Showing papers on "Portal frame published in 2008"

Steel column base classification

Abstract: The influence of the rotational characteristics of the column bases on the structural frame response is discussed and specific design criteria for stiffness classification into semi-rigid and rigid joints are derived. The particular case of an industrial portal frame is then considered.

Dynamic analysis of frames with material and geometric nonlinearities based on the semirigid technique

Abstract: This paper presents a method for nonlinear dynamic analysis of frames with material and geometric nonlinearities which is based on the semirigid technique. The plastic hinge that accounts for the material nonlinearity is modeled as a pseudo-semirigid connection with nonlinear hysteretic moment-curvature characteristics at the element ends. The stiffness matrix of a frame element with material and geometric nonlinearities is expressed as the sum of products of the standard stiffness matrix and the geometric stiffness matrix of the element, with their corresponding correction matrices based on the plasticity factors developed from the section flexural stiffness at the plastic hinge locations. The combined stress yield condition is used for the force state determination of plastic hinges, and force equilibrium iterations and geometry updating for frames are carried out in every time step. When the key parameters of a structure are updated in a time step, the time step is split up into substeps to ensure accuracy while keeping the computations to a reasonable amount. The plastic rotation history can be calculated directly or in an approximate indirect way. The method is computationally efficient and it needs no additional connection elements, which makes it convenient for incorporation into existing linear dynamic analysis programs. Besides, the method can handle accurately and efficiently the dynamic analysis of nonlinear frames using relatively large time steps in conjunction with time step subdivision to cope with key parameter changes. A portal frame is used to verify the correctness of the proposed method. A more complicated five-story frame is used to illustrate the applicability and performance of the proposed method.

Awning device and its control method and embarking bridge with the awning device

Abstract: The canopy apparatus for aerobridge includes one flexible frame capable of contacting the airplane covering, one portal frame connected to the aerobridge and one corrugated canopy connected between the flexible frame and the portal frame. The canopy apparatus includes also at least two independent operation mechanisms with one driving unit hinged between the portal frame and the flexible frame to push out the flexible frame each, one retracting mechanism installed onto the portal mechanism and one drawing rope with one end fixed onto the flexible frame and the other end fixed onto the control mechanisms. The retracting mechanism controls the retraction of the flexible frame through the drawing rope. The canopy apparatus of the present invention can well contact airplane covering hermetically.

Hybrid simulation of structural collapse

Abstract: The ability to model structural collapse is essential for improving our understanding of the performance of structures during very rare earthquake events. However, experimental investigations of collapse are complex, expensive and potentially dangerous. This paper demonstrates a novel extension of the hybrid simulation testing method to model structural collapse. The principal advantage of this extension is that, contrary to shaking table testing, no large physical masses and equipment protection systems are needed for the experimental part of a hybrid simulation, making the collapse experiment less expensive and significantly safer. The Open System for Earthquake Engineering Simulation (OpenSees) structural modeling software and the Open Framework for Experimental Setup and Control (OpenFresco) hybrid simulation software are used to consistently model geometric nonlinearities in the analytical portion of the hybrid model, including the geometric transformation involving the degrees-of-freedom of the experimental subassemblies. A hybrid simulation of the seismic response of a one-story portal frame with two ductile columns is carried out until collapse to demonstrate the newly proposed implementation. The columns, modeled using physical specimens, were not axially loaded: instead, second-order analytical geometric transformations were used to affect the actions of the axial load. A direct comparison of the results of two hybrid simulations, with and without accounting for gravity load effects, shows that the hybrid model with P-Delta effects develops negative postpeak stiffness, incrementally increasing lateral displacements until collapse.

Mobile crane for automobile maintenance

Abstract: The utility model relates to an automobile maintenance device, in particular to a mobile automobile maintenance crane used for automobile maintenance The crane comprises a beam and hoisting equipment arranged on the beam and is characterized in that the beam is fixed on two columns to form a portal frame and the bottom ends of the two columns are provided with wheels The automobile maintenance device is characterized by simple structure and convenient using, and can effectively improve automobile maintenance efficiency When in use, the motor or other large-size parts can be conveniently hoisted by pushing the portal crane to the place where the automobile waiting to be repaired is located

