ECCS News:
ECCS R&D activities
News from ECCS Members
European Steel Design Awards 2019
Austria: The New ÖAMTC Headquarters, Vienna
Czech Republic: Replacement bridge over the Dam Hracholusky
Denmark: K.B. Hallen, Copenhagen
France: Simonne-Mathieu Tennis Court, Roland Garros
Germany: Adidas Arena, Herzogenaurach
Norway: PAN Treetop Houses, Gjesasen
Portugal: Hippodrome de Longchamps, Paris
Sweden: Kristallen, Kiruna
Switzerland: Jet deau Movable Footbridge, Geneva
The Netherlands: Station E-line, Den Haag
Turkey: Sveti Stephan Bulgarian Church Restoration, Istanbul
Winners, The Awards of Excellence

News: Tomá Vraný SDSS Award for experimental study on lateral torsional buckling of welded sections
Bernt Johansson Outstanding Paper Award for studies on the influence of imperfections on the post-buckling behaviour of square hollow sections
Professor Eduardo de Arantes e Oliveira Award at XII Conference on Steel and Composite Construction in Coimbra

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The new intercity line Toluca - Mexico City has a length of 57.7 km. The daily passenger estimate is about 230,000 to 300,000. The investment volume amounts to 2.5 bn US$. Its special feature is the MAURER seismic protection system for two long viaducts. The company installs for this purpose so-called guided cross-ties, the first absolutely earthquake-proof railroad bridge expansion joints. Together with a complex system consisting of bearings, dampers and elastomeric spring isolators they ensure structural stability, function and safety for various load cases: from braking and acceleration forces in normal operation to the Maximum Considered Earthquake (MCE). MAURER startet to work for this project in 2016. The last step scheduled is the installation of the guided cross-ties at viaduct 4 in the third quarter of 2020. (© MAURER SE)

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No short description available.

Nominated for the Bernt Johansson Outstanding Paper Awards at Nordic Steel 2019
The growing popularity of high-strength steel grades leads to the need for more accurate design specifications, with the aim of fully exploiting the material benefits and creating economic advantages. According to Eurocode 3, the maximum rotational capacity of a section is limited and linked to the definition of cross-sectional classes. For class 1, the rotational limit &thgr; is assumed to be “infinite”, whereas it drops significantly for classes 2 and 3 to a maximum rotation of &phgr;pl and &phgr;el, respectively. In reality, despite their lower hardening capacity and ultimate strains, high-strength steel sections exhibit a non-negligible rotational capacity that exceeds these code predictions, which were developed for mild steel and with a level of analysis in mind that is suitable for hand calculations. In order to achieve greater use of high-strength steel sections, it is thus very important to understand and be able to predict a section's deformation and rotational capacity more accurately, with the aim of implementing the findings in tools for advanced, FEM-based design by analysis (DbA) approaches. As an initial step in this direction, this paper shows the results from numerical calculations of the rotational capacity of HSS rectangular hollow sections. The numerical results were calibrated against laboratory tests. Consequently, different rectangular cross-section dimensions and variations of the steel grade and thickness were chosen and analysed in the ABAQUS finite element software.

Nominated for the Bernt Johansson Outstanding Paper Awards at Nordic Steel 2019
The current design rules of EN 1994-1-1 covering headed stud shear connectors for composite beams with profiled sheeting lead, in some cases, to an overestimation of the load bearing capacity. Owing to their empirical nature, these equations are not able to capture the real behaviour of the connector. Therefore, the load bearing mechanisms of the shear connection are identified in this work with the support of experimental and numerical results. According to the static system proposed, the concrete rib is modelled as a system of diagonal struts in combination with the stud in bending. It was observed that at 1-4 mm slip, a “strut and beam” mechanism prevails, where the resistance of the connector depends on the activation of the plastic hinges in the stud and on the capacity of the diagonal strut in front of it. By increasing the slip (approx. 4-10 mm), the surrounding concrete gradually crushes, while the tensile stresses at the edge of the rib reach the tensile strength of the material. Because of this loss of rotational stiffness, the bending moment in the stud decreases and the upper plastic hinge gradually moves towards the slab. At higher displacements (approx. 20-40 mm), high tensile forces develop in the stud due to non-linear geometric effects and the load is carried through a “strut and tie” resistance mechanism, provided that the embedment of the stud is sufficient to prevent the rotation of the rib. As the slip increases further, failure occurs either in the form of concrete pull-out or stud rupture.

Nominated for the Bernt Johansson Outstanding Paper Awards at Nordic Steel 2019
Most steel moment frames are designed so that the beams act as structural fuses during earthquake loading. This approach, while good for saving lives, has poor resilience because it is difficult to replace damaged beams in a building. A repairable steel moment-frame connection has been developed that may be attractive to engineers and building contractors. The connection has a fuse plate bolted to the beam bottom flange which experiences shear yielding during severe earthquakes, protecting both the column and the beam. After an earthquake, the fuse plates can be removed and replaced to unlock residual frame deformations and prepare the building for another event.
Full-scale experiments were conducted to validate the performance of this repairable connection. Two tests were performed with a W690 × 125 beam and W530 × 196 column. The tests demonstrated rotation capacities of at least 0.05 rad, which exceeds AISC requirements for special moment frames. The fuse plate was effective in preventing beam damage in each test, and the second test demonstrated that the connection could be repaired by replacing the fuse plate.

