1. If the erection height of the landing house is 1 1m, that is, the sum of the height of the basement and the height of the first floor, the cantilever frame is erected from the top of 1 floor, that is, the height of the frame body is 18m (including the height of the parapet and the height of the protective railing). The advantage of this is that the basement exterior wall can be directly waterproof after the floor frame is removed and accepted. However, the shortcomings are also obvious. A large number of cantilever beams (generally 16# I-beam or channel steel) are put into use at one time, as well as wire ropes and U-shaped pull rings. The rest is the increase of labor costs and the delay of construction period.
2. If there is no hurry to backfill, it is recommended to build a roof at one time, with a total height of 30m. Single-pole double-row scaffolding can be realized completely, which can speed up the construction period and save labor, but the disadvantage is that the investment of steel pipe fasteners is too large and the service life is long. That's about it. You can use that scheme according to your actual situation.
Scaffolding requirements:
(1) Set up shelves to ensure a clean and beautiful appearance. Rectangular shelves are erected on all sides of the project, and the large surfaces are flush. The platform frame at the groove of the building is connected with the integral shelf. The waste of the shelf should be fixed by stay wires to ensure the position of the outer shelf is flush. Spacing between vertical poles 1.5m, spacing between main poles 1.8m, spacing between small poles 1.0m, and scaffolding width 1.0m (four boards). Lippi uprights are 500mm away from the wall (wooden boards are added between Lippi frame and the wall during construction).
The large surface of the shelf consists of five or eight poles (five vertical poles and eight-step crossbar) from bottom to top, and the poles are parallel bars. At the bottom of each column, there should be a 5 cm thick pad. Horizontal and vertical sweeping poles must be set at the bottom, and the vertical sweeping poles should be fixed with right-angle fasteners, with a distance of not more than 200mm from the pad epithelium. The horizontal sweeping bar should be tied to the vertical sweeping bar near the bottom of the vertical sweeping bar. The poles must be reliably connected to the building through wall connecting pieces, which are vertically fixed on the top plate of each ring beam, and the horizontal spacing is set to one point for every three poles. Columns and horizontal covers shall be connected by butt fasteners, which shall be staggered. The joints of two adjacent uprights should not be set synchronously. The staggered distance between two joints separated synchronously by a vertical rod is not more than 500mm, and the distance from the center of each joint to the nearest node is not more than 1/3 step, that is, 600mm. The top of the vertical pole is higher than the cornice epithelium1.5m.. The longitudinal horizontal bar of the ledger should be located inside the vertical bar, with a length of 6m, connected by butt fasteners, and the joints should be staggered. Two adjacent rail joints cannot be located in synchronization or within the same span, and the horizontal stagger distance is greater than 500mm. The distance from the center of each joint to the nearest node is not greater than 1/3 of the longitudinal distance, that is, 500mm. The row spacing of putlog is 1.0m, scaffolding is flat butt-jointed and overlapped, and the butt-jointed position should be provided with double rows of square timber, with the spacing not more than 300 mm ... The scaffold ends should be pressed with steel wires or φ6 steel bars.
(2) Rigid connection is required for erection: connection points are reserved at the position of roof beam of each floor with a distance of 6m, steel pipes are embedded and scaffolding is effectively connected with fasteners. Protective measures: The scaffold is more than 2m from the ground, and two protective fences and a 18cm high footboard are tied at each step. The height of the top of the shelf must exceed 65438+ 0.2m of the parapet. Scaffolding facades are all closed with eyelet nets. During construction, two protective poles are tied at the frame column in the building, and a shelf passage is set. Lightning protection measures: connect the lightning rod to the vertical steel pipe at the bottom of the scaffold, introduce it into the ground and bury it deeply. All lightning protection and grounding materials are galvanized and all connections are welded. The lap length of round steel is 6 times the diameter of round steel, and it is welded on both sides. The lap length of flat steel is twice the width of flat steel, and it is welded on three sides. All joints shall be treated with anticorrosion (except in concrete), and the grounding resistance shall not be greater than 4Ω. External elevator: The external elevator adopts two double cage elevators for people and goods.
(3) The order of shelf erection: foundation treatment → paving wood → pulling wires to put the base → placing sweeping poles → erecting vertical poles and fixing them with sweeping poles → installing the first small bar and fixing it with vertical poles → installing the second small bar → installing the third small bar → installing the third small bar → adding temporary diagonal braces. Fasten the upper end of the main rail and the third step (remove it after installing the wall pole) → spread the scaffold board → tie the protective railing and foot board → install the fourth and fifth steps of the main rail and small rail → tie the window pole → connect the column → add scissors → spread the steel scaffold board → tie the protective railing and foot board, and hang the net for protection ……………………………………………………………………………………………………………………………………………………………………………………………………
(4) Scaffolding Demolition Scaffolding shall be dismantled step by step from top to bottom. First, remove the protective railings, scaffolding and rafts, and then remove the upper fasteners and connecting rods of the cross cover in turn. Before removing all horizontal covers, and when the shelf is removed to the bottom, temporary supports must be attached to prevent the shelf from tilting. It is forbidden to dismantle by pushing or pulling down.
1. Installation and fixation of cantilever structure Before installing cantilever structure, it is necessary to accurately set out and locate the building structure and check the quality of embedded parts. When the structural concrete reaches a certain strength, the cantilever structure can be installed and fixed. If welding connection is adopted, the quality and length of weld should be guaranteed. The stressed anchor rod and anchor plate shall be welded in T-shape. When the anchor bar diameter is not more than 20㎜, pressure submerged arc welding should be adopted. When the diameter of anchor bar is greater than 20㎜, it is appropriate to use perforated plug welding. When manual welding is used, the weld height should not be less than 6㎜ and 0.8d(d is the diameter of steel bar). If the bolt connection is adopted, the embedded anchor bolt shall be installed with sleeve plate and double nuts, so as to ensure that no less than three nuts are exposed on the screw. If the embedded connection is adopted, the embedded steel cantilever beam should be placed inside the main reinforcement of the outer layer of the structure, and the embedded end should be provided with shear anchor bars, and the anchor bars should be pinned into the holes at the end of the cantilever beam.
2. Scaffolding can be erected only after the cantilever structure is firmly connected with the building structure. If the site permits, before installing the cantilever structure, the scaffold below the installation point should be erected according to the conventional floor-standing scaffold, which is one step higher than the installation point, and a longitudinal horizontal bar should be set below the cantilever structure to support the load of the protruding part of the cantilever structure. After the first unloading device is installed, the scaffolding under the cantilever structure can be removed, and then the flat bridge and the building on this floor can be tightly closed. In the case of limited space, if scaffolding is to be built directly on the cantilever structure, it is necessary to gradually lay a firm and tightly closed flat bridge on the cantilever structure from the edge of the building, and then build a frame on the flat bridge. The erection of the frame body shall meet the relevant requirements of the specification.
3. The lifting point of the unloading device is located at the intersection of the vertical rod and the longitudinal and transverse horizontal rods, and the steel wire rope passes through the bottom of the longitudinal and transverse horizontal rods. Set a collar at the place where the wire rope passes through the lifting ring to reduce the wear of the wire rope by the lifting ring. Tighten the wire rope through the flower basket bolt, so as to make all the wire ropes have the same tension as far as possible, and avoid uneven stress on the wire rope. The rope ends of the steel wire rope are fixedly connected through rope clamps. The number of working rope clamps shall not be less than three, and a safety rope clamp shall be added at the end. The spacing between rope clamps shall not be less than 6 times of the diameter of steel wire rope, and the distance between rope head and safety rope clamp shall not be less than 140㎜, which shall be bound with thin steel wire. When working, the rope clamping saddle is placed on the stressed side of the wire rope, and the U-shaped bolt is buckled at the end of the wire rope.
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