About: Portal frame is a(n) research topic. Over the lifetime, 1778 publication(s) have been published within this topic receiving 7210 citation(s).
Papers published on a yearly basis
TL;DR: In this paper, a finite element solid idealisation of a bolted lap-joint in shear is described that can be used to determine the initial bolthole elongation stiffness, and the results obtained are validated against experimental data.
Abstract: The authors have recently described a cold-formed steel portal framing system in which simple bolted moment-connections, formed through brackets, were used for the eaves and apex joints. Such connections, however, cannot be considered as rigid because of localised in-plane elongation of the bolt-holes caused by bearing against the bolt-shanks. To therefore predict the initial stiffness of such connections, it is necessary to know the initial bolt-hole elongation stiffness kb. In this paper, a finite element solid idealisation of a bolted lap-joint in shear will be described that can be used to determine kb; the results obtained are validated against experimental data. A beam idealisation of a cold-formed steel bolted moment-connection is then described, in which spring elements are used to idealise the rotational flexibility of the bolt-groups resulting from bolt-hole elongation. Using the value of kb in the beam idealisation, the deflections predicted are shown to be similar to those measured experimentally in laboratory tests conducted on the apex joint of a cold-formed steel portal frame.
TL;DR: In this article, the structural and acoustic response of a building to an incoming wave field generated by high-speed surface railway traffic was investigated by means of a spectral finite element formulation.
Abstract: This paper deals with the numerical computation of the structural and acoustic response of a building to an incoming wave field generated by high-speed surface railway traffic. The source model consists of a moving vehicle on a longitudinally invariant track, coupled to a layered ground modelled with a boundary element formulation. The receiver model is based on a substructuring formulation and consists of a boundary element model of the soil and a finite element model of the structure. The acoustic response of the building's rooms is computed by means of a spectral finite element formulation. The paper investigates the structural and acoustic response of a multi-story portal frame office building up to a frequency of 150 Hz to the passage of a Thalys high-speed train at constant velocity. The isolation performance of three different vibration countermeasures: a floating-floor, a room-in-room, and base-isolation, are examined.
TL;DR: In this article, a practical problem of synchronization of a non-ideal (i.e., when the excitation is influenced by the response of the system) and non-linear vibrating system was posed and investigated by means of numerical simulations.
Abstract: A practical problem of synchronization of a non-ideal (i.e. when the excitation is influenced by the response of the system) and non-linear vibrating system was posed and investigated by means of numerical simulations. Two rotating unbalanced motors compose the mathematical model considered here with limited power supply mounted on the horizontal beam of a simple portal frame. As a starting point, the problem is reduced to a four-degrees-of-freedom model and its equations of motion, derived elsewhere via a Lagrangian approach, are presented. The numerical results show the expected phenomena associated with the passage through resonance with limited power. Further, for a two-to-one relationship between the frequencies associated with the first symmetric mode and the sway mode, by using the variation of torque constants, the control of the self-synchronization and synchronization (in the system) are observed at certain levels of excitations.
TL;DR: In this article, a simple linear beam idealization of a cold-formed steel portal frame is presented, in which beam elements are used to idealize the column and rafter members, and rotational spring elements were used to represent the rotational flexibility of the joints.
Abstract: A simple linear beam idealization of a cold-formed steel portal frame is presented in which beam elements are used to idealize the column and rafter members, and rotational spring elements are used to represent the rotational flexibility of the joints. In addition, the beam idealization takes into account the finite connection length of the joints. Deflections predicted using the beam idealization are shown to be comparable to deflections obtained from both a linear finite element shell idealization and full-scale laboratory tests. Using the beam idealization, deflections under rafter load are divided into three components: Deflection due to flexure of the column and rafter members, deflection due to bolt-hole elongation, and deflection due to in-plane bracket deformation. Of these deflection components, the deflection due to bolt-hole elongation is the most significant and cannot, therefore, be ignored. Using the beam idealization, engineers can analyze and design cold-formed steel portal frames, including making appropriate allowances for connection effects, without the need to resort to expensive finite element shell analysis.
01 Apr 1992-Composites Engineering
TL;DR: In this paper, the authors investigated the long-term creep and short-term failure of a plane portal frame structure constructed entirely of pultruded fiber-reinforced plastic (FRP) components.
Abstract: The long-term creep and the short-term failure of a plane portal frame structure, constructed entirely of pultruded fiber-reinforced plastic (FRP) components, has been investigated both experimentally and analytically. Two, 6 feet high by 9 feet wide, plane portal frames were designed and constructured using standard “off-the-shelf” glass/vinylester pultruded beams, nuts and threaded rods produced by Creative Pultrusions, Inc. One frame was subjected to a constant long-term load and analyzed for its creep characteristics while the other was tested to failure under short-term loading. The creep analysis considered both the time-dependent response of the FRP structural members and the contribution of shear-deformation effects. The use of viscoelastic moduli in conjunction with a shear-deformable beam theory is detailed. Theoretical predictions are compared with the experimental data. Design recommendations are suggested for structural applications.
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