The 2010 AISC Specification for Structural Steel Buildings has expanded its scope in chapter K “Design of HSS and Box Member Connections” to include a section K4 “Welds of Plates and Branches to Rectangular HSS”. This paper discusses the historical development of the effective weld properties and analyses the structural reliability of the provisions. Additionally, there is a discussion on recent changes in U.S. and Canadian specifications/ codes with regard to the limit states for fillet weld design and the acceptance/rejection of the (1.00 + 0.50 sin1.5) term. Finally, there is a discussion of the details of an experimental research programme being performed at the University of Toronto in collaboration with AISC to determine the weld effective length in RHS T-connections under branch in-plane bending moments. In conclusion, it is found that the inclusion of the (1.00 + 0.50 sin1.5) term for RHS gapped K-connections as well as T- and X-connections, based on the limit state of shear failure along the effective throat of the weld, may be unsafe for fillet weld design when used in conjunction with the current effective weld length rules.

Eurocode 8 has introduced the possibility of adopting partial-strength joints for seismic-resistant MR frames, provided it is demonstrated that connections perform adequately under cyclic loads. A programme of experiments devoted to investigating the cyclic behaviour of traditional joint details has recently been carried out by the authors. Within this programme, the analysis of the results obtained has revealed that even though connections designed to dissipate the seismic energy in bolted components can provide significant advantages because they are easy to repair after a destructive seismic event, they possess reduced dissipation capacity when compared with RBS connections and traditional full-strength joints. An advanced approach aimed at enhancing the hysteretic behaviour of double split tee (DST) joints and the ambitious goal of preventing joint damage is presented here. The system proposed is based on the idea of using friction dampers within the components of beam-to-column joints. A preliminary set of prototypes has been tested experimentally and the performances of joints under cyclic loading conditions have been compared with those of traditional joint details. The experimental work was carried out at the Materials

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A design model for composite beam-to-reinforced concrete wall joints is presented and discussed in this paper. The model proposed is the component method extended to this type of joint. The characterization of the active components is therefore performed in terms of force-deformation curves. In this type of joint, special attention is paid to the steel-concrete connection where “new” components, not covered in EN 1993-1-8, are activated. The application of the model allows the designer to obtain the joint properties in terms of the moment-rotation curve. The accuracy of the proposed model is verified by comparing it with available experimental and numerical results. The latter were developed in the FE program ABAQUS and previously validated by experimental results.

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Several national design standards allow the use of hollow sections with minimum nominal wall thicknesses down to 1.5 mm. However, the international standards that will be used in the future, based on the work of the International Institute of Welding (IIW-XV-E), still prescribe a minimum thickness of 2.5 mm. This paper presents the background to the IIW-XV-E higher thickness limit and presents strong arguments for extending the scope of these international standards to include structural hollow sections with wall thicknesses down to 1.5 mm.

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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.

A study into the feasibility of monopile foundations at sites in the North Sea with water depths as great as 35 m has been carried out in which various options for the geometric configuration and the selection of material were considered. In parameter studies, simplified design methods were applied to assess the effects of the individual load components at the draft design stage. The fatigue limit state becomes more and more relevant as the water depth increases; therefore, dynamic effects must be examined with special care. Turbine concepts with low RNA mass and low rated speed help to achieve the desired design in the soft-stiff regime. As a result, it can be said that monopile foundations with their great manufacturing advantages can be constructed for water depths beyond the current limits of practical experience if the logistical challenges in handling large masses are solved.

The technology of assembling the roof over the stadium built in Gdan´sk for the EURO 2012 European Football Championship is discussed here. The stadium has a characteristic silhouette - its shape and the colours of the façade resemble a cut block of amber. The steel roof structure has a quasi-elliptical form, with a maximum diameter of 220 m and minimum diameter of 187 m. It is 38 m high and the roof girders extend 48 m over the grandstand below. The roof structure weights 7150 t and was assembled in 226 days.

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This paper presents information about structural elements of the roof covering to the stadium in Gdan´sk built for the 2012 European Football Championship in Poland and the Ukraine. The paper discusses elements of the polycarbonate covering, the supporting structure and the drainage system. It also provides information about tests and research performed prior to construction, which determined the solutions adopted as well as the roof’s present and future condition.

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This paper presents numerical and analytical investigations of thin-walled steel C-section members subjected to both local and global buckling. The results presented here are based on experimental tests which are dealt with in a previous publication [1]. Numerical calculations using the finite element method are performed to recalculate test results from stub column tests with local buckling and long column tests with coupled local and global buckling failure. These results are analysed using different design procedures based on Eurocode 3. Using modified buckling factors and an approach considering effective stiffness by approximation, it is possible to determine the ultimate buckling loads from tests and numerical investigations efficiently.