Energy-saving and environment protecting integral vehicular rain test apparatus

Abstract: An energy-saving and environment-friendly entire car rain test device comprises a portal frame which is composed of steel pipes, spray heads installed on the portal frame, a shift device of the portal frame and a water circulation system, wherein, the shift device of the portal frame consists of a towing plate that is fixedly connected with the upper part of the portal frame, a motor fixed at the end part of the towing plate, an idler wheel fixed with an output shaft of the motor and a lead rail corresponding to the idler wheel that is installed on the lead rail. The entire car rain test device adopts the form that the portal frame evenly and slowly moves along the vertical direction of the vehicle, and utilizes spray heads or nozzles with the corresponding quantity installed on the portal frame to spray out the water flow with the intensity of pressure and water discharge achieving iron standard requirements, thereby ensuring all the parts of the vehicle to have consistent water reception time and leading the spraying effect of the entire car to achieve the iron standard requirements; after the entire car is sprayed, the waste water returns into a water storage trough, environmental pollution is not caused, thereby achieving the aim of environmental protection; the back flowed waste water is recycled after being precipitated and filtered, thereby saving the water resource.

Full-automatic high altitude material fetching machine

Abstract: The utility model relates to a fully automatic high-altitude material fetcher which comprises a base plate, a driving motor, a driving wheel, a universal wheel, a fixing portal frame, a movable portal frame, a manned carriage frame and an electro-hydraulic device that drives the lifting of the carriage frame. The electro-hydraulic device which is arranged on the base plate comprises an electrical source, an electric oil pump, a hydraulic cylinder and a chain wheel seat component that consists of a chain wheel and an installation seat, the chain wheel seat component is fixedly arranged on a horizontal cross rod of the movable portal frame, one end of a chain is articulated with a horizontal rod of the fixing portal frame and the other end of the chain is articulated with a sliding block; the top end of a piston rod of the hydraulic cylinder is fixedly connected with the horizontal cross rod of the movable portal frame. A control switch of the driving motor and a control switch of the electro-hydraulic device are arranged in the same electrical control box. The utility model adopts the fully automatic lifting carriage frame and the movable base plate, thereby having the advantages of no pollution problem, environment-friendly benefit, simple structure, light volume, convenient transportation and simple and safe operation.

Simple nonlinear static analysis of steel portal frame with pitched roof exposed to fire

Abstract: Plane steel portal frames, with pitched roof, exposed to fire, are examined. First, a determinate frame is analysed by hand. For flexible columns and shallow roof, snap-through occurs before plastic hinges mechanism is formed. An indeterminate frame with shorter columns and taller roof is also analysed by hand. Then, the same frame is simulated by a truss and a nonlinear static analysis is performed by use of a short computer program. The results of computer analysis by use of truss model are compared with those of analysis by hand and a satisfactory approximation between them is observed.

Optimal design of steel portal frames based on genetic algorithms

Abstract: As for the optimal design of steel portal frames, due to both the complexity of cross selections of beams and columns and the discreteness of design variables, it is difficult to obtain satisfactory results by traditional optimization. Based on a set of constraints of the Technical Specification for Light-weighted Steel Portal Frames of China, a genetic algorithm (GA) optimization program for portal frames, written in MATLAB code, was proposed in this paper. The graph user interface (GUI) is also developed for this optimal program, so that it can be used much more conveniently. Finally, some examples illustrate the effectiveness and efficiency of the genetic-algorithm-based optimal program.

Stereo parking garage

Abstract: The utility model provides a technical scheme of cubic parking garages, and the scheme comprises a storage frame of a plurality of parking units. Each parking unit in parking frames is provided with two parking frames, each parking frame is provided with frame roller ways composed of cylindrical rollers, and two frame roller ways are driven by a driving mechanism of the frame roller ways. One side of the storage frame is provided with transverse guide rails which are provided with a portal frame, a transverse driving mechanism is arranged between the portal frame and the transverse guide rails, the portal frame is internally provided with a lifting frame capable of moving upwards and downwards along the portal frame, and the lifting frame is driven by a lifting mechanism arranged on the portal frame. The bottom portion of the lifting frame is provided with two frame roller ways composed of cylindrical rollers, and two frame roller ways are driven by a driving mechanism of the frame roller ways. The driving mechanism of the frame roller ways is driven by a roller way drive mechanism, and the drive mechanism of the frame roller ways is driven by the roller way driving mechanism via a roller way driving clutch mechanism. A line positioning device is arranged between the portal frame and the parking fames, and a row positioning device is arranged between the lifting frame and the parking frames.

