Nowadays, in prefabricated composite construction, composite action between steel beam and concrete slab is often achieved with positioning of shear connectors in envisaged openings of concrete slabs. Prefabricated concrete slabs are used for composite steel-concrete buildings and bridges, both for the construction of new structures and for renovation of existing ones, significantly reducing construction time. Development of different types of shear connectors represent alternative solution to the traditionally used headed studs, considering their shear resistance, stiffness and ductility. New types of shear connectors tend to reduce the construction time and overall construction cost. Mechanically fastened shear connectors represent a viable alternative to headed studs, considering their fast installation process and shear resistance. X-HVB shear connectors are attached to the steel beam with two cartridge fired pins. The first step towards extensive implementation of X-HVB shear connectors in composite construction is to understand their behaviour through experimental investigation. Results of the push-out tests, in accordance to Eurocode 4, with X-HVB 110 shear connectors positioned in envisaged openings of prefabricated concrete slabs are presented in this paper. The experimental investigation comprised three different specimen's layout. Group arrangement of X-HVB shear connectors in envisaged openings included specimens with minimal recommended distances and specimens with reduced distances between connectors in both directions. Influence of different installation procedures on overall behaviour of the connection is presented, as well as the orientation of shear connectors relative to the shear force direction. Influence of variations is characterized in terms of failure mechanisms, shear resistance and ductility.

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Existing design codes for steel-concrete composite structures give only general information about the shear connection provided by headed studs in group arrangement. Grouting of the openings in prefabricated concrete slabs, where the grouped headed studs are placed in the deck pockets is alternative to cast-in-place decks to accomplish fast execution of composite structures. This paper considers the possibility to reduce the distance between the studs within the group, bellow the Eurocode limitations. This may lead to increased competitiveness of the prefabricated construction because more studs are placed in the group if negative effectives of smaller distances between studs are limited. The main purpose of this work is to investigate these limits and propose an analytical calculation model for prediction of the shear resistance of grouped stud arrangements in the deck pockets. An advanced FEA model, validated by results of push-out experiments, is used to analyze the shear behavior of the grouped stud with smaller distance between them than recommended by EN 1994-1. Calculation model for shear resistance, which is consistent with the existing Eurocode rules, is proposed based on a newly introduced equivalent diameter of the stud group, dG. The new calculation model is validated by comparison to the results of FE parametric study. The distance between the studs in the longitudinal direction and the number of stud rows and columns in the group are considered as the main variables.@en

In parallel with an experimental investigation of the flexural buckling behaviour of built-up stainless steel columns presented in the accompanying paper (Dobrić et al., submitted for publication), a detailed Finite Element Analysis (FEA) has been performed to simulate the experiment and identify the key factors affecting the buckling response. The FEA entailed realistic geometry, measured geometric imperfections and material properties of the specimens. Very good agreement was obtained between the experiment and FEA, which proved the capability of the computational approach to replicate experimental results and predict ultimate buckling loads. In the absence of explicit design rules for flexural buckling resistance of stainless steel closely spaced built-up members, the experimental results were compared with design predictions according to the existing European Standard and American Specification for carbon steel structures. The findings indicate that the mentioned design standards may be very conservative regarding the buckling resistance of stainless steel built-up members; this under-prediction may be associated with the impact assessment of chord slenderness and interconnection stiffness on the buckling response. The main purpose of this research is to establish a qualitative data base reliable for the further quantitative numerical parameter analysis and for the development of new design rules for compressed stainless steel cold-formed built-up members.

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The Railway road bridge in Novi Sad is situated on the international railroad Belgrade-Budapest. The bridge is designed for two railway tracks (with design speed of 160 km/h), two road lanes and two footpaths. The bridge structure consists of four structures: two approach composite bridges at the banks and two steel tied network arch bridges over the river and transition structure between two arches. The spans are 27.0 + 177.0 + 3.0 + 219.0 + 48.0 m, totally 474.0 m in length. The rises of arches are 34.0 m and 42.0 m respectively. The width of the bridge is 31.440 m. The arches and ties, as well as the girders of the approach spans, are steel box girders. The decks of all bridge structures are the composite reinforced concrete slabs with thickness of 300 mm, locally 400 mm. The launching was very complex, in both analysis and construction. The arch bridges were fully assembled on the banks and launched by skids over the bank and by pontoons over the river, to the final position on piers. The bridge was designed fully according to European standards and additionally - according to requirements of German codes DIN-Fachbericht 101 to 104 Edition 2009 and Deutsche Bahn Richtlinie 804, Edition 2003. The bridge is, despite of heavy loads and structural complexity, very rational in steel volumes and construction costs as well. The bridge is also, with the arch span of L = 219 m, the bridge with the longest span in the world in the category of tied network arch bridges with two rail tracks. The bridge is open to rail traffic at 7th April 2018.@en

One of the most important acceptance issues regarding the implementation of small-scale wind turbines in urban environments is related to human comfort. Turbine-induced vibrations can have a large influence on small-scale turbine implementation for urban wind harvesting. A typical five-storey steel-framed office building with a roofmounted, horizontal-axis wind turbine was numerically analysed. The aim of the work was to investigate the increase in vibration after the installation of the turbine. A comparison was made between floor vibrations caused by wind action on the building only and by wind action on the building and turbine combined. The results were then compared with requirements given in various design codes. The main outcome of the analysis is that the installation
of the turbine did not compromise the building’s serviceability.@en

Grouped headed studs may be successfully utilized to achieve the longitudinal shear connection between prefabricated slabs and steel beams. The behaviour of the studs and the ultimate resistance of the group were analysed using the results of experimental push tests and by employing advanced FE analyses. Different arrangements of studs in the group were investigated, focusing on minimal distance between the studs. It is demonstrated that the full shear resistance of a group of headed studs is achieved even when the distances between the studs are less than the minimum requirement according to EN 1994-1-1. Concrete class C30/37 is the minimum that should be used. Furthermore, the paper presents a new model for calculating the shear resistance of grouped headed studs. The proposed design model is based on an equivalent stud diameter and can be used for various arrangements of headed studs in a group. The shear resistance formula and the requirements for ductility are consistent with the existing Eurocodes. Fatigue loading is not considered in this paper, so the proposed recommendations are valid for buildings including multi-storey car parks.

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