PSI - Issue 47

Calin-Ioan Birdean et al. / Procedia Structural Integrity 47 (2023) 87–93 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Liu et al. (2018) showed the influence of the endplate thickness on the prying force for bolted flange connection with the bolts positioned outside the profile perimeter. The study was performed both experimentally as well as numerically, considering 10 mm and 16 mm flange thickness. Due to the small distance between the compressed area and the tensioned bolt, the rigidity of such connections is limited and the joint is considered as semi-rigid joint. For structures with semi-rigid joints, the real deformation of the structure is obtained only if the rigidity of the joints is considered. The rigidity of the semi-rigid joints is influenced by the axial and bending level as presented by Urbonas and Daniunas (2006). In a numerical study, Urbonas and Daniunas (2003), showed the significant influence of inclination of beam and quantity and location of bolts on the joint rigidity. These connections are mostly used for axial force transfer between the elements but bending can also occur, thus the response of these joints to flexural loading is necessary to be studied. Prefabricated parts may be used to obtain in-line connections as showed in Arcat (2022) which represent cast steel fittings that enable unobtrusive field bolted splices between circular hollow sections. The fittings are designed such that the bolted connection is inboard of the outer diameter of the connected elements. These splices can be sheathed in thin-gauge plate to completely conceal the splice or can be left uncovered as presented in Arcat (2022). Another fast erecting joint is presented in [9] where gusset plates are shop ‐ welded to the round, square or rectangular HSS members, projecting outwards from the HSS to be joined, plus additional splice plates are prepared and drilled in the shop, then the connection is bolted together on site. In practice, the assessment of the capacity can be determined using the method developed by Stephan and Stutzki (2002), based on the classical strain iteration algorithm for cross sections. Although the method is suitable for computer programs, the magnitude of the joint separation in the tensioned area is not available, although it can be a serviceability criterion for design. The aesthetic aspect of the element can be maintained using an end plate with the same perimeter as the hollow profile as presented by Both et. al. (2019). They showed the failure modes development of in-line connections for rectangular hollow sections. The current study presents the response of an in-line bolted connection with the end plate positioned inside the hollow section at 2 mm from the profile end plane. Based on experimental results, a numerical model is defined using finite element method. The influence of the access hole, the preload level and the end plate thickness is presented. 2. Reference Results An experimental stand was setup to determine the response of an in-line connection of two RHS profiles. Each element assembly consists of the RHS250x150x8 profile with a support end plate and a connection endplate welded inside the RHS profile, Fig. 1a). Each element assembly had a cut 150x110, for access to the M20 gr. 10.9 bolted connection as can be seen in Fig. 1b), which reduces the capacity of the structural element.

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Fig. 1. (a) Element assembly; (b) In-line connection.