For scaffolding, people have long been commonplace and are often used at construction sites. However, if the scaffolding is not well taken, it will affect the lives of workers, and it will even lead to innocent people. The consequences will be disastrous. How much do you know about the scaffolding standards for external scaffolding ? Here we will take a look at the specification of the scaffolding for the installation of external scaffolding .
Exterior scaffolding installation specifications detailed
First, the construction program
1. Before erecting the scaffolding, the erection plan shall be determined according to the characteristics of the type of work and the construction process. The content shall include: basic treatment, erection requirements, spacing of rods, setting position and connecting method of connecting rods, and drawing of construction details and sample plots. .
2. The erection height of the scaffold exceeds the specifications to be calculated.
(1) When the fitting size of fastener-type steel pipe scaffold meets the following table, the corresponding member can no longer be designed and calculated. However, the bearing capacity of wall elements and upright foundations should still be designed and calculated according to the actual load and the construction drawings should be drawn.
(2) When the erection height is 25-50m, the overall stability of the scaffold should be strengthened from the structure. For example, the vertical scissor support must be continuously installed to increase the horizontal scissor support so that the strength of the wall rod can be increased accordingly, the spacing can be reduced, and a scaffold with a height of more than 40m can be erected in a windy area. Considering the upward force of the wind vortex, it should be set horizontally. At the same time as the wall elements, there should also be countermeasures against wall-falls, etc. to ensure the safe use of scaffolding.
(3) When the erection height exceeds 50m, the double poles can be used to strengthen or use the sectional unloading, and the scaffold and the beam plate structure can be lifted along the full height section of the scaffold and the part load of the scaffold can be transmitted to the building; Or use segmental erection to carry the scaffolds to the cantilever beam and frame projected from the building, and calculate and design them.
(4) The design and calculation of the scaffolding must comply with the relevant provisions of the scaffolding specification and be subject to approval by the enterprise technical person in charge.
3. Scaffolding construction plans should be consistent with the type of scaffolding erected on the construction site. When the site changes the type of scaffolding, the scaffolding plan must be revised and approved before construction.
Second, the pole base
1. The scaffold pole foundation should meet the requirements of the program.
(1) When the erection height is under 25m, the concrete can be leveled and leveled. A 125px thick plank is laid on the upper surface. When the length is 2m, it is placed perpendicular to the wall surface; when the length is more than 3m, it is placed parallel to the wall surface.
(2) When erecting a height of 25-50m, a foundation method shall be designed based on the endurance conditions at the site, or when the backfill soil is layered and compacted to meet the requirements, a sleeper support pad may be used, or a 500px thick ballast may be overlaid on the foundation and a concrete slab may be laid thereon. , and then shop back channel No. 12-16.
(3) When the erection height exceeds 50m, it shall be calculated and the basic practice shall be designed based on the endurance of the ground, or the ash foundation shall be applied at a depth of 1m below the ground, or the 50m-thick concrete foundation shall be poured, and the pillow support shall be used.
2. The base of the fastener-type steel scaffold has malleable cast iron and welded bases. When erecting, the wooden pallets should be laid flat, and the base should be placed. Then the poles should be placed in the base and the poles must not be placed directly on the boards. , otherwise it will change the stress state of the pad. The setting of the backing plate under the base is beneficial to load transfer. Tests have shown that: Under the standard base, a wood backing plate (thickness 125px, plate length ≥ 5000px) is added, which can increase the carrying capacity of the foundation soil by more than 5 times. When the length of the wood board is more than 2 spans, it will help to overcome uneven settlement between the two poles.
3. When the pole is not buried, 500px from the ground, set vertical and horizontal sweeping poles. The method of setting the sweeping bar is the same as that of the large cross bar. Its function is to fix the bottom of the vertical bar and limit the horizontal position of the vertical bar. The trial shows that the carrying capacity of the scaffold without the sweeping bar also decreases.
4. When the wooden scaffold pole is buried, the sweeping pole may not be set. The buried depth is 30-1250px. The bottom of the pit should be tamped with broken bricks. The backfill soil in the pit should be layered and compacted.
5. When the foundation of the scaffold is low, consider that there are no drainage measures around it. After the wooden scaffold scaffolds are embedded in the backfill, mounds should be left above the ground to prevent the accumulation of water.
Third, the frame and the structure of the structure of the knot
1. When the scaffold height is 7m or less, you can set up the throwing method to maintain the stability of the scaffold. When the erection height exceeds 7m, it is inconvenient to set up the throwing support and should be connected with the building.
(1) The connection between the scaffold and the building can not only prevent the inward or outward rollover accident due to wind load, but also can be used as the intermediate constraint of the frame to reduce the calculated length of the pole, increase the bearing capacity, and ensure the scaffolding. Overall stability.
(2) The distance between wall bars should generally be set according to the distance specified in the table. When the erection height of the scaffold needs to reduce the distance between the connecting rods, reducing the vertical spacing is more effective than reducing the horizontal spacing. From the scaffold load test, when the connecting rod is set in a two-step, three-span setting, the three-step, two-span setting Carrying capacity increased by 7%.
(3) The connecting rod should be close to the node and set from the first step of the first large crossbar.
(4) The connecting rod should be set close to the main node and not more than 300mm from the main node.
2. The connecting rod must be connected with the structural part of the building to ensure the carrying capacity.
(1) The position of the connecting rod should be determined in the construction plan and the drawing details should be drawn. It must not be arbitrarily set in the operation. It is forbidden to remove the connecting rod during use of the scaffold.
(2) Connecting wall bars to buildings can be made into flexible or rigid connections. Flexible connection can be embedded in the wall φ8 steel reinforcement ring, with double strand 8 (φ4) lead wire and frame body at the same time increase the top of the measure, limiting both inside and outside the scaffold deformation. When scaffolding height exceeds 24m, no flexible connection is allowed.
(3) When scaffolding is erected, the wall rods shall be erected synchronously with other rods; when the scaffolding is removed, the wall rods shall be finally removed when the other rods are dismantled to the height of the wall rods. Before the last wall rod is dismantled, it is necessary to set the bracing and then remove the wall rod to ensure the stability of the scaffold during the demolition.
Fourth, rod spacing and scissors support
1. Spacing between poles, large crossbars, and small crossbars shall meet the requirements of the specifications and construction plans. When there is a need to increase the distance between the doorway and other places, reinforcement shall be carried out in accordance with the provisions of the code.
2. Pole is the main stress member of the scaffold. The spacing should be set evenly. The spacing should not be increased. Otherwise, the bearing capacity of the pole can be reduced. The change in the step size of the horizontal bar also directly affects the carrying capacity of the scaffold when the step distance increases from 1.2m. By 1.8m, the critical load decreased by 27%.
3, Scissor support is an important measure to prevent the vertical deformation of the scaffold, and reasonable setting of the scissor support can also increase the overall stiffness of the scaffold, and improve the scaffolding capacity of more than 12%.
(1) The number of poles in each group spans 5 to 7 poles (>6m), and the angle between the poles and the ground is between 45° and 60°.
(2) Single and double row scaffolds with a height of 24m or less must be provided with a set of scissors at both ends of the lateral facade. The scaffolding shall be continuously set from the bottom to the top with a scaffolding; the middle part may be spaced no more than 15m apart.
(3) Double-row scaffolds with a height of 25m or more shall be continuously set along the length and height on the outside facade.
(4) The scissor bracing slant should be connected with the pole and the protruding small cross bar, and the bottom end of the bottom slant bar should be placed on the shim plate.
(5) The lengths of the scissor stays are all lap joints. The lap length is not less than 0.5m, and 2 twisting parts are provided.
4, horizontal scissors support. When the height of scaffolding is over 24m, in order to enhance the rigidity of the lateral plane of the scaffold, every 6 spans can be strung in the corner of the scaffold and in the middle of the scaffold, and a diagonal bar is added in the transverse plane so that it becomes a zigzag or a zigzag shape. . In case of operation layer, it can be temporarily dismantled, and when it is transferred to other layers, it should be replaced in time.
Five, scaffolding and protective railings
1. The scaffolding board is the construction platform for construction workers and must be fully laid according to the width of the scaffolding, and the board should be close to the board. When using butt joints, two small crossbars shall be provided at the joints; when the overlap is adopted, the direction of the crossover shall follow the direction of the heavy vehicle; the scaffolding of the bamboo raft shall be laid perpendicular to the direction of the large crossbar in the direction of the main bamboo bar, and the docking tile shall be used. Four corners are affixed with φ1.2mm galvanized steel wire and fixed on large crossbars.
2, the scaffolding can use bamboo, wood, steel scaffolding, its material should meet the specification requirements. The bamboo scaffolding should be made of bamboo or bamboo bamboo panels made from bamboo or bamboo. The bamboo plate must be solid and have no broken bamboo pieces; the wooden scaffold plate should be 125px thick, and the non-brittle wood (such as birch, etc.) should not be rotted or split; the steel scaffold plate should be stamped and made of 2mm thick plate. Corrosion, crackers can not be used.
3, where the scaffolding plate extends beyond the small cross bar is called the probe plate greater than 500px. Since most of the phoenix scaffoldings are not tied tightly with the scaffolding, if a probe plate may cause a fall accident, the probe plate must be strictly prohibited. When the operation layer does not need to fully step on the scaffolding along the length of the scaffold, guardrails and vertical nets may be used at the ends to define the work surface and the probe plate may be enclosed outside the work surface.
4. The outer side of the trapped hand should be provided with a close-packed safety net in accordance with regulations. The safety net is set inside the outer row of poles. The dense mesh must use the tether required to fasten the perimeter of the network at every 1125px (each buckle interval) on the scaffolding.
5, in the case of operation layer, but also in the outside of the scaffold between the large crossbar and the scaffolding, according to the requirements of the border protection set protection bar and footrest, to prevent the operator from falling and the material on the scaffolding roll.
Sixth, delivery and acceptance
1. Before erecting the scaffolding, the person in charge of the construction shall, in accordance with the requirements of the construction plan, combine the working conditions and team conditions at the construction site, make detailed disclosure, and have special personnel direct.
2. After the scaffolding is erected, it shall be organized by the person in charge of the construction, and the relevant personnel shall participate in the inspection and inspection of the items in accordance with the construction plan and specifications. After confirming that the requirements have been met, the scaffolding may be put into use.
3, inspection standards: (should be in accordance with the corresponding specification requirements)
(1) The vertical deviation of the steel pipe stem is ±50mm.
(2) The deviation of the verticality of the vertical steel pipe shall not be greater than 1/100H and not greater than 250px (H is the total height).
(3) The fastener fastening torque is: 40-50N.m, not more than 65N.m. Check the number of installations by 5%. The number of unqualified fasteners is no more than 10% of the number of random inspections.
(4) Fastener fastening procedures directly affect the load-bearing capacity of the scaffold. Tests have shown that when the torque of fastener bolts is 30 N.m, the scaffolding capacity is reduced by 20% when compared to 40 N.m.
4. The inspection and acceptance of scaffolding shall be carried out in accordance with the regulations. Any failure to comply shall be immediately rectified. The inspection results and rectification shall be recorded according to the measured data and signed by the inspection personnel.
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