Showing papers on "Portal frame published in 2003"

Serviceability design of a cold-formed steel portal frame having semi-rigid joints

Abstract: Details are given of a cold-formed steel portal framing system that uses simple bolted momentconnections for both the eaves and apex joints. However, such joints function as semi-rigid and, as a result, the design of the proposed system will be dominated by serviceability requirements. While serviceability is a mandatory design requirement, actual deflection limits for portal frames are not prescribed in many of the national standards. In this paper, a review of the design constraints that have an effect on deflection limits is discussed, and rational values appropriate for use with cold-formed steel portal frames are recommended. Adopting these deflection limits, it is shown through a design example how a cold-formed steel portal frame having semi-rigid eaves and apex joints can be a feasible alternative to rigid-jointed frames in appropriate circumstances.

On Nonlinear Dynamics and Control of a Particular Portal Frame Foundation Model, Excited by a Non-Ideal Motor

Abstract: The nonlinear dynamic response and a nonlinear control method of a particular portal frame foundation for an unbalanced rotating machine with limited power (non-ideal motor) are examined. Numerical simulations are performed for a set of control parameters (depending on the voltage of the motor) related to the static and dynamic characteristics of the motor. The interaction of the structure with the excitation source may lead to the occurrence of interesting phenomena during the forward passage through the several resonance states of the systems. A mathematical model having two degrees of freedom simplifies the non-ideal system. The study of controlling steady-state vibrations of the non-ideal system is based on the saturation phenomenon due to internal resonance.

Components mounting device for substrates and its calibrating methode

Abstract: The machine frame (6) holds the calibration system (1) which has two transport projections (8) on either side of a portal frame (5). Each transport projection holds a strip of glass (12) with calibration markings (11). The portal frame incorporates a camera (10) and holds a turntable (2) carrying small objects (3) to be attached to a substrate. The camera is aimed toward the calibration marks, and distortion (14) of the portal frame may be measured.

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.

Neural Networks in Updating of Dynamic Models with Experimental Verification

Abstract: This paper presents the application of artificial neural networks in updating of dynamic models of engineering structures. There are presented examples of updating of two models: a model of a beam hung on two strings and a model of a portal frame. There are used multi-layer feed-forward networks and networks with radial basis function, the input vectors consist of preprocessed data obtained from the measurements done on a laboratory models of considered structures.

Compaction device of earth under pipe

Abstract: PROBLEM TO BE SOLVED: To save the labor by efficiently performing a work for compacting back-filled earth after back filling earth to the circumference of an existing pipe in the repair of a pipeline without damaging the pipe surface. SOLUTION: A portal frame 41 is arranged on the tip part of the arm 5a of a hydraulic bacikhoe 5C through a rotating mechanism 40 so as to straddle the existing pipe 1, and vibration compacters 42 and 43 are installed to the lower part of the frame 41. A guide protector 44 is arranged on the inside of the frame 41.

Analysis of the retaining and protection mechanism of double-row cantilever piles

Abstract: The retaining and protection mechanism, structural distribution and internal forces of doublerow cantilever piles are studied and discussed on the basis of engineering practice Based on a series of reasonable assumptions, the supporting structure is considered as the portalrigid frame,and the pile top bending moment and shear force are calculated, which provide a theoretical guidance for the design of spacing between front and back piles and the embedded depth The designing and constructing process of a certain project using doublerow piles as supporting structure is introduced In this project, observation point is sited on the top beam to measure the maximum deformation of the side of foundation The results show that doublerow cantilever piles have many advantages—smaller displacement and bending moment and convenience in the construction as well

Device for and method of embedding underground pipe

Abstract: PROBLEM TO BE SOLVED: To perform an embedding construction effectively without taking time and load, without blocking traffic and without using construction equipment. SOLUTION: The device is provided with a portal frame 11 having a overturn preventing supporting stand 13 straddling an excavation channel 4, a pipe hanging and lifting mechanism 15 which is installed in a cross beam 14 of the portal frame 11, capable of hanging a pipe 7 buried in the excavation channel 4 and lifts the pipe 7 hanged, a pipe moving and supporting member 25 which is removably mounted on the leg part side of a pair of support 12 of the portal frame, supports the pipe 7 mounted on the support and has a plurality of rollers 29 capable of moving the pipe 7 in the axial direction, and a pipe horizontally swinging mechanism 20 which is installed in the portal frame 11 and capable of horizontally swinging the pipe hanged by the pipe hanging and lifting mechanism 15. COPYRIGHT: (C)2003,JPO

Method of construction of middle tunnel of deep-seated column station in loose grounds

