Showing papers on "Portal frame published in 2007"

Simplified seismic design approach for steel portal frame piers with hysteretic dampers

Abstract: A simplified seismic design procedure for steel portal frame piers installed with hysteretic dampers is proposed, which falls into the scope of performance-based design philosophy. The fundamental goal of this approach is to design a suite of hysteretic damping devices for existing and new bridge piers, which will assure a pre-defined target performance against future severe earthquakes. The proposed procedure is applicable to multi-degree-of-freedom systems, utilizing an equivalent single-degree-of-freedom methodology with nonlinear response spectra (referred to as strength-demanded spectra) and a set of formulae of close-form expressions for the distribution of strength and stiffness produced in the structure by the designed hysteretic damping devices. As an illustrative example, the proposed procedure is applied to a design of a simple steel bridge pier of portal frame type with buckling-restrained braces (one of several types of hysteretic dampers). For the steel portal frame piers, an attempt is made to utilize not only the displacement-based index but also the strain-based index as pre-determined target performance at the beginning of design. To validate this procedure, dynamic inelastic time-history analyses are performed using the general-purpose finite element program ABAQUS. The results confirm that the proposed simplified design procedure attains the expected performance level as specified by both displacement-based and strain-based indices with sufficient accuracy. Copyright © 2006 John Wiley & Sons, Ltd.

Inelastic response analysis of reinforced concrete structures using modified force analogy method

Abstract: A modified force analogy method (MFAM) is developed to simulate the nonlinear inelastic response of reinforced concrete (RC) structures. Beam–column elements with three different plastic mechanisms are utilized to simulate inelastic response caused by moment and shear force. A multi-linear hysteretic model is implemented to simulate the nonlinear inelastic response of RC member. The P-Δ effect of the structure is also addressed in MFAM. Static and dynamic inelastic response of structure, damage condition and failure type for structural element, structural limit state and collapse time can also be simulated using MFAM. Compared with the general algorithm, the MFAM provides less computational time especially in the case of large structural system. It is also easier to be written as computer program. Three test data groups, which include cyclic loading test data of a non-ductile RC bridge column, a two-storey RC frame, and dynamic collapse test data of a non-ductile RC portal frame, are selected to confirm the effectiveness of applying MFAM to simulate the inelastic behaviour of structures. Copyright © 2007 John Wiley & Sons, Ltd.

Experimental investigation of the use of ferrocement laminates for repairing masonry in filled RC frames

Abstract: An experimental study was carried out to investigate the in-plane strength of masonry infilled reinforced concrete portal frame rehabilitated with ferrocement. A model of a portal frame having masonry infill panel was constructed and tested in the laboratory for this purpose. The load was applied monotonically at the top of the frame till the ultimate capacity was reached accompanied by substantial formation and propagation of cracks. Then both the infill and the frame were repaired by ferrocement coating. After rehabilitation, the frame was tested in the laboratory following the same procedure as for the original frame. The masonry infill frame repaired with ferrocement showed significant improvement in performance and more than original strength was achieved. This reveals the potential use of ferrocement as a retrofitting and strengthening material of the existing infilled frame.

Portal gantry type machine tool

Abstract: PROBLEM TO BE SOLVED: To compensate for the displacement of a spindle end position due to inclination of a column or twist of a cross rail caused by movement of a saddle and to avoid a decline of life of a slider due to offset load. SOLUTION: Load compensating sliders 58R, 58L, 59R, 59L respectively engaged with guide rails 13R, 13L to bear the load of a portal frame 20 are fitted to right and left columns 21R, 21L by hydraulic cylinder devices 50R, 50L, 51R as a pressing load adjusting means. COPYRIGHT: (C)2007,JPO&INPIT

Thermal flattening machine for mounting books and pictures

Abstract: The utility model discloses a painting and calligraphy mounting heat-sealing leveling machine. The leveling machine consists essentially of a bin-type housing, a portal frame, an active compressive plate, an extractable power lever and a electric control system. The portal frame is fixed at and connected with the backside of the bin-type housing. A pin roll is fixed at and connected with the inner side of the vertical post of the portal frame. The active compressive plate is positioned on the top of the bin-type housing. The backside surface of the compressive plate is fixed and positioned with a backward-extended bracket with a guide slot at the head. The guide slot is provided with a sliding block with a hole in the middle. The hole in the middle of the sliding block and the pin roll in the arc-shaped vertical post of the portal frame form a revolving pair. The extractable power lever is hinged between the beam of the portal frame and the active compressive plate. Because the structure not only vertically or horizontally descends to press and heat-seal the positioned painting or calligraphy as the painting and calligraphy mounting heat-sealing leveling machine, but also obtains a sector operation space with a greater opening within the limited space, greatly convenient to observe, get or put the positioned painting or calligraphy and relieving the labor intensity.

Cyclic behaviour of beam–column connections in steel portals

Abstract: This paper presents an experimental study on the cyclic behaviour of bolted and welded beam-to-column connections in a steel portal frame. The test focuses on: (a) an experimental analysis for investigation of the behaviour of beam-to-column connections under cyclic loading, (b) the failure modes of each connection under cyclic loading; and (c) the capacity of the high-strength bolted angle connections compared with the fully welded counterpart. The behaviour of the high-strength bolted frame under cyclic lateral loading is studied, and it is compared with that of the welded frame subjected to the same loading. The results obtained from six tests on steel portal frames showed that the initial connection stiffness of the specimen composed of top-seat angle and double web angle (TSD) was developed for about 48% of the specimen with welded connection (FW), and the specimen composed of double web angle (DWA) was about 15%. Based on these tests, conclusions are presented.

