Britain was on the fringes of European steel making; her manufacturers were dependent upon imports from the German lands. A century later, Britain was Europe’s most dynamic centre of steel production. This paper offers a provisional guide to the changes that occurred. Two were of special significance: the spread of the cementation method of converting iron into “blister steel” and the success of British merchants in securing control over Swedish “Orground” iron – the essential input for the cementation technique. It is argued that the most famous development in eighteenth-century British steel making, Benjamin Huntsman’s making of cast steel, was of limited importance.

Afin de mieux appréhender le rôle joué par le fer et l’acier dans les sociétés médiévales et modernes, les définitions et les descriptions que l’on peut trouver dans la littérature consacrée aux métaux durant cette période ne doivent pas être négligées. Toutefois, pour être pleinement compris, les écrits « scolastiques » doivent être replacés dans le contexte culturel qui leur est propre. Si nous les lisons à la lumière de ce qui était alors considéré comme la science « normale », les idées qu’ils contiennent – pouvant sembler folkloriques ou primitives à l’aune de nos connaissances actuelles – se révèlent solidement ancrées dans les théories physiques et « météorologiques » d’Aristote et de ses successeurs arabes ; ce cadre de pensée dura très longtemps et était encore bien vivant à la fin du xviie siècle. Les conceptions médiévales concernant la nature des métaux furent aussi fortement influencées par l’alchimie arabe, qui offrait une description de la génération des métaux à partir du vif-argent et du soufre généralement considérée comme valable par les savants médiévaux, quelle que fût leur opinion sur la question controversée de la possibilité des transmutations. Cet article contient des présentations détaillées des descriptions du fer et de l’acier données par Avicenne, Albert le Grand, Thomas de Cantimpré, Roger Bacon et d’autres, et met en relief l’importance des traductions latines d’œuvres arabes telles que l’anonyme Livre des vapeurs cité par Vincent de Beauvais, le Livre des secrets de la nature et des causes occultes des choses du pseudo-Apollonius de Tyane et le traité alchimique pseudo-avicennien intitulé De l’âme. For a thorough investigation of the role played by iron and steel in medieval and early modern societies, the definitions and descriptions that can be found in the literature dedicated to metals during this period should not be overlooked. But, to be fully understood, the “scholastic” works must be put in their proper cultural context. If we read them in the light of what was then considered as “normal” science, the conceptions they contain, which might easily be judged folkloric or primitive from our own point of view, reveal themselves as firmly grounded on the physical and “meteorological” theories of Aristotle and his Arabic followers, a frame of knowledge which lasted a very long time and was still well alive in the end of the 17th century. The medieval conceptions of the nature of metals were also heavily influenced by Arabic alchemy, which offered a description of the generation of metals from quicksilver and sulphur, generally considered as valid by medieval scholars, whatever their opinion on the controversial question of the possibility of transmutations. This paper contains detailed presentations of the descriptions of iron and steel given by Avicenna, Albert the Great, Thomas of Cantimpré, Roger Bacon and others, and stresses the importance of the Latin translations of Arabic works, such as the anonymous Book of Vapours quoted by Vincent of Beauvais, pseudo-Apollonius of Tyana’s Book of the Secrets of Nature and of the Occult Causes of Things, and pseudo-Avicenna’s alchemical treatise On the Soul.

Le but de cet article est d’analyser ce que j’ai appelé ironiquement « le meilleur fer du monde », le fer Öregrund, produit dans quelques forges de Suède, et comment depuis le début du xviiie siècle il est devenu le principal matériau pour la fabrication de l’acier anglais. Ce fer était produit grâce à la combinaison heureuse du minerai de haute qualité de la mine du Dannemora dans l’Est de la Suède, des entrepreneurs hollandais, du capital et des ouvriers qualifiés. Pendant longtemps, ce fer a été vendu sur le marché d’Amsterdam mais à partir du début du xviiie siècle, le marché britannique s’est développé et rapidement un lien important a été établi entre ces producteurs et l’acier anglais. Le fer Öregrund est resté présent dans l’industrie de l’acier à Sheffield jusque dans les années 1940. Cet article examine des aspects de cette relation. The aim of this paper is to discuss what I ironically called “the best iron in the World”, the Öregrund iron, made at a few Swedish ironworks, and how it became from the early eighteenth century the main raw material for English steel making. This iron was made according to a fruitful combination of high-quality iron ore from the Dannemora mine in eastern Sweden, and Dutch entrepreneurs, capital and skilled workers. For a long time this iron was sold on the Amsterdam market but from the early eighteenth century the British market rose in importance, and soon an important link between these producers and the English steel making was forged. Öregrund iron was used in the Sheffield steel industry as late as the 1940s. The article analyses the features of this relationship.

