First, safety requirements for the erection of disc-type scaffolding
Building structure safety has always been the most important goal in the process of realizing various project construction, especially for public buildings. It is necessary to ensure that the building can still ensure structural safety and stability during earthquakes. The safety requirements for the erection of disc-type support frames are as follows:
1. The erection must be carried out according to the approved plan and the requirements of the on-site briefing. It is strictly forbidden to cut corners and strictly abide by the erection process. Deformed or corrected poles shall not be used as construction materials.
2. During the erection process, there must be skilled technicians on site to guide the shift, and safety officers must follow the shift to inspect and supervise.
3. During the erection process, it is strictly forbidden to cross the upper and lower operations. Practical measures must be taken to ensure the safety of the transfer and use of materials, accessories, and tools, and safety guards should be set up at traffic intersections and above and below the working site according to the on-site conditions.
4. The construction load on the working layer should meet the design requirements, and it shall not be overloaded. Materials such as formwork and steel bars shall not be concentrated on the scaffolding.
5. During the use of scaffolding, it is strictly forbidden to dismantle the frame structure rods without authorization. If dismantling is required, the technical person in charge must agree to it and the remedial measures must be determined before implementation.
6. The scaffolding should maintain a safe distance from the overhead power transmission line. The erection of temporary power lines on the construction site and the grounding and lightning protection measures of the scaffolding should be implemented by the relevant provisions of the current industry standard “Technical Specifications for Temporary Power Safety at Construction Sites” (JGJ46).
7. Regulations for high-altitude operations: ① When encountering strong winds of level 6 or above, rain, snow, and foggy weather, the erection and dismantling of scaffolding should be stopped. ② Operators should use ladders to go up and down the scaffolding, and are not allowed to climb up and down the bracket, and tower cranes and cranes are not allowed to hoist personnel up and down.
Second, the construction process of the disc-type scaffolding:
When installing the disc-type support frame, the vertical poles should be installed first, then the horizontal poles, and finally the diagonal poles. After forming the basic frame unit, it can be expanded to form an overall bracket system.
Construction process: foundation treatment → measurement and layout → installation of base, adjustment of level → installation of vertical poles, horizontal poles, diagonal tie rods → erection according to construction drawings → installation of the top supports → adjustment of height → laying of main and secondary keels → installation of protective measures → installation of templates → inspection, acceptance, and record keeping.
Third, key points for the erection of disc-type scaffolding:
1. According to the dimension marking on the support frame configuration drawing, the layout is correct. The erection range is based on the design drawings or the designation of Party A, and corrections are made at any time as the support frame is erected.
2. After the foundation is laid out, the adjustable base is placed in the corresponding position. Pay attention to the base bottom plate when placing it. It is strictly forbidden to use materials with uneven bottom plates. The base wrench can be adjusted to a position of about 250mm from the bottom plate in advance to facilitate the adjustment of the elevation during erection. The main frame sleeve part of the standard base is inserted upward onto the top of the adjustable base, and the lower edge of the standard base must be completely placed in the groove of the wrench force plane. Put the crossbar casting head into the small hole of the disc so that the front end of the crossbar casting head is against the main frame round tube, and then use the inclined wedge to penetrate the small hole to knock it tight.
3. After the sweeping rod is erected, the frame is leveled as a whole to ensure that the frame is on the same horizontal plane, and the horizontal deviation of the frame crossbar is no more than 5mm. The exposed length of the adjustable base adjustment screw should not be greater than 300mm, and the height of the bottom horizontal rod of the sweeping rod from the ground should not be greater than 550mm.
4. Arrange the vertical diagonal rods according to the requirements of the plan. According to the requirements of the specification and the actual erection situation on site, the vertical diagonal rod arrangement is generally divided into two forms, one is the matrix spiral type (i.e. lattice column form), and the other is the “eight” symmetrical form (or “V” symmetrical). The specific implementation is based on the plan.
5. Adjust and check the verticality of the frame as the frame is erected. The verticality of each step of the frame (1.5m high) is allowed to deviate by ±5mm, and the overall verticality of the frame is allowed to deviate by ±50mm or H/1000mm (H is the overall height of the frame).
6. The cantilever length of the adjustable bracket extending from the top horizontal bar or double-slot steel beam is strictly prohibited to exceed 500mm, and the exposed length of the screw rod is strictly prohibited to exceed 400mm. The length of the adjustable bracket inserted into the vertical bar or double-slot steel beam shall not be less than 200mm.
