(1) The maximum erection height of portal steel pipe scaffold can be determined according to the following table.

Standard value of construction load (kN/m2) and installation height (m)

3.0~5.0 ≤45

≤3.0 ≤60

(2) Acceptance of portal frame connectors and steel bars, and the use of unqualified components is prohibited.

(3) Clean and level the scaffold site, and do a good job of drainage.

(4) Basic treatment:

In order to ensure that the foundation has enough bearing capacity, the construction of vertical pole foundation should meet the requirements of structure and construction organization design; On the basis of scaffolding, the vertical pole position line of gantry should pop up, and the position of pad and base should be accurate.

(5) Portal scaffold erection procedures:

1) Scaffolding shall be gradually erected from one end to the other, and the erection direction shall be gradually changed to reduce error accumulation. It is not allowed to erect or alternate from both ends to avoid joint dislocation and difficult connection.

2) The order of scaffolding. Laying the skids (slabs)+installing the pedestal-erecting the gantry from one end and then installing the cross braces-installing the horizontal braces (or scaffolding)-installing the steel ladder-installing the horizontal steel bars-installing the wall connecting rods-according to the above steps, step by step+installing the scissors at the designated position-assembling the top railing.

3) The erection of scaffolding must be coordinated with the construction progress, and the erection height at a time shall not exceed three top wall pieces or the free height shall be less than 6m, so as to ensure the stability of scaffolding.

(6) Precautions for installation of gantry and accessories:

1) The setting of cross support, horizontal frame, scaffold board, connecting rod and locking arm shall comply with the construction regulations.

2) The same scaffold shall not be mixed with portal frames and accessories of different products.

3) After the portal frame is installed, bracing, horizontal frame and scaffolding shall be set in time.

4) Locks and hooks of all parts must be locked.

5) The horizontal frame or scaffold board should be set continuously in the same step, and the scaffold board should be spread all over.

6) The location of the steel ladder shall meet the requirements of assembly layout. Φ 42 steel pipe should be added at the bottom of the bottom steel ladder, and fixed on the vertical pole of gantry with fasteners. Handrails should be set on both sides of the steel ladder span. Each steel ladder can cross two or three stages of portal frame and then turn.

7) Scaffolding boards (basketry) should be set on both sides of the scaffold construction layer, railings (poles) should be set at the outer height of the scaffold construction layer, and railings and scaffolding boards should be set at the inner side of the mast.

(7) Installation of horizontal reinforcement and bracing:

1) The installation of horizontal steel bars and bracing shall meet the structural requirements and be carried out at the same time as the erection of scaffolding.

2) The horizontal steel bars are fastened to the inner side of the column with fasteners, and the bracing is fastened to the outer side of the gantry column with fasteners.

(8) Installation of wall fittings:

1) Even the installation of wall parts must be carried out at the same time as the erection of scaffolding, and it is forbidden to make up after the erection is completed.

2) When the scaffold operation floor is more than two steps higher than the adjacent wall parts, temporary measures should be taken to strengthen the stability until the wall parts can be removed after erection.

3) Even the wall parts buried in the wall must be solid and reliable, and even the wall parts must be perpendicular to the wall surface, and upward inclination is not allowed.

4) Even the wall parts should be connected with the joint of upper and lower portal frames.

5) When the single-pull flexible diaphragm wall structure is adopted, the distance between brace and fulcrum should not be greater than 400 mm ..

(9) When connecting steel bars, even wall pieces and portal frames with fasteners, the following requirements shall be met:

1) Fastener specifications should match the outer diameter of the connecting steel pipe.

2) The tightening torque value of the fastening bolt is 45-65N m, which should not be less than 40N m. ..

3) The length of each steel bar protruding from the edge of the fastener cover plate shall not be less than100 mm. ..

(10) Inspection and acceptance requirements:

1) scaffold engineering quality should be inspected after scaffold erection is completed or sectional erection is completed, and it can be delivered only after it is qualified.

