Current design equations given in EN 1993-1-3 for calculating the web-crippling resistance of cross-sections with one web were copied from the AISI's Specification for the design of cold-formed steel structural members, taking into account the different safety concepts: load and resistance factor design (LRFD), with resistance factors&phgr;w applied to nominal values, and limit state design, with partial factors &ggr;M applied to characteristic values as defined in EN 1990. Furthermore, the web-crippling equations of subsequent editions of the AISI specification (then designated AISI S100) were completely revised based on the web-crippling data collected and evaluated by Beshara and Schuster [5].
This paper presents the results of a calibration of a generalized web-crippling equation to be used for cross-sections with one web (i.e. C- and Z-sections). The coefficients of the generalized web-crippling equation were calibrated to comply with the safety concept described in EN 1990, taking into account EN 1990, Annex D, and a partial factor &ggr;M1 = 1.1. This paper therefore provides an introduction to as well as background information on proposed changes and amendments to EN 1993-1-3.

Dedicated to Prof. Dr.-Ing. Helmut Saal on the occasion of his 75th birthday
Diaphragms made of trapezoidal profile sheeting are often used to stabilize members or work as bracing to transfer horizontal loads (wind or seismic loads) to the ground. In Europe there are currently two approaches for the design of these shear diaphragms, both often denoted by the names of their corresponding developers: Schardt and Strehl and Bryan and Davies. Although the mechanical background to calculating the diaphragm stiffness is more or less identical in both approaches, there are differences in the level of detailing, i.e. in the number of parameters regarded as significant for practical design. Generally, the Schardt/Strehl approach was reworked much more and is therefore easier to use in practical design. On the other hand, the Bryan/Davies approach is much more realistic regarding the failure modes (shear buckling, failure of fasteners) and loadbearing capacity. This paper discusses the differences and similarities in detail, makes an assessment and highlights the particular advantages.
Recently, a new approach was elaborated based on work previously carried out by Baehre and Wolfram and taking into account new developments and findings. This “combined approach” presented here combines the advantages of the Schardt/Strehl and Bryan/Davies approaches as given above. The paper includes a comparison with test results with regard to both diaphragm stiffness and loadbearing capacity.
Detailed information is given on how to elaborate the sheeting-related parameters in tables, allowing for easy use in practical design. This is of special importance for implementation in practical design and in relation to the further development of the Eurocodes.

Stahlkassettenprofile sind ein gängiges raumabschließendes Bauelement. Sie dienen als Innenschale von zweischaligen wärmegedämmten Wandkonstruktionen und werden mit einer vorgesetzten Außenschale kombiniert. Das Tragverhalten und die Tragfähigkeit der Stahlkassettenprofile hängen stark von der Stabilisierung der schmalen Gurte im Bereich der Außenschale ab. Sowohl der Abstand der Verbindungen als auch die Biegesteifigkeit und Schubsteifigkeit der Außenschale sind maßgebende Parameter. Im vorliegenden Beitrag werden die grundsätzlichen Wandkonstruktionen mit Stahlkassettenprofilen vorgestellt und diskutiert. Die jeweils zugehörigen mechanischen Modelle für winddruckbelastete Systeme werden identifiziert. Basierend auf Vergleichsberechnungen mittels Finite-Elemente-Berechnungen werden die Grundlagen für überarbeitete Bemessungsmodelle eingeführt und erläutert.

Load-bearing behaviour of liner tray walls with directly or indirectly fixed outer façades.
Liner trays are a common thin-walled building component for building envelope. They are used as inner layer of double layer walls with thermal insulation and combined with an outer façade layer. The load-bearing behaviour and capacity of the liner trays strongly depends on the stabilisation of the narrow flanges adjacent to the outer façade layer. Both distance of connections and bending stiffness and shear stiffness of the outer layer are relevant parameters. The paper presents and discusses the principal types of wall constructions using linear trays. The corresponding mechanical models for systems under wind pressure loading are identified. Comparative calculations are done using a Finite-Element-Model. Basic principles for a revised design model are introduced and explained.

