Portal frame

About: Portal frame is a research topic. Over the lifetime, 1778 publications have been published within this topic receiving 7210 citations.

Strength and stiffness of cold-formed steel portal frame joints using quasi-static finite element analysis

Abstract: This paper describes a quasi-static finite element analysis, which uses the explicit integration method, of the apex joint of a cold-formed steel portal frame. Such cold-formed steel joints are semi-rigid as a result of bolt-hole elongation. Furthermore, the channel-sections that are being connected have a reduced moment capacity as a result of a bimoment. In the finite element model described, the bolt-holes and bolt shanks are all physically modelled, with contact defined between them. The force-displacement curves obtained from the quasi-static analysis are shown to be similar to those of the experimental test results, both in terms of stiffness as well as failure load. It is demonstrated that quasi-static finite element analysis can be used to predict the behavior of cold-formed steel portal frame joints and overcome convergence issues experienced in static finite element analysis.

Spatial Temperature Differences in Portal Frame Bridges

Abstract: Thermal actions are considered in the design of bridges, as temperature variations can lead to restraint stresses and subsequent cracking. However, load descriptions are in some cases oversimplified or incompatible with modern applications, and background studies are limited. This paper therefore aims to develop a more detailed load description for the load case describing temperature differences between structural parts in bridges, focusing on portal frame bridges. The temperature in portal frame bridges is investigated by performing long-term thermal simulations using weather data from several locations in Sweden, and thereafter performing statistical analyses of the resulting temperature variations over time. The study gives suggestions of both characteristic and quasi-permanent values to be used in design based on the statistical analyses, and also notes a gradual change in temperature between structural parts, which could be considered in the design. The resulting quasi-permanent values are significantly lower than the values given in the Eurocode for temperature differences between structural parts, which, in turn, will lead to smaller and more realistic stress values in bridge design. (Less)

Vehicle taking device and use method thereof

Abstract: The invention discloses a vehicle taking device and a use method of the vehicle taking device. The vehicle taking device comprises a translation mechanism, a rotation mechanism and a lifting mechanism. The translation mechanism comprises a translation portal frame, wherein the translation portal frame moves back and forth along a preset track when the vehicle taking device is matched with a stereo garage to be used. The rotation mechanism comprises a rotating portal frame and a rotation driving device, wherein the rotation driving device drives the rotating portal frame to rotate, and one vertical beam of the rotating portal frame and one vertical beam of the translation portal frame are arranged in parallel and are hinged. The vehicle taking device is provided with a counterpoint platform, wherein the counterpoint platform is used for carrying a vehicle parking platform, ascends and descends on the vehicle taking device, and is arranged on the rotating portal frame, the counterpoint platform and two vertical beams of the rotating portal frame are in sliding fit through a lifting base, and the lifting base moves up and down under the action of the lifting mechanism. The vehicle taking device can be independently machined in a batch mode, and is combined with the stereo garage to be applied when the vehicle taking device is used; the vehicle taking device integrates the translation mechanism, the rotation mechanism and the lifting mechanism, so that the stereo garbage does not need to be provided with various mechanisms on each layer and each parking space, and the cost is greatly reduced.

RC building seismic reinforcement method utilizing steel portal frames without braces

Abstract: A portal frame 3 made of wide flange sections without braces is fixed to the external surfaces of an existing RC-column 5 extending in the vertical direction and to the external surfaces of existing RC-beam 8 extending in the horizontal direction of a reinforced concrete building. The wide flange section column 4 fixed to the existing RC-column 5 is assigned a bending rigidity roughly equivalent to that of the existing RC-column 5 , thereby reducing the stress additionally occurring at the connecting part between the existing RC-column 5 and column 4 by deforming the column 4 similarly to the existing RC-column 5 under the horizontal load transmitted from existing RC-beam 8 and/or wide flange section beam 6 during an earthquake. Using a steel portal frame without braces preserves the building appearance and avoids bracing which may block windows while increasing earthquake resistance.

Duplex position laser beam machining device

Abstract: The utility model discloses a duplex position laser beam machining device, including the base, the laser cutting head is fixed in the portal frame on the base, in the crossbeam of portal frame set up side by side down in first workstation and second workstation on the base for the first workstation of separately -driven and second workstation be along a Y axle subassembly and the 2nd Y axle subassembly of the motion of Y axle orientation, is used for driving laser cutting head along the Z axle subassembly of Z axle orientation motion, and set up in be used for driving the X axle subassembly of Z axle subassembly along the motion of X axle direction on the crossbeam of portal frame. Through adopting the double workbench mode of processing in turn, realized carrying on in succession laser cutting, improved production efficiency, workstation linear motion's mode has improved positioning accuracy and machining precision through adopting the portal frame to fix.