Mechanical behaviour of bolt-channel joining technology for aluminium structures Luigi Fiorino, Vincenzo Macillo, Federico Massimo Mazzolani ⇑ Department of Structures for Engineering and Architecture, University of Naples ‘‘Federico II’’, Naples, Italy highlights  The extrusion process allows to conceive more rational connections: special joints.  Bolt-channel joints consist in an extruded track where the bolt can be located.  These joints are very competitive with respect to the traditional joining systems.  Experimental tests aimed at investigating joint behaviour has been carried out.  On the basis of experimental results, FEM models have been developed and calibrated. article info Article history: Received 24 February 2014 Received in revised form 15 September 2014 Accepted 25 September 2014 Keywords: Aluminium Bolt-channel Experimental tests Joining technologies Numerical modelling abstract The wide choice of cross-sectional shapes obtainable by extrusion process provides the possibility to indi- viduate new joining solutions for aluminium profiles. The achievable joining technologies are very com- petitive with respect to conventional solutions, because of the possibility of rapid execution, optimization of parent material, treatments and machining reduction. For these reasons, the aluminium industry is very interested to enhance the knowledge about the structural behaviour of these joint systems. Bolt channel joints are one of the possible technologies that entail the advantage of the extrusion shapes for joining aluminium elements. The system consists of a track or channel section profile where a bolt head, nuts or plates with threaded holes can be located. Bolt-channel joints are commonly used in build- ing applications and in transportation structures. Nevertheless, very little literature is available for this system and no specifications are provided by aluminium structural codes. In order to evaluate the struc- tural behaviour of bolt-channel joints, an experimental campaign has been carried out at University ‘‘Federico II’’ of Naples. Two different cross-sections corresponding to different bolt diameters have been selected and three different load directions have been considered. The obtained experimental results have been used for the calibration of non-linear numerical models. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction The profiles for aluminium structures are usually obtained by means of extrusion process that, as well-known, allows many pos- sibilities of cross-sectional shapes. In particular, extruded shapes can be customized according to the different possible uses by incorporating essential design features, such as stiffener, rib, bulbs, slots and tracks. These features can be exploited to conceive, in a more rational way, connection technologies to join together aluminium profiles. The achievable joining methods are various and they may or may not involve the use of fasteners. These sys- tems are generally known as ‘‘special joints’’ or ‘‘non-conventional joints’’ for aluminium extrusions. Typical special joints consist in tracks and slots obtained in the extruded shapes, in which mechan- ical fasteners, such as bolts and screws, can be located. The high competitiveness of these joining technologies is related to the ease and rapidity of assembly, machining reduction, optimization and saving of the parent material with a consequent cost reduction. These joint typologies are commonly used in many structural applications not only in building and civil engineering, but also in transportation industry. Typical applications in buildings are door and windows frames, photovoltaic support systems, stair- cases, shelves and industrial furniture. The possibility to use these joints in structural applications, even if under moderate loads, http://dx.doi.org/10.1016/j.conbuildmat.2014.09.086 0950-0618/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Department of Structures for Engineering and Architecture, University of Naples ‘‘Federico II’’, University of Naples ‘‘Federico II’’, p.le Tecchio, 80 – 80125 Naples Italy. Tel.: +39 081 7682443; fax: +39 081 419215. E-mail addresses: lfiorino@unina.it (L. Fiorino), vincenzo.macillo@unina.it (V. Macillo), fmm@unina.it (F.M. Mazzolani). Construction and Building Materials 73 (2014) 76–88 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat