External Scaffolding Construction Organization Design

Construction preparation

1.1 configuration accessories

1.1.1 Steel pipe

1 Scaffolding steel pipe adopts Φ 48mm , wall thickness 3.5mm ; horizontal horizontal bar maximum length 2200mm , other bars maximum length 6500mm , and the maximum quality of each steel pipe should not exceed 25kg .

2 The size and surface quality of the steel pipe should meet the following requirements :

1) The new steel pipe should have quality certificate and quality inspection report; the surface of the steel pipe should be straight and smooth, there should be no cracks, scabs, delamination, dislocation, hard bend, burr, indentation and deep scribe; See the table below:

2) Drilling on steel pipe is prohibited.

1.1.2 Fasteners

1 Fastener-type steel scaffolds are made of malleable cast iron fasteners, and their materials are to comply with the current national standard "Steel Pipe Scaffolding Fasteners" ( GB15831 ). Fasteners made of other materials should be tested to prove that their quality meets the requirements of the standard. Can be used afterwards.

2 scaffolding fastener employed, the bolt tightening torque of 6.5N. M, the damage can not occur.

1.1.3 scaffolding

The scaffold board is made of bamboo string boards made of bamboo or bamboo, and the mass of each piece should not be more than 30kg .

1.1.4 Wall attachment

The material of the wall joints should meet the requirements of Q235-A in the current national standard "carbon structural steel" ( GB/T700 ) .

1.2 The qualified components and parts that are inspected shall be classified according to their types and specifications, stacked neatly and stably, and the stacking site shall not have any accumulated water.

1.3 The debris on the erection site shall be cleared, the site erected and the drainage shall be open.

1.4 When there are equipment foundations and trenches under the scaffolding foundation, no excavation shall be carried out during the use of the scaffolding, otherwise reinforcement measures shall be taken.

two   Foundation and foundation

2.1 Calculation of Bearing Capacity of Pole Foundation

P≤f g

In the formula   p---- The average pressure of the bottom of the foundation of the pole, p=N/A ; N----The design value of the axial force transmitted from the superstructure to the foundation top; take N=   A---- Base surface area;

f g ---- design value of foundation bearing capacity, f g =kc . f gk =

---- adjustment coefficient kc ground bearing capacity of soil gravel, sand, backfill should take 0.4, 0.5 to be taken clay; rock, concrete should take 1.0.

This results in A=

2.2 Scaffold base bottom elevation should be higher than the natural floor 50mm .

2.3 After the scaffolding foundation has passed the experience, it shall be positioned as required.

three   Set up

3.1 The scaffolding must be erected in accordance with the construction schedule . The height of one erection should not exceed two steps above the adjacent wall element.

3.2 After each step of scaffolding, correct the pitch, vertical distance, horizontal distance, and verticality of the vertical pole.

3.3 Base mounting should meet the following requirements:

1 The base and the pad should be accurately placed on the positioning line;

2 It is recommended to use wood backing plates with a length of not less than 2 spans and a thickness of no less than 500 mm . Channel steels may also be used.

3.4 The erection of poles shall meet the following requirements:

1 It is forbidden to mix 48mm outer diameter and 51mm steel pipe.

2 In addition to the top pole, the vertical poles can be connected by laps, and the joints at each step of the other layers must be connected by butt-fasteners; the butt-fasteners of adjacent poles must not be within the same height, and should comply with the following provisions:

1 ) The joints of two adjacent poles should not be set in synchronization. The distance between two spaced joints of a vertical pole separated by a vertical joint in the height direction is not less than 500 MM ; the distance from the center of each joint to the main joint should not be greater than the step distance. 1/3;

2 ) The lap length should not be less than 1M . It should be fixed with not less than two rotating fasteners . The distance from the edge of the end fastener cover to the rod end should not be less than 100MM .

3 When starting to set up the pole, one throwing strut should be set every 6 spans until the wall is firmly installed, before it can be removed according to the situation;

(4) When erecting a structural point with wall joints, immediately after erecting the vertical pole, vertical horizontal pole, horizontal horizontal pole, the wall attachment shall be set immediately;

5 The top of the pole should be 1m higher than the daughter's wall skin , 1.5m higher than the squamous epithelium .

3.5 Longitudinal horizontal pole erection should meet the following requirements:

1 Longitudinal horizontal rod should be set inside the vertical rod, its length should not be less than 3 spans;

2 Longitudinal horizontal rods are suitable for docking fasteners, but they can also be lapped. Docking and splicing should meet the following requirements:

1 ) The docking fasteners of the vertical horizontal bars shall stagger the arrangement of the joints to the nearest main joints in a distance of no more than 1/3 of the longitudinal distance .

2) lap length not less than 1M, should be provided with three equally spaced fasteners securing the rotation, the edge portion of the end cover fastener to the rod end of the distance of not less than 100MM.

3 ) The vertical horizontal bar should be used as a support for the horizontal horizontal bar and fixed on the vertical bar with a right angle fastener.

2 In the same step of the enclosed scaffolding, the vertical horizontal bar should be circled around and fixed with the right angle fasteners and the inner and outer corners.

3.6 horizontal horizontal pole erection should meet the following requirements:

1 The main contact must be set with a horizontal horizontal bar, buckled with right angle fasteners and prohibited from being removed. The center distance between the two right angle fasteners at the main contact should not exceed 150mm .

2 The horizontal horizontal bars at the non-master nodes on the operation floor should be set at equal intervals according to the needs of the supporting scaffold board, and the maximum distance should not be greater than 1/2 of the vertical distance .

3 The distance from the end of the horizontal horizontal bar of the double-row scaffold to the decorative surface should not exceed 100 mm .

3.7 Scaffolds must have vertical and horizontal sweeping bars. Longitudinal sweeping rods shall be fixed on the poles at a distance of not more than 200 mm from the base of the base with right angle fasteners . Lateral sweeping rods should also be fastened with vertical fasteners to the vertical rods below the vertical sweeping rods. When the foundation of the pole is not at the same height, the vertical sweeping pole at the height must be extended to the low position to extend the two spans and the pole. The height difference should not exceed 1M .

3.8 The erection of wall elements, scissors braces, transverse braces, etc. shall meet the following requirements:

1 The strength, stability and connection strength of 1 wall joints shall be in accordance with the current national standards "Technical Specification for Cold-formed, Thin-walled Steel Structures" ( GBJ 18 ), "Code for Design of Steel Structures" ( GB 17 ), and "Specifications for Design of Concrete Structures" ( GBJ 10 ) and other provisions.

2 axial wall force design value:

N l =N lw +N 0

In the formula    N l - with wall element axial force design value ( KN );

N lw ---- design value of the axial force of the connected wall element generated by the wind load,

N lw =1.4*ω k A W =

N 0 ---- Axial forces generated by the out-of-plane deformation of the scaffold constrained by the wall elements. The double-row scaffold is 5KN .

---- The windward area of ​​the outer side of the scaffold within the area covered by each wall element.

The design value of the axial force of the wall member should be less than the design value R C of the anti-sliding bearing capacity of the fastener . R C =8KN to meet the requirements. 3 The width of each scissor support should not be less than 4 spans, and should not be less than 6M . The angle between the inclined rods and the ground should be 45o-60o and should meet the requirements of Table 3.

4 Scaffolds with a height less than 24M must be provided with a scissor support at both ends of the lateral facade, and should be set continuously from bottom to top; the distance between the scissor supports in the middle of each road should not exceed 15M . Scaffolds with a height of 24 M or more shall be provided with continuous support for the entire length and height of the entire outer facade.

5 Scissor stays and lateral braces shall be installed synchronously with vertical poles, vertical and horizontal horizontal poles, etc. The lower ends of the bottom diagonal poles shall all be supported on the pads or pads.

3.9 fastener installation should meet the following requirements:

1 fastener specifications must be the same as the outer diameter of the steel tube;

2 bolt tightening torque should not be less than 40N . M , and should not be greater than 65N . M ;

3 The mutual distance between the center points of the right-angled fasteners used for fixing vertical and horizontal horizontal rods, scissors braces, transverse braces, etc. at the main node shall not be greater than 150 MM ;

4 The opening of the docking fastener should face upwards or inwards;

3.10 The erection of rails and baffles on the working floor, chutes, and slopes shall comply with the following provisions:

1 railings and baffles should be set up on the inside of the outer pole;

2 The epithelial height on the railing should be 1.2M ;

3 block height should not be less than 180MM ;

4 rails should be set in the middle.

3.11 The laying of scaffolding shall comply with the following provisions:

1 The scaffolding board shall be fully covered and left from the wall 120-150MM ;

2 The probe of the scaffolding plate is fixed on the supporting rod member by using a galvanized steel wire with a diameter of 3.2 mm ;

3 The scaffolding plate at the corners of the corners and inclined platforms shall be reliably connected with the horizontal horizontal bar to prevent slipping;

4 From the top floor of the scaffolding, count down, it is advisable to lay a layer of scaffolding every 12M .

four   tear down

4.1 The accurate preparation before removing the scaffold shall meet the following requirements:

1 It is necessary to comprehensively check whether the fasteners of the scaffold, connection wall parts, and support systems meet the construction requirements.

2 According to the inspection results, the demolition order and measures in the construction organization design shall be complemented and perfected, and shall be implemented only after the approval of the competent department;

3 Remove debris and obstacles on the scaffold.

4.2 When removing the scaffold, the following requirements shall be met:

1 Demolition work must be carried out from top to bottom, and it is forbidden to work from top to bottom simultaneously;

2 Walls must be removed with the scaffolding layer by layer. It is strictly forbidden to remove the whole or multiple layers of the wall joints before dismantling the scaffold; the height difference of the section removal shall not exceed 2 steps. If the height difference is greater than the step, additional wall elements shall be added. Reinforcement

3 When the scaffold is dismantled to the height of the last long pole of the lower part (about 6.5m ), a temporary forklift shall be erected in place and then the wall part shall be removed;

(4) When the scaffolding is to be divided and separated, the two sides of the scaffold that are not to be dismantled shall be reinforced with a wall member and a transverse diagonal bar.

4.3 Discharge should meet the following requirements:

1 It is forbidden to throw various components into the ground;

2 The parts and components transported to the ground shall be promptly inspected, refurbished and maintained, and stored at any time according to the variety and specifications.

5   Safety management

5.1 Scaffold erection personnel must be professional shelf workers qualified according to the current national standard “Safety Technical Personnel Assessment and Management Rules for Special Operations” ( GB 5036 ). Staff on duty should undergo regular physical examinations, and qualified personnel can take up their posts.

5.2 scaffolding staff must wear safety helmets, wearing safety belts, wear non-slip shoes.

5.3 The quality and erection quality of the scaffolding components shall be used in accordance with the regulations before acceptance.

5.4 The construction load on the working layer shall meet the design requirements and shall not be overloaded. No template supports, cable wind ropes, pumped concrete, etc. shall be fixed on the scaffold; hoisting equipment shall not be suspended.

5.5 Scaffolding erection and demolition work shall be stopped when there are winds and fogs, rain and snow at grades 6 and above.

5.6 In the use of scaffolds, the connection of the rods should be regularly checked to see if the structure of the wall elements, supports, trusses, etc. meets the requirements; whether there is water accumulation in the foundation, whether the foundation is loose, whether the pole is vacant, and whether the fasteners are loosened or not. Scaffolding vertical deviation; whether the safety protection measures meet the requirements; whether to overload.

5.7 During the use of the scaffold, it is strictly prohibited to remove the vertical and horizontal horizontal rods, sweeping rods and connecting wall parts at the main node.

5.8 Excavation work shall not be carried out on the basis of scaffolding and adjacent locations, otherwise safety measures shall be taken.

5.9 When conducting electric and gas welding work on scaffolds, fire prevention measures and special guards are required.