The paper deals with the strength and stiffness of fastenings with fastening screws or rivets in thin-walled sheeting and sections. After a brief review of the design equations given in some codes, an additional proposal is given. A further review covers the stiffness equations from both codes and research papers, and concludes with a recommendation for applications.

This paper deals with the parameters for choosing the materials for fastening screws used in connections involving thin-walled sections and thin sheeting. Different types of corrosion processes and repeated bending due to thermal elongation are identified as the most important parameters; these are explained in detail here. Based on that, some general recommendations for choice of material are given.

As part of the ongoing revision of the Eurocodes, design provisions in EN 1999-1-1 on the buckling of longitudinally welded aluminium compression members have been subjected to a critical review. The numerical investigations described in part 1 of the paper were conducted because a need for improvement was identified. In part 2 the main observations were presented qualitatively. Part 3, the final part of the paper, presents the statistical evaluation of the numerical investigations and the determination of the buckling curves. Two different approaches are conceivable for these buckling curves: conventional buckling curves with explicitly specified imperfection factor and plateau length parameters, and a modified Ayrton-Perry approach with interpolated parameters. Both approaches are compared with the results of the numerical investigations and with test results.

As part of the ongoing revision of the Eurocodes, design provisions in EN 1999-1-1 on the buckling of longitudinally welded aluminium compression members have been subjected to a critical review. The numerical investigations described in part 1 of the paper were conducted because a need for improvement was identified. In part 2 of the paper, the main observations are presented in qualitative terms. Those observations are: the influence of the allocation of the materials to buckling classes, the influence of the imperfections plus the cross-section geometry including the position and size of the HAZ within the cross-section. Part 3 will conclude this paper by discussing the proposed design approaches in detail.

As part of the ongoing revision of the Eurocodes, design provisions in EN 1999-1-1 on the buckling of longitudinally welded aluminium compression members have been subjected to a critical review. Numerical investigations were conducted because a need for improvement was identified. This part 1 of the paper describes the individual steps of the revision and the modifications discussed, which include the introduction of longitudinally welded members. Before going into the numerical investigations in more detail, previous observations are presented regarding buckling classes and plateau lengths. In part 1 of the paper, explanations of the numerical investigations are limited to presenting the modelling of the geometry, the mechanical properties and the imperfections as well as their respective variation in the context of the parametric studies. The results of the numerical investigations and the proposed design approaches will be presented in detail in parts 2 and 3.

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.

Sowohl Sicken und Versätze als auch angeschäumte oder geklebte Dämmstoffe können ebene Teilflächen dünnwandiger Bauteile stabilisieren: Sicken und Versätze sind sowohl bei Trapezprofilen als auch bei Sandwichelementen anzutreffen, der stabilisierende Einfluss des Dämmstoffs hingegen nur bei Sandwichelementen. Werden Trapezprofile mit einer kraftschlüssig angeschäumten Dämmstoffen versehen, treten auch hier beide Stabilisierungseffekte auf. Die kombinierte Berücksichtigung beider Effekte in den üblichen Bemessungsprozeduren wird erläutert. Basierend auf den dabei entwickelten Modellen werden Grundzüge für ein neues Bemessungsverfahren für Sandwichelemente mit leicht-profilierten Deckschichten eingeführt.

Load-bearing capacity of longitudinally stiffened thin-walled sheeting on an elastic foundation.
Both stiffeners and insulation materials bonded to the sheets can provide stabilization to cross-section parts of thin-walled building components. While stiffeners can be found both with trapezoidal sheeting and sandwich panels, the stabilizing effect of the insulation material can only be found with sandwich panels. If trapezoidal sheeting is provided with a force-fit connected insulation material, also both stabilizing effects apply. The inclusion and combination of both stabilization effects in the usual design and calculation procedures is explained in the paper. Based on the knowledge obtained with the design of trapezoidal sheeting, a new design and calculation concept for sandwich panels with lightly profiled faces is introduced.

Bei der Anwendung erdverlegter Rohre als Fahrrohre für Rohrbahnzüge im Transportwesen muss neben den Lastfällen Erdauflast, horizontaler Erddruck, Rohreigengewicht und Verkehrslast auf dem Rohr auch der Lastfall "Raddruck" des Rohrbahnzuges berücksichtigt werden.