Principles of Mechanics Model for Wood Structural Panel Portal Frames

Abstract: A principles of mechanics model to predict the strength of wood structural panel portal frames has been developed. The wood structural panel portal frame consists of a wood structural panel overlapping a header to form a moment resisting connection to resist in-plane lateral loads. The advantage of portal frames is that they can resist relatively high lateral loads for a small wall width. The model is based on moment couples and shear strength of the components. Model predictions are compared to test results for a variety of portal frame constructions that have been tested. All portal frame walls were tested with the SEAOSC [1996] SPD cyclic load protocol for in-plane shear resistance. Portal frame constructions investigated in this study range from 16 to 24-inch wide, 8 to 10-ft tall, sheathed with OSB or plywood, and with and without hold down devices at the base of the wall segment. Also investigated are portal frames built on raised wood floor assemblies with variable base of wall restraint configurations which are modeled with moment couples. The model is compared to ten unique portal frame constructions that were tested. Comparing the model to the test results shows that the model accurately predicts the strength to within about 5% on average.

Ceramic sanitary equipment gypsum testing die digital control processing machine

Abstract: The utility model relates to a ceramic sanitary equipment gypsum test mold digital control processing machine, which is used for processing the sanitary equipment gypsum test mold comprising a computer kinetic control system, a cutter and rotating machine, a framework and a platform, wherein the microcomputer kinetic control system comprises X, Y, Z axles operation systems which are respectively constituted by a rectilinear orbit, a ball screw, a displacement transducer and an actuating motor, the framework comprises an underframe, a portal frame and a platform, wherein the X axle system is positioned under the underframe, while the Y axle system and the Z axle system are positioned on the portal frame, and the cutter rotating machine is positioned on the Y axle system. The execution effective displacement value of the X, Y, Z axles is within the range of 1500mm*1200 mm*600 mm, the positional accuracy is within the range of 0.1 mm/M, and the height of the portal frame satisfies the Z axle displacement. As adopting the computer technology, the product mould is abundant and the product development cycle is reduced from 2 months to about 10 days, greatly reducing the development cost of novel products, furthermore, the different periods of the identical product are still capable of veritably reproducing.

Hydraulic telescopic door frame type drill

Abstract: The utility model mainly aims to provide a drilling rig which does not change the drill pipe with good stability. The utility model is a hydraulic pressure telescopic portal frame type drilling rig; a drill pipe is connected with a power source output shaft; the power source is fixed on a power combinational frame; the power combinational frame is fixed on a sliding block frame; the sliding block frame is connected with the portal frame by a sliding rail pair; the portal frame is fixed on a lifting mechanism; the lifting mechanism is fixed on the chassis of a motor vehicle; the upper part of the lifting mechanism and the upper part of the sliding block frame respectively are fixed on the two ends of the traction string; the traction string is surrounded on a traction string wheel on the top of the portal frame. The key point of the utility model is that the stable sliding principle of the lifting fork vehicle arm mechanism of the prior technology is applied and a dismountable coupling is mounted between the drill pipe and the power source output shaft. Compared with the prior technology, as a long journey drill pipe is applied, the repeated replacement of the drill pipe and the repeated regulation of the aligned stake number are avoided.

Door type rigid-frame beam column connection node structure

Abstract: The utility model relates to a portal frame beam-column link joint structure which aims at improving the mechanical characteristics of the portal frame beam-column link joints, and increasing the joint rigidity. The portal frame beam-column comprises a vertical column 2 and a crossbeam 1 arranged on the vertical column 2, a first included angle Alpha is formed at a link joint of the vertical column 2 and the crossbeam 1, the utility model is characterized in that a curved hunched slab 3, consisting of a curved sheet 3' and a rectangular sheet 3'', is arranged at a portal frame beam-column link joint. The plane of the curved sheet 3' is vertical to the plane of the rectangular sheet 3'',and the geometrical extension lines of the two edges AC, BD of the curved sheet 3' are intersected at a point O; the geometrical extension lines of a first edge AC and a second edge BD form a second included angle AOB, the angle of the first included angle Alpha is equal to the second included angle AOB; and the two edges AC and BD are respectively arranged on the crossbeam 1 and the vertical column 2.

