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Cartridge fired pins, also known as powder actuated fasteners, have a wide application in different construction industry fields, mostly for joints of cold-formed structural elements and profiled steel sheeting, or for installation of shear connectors in composite steel-concrete structures. Installation of cartridge fired pins is mostly governed by high energy introduction from installation device and mechanical fastener to the steel base material, without initial predrilling of holes. Therefore, large plastic deformations of base material are developed through installation procedure, together with various anchorage mechanisms between fastener and base material. This paper presents experimental investigation of most important influence parameters on behaviour and resistance of cartridge fired pins, such as adjusted installation power level on installation device and steel base material strength. Experimental investigation involved X-ENP-21 HVB cartridge fired pins through double-sided shear tests, tension tests with fasteners installed over X-HVB shear connector with two different steel grades (S275 and S355) and two installation power levels (2 and 3.5), and tension tests with fasteners installed over two thicknesses of pro-filed steel sheeting (0.8 mm and 1.0 mm). Cartridge fired pin resistances together with corresponding failure mechanisms were experimentally quantified and presented in this paper.

Implementation of demountable beams in steel-concrete composite floors enables structure reuse during several life cycles, consequently leading to savings in material consumption and reduction of emissions, providing overall ecological benefits. The behaviour of the innovative demountable beam with a shear connection consisting of headed studs and bolts is analysed in this paper. The proposed beam is formed of a steel profile and a steel-concrete composite slab cast in open trough profiled steel sheeting. Headed studs, welded to the additional steel angles, are placed in sheeting ribs, whereas bolts are installed between ribs, connecting the steel angles and profile flange. A numerical FE model of a full-scale steel-concrete composite beam has been developed to analyse the beam behaviour under service loads. Experimental results of push-out tests have been used to describe the loadslip behaviour of headed studs, whereas bolt response has been simulated according to the experimental investigations of lap joints with preloaded bolts and oversize holes. The parametric study has been conducted by varying the bolt diameter, grade and bolt hole size. The results have validated the applicability of the proposed system, confirming the fulfilment of serviceability limit state requirements.

For obtaining shear resistance of a welded headed stud in profiled steel sheeting, EN 1994-1-1:2004 defines reduction factors that should be multiplied with the resistance of a headed stud in a solid concrete slab. Two reduction factors are prescribed, for sheeting ribs that are parallel and transverse to the supporting beam. However, the design code does not recognise cases when the angle between ribs and the beam is in the range between 0° and 90°. This research is focused on the specific case in the steel-concrete composite beam design when the angle between profiled sheeting ribs and the beam is 45°. The experimental investigation has been conducted through push-out tests, comparing the response of the connection with a rib-to-beam angle of 45° and the connection with ribs transverse to the supporting beam. In addition, numerical models based on finite element analysis have been made and validated against experimental data. According to the obtained results, similar failure mechanisms manifested through concrete pull-out failure and separation of the concrete cone are observed in shear connections with rib-to-beam angles of 45° and 90°. An increase in the connection resistance is noticed with the decrease of a rib-to-beam angle.

During the assembling of a steel structure with anchors, grout should be used in connections be- tween steel elements and a reinforced concrete support element. In horizontal and vertical joints, grout is used as a good construction practice for solving geometric tolerance problems. Grout can be used with cast-in anchors or post-installed anchors. However, the relation between anchor shear resistance and characteristic grout compressive strength is not described in detail in tech- nical regulations. The behaviour of a connection considering achieved slip tolerances should match the boundary conditions set in the global analysis. In the support joint, grout properties could influence the value of the slip between a steel part and a concrete part of the joint. Slip value could be significant for the relevant design cases featuring the interaction of shear force and ten- sion force. In this paper, results of the push-out test conducted on anchors are presented. Based on the experimental test, the finite element analysis was performed to investigate the shear con- nection behaviour. According to the preliminary results, it can be concluded that a grout strength and a grout thickness influence the connection response when serviceability loads are applied, alt- hough they do not influence the ultimate load bearing capacity of anchors. In some cases, using the contemporary solutions of high strength grout materials, the slip between steel and concrete parts in the connection could be reduced.

Stainless steel sections are used for structures in aggressive environments where the greater material cost can often be justified in return for longer maintenance-free periods, for example in the water treatment, nuclear, petrochemical and food and beverage sectors. This paper presents a comparative imperfection sensitivity study of hot-rolled and laser-welded pin-ended equal angle columns made of austenitic stainless steel grade 1.4301. Although the initial geometric imperfections in these structural elements are similar, there is a difference in the initial stress state due to the different manufacturing processes. The study includes three-dimensional geometric imperfection measurements conducted by a laser scanner, and, in parallel residual stress measurements performed by the sectioning method using water jet cutting. The overall bow, camber, and twist imperfections are determined from the scanned specimens. In addition, the shapes of the residual stress patterns through the thickness of the angle leg are shown. Based on the findings related to imperfection distributions and amplitudes, a FE analysis is performed both on hot-rolled and laser-welded angles to study the influence of the variability of initial imperfections on compression resistance. The separate and combined effects of the measured residual stresses and initial out-of-straightness are considered and the reduction in the buckling resistances of initially straight angle columns is determined. The structural responses of hot-rolled and laser-welded columns are compared and discussed.

