Showing papers on "Portal frame published in 1993"

Method and equipment for construction of concrete cylinder

Abstract: The construction method for concrete cylindrical shaft without derrick and scaffold is characterized by that the lifting portal frame is attached to the wall of the shaft body, it has lifting device, the portal frame can be raised along the wall of the shaft, it has platform and form board system to play the role of derrick and scaffold; it utilizes coordinate, centering method to control the central axis of the cylindrical shaft free from deviation, the present method is suitable for construction of concrete cylindrical shaft of any height with no need of derrick and scaffold, so that it can save steel material and raise economic benefit.

Structural repair of reinforced concrete portal frame

Abstract: The Paper describes repairs carried out on a reinforced concrete portal frame that had suffered damage over the previous 25 years as a result of alkali–silica reaction (ASR). This particular structure has been the subject of intense study since 1978 and several previous papers have described its behaviour.3,5 The repair consisted of partly demolishing and rebuilding the upper beam of the portal, while keeping the motorway it supports open to traffic. Results are given for the shrinkage of the replacement concrete, and for depropping movements and surface strain measurements taken on the structure over the year following the repair.

Portal frame system

Abstract: A precast concrete portal frame system includes two column sections and a rafter section, each of which are pre-cast off-site, each column section extending integrally toward a plane of symmetry of the portal frame to an uppermost articulated surface of each of the column sections which meet lowermost articulated surfaces of the rafter section, defining respectively opposing planes in complemental keyed relationship, the opposing planes also defining, in longitudinal cross-section, mating L-shaped surfaces, the inclined planes of the column and rafter sections provided with transverse bolting holes to provide a bolted connection between the rafter and column sections of the system. The upper part of each column section is enlarged to provide resistance to high bending moments.

Cutting device for semiplastic body

Abstract: PURPOSE:To make it possible to precisely cut a semiplastic body such as lightweight cellular concrete before being cured and bore a window-like opening by providing a truck provided with cutting tooth which are movable reciprocally in a vertical direction and pivotable in a horizontal direction so as to be movable over the semiplastic body in longitudinal and lateral directions. CONSTITUTION:A semiplastic body 1 is placed on a horizontal frame 3. Rails 4 are fixed on both edges of the frame 3 in the longitudinal direction thereof, on which rails a portal frame 6 is provided so as to be reciprocally movable. A truck provided with a cutting blade 20 is provided so as to be movable on a pair of rails 15 installed on the frame 6 over the entire width of the frame 6. The cutting blade 20 has a rectangular shape and its upper part is held by a vertically movable cylindrical holder 21 so as to be reciprocally moved in a vertical direction by means of a motor driven crank 26a and also rotated by a rotary cylinder. As a result, the semiplastic body can be precisely cut off in longitudinal and lateral directions and a window-shaped opening can be bored.

Portal frame for metal framework, and method for producing it

Abstract: In this portal frame, at each connection between two girders (1), there is provided at least one connection plate (7 or 8) which joins the ends of the two girders (1) and which is fixed by bolting to the web (1a) of each of them. Sets of holes for the assembly bolts are pierced respectively in the connecting pieces (7 and 8) and in the webs of the girders, close to their ends, with relative layouts such that once the connection has been made, the longitudinal axes of two girders (1) thus assembled form a predetermined angle ( alpha or beta ) between them.

Turret punch press

Abstract: PURPOSE:To prevent the inclination of press axial line against the frame deformation due to the press loading and the heat, etc., improve the precision of product and reduce the assembling man-hour and the assembling time by making the portal frame to the divided type. CONSTITUTION:A vertically standing frame 7 is set at an end of the longitudinal direction of a base 5 of the portal frame 3 composing a turret punch press 1, a horizontal frame 9 extending to the horizontal direction is set by a body at the upper part of the vertically standing frame 7, an upper turret 25 is attached at the horizontal frame 9, a lower turret 27 is attached at the base 5, side frames 15 are set in hanging down at both sides of an upper frame 13 which provides a press driving means 11 operating an upper die 45 attached to the upper turret at almost central part, and the down surface of the side frames 15 are composed to be fixed by tying with the upper surface of the base 5.