Die im Jahr 1904 errichtete Eisenbahnbrücke von Lanciau musste durch eine neue Brücke ersetzt werden, die eine durchgehende Schotterbahn ermöglicht. Die neue Brücke wurde mit der Idee entworfen, den Geist der alten Pont du Lanciau beizubehalten und diese als Fachwerkkonstruktion auszuführen. Allerdings wurde sie sowohl hinsichtlich ihrer Form (räumlicher Dreiecksbinder mit variabler Höhe) als auch ihrer Profilquerschnitte (Rohre) modernisiert. Eine auf dem Tragwerk aufgesetzte und mit den Obergurten verbundene Betonwanne wird genutzt, um die Steifigkeit der Brücke zu erhöhen. Pont du Lanciau ist damit eine der ersten Eisenbahnbrücken mit einem tragenden Fachwerk aus Hohlprofilen, das dank der kompakten, direkt verschweißten Rohre ein ästhetisches Erscheinungsbild liefert, das sich perfekt in die Umgebung integriert. Im Folgenden wird auf die verschiedenen Aspekte bei der Realisierung dieses Vorhabens eingegangen.

Pont du Lanciau - a tubular truss bridge as replacement of an old bridge
Built in 1904, the old railway bridge of Lanciau had to be replaced by a new bridge, which allows a continuous ballasted track. The new bridge was designed with the idea of maintaining the spirit of the old Pont du Lanciau by keeping a truss structure. However, it has been modernized both in terms of its shape (spatial triangular truss with variable height) and its cross sections (tubes). A concrete trough attached to the structure and connected to the upper chords is used to increase the rigidity of the bridge. Pont du Lanciau is thus one of the first railway bridges with a truss made of hollow sections, which thanks to the compact directly welded tubes provides an aesthetic appearance that integrates perfectly with the surroundings. In the following, the various aspects of the realization of this project will be discussed.

Die Verwendung von eingeschweißten Stahlprofilen als Netzwerkhänger in Kombination mit den auf Schwingbreiten und Vermeidung von Hängerausfall optimierten Netzwerklayouts führt zu technischen Herausforderungen, welche in der jüngeren Vergangenheit nicht immer befriedigend gelöst werden konnten [1]. Insbesondere bei langen, flach geneigten Hängern treten Schwierigkeiten im Zusammenhang mit der Durchbiegung infolge Eigengewicht und Veränderung der Durchbiegung infolge Normalkraftamplituden sowie Zusatzbeanspruchungen aus winderregten Schwingungen auf [1, 2].
Durch die Verwendung von Zugstangen aus CFK (im Weiteren “Carbon”) als Hänger ändern sich die Randbedingungen für die Gestaltung der Hängeranordnung grundlegend, was Auswirkungen auf das gesamte Tragverhalten des Netzwerkbogens hat: Aufgrund des hohen Ermüdungswiderstands von Carbonbauteilen können die Hänger ohne Rücksicht auf begrenzte Schwingbreiten rein unter dem Aspekt der Ausnutzung auf Zug angeordnet werden. Der hierfür erforderliche Querschnitt beträgt bei der Verwendung von Carbonhängern weniger als ein Viertel des erforderlichen Stahlquerschnitts. Dies in Kombination mit einem geringen E-Modul bei CFK führt zu deutlich größeren Dehnwegen in den Hängern, womit die Problematik ausfallender Hänger entfällt. Gleichzeitig verlagern sich die Eigenfrequenzen der Carbonhänger aufgrund der geringen Masse und der höheren möglichen Vorspannung.
Durch die Verwendung von Carbonzuggliedern als Hänger lassen sich ästhetisch hochwertige und gleichzeitig sehr effiziente Hängeranordnungen mit vergleichsweise steilen Hängern ohne Hängerausfall und ohne Beeinträchtigung der Lebensdauer infolge winderregter Schwingungen realisieren. Der wirtschaftlich sinnvolle Anwendungsbereich für Netzwerkbogenbrücken kann damit deutlich über 300 m Spannweite ausgedehnt werden.