Different types of shear connectors which assure composite action between steel profile and concrete slabs have been developed during decades, considering different shapes, installation equipment and installation process. Also, three main characteristics of shear connectors, shear resistance, stiffness and ductility are specific for each type of shear connector. Widely used shear connectors for composite constructions of buildings and bridges are headed studs and different types of perfobond shear connectors. Different behaviour of these types of shear connectors, mainly reflected in unsatisfactory behaviour of headed studs resulted from fatigue problems, reflects in their various applications. Numerous experimental and numerical investigations performed with headed studs and perfobond shear connectors through standard push-out tests resulted in development of design procedures which are proposed by different authors or can be found in current design codes such as EN 1994-1-1, ANSI/AISC-360-05 and JSCE. Comparison of heads stud’s and perfobond shear connector’s beahviour through experimental results of standard push-out tests are presented in this paper. Experimentally obtained shear resistance of four headed studs with 16 mm diameter and 100 mm height, positioned in one row into envisaged openings of prefabricated composite decks, with shear resistance of perfobond shear connectors are compared. Main differences in respect of ductility, stiffness and different failure modes which can be noticed for these types of shear connections, obtained from experimental investigation are analyzed in this paper. Comparative analysis includes different shapes, dimensions and specimen’s layout of perfobond shear connectors, experimentally investigated through standard push-out tests which results are available in different literature. Numerical analysis included perfobond shear connectors positioned into envisaged openings of prefabricated composite decks with same dimensions and

Although all metals lose strength and stiffness when they are exposed to fire, the reduction of mechanical properties considerably varies between different metals. In contrast to carbon steel, austenitic stainless steel has better response at elevated temperatures due to relatively high content of alloying elements. The type of metallurgical microstructure crucially affected on material response and global behaviour of structural elements under fire conditions. Despite the fact that carbon steel and stainless steel have different constitutive patterns, EN 1993‐1‐2 states that resistance of structural elements made from these materials should be checked using the same fire design procedure. This paper presents numerical analysis of buckling resistance of compressed members exposed to fire, without fire protection. Finite element analysis is conducted using the ABAQUS software. The study points out the structural performance of columns made of stainless steel cold‐formed hollow section and hot‐rolled I‐section in grade 1.4301 and identical columns from carbon steel grade S235 at high temperatures. Sensitivity to initial imperfections is also assessed. The thermal and mechanical properties of carbon and stainless steel are taken from EN 1993–1‐2. Development of temperature into the columns in fire condition is obtained from standard fire curve, according to ISO834. The numerical predictions of buckling response are compared with results of design procedure according to Eurocodes EN 1991–1‐2 and EN 1993–1‐2. The aim of this paper is estimation of acceptability and accuracy level of the mentioned design guidelines in the treatment of buckling phenomena of stainless and carbon steel structural elements at elevated temperatures.

Construction industry is constantly facing new demands towards fast construction and smallest possibly quantity of work at the construction site. These increasing demands, in the field of composite construction of buildings and bridges, resulted in development of different types of prefabricated composite decks during decades and group arrangement of different types of shear connectors. Positioning of shear connectors into envisaged openings of prefabricated composite decks contributes to smaller quantity of concrete needed to infill openings of prefabricated composite decks. Composite action between steel profile and concrete decks can be achieved using X‐HVB shear connectors with powder‐actuated fasteners. Anchorage mechanisms developed between steel profile and fasteners during installation process of powder‐actuated fasteners are resulting in composite action between steel and concrete. Relatively simple and fast installation process, without requirements for additional equipment and electrical power on the site is characteristic for this type of shear connectors. Experimental investigation of X‐HVB shear connectors in prefabricated composite decks through standard push‐out tests, according to EN 1994‐1‐1 is presented in this paper. Shear connectors are positioned at the envisaged openings of prefabricated composite decks at the minimal longitudinal and transversal distances, recommended by the manufacturer. Two different orientations of shear connectors, forward and backwards to shear force direction are experimentally investigated and presented in this paper. Experimentally obtained characteristic shear resistance are compared with recommendations given by manufacturer. Characteristic slip at failure obtained from experimental investigation is compared with requirements given in EN 1994‐1‐1 in order to determine if this type of shear connector is considered as ductile. Eight specimens in two series are experimentally investigated through standard push‐out test