Abstract: FIELD: construction of underground structures. SUBSTANCE: method includes construction of leading support in form of slot following face contour and filled with concrete mix, erection of permanent lining under protection of leading support and extraction or face rock. Permanent monolithic concrete lining is made under protection of leading support with minimal logging from face. Then, after concrete setting of newly made leading support, rock is extracted by one stope in upper part of face, face front is supported, rock of middle and lower part of face is successively extracted, tunnel upper vault is erected, and reverse vault is made as driving of tunnel is advanced. Middle tunnel of column station is constructed by means of device for cutting slot by face contour with guide arch metal structure and carriage moving over said metal structure with bar actuating member, and device for making of permanent monolithic concrete lining with two rocking platforms; both devices installed on self- propelled portal frame, with the second device installed on said portal frame symmetrical to middle part of folded forms with help of hinges. EFFECT: solved problem in provision of combined operation of leading support and permanent monolithic concrete lining in taking up loads and prevention of day surface sagging. 5 dwg

Narrow Shear Walls - A Portal Frame Solution

Abstract: 1. Summary In the past 5 years, there has been an unprecedented amount of research in the U.S. related to the performance of narrow shear walls or bracing units. Confusion has existed regarding how to properly design and construct narrow walls (defined as having an aspect ratio of greater than 2:1). In order to develop a solution that provides adequate strength and stiffness for use as bracing in traditional North American light-frame wood construction for narrower walls, a portal frame design was developed by APA - The Engineered Wood Association. Monotonic and cyclic testing has been conducted on the APA portal frame design. Recommended design values for engineered use of the portal frames have also been developed and these have been compared to existing prescriptive bracing wall designs. This paper will review this testing program and provide guidance for the design of these narrower wall elements to resist both wind and seismic forces.

Motor vehicle pile-examination device

Abstract: The utility model relates to a motor vehicle post examination device comprising a front and a back portal frame, central posts fixed and arranged on the front and the back portal frame, bilateral posts driven by the driving rope system of the posts installed on the front and the back portal frame, a computer arranged in the computer room and a camera erected on the site by a support frame. The utility model is characterized in that the front and the back portal frame are both rope tension structures comprising two diagonal stays arranged on two sides of the site and fixed devices of the diagonal stays, main ropes arranged between each pair of the diagonal stays, a plurality of stayed ropes arranged between the diagonal stays and the main ropes, as well as tension ropes arranged between the upper part of the diagonal stays and the fixed devices of the diagonal stays. The central posts are arranged above the main ropes and connected with the main ropes. The bilateral posts are hung on the main ropes and fixed on the driving rope system of the posts relatively. The utility model has flexible portal frame structure and small size, light weight, and lower cost. The utility model can be used in the examination of the posts-through for all kinds of motor vehicles.

Novel altitude operation platform

Abstract: The utility model relates to a novel aloft work platform, which is provided with a chassis and a lifting device on the chassis. The aloft work platform is characterized in that the chassis is connected with a spanning device which comprises two portal frames, a raiser and a travelling wheel that are respectively connected to the upper and the lower parts of the portal frames, and portal beams that are connected with the raiser, wherein, the portal beams are connected with a cross beam which is connected to the chassis, and an uplifter which is provided with travelling wheels are arranged at the inner side of the portal frame. The spanning device can conveniently span obstacles in the process of movement, can correctly move the aloft work platform the position for convenient operations, has simple structure and convenient installation and disassembly, and can be used selectively according to different operational fields.

Trestle for scaffolding

Abstract: PROBLEM TO BE SOLVED: To provide a trestle for scaffolding, which allows the scaffolding to be horizontally erected even at an uneven place. SOLUTION: Paired support materials 2, which are erected in parallel, are coupled together by a horizontal material 3, so that an approximately portal frame body 4 can be formed; and base materials 5, which are horizontal and capable of being fixed at an arbitrary angle with respect to the horizontal material 3, are provided at lower ends of the support materials 2 of the frame body 4, respectively. Clamps 8 for fixing the base material 5 to a steel frame B, etc., are provided at both ends of the base material 5. The trestle 1 for the scaffolding A is placed on the steel frame B; the base material 5 is turned and fastened to a flange part of the steel frame B by the clamps 8, so that the trestle 1 can be fixed; and after that, a locking clamp at one end of the scaffolding A is locked to the horizontal material 3 of the trestle 1. Thus, a step is eliminated so that the horizontal scaffolding A can be erected. COPYRIGHT: (C)2003,JPO

Minimum weight elastic design of rigid portal frames

Abstract: Development of an optimization model for minimum weight elastic design of indeterminate portal frames is documented in this paper. The optimization model minimizes the self weight of the portal frame. The portal frame members are assumed to be made up of built-up I-sections. The minimum weight design is subject to the maximum limits for (i) allowable combined axial and bending compressive stresses; (ii) bending tensile stresses; (iii) limits of search for the decision variables, (iv) restrictions on the structural behaviour; and (iv) structural response in terms of bending moments, shear forces, axial forces, and support reactions corresponding to the specified loading condition. The developed minimum weight design model was applied to design a standard single-bay single-storey portal frame for which the minimum weight design is already reported in literature.