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A special class of steel plates, called bracket plates, is commonly used for brackets and stiffeners. Designing these structural elements has proved to be a complex problem involving many parameters and different types of behaviour. The methods used for design are often conservative and simplified because the subject has received little attention. This paper attempts to shed light on the problem and develop a new and improved design method for triangular bracket plates, derived on the basis of a consistent theory. The new design method proposed is based on the theory of plasticity, practically the yield line theory. Using the new method to solve the buckling problem for bracket plates leads to a method that, compared with existing test results, supplies very good results.

This paper presents innovative solutions for connecting steel and composite beams to structural reinforced concrete walls, as developed within the RFCS research project “InFaSo”. Two types of joints were studied: pinned and moment-resistant. The evaluation of the behaviour of the joints was performed experimentally and complemented by the development of analytical component-based models. The comparison of the results revealed good agreement between models and experiments. The joints analysed were shown to be competitive solutions taking into account their structural performance, simplicity of modelling and execution.

Bolts were tested under different combinations of tension and shear in order to estimate how bolts generally behave in combined tension and shear, what influence the strength grade has and to be able to assess the validity of the old and new standard rules. To assure results that not only represent the behaviour of round steel, but of a bolt as such, a test setup was developed that ensured a construction situation as realistic as possible. The results of these tests are summarized in this paper.

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Cold-formed hollow sections are the dominant tubular construction material. The applicability of cold-formed tubes is sometimes questioned because of doubts about low-temperature ductility, deformation capacity of welded joints, suitability for welding in the cold-formed corner, poor fatigue behaviour of the corner or suitability for hot-dip galvanizing. It is also claimed that by choosing hot-finished tubes, such risks can be automatically avoided. This study confirms that appropriate tube manufacturing yields cold-formed EN 10219 tubes in grades S355J2H to S460MH with a performance equal to or better than hot-finished tubes. Properly made cold-formed high-strength tubes are available for fabricating efficient lightweight structures and can be safely used even at low temperatures without the aforementioned doubts.

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EN 1090-2 provides several tightening methods for the preloading of bolting assemblies. One of the prescribed procedures is the use of direct tension indicators, so-called DTIs, with lubrication according to k-class K0. According to the definition of k-class K0, the lubrication should not have an influence on achieving the required preloading force Fp,C. For this reason, the main focus of the investigations presented here was how the lubrication influences the behaviour of preloaded HV bolting assemblies with and without DTIs. The experimental investigations were carried out on the institute’s own tightening torque testing machine.

In a fire the buckling strength of steel columns is heavily influenced by the distinctly non-linear material behaviour of steel at elevated temperatures. A general analytical model that explicitly includes the non-linear material behaviour is presented here and verified with full-scale tests at elevated temperature. Based on test results and this general model, a new model for flexural buckling is developed which can be used to design slender columns and allows non-linear stress-strain relationships, geometrical imperfections and load eccentricities to be considered. In addition, the model can be easily extended to include local cross-section instabilities describing the interaction between local and global buckling phenomena.

First of all, this article outlines and discusses the design rules for torsional loading according to EN 1993-1-1. Afterwards, the partial internal force method for I-, U- and Z-sections is presented. The verification for arbitrary internal forces is possible with this alternative method. The methods are compared and verified by existing test results.

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The aim of this paper is to present a detailed methodology for the three-dimensional finite element analysis of asymmetric slim floor beams under fire conditions. A fully controlled solution process is suggested through a detailed step-by-step presentation of the simulation parameters incorporated into the model. Work has been carried out so that any asymmetric slim floor beam can be assessed using the same consistent method, which is validated against two reported fire tests. Time-temperature and time-vertical displacement curves are calculated for the appropriate comparisons with experimental results, which show that the proposed methodology can accurately predict the thermal and structural behaviour of such beams.

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This article summarizes the rules given in EN 1993-1-1 [2] for using second-order analysis to check the flexural and lateral-torsional buckling of members and systems loaded in the strong plane of their cross-section which may not fail due to out-of-plane instability.
The rules relevant in EN 1993-1-1 [2] are those for equivalent geometrical imperfections resulting from the elastic buckling modes with amplitudes derived from column buckling tests according to EN 1990 Annex D [1] plus those for the linear superposition of utilization rates in the strong and weak planes as used for evaluating tests to determine the amplitude of imperfections and the partial factors.
Computer assistance is generally required for determining the elastic buckling modes; the computer outputs gives both modal out-of-plane displacements and modal out-of-plane bending moments for the relevant flanges of the sections. The use of out-of- plane bending moments makes the assessment clear and simple. It leads to a magnification factor for the in-plane-utilization rate that allows the design point x = xd to be found along the length of the member or system where the cross-sectional check is relevant. It also shows that the results of the second-order analysis for this design point and the use of buckling curves for member checks at this design point are identical.
The assessment procedure with second-order analysis is generic and applicable to all design cases, whereas the member checks with buckling curves as specified in EN 1993-1-1 [2] are intended to be valid for specific loadings and boundary conditions only (object-oriented rules). They should be consistent with the generic rules. In this respect, this article is a contribution towards the further evolution of EN 1993-1-1 [2].

This paper presents experimental investigations on thin-walled steel members with C-cross sections subjected to both local and global buckling failure. Different cross sections, buckling length and steel grades have been investigated for welded and cold-formed sections. Experimental tests on stub columns with only local buckling failure and on longer columns with combined local and global buckling will be presented. The stub column tests focused on the local buckling mechanisms with respect to axial compression loading and combined compression and bending. By testing longer columns subjected to both local and global buckling, the interaction of local and global buckling failure will be addressed. Therefore results will be based on general observations from the local buckling stub column tests. The influence of initial global geometric imperfections with respect to size and shape will be identified as crucial for the overall ultimate buckling strength of C-sections subjected to coupled instabilities.

Since the 1960s, orthotropic deck plates of highway bridges have been built with large cold-formed trapezoidal stiffeners supporting a deck plate with a thickness of approx. 12 mm. The maximum cross-beam spacing is approx. 4 m. A number of these bridge decks in The Netherlands suffer from fatigue cracks in the deck plate. First cracks have been observed after about 30 years in service. In one particular movable bridge, the cracks were found after only seven years. In many other countries, this type of crack has not yet been observed.
This article provides a fatigue assessment procedure for deck plates. The procedure is calibrated with the conditions and observations in The Netherlands. It gives a fatigue life prediction and takes account of inspection results quantitatively. Although aspects such as the type and thickness of the surface finishes and the traffic load may vary between countries, the principles of the assessment procedure in this article are generally applicable and can be used to identify reasons for differences in fatigue life and to develop strategies for increasing the life.

Literature of modelling steel frames in 3D using beam finite elements is presented. The development of member modelling is described first followed by joint modelling. The review ends with a brief introduction of the 3D component model for end plate joints. The next part includes three examples of the 3D component method: base bolt joint, beam- to-column joint and member splice joint.