Cet article étudie l’usage de l’acier pour la fabrication des limes durant l’Antiquité romaine et le Moyen Âge. Quatre limes antiques ont été étudiées par métallographie, faisant apparaître deux techniques de fabrication utilisant l’acier. L’usage systématique de la trempe a été également observé. Pour le Moyen Âge, le traité De diversis artibus du moine Théophile décrit la mise en forme de limes faites d’acier qui pourraient avoir été semblables aux limes romaines étudiées. This paper details the use of steel in files during Roman Antiquity and the Middle Ages. Metallographic examinations have been performed on four Roman files showing two types of manufacturing processes both making use of steel. Quenching was also used systematically. For the Middle Ages, the treaty De diversis artibus by Theophilus describes operating processes using steel that could create files very similar to the Roman ones. Thus this file technology seems to have existed as early as Roman Antiquity.

Cet article concerne la mode et, en particulier, la bijouterie d’acier diamant au xviiie siècle en Europe, se concentrant sur la popularité des articles anglais fabriqués d’abord à Wolverhampton puis à Birmingham. Le raffinement de l’acier, associé à la réputation anglaise pour les articles de métal a entaîné une domination du marché pendant la fin du xviiie siècle, non seulement en Grande-Bretagne, mais aussi en France et en Espagne. Conçue pour imiter les diamants, la bijouterie en « cut steel » portée par la fascination pour l’invention et les nouveaux matériaux est admirée et valorisée pour ses propres qualités et, dans certains cas, elle rivalise en prix avec les matériaux même qu’elle cherche à copier. This paper examines the fashion for cut steel jewellery in eighteenth-century Europe, focussing on the popularity of English made wares manufactured first in Wolverhampton then Birmingham. Development in the refinement of steel, short cuts in assembly allied with the English reputation for metalwares meant that it dominated the market during the late eighteenth century, not only in Britain, but also in France and Spain. Devised in imitation of diamonds, the contemporary fascination with invention and new materials meant that cut steel jewellery became admired and valued in its own right, and in some cases vied in price with the very material it sought to copy.

International audience; With an ageing bridge stock and in order to limit economic and environmental costs, developing preventive maintenance, repair and strengthening strategies will help asset owners to make efficient decisions in a sustainable way. For steel and composite steel bridges, preventing fatigue failure is at stake. In this context, easy-to-apply preventive strengthening techniques should be developed to extend fatigue life-time of steel bridges and delay resource-consuming major interventions such as traditional steel strengthening, rehabilitation, or decommissioning and new construction.This paper investigates the cost and environmental burdens associated with several strategies to extend steel bridges fatigue life-time. In particular, one details the needed information and the methodology for the implementation of an overall life-cycle analysis of an adhesively bonded CFRP solution compared with traditional techniques (use of steel plates). This is carried out considering economic, environmental and social benefits of the preventing policy and illustrating the developed methodologies with a case study corresponding to the strengthening of an existing steel bridge during its service life.

This paper reports an experimental study performed to investigate the effectiveness of carbon fiber reinforced polymer (CFRP) laminates in extending fatigue life of old cracked metallic structures. Specimens consist of old metallic plates, mild steel and wrought iron, with one single crack emanating from a rivet hole. This cracking configuration has never been adopted in literature studies and was chosen to be representative of real cracked elements in riveted connections. Two different initial crack lengths before reinforcement, representing two degrees of fatigue damage, were adopted. Four strengthening configurations were investigated including single-sided and double-sided strengthened specimens, Normal Modulus (NM) CFRP plates with or without pre-stressing, and Ultra High Modulus (UHM) CFRP plates. «Beach marking» technique as well as crack gauge were used to monitor and record the crack propagation during fatigue loading. Experimental results show that the application of CFRP plates can effectively reduce the crack growth rate and extend the fatigue life. CFRP plates with high modulus were found to be more efficient. This study represents a contribution to the present state of research and provides some interesting results on crack propagation in CFRP repaired elements close to real riveted ones.