7. The structural measures such as the frame holding the column and the tie-in should meet the requirements of the plan.
Fourth, the staged inspection and acceptance specifications of the disc-type scaffolding: When the erection height reaches the design height requirement and before pouring concrete, the disc-type support frame should focus on the following inspections:
1. The foundation should meet the design requirements and should be flat and solid. There should be no looseness or hanging between the vertical bar and the foundation;
2. The three-dimensional dimensions of the erected frame should meet the design requirements, and the erection method and the setting of the diagonal bar should meet the specifications;
3. The cantilever length of the adjustable bracket and the adjustable base extending from the horizontal bar must meet the design requirements;
4. Check the vertical Check whether the pin plate of the diagonal rod is tightened and parallel to the vertical rod; check whether the pin plate of the horizontal rod is perpendicular to the horizontal rod;
5. Check whether the installation position, quantity, and form of various rods meet the design requirements;
6. All pin plates of the support frame must be in a locked state; the cantilever position must be accurate, the horizontal rods and vertical diagonal rods at each stage must be installed completely, the pin plates must be installed tightly, and all safety protections must be in place;
7. The corresponding safety measures such as the horizontal safety net must meet the requirements of the special construction plan;
8. The construction records and quality inspection records of the erection should be timely and complete.
Fifth, precautions for the removal of the disc-type scaffolding:
1. The concrete and prestressed pipe grouting must reach the design strength (strength report should be available), and the frame can only be removed after passing the test.
2. The removal of the support frame must be verified by empirical calculation and comply with the “Concrete Structure Engineering Construction Quality Acceptance Code” (GB50204-2015) and other relevant regulations, and the demolding time must be strictly controlled. Before demolding, there must be a demolding application and approval. The frame should be removed in the order of removal designed in the construction plan.
3. Before dismantling the support frame, a special person should be assigned to check whether the materials and debris on the support frame are cleaned up. Before dismantling the support frame, a safe area must be marked out and a conspicuous warning sign must be set up. Special personnel should be assigned to guard, and no other personnel should be allowed to work below the frame when it is dismantled.
4. When dismantling, the principle of first up and then down, dismantling the last one first, and clearing one step at a time should be followed (that is, dismantling from the place with larger deflection deformation). The order of component dismantling is opposite to the order of installation, and it is strictly forbidden to dismantle the upper and lower parts at the same time. The order of dismantling is: adopt the principle of full-hole multi-point, symmetrical, uniform, and slow, first dismantle the middle span and then the side span, and gradually dismantle the bracket symmetrically from the middle of the span to the two end supports.
5. It is not allowed to dismantle the separate surface or dismantle the upper and lower steps at the same time. Carefully carry out cyclic dismantling, clearing one step at a time, and clearing one rod at a time.
6. When dismantling the support frame, to keep the frame stable, the height-to-width ratio of the minimum retained section to be dismantled is strictly prohibited to be greater than 3:1.
7. When removing steel pipes and fasteners, the steel pipes and fasteners should be separated. It is not allowed to transport the steel pipes with fasteners attached to the ground, or two steel pipes should be removed and transported to the ground at the same time.
8. When removing the scaffolding board, it should be erected and transported from the outside to the inside to prevent the scaffolding garbage from falling directly from a high place and injuring people after it is turned from the inside to the outside.
9. When unloading, the operators should pass each accessory to the ground one by one, and throwing is strictly prohibited.
10. The components transported to the ground should be inspected, repaired, and maintained in time, and the contaminants on the rods and threads should be removed. Those with serious deformation should be sent back for repair; after inspection and correction, the accessories should be stored according to the type and specification and properly kept.
11. When removing the rods, inform each other and coordinate the work. The loosened rod parts should be removed and transported in time to avoid mis-support and mis-relying.
12 After the completion of the day, the surrounding conditions of the post should be carefully checked. If any hidden dangers are found, they should be repaired in time or continue to complete the constraints of a procedure and a part before leaving the post.
Sixth, Summary
All the rods of the disc-type support frame are serialized and standardized. According to the actual needs of construction, the spacing of the vertical rod disc nodes is set according to the 0.5m module, and the length of the horizontal rod is set according to the 0.3m module. It can form a variety of frame sizes, which is convenient for curve layout. It can be set up on a slope or stepped foundation and can support stepped formwork. In addition, the disc-type support frame can also be temporarily used for many other purposes, for example, it can be used as a safe passage for vehicles to pass; it can be used for double-row scaffolding; it can quickly set up a temporary work platform; it can be used with a hook-type step ladder to quickly form a safe and reliable cage ladder passage that is convenient for people to go up and down; in addition, it can almost replace all the uses of ordinary steel pipes.
Post time: Jun-06-2024