Nominated for the Bernt Johansson Outstanding Paper Awards at Nordic Steel 2019
This paper presents a Two-Stage-Model for determining the fatigue life of steel structures. The model follows the distinction between crack initiation and crack propagation according to the phenomenological background. The first stage uses the local strain-life approach to predict the number of cycles for crack initiation Ni considering the cyclic material behaviour as well as the load-time history. The second stage calculates the crack propagation based on a linear-elastic fracture mechanics approach. Using X-FEM in combination with cyclic loading, an arbitrary, solution-dependent crack path is achieved to determine the number of cycles for propagation Np. The Two-Stage-Model was applied to butt welds to determine their total fatigue life Nf in terms of a proof-of-concept study. The study investigated the ability of the model to consider the influence of the weld geometry, i.e. plate thickness and weld imperfections (excess and vertical offset). The results are presented by means of S-N curves for initiation life, propagation life and total fatigue life. A comparison with experimental results provided in the literature shows that the Two-Stage-Model can reflect the weld quality of butt welds in terms of fatigue life.

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Nominated for the Bernt Johansson Outstanding Paper Awards at Nordic Steel 2019
A state-of-the-art framework for the design of jacket foundations for offshore wind turbines is presented here. The article illustrates how an efficient, yet highly accurate, structural model can be achieved through a combination of a comprehensive beam finite element model and detailed shell/solid finite element models, where the former suffices for representing the overall global behaviour and the latter improves the representation of non-trivial structural details such as the transition piece and tubular joints. This approach allows the verification of standard structural elements according to various design codes to be automated on beam element level, while the fatigue performance via the hot-spot method as well as detailed stress and buckling analyses of relevant joints and details can be performed based on the detailed shell/solid finite element models readily available for stiffness representation. The computational framework ensures full consistency between the local and global description levels and an efficient cloud interface facilitates the thousands of design load cases that typically require consideration in order that a full detailed design can be simulated within a reasonable timeframe.

Nominated for the Bernt Johansson Outstanding Paper Awards at Nordic Steel 2019
Over the past few decades, the cold-formed steel industry has developed a manufacturing technique for producing self-supporting arches from trapezoidal steel sheets. The press-forming procedure is based on introducing transverse corrugations into the main direction of the flat profile in order to bend it. The main problem is that these indentations, which are essential to curve the profile, change the effective properties of the original steel sheet. Currently, there is no design code or standardized test procedure that can be used to obtain the effective properties of the corrugated profile. This research project analyses the behaviour of the corrugated profile when it is subjected to pure compression and compares it with the behaviour of the flat profile.

Nominated for the Bernt Johansson Outstanding Paper Awards at Nordic Steel 2019
The “column web panel in shear” is known to be a key component in the design of steel and steel-concrete composite joints as it can provide a reserve of ductility at the joint when activated and appropriately designed. Therefore, its behaviour has been studied for years and was thought to have been fully understood. However, some recent research projects have demonstrated that, in many cases, the simple analytical model proposed in Eurocode 3, Part 1-8, significantly overestimates the actual resistance of this component. In this context, this paper will look at the first results of investigations into that problem conducted at Liège University. In particular, beam-to-column welded joints have been studied in order to: i) highlight the aforementioned problem through comparisons between existing experimental results and Eurocode 3 predictions, ii) develop a sophisticated finite element model using the Abaqus© software, iii) validate this FE model using existing experimental results and iv) develop an extensive parametric study in order to highlight the key parameters governing the resistance capacity of the component studied. Based on the investigations conducted, the final goal consists of providing a new analytical formulation that is able to predict more accurately the shear strength of the column web panel.

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Industrial storage operators use not only new pallet racking systems, but also old ones for which certification documents possibly do not exist. In order to check the carrying capacity of such racks, in addition to component tests, full-scale experimental tests were carried out on complete structures to help the development of reliable numerical models. The racks were subjected to vertical and pushover loads in the laboratory using an improved version of the base plates to achieve fixed support conditions. Vertical loading was imposed by filling tanks with water, an operation that was activated and controlled through an innovative hydraulic network specifically designed for this purpose. During the vertical loading tests, a moderate earthquake took place near the experimental facility and this influenced the rack behaviour positively. The spine brace was too flexible in the out-of-plane direction and did not participate in the resistance to lateral forces. Distortional buckling of the columns was observed at high lateral loads. The experimental tests allowed the calculation of conservative values for the behaviour factor q.

When ascertaining the effective widths of class 1 and 2 composite girders, it is claimed that at ULS, Eurocode 4 procedures give highly conservative results. A new approach to the problem is proposed in which the strain limitation values are introduced after deriving a new formula (graphically presented) with the intention of replacing the existing one. It turns out that the new effective width is significantly larger. Such a result leads to some advantages in reinforcement distribution in the support areas of continuous girders. It might also lead to some savings in reinforcing and structural steel. This is demonstrated by an example. Another example shows a situation in which the rough application of Eurocode 4 may produce a design with a lack of reliability for some of the bridge superstructure elements. The results obtained may also be useful for situations where a structure with composite girders already in service has to be redesigned for increased loads.

ECCS News: ECCS R&D activities
ECCS TCs activities
Joint action with ECCREDI partners
European Steel Day 2019 Brussels, 26 June 2019 Transitioning to the future of EU industry
News from ECCS members
Talking with: Sir Philippe Samyn
Bauhaus, Modernism and the Contribution of Engineers: bauhausTWINS - an installation by zukunfsgeraeusche
News: Steel Construction achieves first CiteScore value
Congress Advancements for Metal Buildings 14/15 October in Marseille
Book review: Kurrer, K.-E.: The History of the Theory of Structures: Searching for Equilibrium.
PHD-Thesis: Design Guidelines for highly glazed office buildings in steel composite construction developed by using dynamic thermal simulations, optimisation methods and life cycle assessment

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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.