International audience; Fastening or reinforcement onto an existing steel structure may create constraints such as the use of hot works (i.e. welding) or loss of weathertightness (i.e. drilling holes and bolting). In order to limit these constraints, there may be a strong interest in using adhesively bonded fasteners. Such a solution requires however strong justification especially regarding long-term properties. This paper presents the results of experimental and numerical investigations realized on the creep behaviour of such bonded fasteners developed for offshore steel structures. Experimental investigations were conducted at room temperature following a precise and repeatable implementation protocol. The results of the various investigations revealed a non-linear evolution of creep displacements according to a Burger law. Numerical modelling has therefore been developed on the basis of Burger's law. A preliminary static study aimed at validating the geometric model and analyzing the initial stress state in the adhesive. The creep study was then carried out to compare numerical results to experimental ones. Although additional investigations are needed, numerically determined creep displacements demonstrated a good consistency with the experimental investigations.

TRA 2018, Transport Research Arena, VIENNE, AUTRICHE, 16-/04/2018 - 19/04/2018; Steel bridges present frequent fatigue problems that reduce their load-carrying capacity and residual life. The increase of traffic flows and loads in the last decades has enhanced this problem, especially on ageing structures. Having this in mind, in November 2015, the ERA-NET Plus project FASSTBRIDGE was launched aiming at developing a complete methodology to increase such structures life expectancy that includes a calculation method for assessing the remaining life of steel bridge in terms of fatigue, a design and applyication method for the strengthening intervention, and a strengthening system relying on the use of adhesively bonded CFRP (Carbon Fiber Reinforced Polymer). The paper presents the FASSTbridge methodology, the developed strengthening system that has been specifically developed for the project and the application of the overall solution on a real composite bridge in Spain: Jarama bridge. Main results and conclusions are then presented to emphasize the advantages of the proposed solution.

Shear has been observed to be often the governing failure mode of RC cantilever deck slabs of bridges without shear reinforcement subjected to concentrated loads when tested under a quasi-static application of the load. However, concentrated loads of heavy vehicles have a repetitive nature, causing loss of stiffness and potential strength reductions due to fatigue phenomena. In this paper, the fatigue behavior of cantilever bridge deck slabs is investigated. A specific experimental programme consisting on eleven tests under concentrated fatigue loads and four static tests (reference specimens) is presented. The results show that cantilever bridge deck slabs are significantly less sensitive to shear-fatigue failures than beams without shear reinforcement. Some slabs failed due to rebar fractures. They presented significant remaining life after first rebar failure occurred and eventually failed due to shear. The test results are finally compared to the shear-fatigue provisions of the fib-Model Code 2010 and the Critical Shear Crack Theory to discuss their suitability.

OGRS2016, Open Source Geospatial Research & Education Symposium, PEROUSE, ITALIE, 12-/10/2016 - 14/10/2016; The present paper proposes an ideal Spatial Data Infrastructure (SDI) dedicated to noise monitoring based on volunteers measurements. Called OnoM@P, it takes advantage of the geospatial standards and open source tools to build an integrated platform to manage the whole knowledge about a territory and to observe its dynamics. It intends also to diffuse good practices to organize, collect, represent and process geospatial data in field of acoustic researches. OnoM@p falls within the framework of the Environmental Noise Directive (END) 2002/49/CE. The system relies on the NoiseCapture Android application developed for allowing each citizen to estimate its own noise exposure with its smartphone and to contribute to the production of community noisemaps.