Individual liftout attachment for low-pressure casting

Abstract: The utility model provides a separate tip-out device for low-pressure casting, including dynamic templates, which is connected with portal frame, a tip-out fuel tank is installed on the portal frame whose piston rod within is connected with the tip-out plate, and a tip-out rod is installed on the tip-out plate The utility model applies the portal frame on the dynamic templates of the low-pressure casting equipment, shortens the trip of the processing workpiece and the tip-out workpiece, and the seal components on the hydraulic cylinder are prevented from heat damage, thus can avoid leakage

Analysis of the value and position of the extreme bending moment and the contraflexure point for the design of the single-span portal frame with hinged connection and a gable roof

Abstract: In accordance with the Technical Specification for Steel Structure of Lightweight Buildings with Gabled Frames,the value and position of the extreme bending moment in the oblique beam of the portal frame as well as the contraflexure point are calculated and analyzed.The results provide theoretical support for simplifying the designing procedure of portal frames.

Optimal design using genetic algorithm with nonlinear inelastic analysis

Abstract: An optimal design method in cooperated with nonlinear inelastic analysis is presented. The proposed nonlinear inelastic method overcomes the difficulties due to incompatibility between the elastic global analysis and the limit state member design in the conventional LRFD method. The genetic algorithm used is a procedure based on Darwinian notions of survival of the fittest, where selection, crossover, and mutation operators are used to look for high performance ones among sections in the database. They are satisfied with the constraint functions and give the lightest weight to the structure. The objective function taken is the total weight of the steel structure and the constraint functions are load-carrying capacity, serviceability, and ductility requirement. Case studies of a planar portal frame, a space two-story frame, and a three-dimensional steel arch bridge are presented.

Pile extracting device and pile extracting method

Abstract: PROBLEM TO BE SOLVED: To provide a pile extracting device capable of improving working efficiency, by cutting and removing an upper part of a pile, without fixing the suspended pile to the ground. SOLUTION: This pile extracting device 1 has a portal frame 20 supporting an upper frame body 21 by two columns 22, a plurality of support blocks 30 for supporting the pile K and a rope winding means for the plurality of blocks; and is characterized in that a pulley group 27B for the plurality of blocks is arranged in the upper frame body 21 of the portal frame 20, and a pulley group 31 is arranged in the respective support blocks 30, and a lifting wire 11B (a rope) wound on the rope winding means for the respective blocks is extended to the pulley blocks 27B for the blocks arranged in the portal frame 20 and the pulley group 31 arranged in the support blocks 30, and is constituted to lift the respective support blocks 30 by the rope winding means for the respective blocks. COPYRIGHT: (C)2007,JPO&INPIT

Light structure examples for industrial architecture

Abstract: In the Educational Construction Unit of the Rural and Agricultural Engineering Department of the Polytechnic University of Valencia, we developed a series of spatial structure typologies for industrial warehouses, which have been improved and developed over time. In most cases, the warehouses have been used for agroindustrial activity, although they can also be used for various other applications. In this report, five basic models are described, which have been put into practice on numerous occasions. They stand out for their lightness and their good structural behaviour under different applied loads (0.25-0.30 kN/m 2 , on average). These five models stand out because they have been designed to encompass a large area. Some of them are more adaptable to rectangular plants, while others are better adapted to square distributions. Although the mechanical and architectural qualities of the five models will be described in more detail, their main characteristics are summarised here: 1. Wide-open plan: the structures contain a small number of intermediate pillars, making them well-suited to the arrangement of machinery and other activities that may develop. 2. Rigidity and lightness of cover, excellent structural behaviour, and high degree of bracing against lateral loadings due to the truss of bars and the four-slope disposition. 3. Illumination: the disposition and design of the structural truss allow for skylight bands that provide a high degree of natural illumination and environmental comfort. 4. Ventilation: the disposition of zenithal and lateral openings, together with the ridge-cap height, provide convective static ventilation that improves environmental conditions. 5. Lower deformations and deflections due to truss-cover rigidity. 6. Reduced dimensions of the foundations; the behaviour of the cover is such that small bending stresses are transmitted to the supports.

The critical conditions on eliminating fire protection cover for steel portal frames

Abstract: Using Ansys,the finite element analysis software,the critical temperatures of steel portal frames in fire with varied factors are calculated.By analyzing the results,the simplified calculation table is concluded,using which any steel portal frame's critical temperature can be determined easily(height10 m,span52 m,section height900 mm).Combined with the simplified method which can calculate the temperature—time curve of the steel members in large space building fire,the critical conditions for steel portal frames without fire protection cover are concluded.

Hydraulic equipment processed by fire

Abstract: The utility model discloses a hydraulic device for thermal processing, comprising a portal frame and at least one moving-free hydraulic cylinder arranged on the frame which can freely move. The utility model has the advantages in high product quality, low labor strength, and short manufacture period or the like.

Deformation Behavior and Strength of Beam-To-Column Connections in Steel Portal Frame

Abstract: This paper presents an experimental work on the cyclic behavior of bolted and welded beam-to-column connections in steel portal frame. Three types of connection were used; tests for each specimen were performed twice in order to maintain test reliability. Specimen 1 (DWA) had only a double web angle connection, specimen 2 (TSD) had a top and seat angles with double web angle connection, and specimen 3 (FW) had a fully welded connection. All specimens were tested under cyclic loading conditions in order to simulate the effects of earthquakes. We also conclude that with appropriate design and careful consideration of connection strength and stiffness, the steel project economy may be maximized.