Network arch with hangers made from carbon
The use of welded steel sections as network hangers can lead to technical challenges which may not always be entirely solved, particularly when such sections are used in combination with network layouts which have been optimized for vibration amplitudes while also avoiding hangers getting slack [1]. This is especially true with long flat inclined hangers, where difficulties arise in connection with dead load deflections, variation of sag resulting from changing normal force and additional stress resulting from wind induced vibrations [1, 2].
The use of hanger cables made from CFRP (carbon) fundamentally changes the boundary conditions used in the selection of a hanger layout and thus influences the load bearing system of the network arch. Due to the excellent fatigue load resistance, the layout of carbon hangers can be tuned ignoring any criteria for fatigue stress range limits, allowing the selection of the cable to be based entirely on the criteria of utilization in tension. As a result, the required hanger section can be reduced to less than one quarter of what would be required in steel. This together with the smaller youngs-modulus of CFRP leads to significantly larger elongations of the hangers, which resolves the issue of the hangers going slack. Furthermore, the eigenfrequencies of the hanger cables increase significantly due to the relatively high prestress and the low weight.
By using carbon tension members as hangers, it is possible to realize a high aesthetically quality and at the same time very efficient hanger arrangements with comparatively steep hangers avoiding hangers getting slack and without impairing the service life as a result of wind- induced vibrations. The economically viable range of applications for network arch bridges can thus be extended to well over 300 m span length.

Mit dem Umbau einer Werkhalle soll ein Schulungs-, ein Aufenthalts- und ein Garderobenraum für die Mitarbeiter einer Firma im Fahrleitungssektor geschaffen werden. Da eine Erweiterung der Halle auf dem freien Gelände des Firmenareals den Werkverkehr zu stark beeinträchtigen würde, kam nur eine Ergänzung im Inneren der Halle infrage. Um die Verkehrsflächen in der Halle nicht zu stark zu reduzieren, wurden die Räume aufeinandergestapelt und zwischen die bestehenden Kranbahnen der südwestlichen Ecke der dreischiffigen Stahlhalle gehängt. Durch das Eliminieren des Krangewichts in diesem Bereich konnte das frei werdende statische Potenzial (die Laufkatzen der beiden Krane trugen bis zu 20 t schwere Lasten) des bestehenden Stahltragwerks der Halle genutzt werden. Die beiden aufgehängten Obergeschosse der Sozialräume sind als leichte, hybride Konstruktion aus Stahl und Hohlkastenelementen aus Holz (18 t Stahl und 25 t Ausbaulasten) ausgebildet und anstelle des Krans in die Kranbahnen eingehängt. Die Position der Aufhängung ist so gewählt, dass alle Mehrlasten über die bestehende Tragkonstruktion der Halle abgeleitet werden können, ohne das Tragwerk und die Fundation verstärken zu müssen. Lediglich die fassadenseitige Kranbahn ist partiell mit dünnen aufgeschweißten Blechen an den Flanschen verstärkt worden, sowie die vier nächstgelegenen Kranbahnkonsolen.

Spatial crane girder - common and seminar rooms as stacked formation in a workshop
With the modification of a factory workshop, new social rooms for the employees of a company working in the field of electrifications for trains and busses were created. Since an enlargement of the existing factory workshop on the area of the company ground would interfere with the existing traffic flow, the new rooms had to be built inside the workshop. To minimize the footprint, the new rooms are stacked on top of each other and hung up on the existing crane runway. Closing down the crane in the south-west part of the workshop (the trolley is design for loads up to 20 t) where the new construction is located, allows to use the existing crane runway as support. The stapled rooms are built of a hybrid and light construction of steel and wooden box-section slabs (18 t of steel and 25 t of extension loads). The position of the suspension enables the supporting structure of the workshop to bear the higher loads without having to reinforce the structure or the foundation of the workshop. Merely the crane runway along the façade had to be reinforced by thin plain sheets welded to the flanges of the runway section, as well as four brackets carrying the runway.