Two innovative systems of seismic-resistant steel frames with dissipative fuses were developed within the European Research Programme “FUSEIS”. The first, named FUSEIS 1, resembles a shear wall, whereas in the second system, named FUSEIS 2, the devices are made by introducing a discontinuity into the composite beams of a moment-resisting frame. The main advantage of “FUSEIS” compared with conventional systems is that inelastic deformations are strictly concentrated and controlled in zones that constitute easily replaceable fuses. The dissipative elements can be positioned in small areas of the building and do not interrupt the architectural plan as braces do. Another advantage of the system is the possibility of easy installation and removal within the structure.
This article presents the results of the experimental and analytical investigations of the innovative energy dissipation system FUSEIS 1. The system consists of two closely spaced strong columns connected by dissipative beams within each storey. In order to enhance the stiffness, strength and energy dissipation capacity of the system, several fuses are provided within each storey. During a strong seismic event, the dissipative zones are formed within the pins while the other parts of the structure remain elastic and protected.

The article describes a method for the probabilistic risk assessment of loadbearing bar structures according to second-order theory without having to indicate expressly the limit state equation. The load combination is also considered in the course of the calculation. Time-dependent loads are modelled as pulse processes with a rectangular form. The sequence of load renewals has a Poisson distribution and the magnitude of the load is subjected to a Pearson distribution. The distribution of the maximum values of the safety-relevant load reaction is obtained by means of the Monte Carlo simulation. The basis is a generalization of the deformation method. The probability of cross-section failure is determined for an exemplary loadbearing structure. The probability is sensitive to the distribution parameters of the processes. For certain loading constellations, this analysis contradicts the safety concept of building practice.

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The Institute of Peace’s new facility, a modern conference and an interactive educational center dedicated to the theme of peacemaking, faces the National Mall in Washington, DC and is within sight of the Lincoln, World War II, Korean, and Vietnam Veterans memorials. The building is organized around two atria, one part facing the Potomac River, the other the Mall and the Lincoln Memorial. The north atrium serves as the centerpiece for the spaces devoted to the organization’s work and research, and the south-facing atrium is focused on public programs and conferences. The roof of the building features a series of undulating, wing-like elements constructed of steel frame and white translucent glass forming an image resembling the wings of a dove. The glass appears opaque and white during the day and glows gently from within at night.
The two roofs and four curtain wall façades have been designed, fabricated and installed by seele, being responsible for the realization. Optimisation of conceptual design, structural and detailed design for the free forms of the self-supporting shell structures and the vertical facades was conducted by Knippers Helbig, Advanced Engineering.

Between 1933 and 1938, some 50 Vierendeel-type welded road bridges were erected in Belgium to provide crossings over the Albert Canal or the Campine canals. They were the first significant applications of electric arc welding in Belgium and constitute the majority of the large welded bridges built at that time in Belgium. It was the heyday of the Vierendeel bridge, which had been invented in 1895 but which had found only limited applications before 1930, with less than 40 built in Belgium and Congo in 30 years. But this rapid application of welding to structural steelwork encountered many problems that were probably overlooked in the climate of euphoria surrounding bridge-building. In March 1938 the Hasselt Bridge suffered a brittle failure. This is generally regarded as the first brittle failure of a large all-welded structure and received much attention at that time. But in 1940 at least three other bridges of this series were also badly fractured and there are indications that some others also experienced serious cracking problems. This paper places theses accidents in perspective in the long story of brittle failures.

One key project in the Chinese city of Fuzhou is Langqi Min River Bridge, which connects the business and technology district with downtown Fuzhou. The main bridge is a twin-pylon cable-stayed structure with a main span of 680 m and a steel box girder. This paper presents the detailed design features of the bridge, including foundations, anti-ship collision devices, pylons, steel box girder and stay cables.

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Based on findings from Büchenauer Bridge (1956), the North Elbe Bridge in Hamburg (1963) and the bridge over the Rhine at Leverkusen (1965), Homberg designed and engineered the Friedrich Ebert Bridge across the River Rhine. This was the first bridge in the world with cables that distribute instead of concentrate the load transfer, and thus define the bridge deck as a continuous, elastically supported element and not as a beam on point supports.
After the building of major bridges declined in Germany, Homberg became active in France, and later rounded off his work with multi-cable-stayed bridges in the UK. That work resulted in the Queen Elizabeth II Bridge (1991), Homberg’s late magnum opus.
This article contains a complete catalogue of Homberg’s multi-cable-stayed bridges and discusses for the first time previously unpublished designs by Homberg. These prove that he had already moved on from the classic cable-stayed bridge to the general multi-span cable-stayed bridge as early as 1963.