2) Scaffolds with a height of 20m or less shall be inspected and accepted by the project leader of this unit. Scaffolds with a height of more than 20m shall be inspected and accepted by the technical director of the engineering department, the project director of the unit and relevant technical safety officers in stages with the progress of the project.

(1) The following documents shall be available for acceptance:

Necessary construction design documents and assembly drawings; The factory certificate or quality grading mark of scaffold components; Construction records and quality inspection records of scaffolding engineering; Main problems and treatment records in scaffold erection; Scaffolding engineering construction acceptance report.

(2) When the scaffold project is accepted, in addition to checking the relevant documents, spot checks should also be conducted. Spot checks should focus on the following items, and record the construction acceptance report:

Whether the bars of safety measures are complete and whether the fasteners are qualified; Whether the suspension of safety net and the setting of handrails are complete; Whether the foundation is smooth and solid; Whether the setting of even the wall pole is omitted, complete and meets the requirements; Whether verticality and levelness are qualified.

(3) Scaffolding levelness:

The vertical horizontal deviation of the bottom scaffold along the wall should be ≤L/600(L is the scaffold length).

(4) Allowable deviation of scaffold erection size:

Verticality of scaffolding: the vertical deviation of scaffolding along the longitudinal direction of the wall should be ≤H/400(H is the height of scaffolding) and 50mm；; The horizontal and vertical deviation of scaffolding is ≤H/600 and 50mm；; The vertical deviation of each frame should be ≤ho/600(h2 is the height of portal frame).

2. The portal scaffold demolition safety technical requirements

(1) After the project is completed, it can be dismantled only after the project leader of the unit checks and confirms that scaffolding is no longer needed. The dismantling of scaffolding shall be carried out and approved by the project leader. Dismantling scaffolding shall meet the following requirements:

1) Before dismantling the scaffold, the materials, tools and sundries on the scaffold should be removed.

2) The scaffold shall be dismantled according to the following procedures:

(1) first remove the top handrails and railings from the horizontal side, then remove the scaffolding (or horizontal frame) and escalator section, and then remove the horizontal steel bars and bracing.

(2) Remove the cross brace from the top side, and remove the top wall connecting rod and the top gantry at the same time.

(3) Continue to dismantle the portal frame and accessories in the second step simultaneously. The free cantilever height of scaffold shall not exceed three steps, otherwise temporary Rachel shall be added.

④ Continuous synchronous demolition. Used for wall parts, long rails, scissors, etc. Before dismantling the scaffold, it must be dismantled to the relevant portal frame.

⑤ Remove the sweeping rod, bottom door frame and sealing rod.

⑥ Dismantle the base, transport the pad and pad.

(2) The removal of scaffolding must meet the following safety requirements:

1) Workers must stand on the temporary scaffolding for demolition.

2) During the demolition work, it is forbidden to use hard objects such as hammers to knock and pry. The removed connecting rod should be put into the bag, and the lock arm should be transferred to the ground first and stored indoors.

3) When disassembling the connector, first turn the lock plate on the lock seat and the lock plate on the hook to the open position, and then start disassembling. Hard pulling and knocking are not allowed.

4) The removed gantry, steel pipe and fittings shall be bundled and transported to the ground by mechanical lifting or derrick to prevent collision, and throwing is strictly prohibited.

(3) Precautions for demolition:

1) When dismantling scaffolding, fences and warning signs should be set on the ground, and special personnel should be assigned to guard it. It is strictly forbidden for all non-operating personnel to enter.

2) When the scaffold is dismantled, the dismantled portal frame and accessories shall be inspected. Remove the dirt from the rod and thread, and make necessary shaping. Serious deformation should be sent back to the factory for repair. Should be classified according to the provisions of inspection, maintenance or scrap. After maintenance, the removed gantry and other accessories should be stored according to the varieties and specifications, and properly kept to prevent corrosion.