Combined door opening formwork

Abstract: The utility model relates to construction equipment, in particular to a combined portal template matched with a huge wall template in the shear-wall high-rise construction. The utility model is characterized in that the geometric size combination of a portal corresponding to the periphery of the template is a planar portal; each set comprises two angle templates (1), two lateral templates (2) and a top template (3) connected together; the angle template (1) is connected with the lateral template (2) and the top template (3) through inserting; the two corners of the whole planar portal frame are respectively fixed and obliquely supported through an angle adjusting screw rod (4) on the internal side; the two lateral templates (2) are horizontally supported and fixed through two lateral adjusting screw rods (5) in parallel. The combined template can not only achieve the universality and circulation of the portal templates in different sizes, but also with reasonable design and reliable installation, ensure the pouring quality of the concrete and greatly reduce the project cost.

Mechanical Property Analysis on the Connections of New Style Portal Frames

Abstract: Finite element analysis on the common upright bolted end-plate connections and the connections appending an armpit in steel portal frame based on ANSYS reveals that the improved structure is better than the common structure in load capacity.The armpit is simple and feasible for construction and it forms another line of defence for the connection.The stiffness of the improved structure is very high,meeting the design principle of strong connections and weak bars.It relieves the stress concentration of node area,which can improve the ductility performance and load capacity of node area.The reason for the destructive style of the first component is the displacement too large and the second is the flage of the column yielding failure.

Design and Analysis of Long-span Portal Frame Steel Structures with Prestressed Cable-strut

Abstract: The distributions of stress and deformation were computed for the portal frame with prestressed cable-strut under various load conditions based on a grain warehouse with 72 m span,and the results were compared with that of different long-span portal frames.The method was developed to analyze the mechanical principle of portal frame with prestressed cable-strut.The results show that the effect of prestress of the portal frame with prestressed cable-strut is more effective than common prestressed frames,and effectively improves the mechanical behavior of portal frames due to deformations of the strut and cable should be considered in the design of portal frame;therefore,the deformations should be computed by geometry nonlinearity.

Investigation and Analysis of Total Collapse of a Portal Frame Structure with Large Span

Abstract: Subjected to heavy snow load,a double span portal frame structure totally collapsedThe collapse investigation is carriedThe failure shape and mode of purline,tension steel,portal beams and columns,etcare investigatedAnd some typical phenomena related to failure shape and mode is discussed in this paperAccording to the snow load and design parameters,the collapse process and the reasons inducing the collapse of the structures are analyzed and discussedIt proves that some imperfections which were neglected in design and construction are the fatal factors responsible for the failure of structural members,and the collapse of total structure as wellLearning from the collapse event,some design regulations in different design code are studied and comparedSome key problems related to the safety and reliability of portal frame structures are highlighted In design and construction,these problems must be taken into consideration carefully

Secondary development of the portal frame's analytical program based on ANSYS parametric design language

Abstract: Much developed technical specifications and corresponding design software apply to the common portal frame design,while the higher and longer-span uncommon portal frame are analyzed by using ANSYSThe general finite element software ANSYS,which is widely used in the civil engineering fields,is inconvenient to the concrete projectsIn this paper,ANSYS Parametric Design Language(APDL) is adapted to compile exclusive analytical program for integral model-building,solution and results analysis of the portal frameCombined with an engineering case,the analytical program is concisely introduced for loadcase combinations,seismic response spectrum,seismic and simulation of wind field time-history response of the portal frameIt can be used for solving other similar projects

Application of Hysteretic Dampers to Reduce Blast Response of a Portal Frame

Abstract: In recent years, considerable attention has been paid to research and development of structural control devices, with particular emphasis on alleviation of wind and seismic response of buildings and bridges. One of the effective mechanisms available for the dissipation of energy is through inelastic deformation of metals. The purpose of this paper is to evaluate the effectiveness of metallic yield dampers when used to control blast loading responses on a portal frame. One type of metallic yield dampers is the tension/ compression yielding brace, also called the unbonded brace, which has been studied in this paper. Finite element models of portal frames were developed using the finite element program. Nonlinear computer models were subjected to a dynamic blast loading from 1000 kg TNT at standoff distances of 20, 10, and 5m and comparisons were made between unbraced frames and frames braced.

The Finite Element Analysis for the Structure of Portal Frame of Fork Lifter Based on ANSYS

Abstract: This paper uses large universal finite element analysis software ANSYS to do analysis on the overall structure and main parts of Portal Frame of Fork Lifter and to compute the strength and stiffness of structure The process of analysis is simplified and the precision of analysis is improved The powerful foundation is supplied in order to optimize the design of construction of Portal Frame of Fork Lifter