Assessing the strength of existing structures has become a major issue for structural engineers. Such analyses are often performed after changes of use of the structure or due to new design codes requirements. This is particularly relevant with respect to the shear strength of post-tensioned concrete bridges. Such structures were often designed in the past with fairly low amounts of shear reinforcement and do not comply with current code requirements in terms of amount of transverse reinforcement or shear strength. However, it should be noted that codes of practice cover the design of a wide range of cases and sometimes neglect some load-carrying actions or may be too conservative for assessing others. Therefore, the use of more refined models may potentially increase the predicted shear resistance and avoid unnecessary strengthening of existing structures. In this paper, an investigation on the behaviour of post-tensioned beams with low amounts of shear reinforcement and flanges is presented. First, the results of an experimental programme on twelve reinforced concrete beams (10.0 m long, 0.78 m high) failing in shear are described. The test series is used to analyse the most significant parameters influencing the shear strength and the failure modes. Its results are compared to a number of design codes showing different levels of accuracy. The test results are finally compared to the results of analyses based on elastic–plastic stress fields. This technique shows excellent results when compared to the test results and allows investigating on the role of the various shear-carrying actions, of the prestressing level and on the transverse reinforcement amount with respect to the various potential failure modes.

Reinforced concrete flat slabs are a common structural system for cast-in-place concrete slabs. Failures in punching shear near the column regions are typically governing at ultimate. In case no punching shear or integrity reinforcement is placed, failures in punching develop normally in a brittle manner with almost no warning signs. Furthermore, the residual strength after punching is, in general, significantly lower than the punching load. Thus, punching of a single column of a flat slab overloads adjacent columns and can potentially lead to their failure on punching, thus triggering the progressive collapse of the structure. Over the past decades, several collapses have been reported due to punching shear failures, resulting in human casualties and extensive damage. Other than placing conventional punching shear reinforcement, the deformation capacity and residual strength after punching can also be enhanced by placing integrity reinforcement to avoid progressive collapses of flat slabs. This paper presents the main results of an extensive experimental campaign performed at the Ecole Polytechnique Fédérale de Lausanne (EPFL) on the role of integrity reinforcement by means of 20 slabs with dimensions of 1500 x 1500 x 125 mm (≈5 ft x 5 ft x 5 in.) and various integrity reinforcement layouts. The performance and robustness of the various solutions is investigated to obtain physical explanations and a consistent design model for the load-carrying mechanisms and strength after punching failures.

This paper deals with the propagation of a crack initiated by fretting-fatigue in bridge cables. They are submitted to traffic loads and exposed to environmental conditions (rain, wind, marine environment, de-icing salts …). These loads can lead to two main damage causes: fretting-fatigue and corrosion. These both phenomena can be coupled and lead to premature failures of drawn steel wires. In fact, at specific contact points, cracks are often initiated by fretting-fatigue. Fretting-fatigue is due to the cable bending. Near anchorages, the bending deformations are the highest and can generate damage (wire cracks). Cracks may propagate under traffic or wind fatigue load. They are also often submitted to a severe environment. Indeed, even if cables are initially protected, these protections can deteriorate and then cables are subject to corrosion. Experimental results show that wire cracks are often initiated by fretting-fatigue and crack propagation is due to fatigue or fatigue corrosion. In this study wire crack is initiated by fretting-fatigue first and fatigue tests are set up after with several environments in order to evaluate their influence on the crack propagation. The studied corrosive environments are: distilled water, sodium chloride solution and thiocyanate ammonium solutions with different concentrations. Lifetimes of specimens are compared. Metallographic and fractographic observations show the influence of the different solutions on the crack propagation. Indeed, since the microstructure of the steel wires is fully oriented in the longitudinal direction, corrosion changes the crack propagation modes and favours mixed mode propagation or longitudinal propagation.