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MOCAPE in Shenzhen/China, housing the Museum of Contemporary Art (MOCA) and the Planning Exhibition (PE) is a vast building consisting of many long-span structural elements. The transparent façade highlights the main entrance and circulation zone between the two buildings and allows unobstructed views between the inside and outside. The open, column-free exhibition areas with heights from 6 to 17 m also strengthen the impression of a generous design concept.
(Foto © Duccio Malagamba. Paper: Ruppert et al., S. 98)

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The Eurocodes (EC) represent European norms (EN) for the design and construction of building and bridge structures. The development of these European design codes is carried out on behalf of the European Union (EU) by the “European Committee for Standardization - CEN”. The Eurocodes have been in use for some years now. The motivation behind the development of the Eurocodes is the harmonization of the planning and design process for the structural components and construction elements of buildings and bridges all over Europe. Based on the experience gained through the use of the Eurocode conditions in recent years and many comments from industry, a revision of all parts of the Eurocode is currently in progress. The aim is to adapt the current design standards to the state of the art and research, to simplify the application and to harmonize the Eurocodes with each other. Finally, these modifications will be transferred to the second generation of European standards. An overview of the development phases and project teams is presented in this paper, accompanied by an insight into current standardization work and the technical discussions, mainly focusing on EN 1994-1-1.

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Recently, SBHS (Steels for Bridge High-Performance Structure) has been introduced in Japan because of its remarkable mechanical properties. The main features of SBHS are high yield strength, improved toughness and weldability, which are superior to conventional steel materials at the corresponding tensile strength grades. In this study, these material properties of SBHS were compared with conventional steel materials through experimental studies as well as the Japanese design specifications. The main focus of this paper is the evaluation of the local buckling strength of two SBHS700 stub columns, each with cruciform section through compression tests. The load-displacement relationship, strain bifurcation related to plate buckling and out-of-plane deformation are discussed. Two test specimens with different width-to-thickness ratio parameters RR are compared. As the results indicate, for the specimen having a larger RR, an abrupt decrease in load was observed after the peak load, whereas the decrease in load for the specimen with a smaller RR proceeded gradually after the peak load with a much larger vertical displacement. In terms of local buckling strength, it was found to be possible to evaluate the SBHS700 stub column with cruciform section based on the existing ultimate strength curves.

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This paper presents the development of the method for predicting the reusability of building components and whole structures and a pilot study of three different single-storey steel buildings in Finland. The method enables various building parts and products to be classified through a procedure to calculate their reusability index. These values can be further used to produce a single reusability indicator for the whole end-of-life scenario (e.g. complete or partial building reuse). The aggregated result of the whole building may be very useful when planning demolition or reconstruction works as well as when assessing the environmental impact of the new buildings. The main new thing explored in this paper is the possibility of integrating the economyaspect of the recovered components in the reusability assessment. Indeed, the reusability index developed earlier was purely based on the technical requirements of recovering, remanufacturing and reusing components. Hence, it was a technical reusability indicator. The possibility ofincluding information on the prospective marketability of the recovered component is a valuable extension to this method.

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In 2007 the Austrian architectural firm Coop Himmelb(l)au won an international competition with its design idea for a monolithic, “slightly twisted” structure with a multifunctional façade. This design has been largely retained. The organization of the volumes and the urban planning positioning could also be essentially implemented.
As a cultural centre, the building unites two independent institutions under one roof: the Museum of Contemporary Art (MOCA) and the Planning Exhibition (PE). Both institutions are housed in rectangular volumes under a covered plaza. Also included are community areas such as an auditorium, conference rooms, multifunctional exhibition halls and service areas. Ramps and escalators lead from the large entrance area to the main level at +10 m. This marks the starting point for tours of the museums. There is a silvery, shiny, softly shaped “cloud” in the centre which accommodates a café, bookstores and a museum shop. It also connects the exhibition rooms over several floors via bridges and ramps.
The transparent façade highlights the main entrance and circulation zone between the two buildings and allows unobstructed views between the inside and outside. The open, column-free exhibition areas with heights from 6 to 17 m also strengthen the impression of a generous design concept.