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Die früheste formale Ausbildung von Architekten, Feldmessern und Ingenieuren fand in der Königlichen Akademie der Künste nach dem Statut vom 20. März 1699 statt, 1704 umbenannt in "Academie der Künste und mechanische Wissenschaften". In einer ehemaligen Verbindung dazu steht die Gründung der Akademie der Wissenschaften im Jahr 1700. Beide waren im selben Gebäude untergebracht, und es gab enge wissenschaftliche Kontakte. Die territoriale Expansion Preußens führte zu einem steigenden Bedarf von Baumeistern in Staatsdiensten und der Notwendigkeit einer Ausbildung für Baubeamte durch die Ober-Baudeputation. Am 18. März 1799 wurde von Friedrich Wilhelm III. die Königliche Bau-Akademie gegründet, die mit der Königlichen Akademie für Künste und mechanische Wissenschaften eng verbunden blieb. Ein breites Angebot von Fächern betonte den technischen Schwerpunkt der Ausbildung an der Bau-Akademie. In der letzten Phase der Bau-Akademie, vor ihrer Umwandlung in die Königlich Technische Hochschule von Berlin 1879, wurde der starke Einfluß der Baubeamten geringer.

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Um die Wende zum 20. Jahrhundert hatte der amerikanische Industriebau mit innovativen Konstruktionsmethoden und neuen Bauformen weltweit eine führende Rolle übernommen. Die Standardisierung und Vorfertigung von Bauelementen beschleunigten die Bauzeiten und förderten eine effiziente räumliche Gestaltung der Fabrikgebäude.

Industrial architecture in the United States of America during the first third of the 20th century.
At the turning of the 20th century the American Industrial Architecture assumed a leading role worldwide with new construction methods and new materials. The standardization of building processes and new methods of prefabrication accelerated the reduction of construction-time and promoted an efficiency in the design of factories.

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Am 8. Dezember 2012 jährte sich der 70. Todestag von Albert Kahn, dessen innovative Industriebauten am Anfang des 20. Jahrhunderts in Amerika und weltweit Schule gemacht haben. Wie kein anderer hat er die Industriearchitektur revolutioniert, die sich wegen ihrer sachlichen und technischen Aufgabenstellung im 19. Jahrhundert als Stiefkind der Architektur im Schatten des Eklektizismus nur schwer behaupten konnte. Er wies den Weg zu einer primär konstruktiv bestimmten Industriearchitektur.

Albert Kahn, Architect of Ford
Seventy years ago, on the 8th of December 2012, Albert Kahn died at the age of 73. He developed new types of manufacturing facilities, particularly automobile plants, which soon attracted the attention of avantgarde architects. He revolutionized the design for factory buildings, which until then had been frowned upon by the École des Beaux-Arts trained architects and freed industrial architecture from the traditional stylistic rules of design. He showed the way to a primarily constructive architectural design.

Diese Studie ist eine Reverenz an den Industriearchitekten Albert Kahn, der seit Beginn des 20. Jahrhundert bis zu seinem Tod am 8. Dezember 1942 über 2500 Fabriken geplant hat. Die Industrie-Architektur und der Industriebau standen am Ende des 19. Jahrhunderts und Anfang des 20. Jahrhunderts noch unter dem Einfluss von eklektizistischen Stilen und von dem Historismus verpflichteten Baumeistern. Kahn gebührt das Verdienst, die Industriearchitektur an ihre technisch-rationale Aufgabenstellung zurückgeführt zu haben. Er hat sich dabei nicht nur auf die architektonisch-funktionalen Erfordernisse beschränkt, sondern darüber hinaus neue konstruktive Lösungen für große Spannweiten und stützenfreie Innenräume entwickelt.

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An die Redaktion BAUTECHNIK. Leserbrief von Prof. Dr.-Ing. Miron Mislin. Betr.: Bericht Pontshabités - Teil europäischer Brückenbaukultur, Heft 12, S. 877-885
Erwiderung von Dr.-Ing. Hans-Jörg Vockrodt

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