La région de l’Erzberg styrien était l’une des principales zones de production de fer et d’acier en Europe en termes de quantité et de qualité des produits. L’article analyse les aspects technologiques, les relations sociales de production, le volume et les formes prises par le commerce de l’acier et des objets en acier (couteaux et faux) dans la partie septentrionale de cette région qu’est l’Innerberg aux xvie et xviie siècles. Nous proposons une approche du système productif et de son efficacité commerciale, ce qui nous conduit à définir la zone étudiée comme une périphérie de l’« économie-monde » européenne pendant cette période. La production d’acier et d’objets en acier a connu une expansion majeure pendant le xvie siècle en raison des adaptations significatives de la chaîne productive. Le réajustement de ces structures et l’évolution de l’économie européenne durant la phase B du xviie siècle ont entraîné son déclin. The area surrounding the Styrian Erzberg was one of the most important iron-and steel-producing regions of Europe in terms of output and the quality of the products. The paper analyses the technological features, the social relations of production, and the volume and conditions of the trade in steel and steel tools (knives and scythes) in the northern part of this area, the so-called Innerberg district, in the 16th and 17th centuries. We use a commodity chain approach to analyse the system of production of steel and tools made from steel as well as the trade in these commodities. This enables us to identify the region under study as a semi-peripheral zone of the European world economy in this period. It turns out that the production of steel and steel tools underwent a major expansion during the 16th century due to significant changes in the structure of the commodity chains in which it was involved. The readjustment of the structures and hierarchies of the European economy during the B-phase of the 17th century led to its decline.

This paper aims to present both experimental and numerical studies of the corrosion induced cracking pattern evolution of a reinforced concrete sample subjected to accelerated corrosion. The sample was a concrete beam (1000x250x100 mm3) reinforced with two rebars (20 mm diameter; 25 mm cover). The beam was not mechanically loaded. The corrosion process was applied on 500 mm rebar length on the central part. Rebars were intentiostatically corroded using a current density of 100µA/cm² of steel, in a chloride pond and for a thirty days period. Electrochemical tests (rest potentials, linear polarization resistance and impedance spectroscopy) and visual inspection were performed in order to characterize the rebar state (sound or corroded). Width evolution of the main longitudinal cover crack was measured thanks to ball-extensometer. A numerical modeling of the corroded RC beam has also been realized. The model allows taking into account the most important mechanisms such as the specific behaviour related to rust products. The proposed steel/concrete interface model has been recently developed by the authors and is based on damage mechanics. The experimental and numerical results are in good agreement and confirm the mean crack width induced by the iron oxide swelling. These results are very promising and indicate that this model could become a practical tool for civil engineers dealing with in-site repair and maintenance issues.

Les découvertes récentes de deux ferriers contenant des produits et déchets de tous les stades de la chaîne opératoire sidérurgique sur le site médiéval de Castel-Minier, plus connu pour ses mines de plomb argentifère, apporte un éclairage nouveau et fondamental sur la métallurgie et la diffusion des procédés dans cette région des Pyrénées. Cet article présente les premiers résultats métallographiques obtenus sur le métal mis au jour lors des sondages de ces ferriers au cours des fouilles 2004. Ils permettent de montrer que, très probablement, la production de cette installation sidérurgique est au moins en partie de l’acier dont la teneur en carbone est proche de l’eutectoïde. De plus, la composition des inclusions, indiquant une forte teneur en manganèse confirme que le minerai utilisé pour l’obtention du métal provient de la vallée voisine de Vicdessos, avec laquelle des échanges commerciaux sont attestés pour cette période par les sources historiques. Ces résultats ouvrent la voie à de futures études sur la sidérurgie utilisant des minerais au manganèse, caractéristique de cette région. En effet, le rôle de cet élément dans la production d’acier est encore mal compris bien que des minerais manganésifères soient associés à ces types de production identifiés à l’époque médiévale entre autre dans les alpes italiennes et les Pyrénées. Recent excavations in the archaeological site of Castel-Minier, well known for its silver production, near the town of Aulus Les Bains (France), also reveal the presence of two iron slag heaps. This paper presents the first metallographical results on the iron artefacts found during the 2004 campaign. These artefacts are made of eutectoid steels and the slag inclusion analyses reveal the presence of high levels of manganese oxide. This indicates without doubt the use of a manganese ore coming from the neighbouring valley of Vicdessos. These first results are very important and lead the way for future studies on a specific ironmaking operating chain using manganese ore. Indeed, this element is found in the ore of two regions well known for producing steel in the medieval period (Italian Alps and Pyrenees) but its exact role in the mechanisms conducting to steel in a shaft furnace is not elucidated yet.

