1) The structure of portal scaffolding
Portal scaffolding is composed of jack base, portal structure, wrist arm lock, cross bracing, socket connection buckle, ladder, scaffolding board, scaffolding joist structure, handrail tie rod, truss joist and other components.
2) Portal scaffold erection
The standard of portal scaffolding is: 1700~1950mm high, 914~1219mm wide, the erection height is generally 25mm, and the maximum shall not exceed 45m. A buckle wall pipe should be installed every 4~6m in the vertical and horizontal directions to connect with the outer wall, and the corners of the whole scaffolding should be fastened to two adjacent door frames by steel pipes through fasteners.
When the portal frame exceeds 10 floors, auxiliary supports should be added, generally between 8 and 11 storeys of portal frames, and between 5 portal frames wide, and a group is added to make part of the load bear by the wall. When the scaffold height exceeds 45m, it is allowed to work together on the two-step shelf; when the total height is 19~38m, it is allowed to work on the three-step shelf; when the height is 17m, it is allowed to work together on the four-step shelf.
3) Application requirements
(1) Preparatory work before assembly
Before assembling the mast, the site must be leveled, and a base should be installed at the bottom of the vertical frame of the lower floor. When there is a height difference in the foundation, an adjustable base should be used. The door frame parts should be inspected one by one when they are transported to the site. If the quality does not meet the requirements, they should be repaired or replaced in time. Before assembly, it is necessary to do a good job in construction planning and explain the operational requirements.
(2) Assembly methods and requirements
Vertical frame assembly should be kept vertical, adjacent vertical frames should be kept parallel, and cross braces should be set at both ends of vertical frames. When required to use, the diagonal brace will not loosen. It is necessary to set up a horizontal frame or a steel scaffolding board on the vertical frame on the top floor and every third floor vertical frame, and the locker of the horizontal frame or steel scaffolding board should be locked with the cross bar of the vertical frame. The height connection between the vertical frames is connected with the joint receiver, and the vertical frame connection is required to maintain the vertical height.
(3) Application requirements
The permissible load of each pole of the vertical frame is 25KN, and the permissible load of each unit is 100KN. When the horizontal frame bears the central joint load, the allowable load is 2KN, and when it bears the uniform load, it is 4KN per horizontal frame. The allowable load of the adjustable base is 50KN, and the allowable load of the connecting wall rod is 5KN. During use, when the construction load is to be increased, it must be calculated first, and the snow, rain, and mortar machine garbage on the scaffolding board must be cleaned frequently and other sundries. Safety measures are required for the erection of wires and lamps. At the same time, a group of ground wires should be connected every 30m, and a lightning rod should be installed. When placing prefabricated components or equipment on steel scaffolding, it is necessary to lay skids to prevent the load from converging and crushing the scaffolding.
(4) Revocation and maintenance processing requirements
When dismantling portal scaffolding, use pulleys or ropes to hang it down to avoid falling from a high place. The removed parts should be cleaned up in time. If deformation, cracking, etc. are caused by collisions, etc., they should be corrected, repaired or reinforced in time to keep all parts intact.
The dismantled mast parts should be sorted and stacked according to the standards, and should not be stacked arbitrarily. The door frame should be placed in the shed as much as possible. If it is piled up in the open air, choose a place with flat and dry terrain, use bricks to level the ground, and cover it with a rain cloth to prevent rust.
As a special construction tool, portal scaffolding should effectively strengthen the management responsibility system, establish a full-time organization as much as possible, carry out full-time management and repair, actively promote the leasing system, and formulate rewards and punishments for use and management, so as to improve the number of turnover and reduce loss.
Post time: Mar-31-2023