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This paper focuses on the behaviour of connections with stiffened top and seat angles. There is a discussion of nine statically loaded full-scale tests carried out in three groups for different thicknesses of top and seat angle stiffeners. The purpose was to provide the necessary data to develop Eurocode 3. The maximum bending moment increased with the increase in stiffener thickness from 6 to 10 mm. Moreover, the plastic flexural resistance and bending moment capacity increased as the length of top and seat angles decreased. Furthermore, the plastic region of the seat angle section parallel to beam was greater than the vertical section of the angle, and the dissipated energy depended on the lengths of the angles.

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Dedicated to Dipl.-Ing. Dr.-Ing. E.h. Reiner Saul on the occasion of his 80th birthday
This paper describes the selection of box girders for cable-supported railroad bridges from the point view of structural behaviour, fabrication, transportation and erection. There is a review of the use of wide single box girders and vented box girders with dual and triple separate boxes. The number of cable planes and the different transverse locations of pylon legs and main girders are also studied. A cable-stayed bridge with a main span of 520 m and a triple separate box girder accommodating four high-speed railway tracks and a six-lane carriageway is researched as a case study. The result reveals that the triple separate box girder is very suitable for long-span cable-supported railroad bridges with multiple railway tracks and traffic lanes.

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Connections in steel structures play an essential role in the structural stability of the entire construction. This is also true in the event of a fire. The difficulty in designing connections for fire lies in the fact that not only material properties, but also loads applied to the connections change depending on temperature. In addition, the temperature-dependent decrease in the tensile strength of high-strength bolts does not coincide with the decrease in shear strength. So far, the influence of combined tension and shear loading on high-strength bolts has not been studied in detail.
This project included carrying out interaction tests on high-strength bolts of property class 10.9 (fu = 1000 N/mm2). Post-fire performance was examined in addition to observing the loadbearing behaviour during fire. The examinations were completed with additional material tests. The results were compared with earlier research on the temperature-dependent loadbearing capacity of high-strength bolts during and after temperature loading as well as on the loadbearing behaviour of bolts in steel structures under combined tension and shear loads. This investigation contributes to a better understanding of the loadbearing capacity of high-strength bolts under combined loading during and after a fire.

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Many recent earthquakes clearly illustrate the importance of local ground properties for the dynamic response of structures. The dynamic response of an engineering structure is influenced by the medium on which it is founded. On solid rock, a fixed-base structural response occurs which can be evaluated by subjecting the foundation to the free-field ground motion occurring in the absence of the structure. However, on deformable ground, a feedback loop exists. In other words, when a feedback loop exists, the structure responds to the dynamics of the soil, while the soil also responds to the dynamics of the structure. Structural response is then governed by the interplay between the characteristics of the ground, the structure and the input motion. This study involved a numerical investigation of the dynamic behaviour of unbraced steel frames resting on soft ground. Two types of mid-rise unbraced steel frame, including 5- and 15-storey buildings on a soft soil deposit, were selected and analysed under the influence of three different earthquake acceleration records. The above-mentioned frames were analysed under two different boundary conditions: i) fixed-base (no soil-structure interaction) and ii) flexible-base (considering soil-structure interaction). The results of the analyses in terms of structural forces and lateral displacements for the above-mentioned boundary conditions are compared and discussed.

Numerical investigations of compression members made of aluminium are presented and recommendations for reorganizing the buckling classes and curves are derived from these. Finally, the curves are compared with test results.

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