International audience; Owners of structures and infrastructure base their maintenance decision schemes mainly on structural integrity assessment and consequence analysis. The major inputs come from information collected by inspections employing non-destructive or destructive tools. Uncertainties and errors of measurement can lead to bad decisions but these effects are rarely integrated into the decision making process. Risk Based Inspection (RBI) provides the basics for optimizing the maintenance plans of existing structures while ensuring satisfactory safety and availability of the structure during its service life. This basis depends both on computation of reliability index and probabilistic modeling of inspection results. Probabilistic modeling of inspection results leads to specifying the Probability of Detection (PoD), the Probability of False Alarms (PFA) and the Receiver Operating Characteristics (ROC) curve that are usually considered as key parameters in RBI. Under these circumstances the comparison of Non destructive Testing (NDT) tools in terms of cost/benefit is difficult to be established as well as the method for optimizing a given technique. This paper starts from the αδ method that gives a new performance indicator in this context, and apply it to the field of inspection of steel harbor structures, after a detailed analysis of uncertainties during corrosion assessment by ultrasonic measurements.; Les gestionnaires de structures et d’infrastructures fondent leurs décisions de maintenance sur des analyses d’intégrité structurelle et des conséquences de défaillances. Les entrées principales de ces méthodes sont les inspections par contrôles destructifs ou non destructifs. Les erreurs de mesure peuvent conduire à de mauvaises décisions, celles-ci étant rarement prises en compte dans les analyses de risque. Les méthodes d’inspection basées sur les analyses des risques fournissent le cadre méthodologique d’optimisation des inspections. Les résultats dépendent de l’évaluation de la fiabilité et de la modélisation probabiliste des données d’inspection. Cette dernière est généralement basée sur l’évaluation des Probabilités de Détection, Probabilités de Fausses Alarmes et Courbes ROC. Au vu de la difficulté d’une évaluation précise de ces grandeurs, il reste difficile de disposer des outils d’optimisation du rapport coût/bénéfice ou de comparaison des techniques. Cet article s’appuie sur la méthode αδ qui fournit un indicateur de performance dans ce contexte appliqué au contrôle de la corrosion de palplanches métalliques; on décrit et modélise en particulier les incertitudes de mesure par ultrasons selon différents protocoles.

This paper describes the insulative value of spray-applied, cementitious and mineral-fiber fire resistive coatings for steel building columns. It presents results of high- temperature thermal property tests of the materials used as input to a two-dimensional heat flow analysis designed for predicting the fire resistance of hollow steel columns. The prediction is compared with actual fire test data. The influence of the thermal properties of the materials and their application thickness on fire resistance is discussed., Reprinted from: Fire Resistive Coatings: the Need for Standards, ASTM Special Technical Publication, 826, 1983, p. 40-55, Symposium on Fire Resistive Coatings : the Need for Standards: 18 October 1982, Philadelphia, PA, USA

The sources of the information contained herein are the published reports of fire tests conducted in accordance with the standard methods of test ASTM E119 and BS 476 that are available to the Division of Building Research at present. No tests, so far as is known, have yet been conducted in accordance with CSA B54.3. A number of countries have adopted methods of fire tests that differ in some respects from those recognized by the National Building Code. Reports of these tests may be the subject of further investigation. Tests of assemblies that contain materials indentified by trade name only have been excluded from this paper because these assemblies are not adequately identified by description.

In the past five years, a number of high-rise apartment buildings have been erected in Western Canada that incorporate non-loadbearing exterior steel frame walls. Steel-stud manufacturers have recently been pressing for the acceptance of these walls for more general use in residential construction. A major consideration in determining the acceptability of steel wall systems for cold- weather regions is their thermal performance. In order to provide a rational basis for acceptance and to assist the designers of steel wall systems, the Division of Building Research undertook laboratory and field investigations on the thermal performance of steel frame walls. The results of the field investigation on a number of existing buildings are presented in this paper., Reprinted from Specification Associate, vol. 13(6), November - December 1971, p. 21-35.

This paper reports upon work that has been done in a study of the behaviour of paints on steel and their ability to protect steel under a variety of environmental conditions.

