First, the structural requirements of the scaffolding
(1) The height-to-width ratio of the scaffolding should be controlled within 3; when the height-to-width ratio of the scaffolding is greater than 3, anti-overturning measures such as guying or guy ropes should be set.
(2) When erecting double-row external scaffolding or when the erection height is 24m or above, the geometric dimensions of the frame should be selected according to the use requirements, and the step distance between adjacent horizontal bars should not be greater than 2m.
(3) The first-layer vertical poles of the double-row external scaffolding should be staggered with vertical poles of different lengths, and the bottom of the vertical poles should be equipped with adjustable bases or pads.
(4) When setting up a double-row external scaffolding pedestrian passage, a supporting beam should be installed on the upper part of the passage. The cross-section size of the beam should be determined according to the span and the load to be borne. Diagonal bars should be added to the scaffolding on both sides of the passage. A closed protective plate should be laid on the top of the opening, and safety nets should be installed on both sides; safety warning and anti-collision facilities should be installed at the opening for motor vehicles.
(5) Vertical diagonal bars should be installed on the outer facade of the double-row scaffolding and should comply with the following regulations:
① At the corners of the scaffolding and the ends of the open scaffolding, diagonal bars should be installed continuously from the bottom to the top of the frame;
② A vertical or diagonal continuous diagonal bar should be installed every 4 spans; when the frame is erected at a height of more than 24m, a diagonal bar should be installed every 3 spans;
④ Vertical diagonal bars should be installed continuously from bottom to top between adjacent vertical bars on the outer side of the double-row scaffolding.
(6) The setting of wall ties shall comply with the following provisions:
① Wall ties shall be rigid rods that can withstand tensile and compressive loads and shall be firmly connected to the main structure and frame of the building;
② Wall ties shall be set close to the knot nodes of the horizontal rods;
③ Wall ties on the same floor should be on the same horizontal plane, and the horizontal spacing should not be greater than 3 spans. The cantilever height of the frame above the wall ties shall not exceed 2 steps;
④ At the corners of the frame or the ends of the open double-row scaffolding, they should be set according to the floor, and the vertical spacing should not be greater than 4m;
⑤ Wall ties should be set from the first horizontal rod on the bottom floor; wall ties should be arranged in a diamond shape or a rectangular shape;
⑥ When wall ties cannot be set at the bottom of the scaffolding, multiple rows of scaffolding should be set outward and inclined rods should be set to form an additional ladder frame with an outer inclined surface.
Second, the installation and removal of scaffolding
(1) The scaffolding poles should be accurately positioned and should be erected by the construction progress. The erection height of the double-row external scaffolding should not exceed two steps of the top wall connection, and the free height should not be greater than 4m.
(2) The wall connection parts of the double-row external scaffolding should be installed synchronously at the specified position as the scaffolding height rises. They shall not be installed late or removed arbitrarily.
(3) The setting of the working layer shall comply with the following regulations:
① The scaffolding boards should be fully laid;
② The outer side of the double-row external scaffolding should be equipped with footboards and guardrails. The guardrails can be arranged with two horizontal bars at the connection plates of the 0.5m and 1.0m of the poles on each working surface, and a dense safety net should be hung on the outer side;
③ A horizontal protective net should be set in the gap between the working layer and the main structure;
④ When using steel scaffolding boards, the hooks of the steel scaffolding boards should be firmly buckled on the horizontal bars, and the hooks should be in a locked state;
(4) Reinforcement members and diagonal bars should be erected synchronously with the scaffolding. When the reinforcements and diagonal braces are made of fastener steel pipes, they shall comply with the relevant provisions of the current industry standard “Safety Technical Specifications for Fastener-Type Steel Pipe Scaffolding in Construction” JGJ130. [That is, reinforcements and diagonal braces can be fastener-type, which is not considered a mix-up]
(5) The height of the outer guardrail of the top layer of the scaffolding should not be less than 1500mm above the top working layer.
(6) When the vertical pole is in a tension state, the sleeve connection extension part of the vertical pole should be bolted.
(7) The scaffolding should be erected and used in sections and should only be used after acceptance.
(8) The scaffolding should be confirmed and signed by the unit project manager before it can be dismantled.
(9) When the scaffolding is dismantled, a safety zone should be marked out, warning signs should be set up, and a special person should be assigned to supervise it.
(10) Before dismantling, the tools, excess materials, and debris on the scaffolding should be cleared.
(11) Scaffolding removal should be carried out according to the principle of installing first and then removing, or installing last and then removing first. The upper and lower parts should not be operated at the same time. The wall connecting parts of the double-row external scaffolding should be removed layer by layer along with the scaffolding, and the height difference of the segmented removal should not be greater than two steps. When the working conditions are limited and the height difference is greater than two steps, additional wall connecting parts should be added for reinforcement.
Third, inspection and acceptance of scaffolding
(1) The inspection and acceptance of scaffolding accessories entering the construction site shall comply with the following provisions:
① There should be scaffolding product identification and product quality certificate, type inspection report;
② There should be scaffolding product main technical parameters and product instructions;
③ When there are doubts about the quality of scaffolding and components, quality sampling and whole frame testing should be carried out;
(2) When one of the following situations occurs, the support frame and scaffolding should be inspected and accepted:
① After the completion of the foundation and before the erection of the support frame;
② After each 6m height of the high formwork over 8m is completed;
③ After the erection height reaches the design height and before concrete pouring;
④ After being out of use for more than 1 month and before resuming use;
⑤ After encountering strong winds of level 6 or above, heavy rain, and thawing of frozen foundation soil.
(3) The inspection and acceptance of the support frame shall comply with the following provisions:
① The foundation shall meet the design requirements and shall be flat and solid. There shall be no looseness or hanging between the vertical pole and the foundation. The base and support pads shall meet the requirements;
② The erected frame shall meet the design requirements. The erection method and the setting of diagonal bars, scissor braces, etc. shall meet the requirements of Chapter 6 of this standard;
③ The cantilever length of the adjustable support and adjustable base extending from the horizontal bar shall meet the requirements of the previous article;
④ The pins of the horizontal bar buckle joint, diagonal bar buckle joint, and connecting plate shall be tightened.
(4) Scaffolding inspection and acceptance shall comply with the following provisions:
① The erected frame shall comply with the design requirements, and the diagonal rods or scissor braces shall comply with the above provisions;
② The foundation of the vertical pole shall not have an uneven settlement, and the contact between the adjustable base and the foundation surface shall not be loose or suspended;
③ The wall connection shall comply with the design requirements and shall be reliably connected to the main structure and frame;
④ The hanging of the outer safety vertical net, the inner interlayer horizontal net, and the setting of the guardrail shall be complete and firm;
⑤ The appearance of the scaffolding accessories used in circulation shall be inspected before use, and records shall be made;
⑥ The construction records and quality inspection records shall be timely and complete;
7 The pins of the horizontal rod buckle joint, the diagonal rod buckle joint, and the connecting plate shall be tightened.
(5) When the support frame needs to be preloaded, the following provisions shall be met: (Preloading eliminates non-elastic deformation)
① A special support frame preloading plan shall be prepared, and safety technical instructions shall be given before preloading:
② The preloading load arrangement shall simulate the actual load distribution of the structure for graded and symmetrical preloading, and the preloading monitoring and loading classification shall comply with the relevant provisions of the current industry standard “Technical Regulations for Preloading of Steel Pipe Full-Span Support” JGJ/T194.
Post time: Nov-12-2024