PSI - Issue 59

Volodymyr Romanіuk et al. / Procedia Structural Integrity 59 (2024) 471 – 478 Volodymyr Romanіuk et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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hinged fixed, hinged movable, etc. This idealization may not entirely align with the actual conditions of their work within structures as a whole (Liu et al., 2019; Rezvani and Ronagh, 2017; Wang et al., 2018; Son, 2018; Shardakov et al., 2018). Largely, this also relevant to bolted flange connections of beams, which are supported by specific supports (such as lower beams, columns, etc) and are attached to them with mounting bolts. In calculations using an idealized calculation scheme, this connection is often considered hinged, with bolts primarily serving to fix the beams in the designated position. In reality, the hinge nodes of freely supported span elements undergo deformations due to the deflection of these elements. As a result, the mounting bolts experience stretching and interfere with free deformations on the supports. This effectively transforms the supports into partially rigid elements, which affects the redistribution of forces along the entire length of the elements. Hence, the authors performed a theoretical evaluation of the actual stiffness of both rigid and hinged bolted joints in elements of steel structures (Romaniuk et al., 2021, 2023). They also developed an effective method for determining the impact of the opening degree in rigid bolted joints and the resistance of mounting bolts to the opening of hinged support nodes on their overall rigidity. The application of the proposed calculation method allows us to determine the stiffness of rigid and hinged bolted joints, taking into account their actual behavior. It also allows for adjustments based on variations in the bolt diameter, material strength, quantity, spacing, or the thickness of connecting elements. This method allows us to use an additional resource of the material due to some reduction of the maximum stresses in sections of the elements. 4. Conclusions 1. The stress-strain characteristics of different types of intermediate supports for two-span continuous perforated beams were determined with finite element analysis using the "Lira" software complex. The calculations were performed under the influence of a symmetrical uniformly distributed load applied across the spans. 2. It was determined that the design of the intermediate support has minimal impact on the magnitude of maximum deflections and stresses within the beam span. However, it does alter the operational characteristics, particularly in the case of use a support part without a stiffening rib and with unwelded holes on both sides of the support axis (type 1). 3. The maximum normal stresses are observed at the characteristic calculation point 3 of cross section 1-1 in the supporting part of the beam. This is true for both the configuration without a stiffener and with unwelded holes on both sides of the support, as well as with a stiffener and with unwelded holes (types 1 and 2). These stress values do not exceed the calculated resistance of the steel beyond the yield point. In section 3-3, point 11 experiences the highest stress for support types 1 and 3, where there is no supporting stiffener. 4. The presence of welded holes and support stiffeners helps to improve the operation of the support parts, since the concentration of both tangential and normal stresses is largely eliminated, although the stress values in all cases are much lower than the calculated resistance of steel. 5. The actual operational configuration of a two-span continuous perforated beam near the intermediate support deviates to some extent from the idealized calculation scheme. This deviation is attributed to the presence of elements and specific details in its attachment to the supporting structures. Therefore, there is a necessity to conduct experimental studies, that will allow to develop a calculation method taking into account numerous factors which affect the bearing capacity of both the support itself and the beam as a whole. References DBN V.2.6 – 198: 2014, 2014. Stalevi konstruktsiyi (Steel structures). Normy proektuvannya. Kyiv. Minrehion Ukrayiny. 198 s. (In Ukrainian) Eurocode 3, 2005: Design of steel structures. EN 1993-1-8:2005. Liu, X.-Ch., et al., 2019. Tension – bend – shear capacity of bolted-flange connection for square steel tube column. Engineering Structures 20115, Article 109798. Rezvani, F.H., Ronagh, H., 2017. Span length effect on alternate load path capacity of welded unreinforced flange-bolted web connections. Journal of Constructional Steel Research 138, 714 – 728. Romaniuk, V. et al., 2023. Determination of rigidness of node bolt joints. AIP Conference Proceedings. Volume 2678, Issue 1. 020016. Romaniuk, V., Supruniuk, V., 2021. Influence of Flexibility of Bolted Joints on Rigity of the Hingeless Frame. Proceedings of EcoComfort 2020. EcoComfort 2020. Lecture Notes in Civil Engineering 100, 371 – 377. Springer, Cham.