Portal frame

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

Novel loading tests on full-scale tapered member portal frames

Abstract: This paper presents the experimental results of loading tests on two 18 m span tapered member portal frames designed to BS 5950. Deflection test results for vertical, lateral and combined loading cases are compared with the predictions given by elastic analysis to BS 5950 and shown to be favourable. The predicted ultimate capacities and modes of failure, which were by lateral–torsional buckling of the columns, were also found to agree with the experimental behaviour. It was found that the method of modelling the tapered members as a series of prismatic elements gave good comparison with test results.

Bifurcation Analysis and Chaos Control of a Fractional Order Portal Frame with Nonideal Loading Using Adaptive Sliding Mode Control

Abstract: We investigate the chaotic oscillations in a fractional order model of a portal frame with nonideal loading. The bifurcation of the fractional order portal frame system for parameters and fractional orders are investigated. Bicoherence analysis shows the existence of quadratic nonlinearities. Fractional order adaptive sliding mode controllers are designed to suppress the chaotic oscillations with uncertain parameters. Power efficiency analysis of the FPGA implemented control scheme shows the maximum power utilization in the fractional order showing the largest Lyapunov exponent.

Circular-rail multifunctional drill jumbo system

Abstract: A circular-rail multifunctional drill jumbo system at least comprises crawler track units, a portal frame, a circular rail system and hydraulic drill rigs. The crawler track units form a four-point support jumbo on two sides of the portal frame, the circular rail system is mounted to the front end of the portal frame and supports the hydraulic drill rigs and a stand support device, and the system further comprises an operating platform moving longitudinally along the portal frame. Reliability and continuity in construction operation are improved effectively, the system adapts to full-face and bench-cut-method operation construction in tunnels, 80% of surrounding rock condition construction in a tunnel line can be completed, the crawler track units can realize efficient and flexible steering and balancing control, the system adapts to severe construction operation environments in the tunnels, the operation platform provides an operation platform for operators to approaching to the tunnel face to perform measurement, ruling, explosive filling and the like, the arch set-up device can assist constructors to finish setting-up of a steel arch and pavement of steel meshes, arch set-up operation efficiency is increased efficiency, and labor intensity of constructors is reduced.

On the interaction between local and overall buckling of an asymmetric portal frame

Abstract: In two previous works the effect of simultaneous overall buckling modes on post-buckling behaviour of a one-bay-two-storey frame with rigid beams, flexible columns and fixed edges has been analysed on the basis of the nonlinear theory of elastic stability developed by Koiter In the present article interaction effect of simultaneous overall and local buckling in a simple portal frame with the same boundary condition described by the same beam model is investigated Far from being conclusive, results so far obtained show that imperfection sensitivity in the presence of local and overall buckling is higher in comparison with the previous case

Portable small-sized multipurpose portal frame

Abstract: The utility model relates to a portable small-sized multipurpose portal frame, which structurally comprises vertical rod legs, vertical rods, pin holes, a hanging ring, a pulley gear, a beam and extended insertion rods The portable small-sized multipurpose portal frame is characterized in that one vertical rod leg is mounted at the bottom of each vertical rod, one extended insertion rod is inserted into each vertical rod and fixed by one pin hole, the beam is mounted on the extended insertion rods, the pulley gear is arranged in the middle of the beam, and the hanging ring is hung in the middle of the beam through the pulley gear The portable small-sized multipurpose portal frame has the advantages that all connecting components of the portable small-sized multipurpose portal frame are detachable, so that the portable small-sized multipurpose portal frame can be detached and mounted rapidly and is small in floor area, convenient in use, simple in structure, safe, reliable and applicable to installation and transport of equipment with limited space or for outdoor operation, and the width and the height of the portable small-sized multipurpose portal frame can be adjusted in a classified manner