This paper outlines the theoretical background of the punching shear provisions implemented in the fib Model Code 2010 and presents a practical example of its applica tion. It is the aim to explain the mechanical model that forms the basis of the punching design equations, to justify the relevance of the provisions and to show their suitability for the design and assessment of structures.

Concrete structures, contrary to steel or timber structures, have not been traditionally considered as significantly sensitive to fire conditions. As a consequence, their performance in fire conditions has generally been assessed on the basis of quite simplified rules provided in codes of practice, mostly dealing with minimum geometric requirements in terms of thickness and concrete cover. Accidents under fire conditions have nevertheless revealed a certain level of vulnerability of concrete structures in fire and have thus shown that code regulations are potentially insufficient to cover this aspect of design. As a reaction to this level of simplicity, some codes are currently available with specific and very detailed provisions with reference to fire design in concrete structures, such as EN 1992-1-2, covering a wide number of simplified and advanced design procedures. Unfortunately, the hierarchy of these procedures and which one is most suitable for a given situation is sometimes unclear for designers. In addition, it is probably not necessary to perform rather complex and detailed analyses for all types of structures, but the level of refinement can be adapted to the sensitivity of the structure to fire conditions and to its significance for the society. In this paper, a possible approach for consistent design of concrete structures under fire conditions is proposed based on the Levels-of-Approximation philosophy. The Levels-of- Approximation approach has been successfully introduced into the new Model Code 2010 for a number of problems (such as shear, punching and 2nd order effects) and allows refining the accuracy of the analysis when necessary. This allows keeping simple rules for most cases but provides a general frame for assessing complex or sensitive structures. In addition, it does not only incorporate calculation methods, but specifies which ductility requirements are to be fulfilled in order to ensure a correct applicability of each method.

Summary The paper presents an analytical comparison of the amount of prestressing required for two similar bridges, one with internal and the other with external prestressing. This comparison shows that bridges with external prestressing can become economically competitive for large girder depths. The detrimental effect of the smaller stress in the prestressing steel at the ultimate limit state is more than compensated by the thinner webs made possible by the absence of ducts.

Design formulations for calculation of bond strength in structural concrete members usually include a number of parameters such as the stress acting in the reinforcement, the concrete cover and the diameter of the reinforcing bars. These parameters are actually necessary to account for geometric, strain and size effect that govern many bond issues and that have been experimentally verified. Unfortunately, most design approaches are still based on empirical formulas that do not lead to a clear understanding why the different phenomena have to be taken into account. In this paper, a mechanical explanation of such effects is presented with reference to the various potential bond failure modes. Analogies to other related problems (such as spalling of concrete cover in arch-shaped members) are finally discussed.

Physical punching shear models such as the Critical Shear Crack Theory (CSCT), which is the basis of Model Code 2010 (MC 2010), describe generally the punching strength as a function of the slab deformation. Thus, the prediction of an accurate load-deformation curve is essential for the prediction of the punching strength as well as the deformation capacity of flat slabs. In the vicinity of columns, the flexural response of flat slabs depends not only on the flexural moments but also on the concentrated shear forces. In the case of slender slabs, slabs with low amounts of flexural reinforcement, or slabs without shear reinforcement, the shear forces are limited and thus their influence in the flexural response is low. However, in the case of thick slabs with shear reinforcement, large shear forces are carried influencing the flexural response of the flat slab. Despite the importance of an accurate prediction of the load-rotation response, little research has yet been performed on this subject. This paper presents an investigation on the flexural response of 6 full-scale flat slab specimens. The specimens presented herein belong to an extensive experimental campaign of 16 full-scale flat slab specimens performed at the Ecole Polytechnique Fédérale de Lausanne (Switzerland) with the aim to investigate the punching strength and the rotation capacity of flat slabs with and without shear reinforcement. The investigated parameters were the column size, the slab thickness, the amount of shear reinforcement, and the type of shear reinforcement system. The investigation of the flexural response consists of the comparison of the experimentally obtained load-rotation responses to the predictions by the CSCT, MC 2010, and a modified approach based on the CSCT.