Issues with portal scaffolding

Construction and Erection Plan for Portal Scaffolding – Bowl-Joint Scaffolding I. Preparation Work for Erection 1. Prepare a construction organization design for the scaffolding project; the requirements and calculation details are the same as those for bolted scaffolding. 2. Before the scaffolding is erected, the technical supervisor must provide technical instructions to the workers responsible for its erection and use, in accordance with the \"Safety Technical Specifications for Portal Scaffolding in Building Construction\" and the requirements of the project’s design. 3. Inspect and approve the jib accessories and reinforcement components; the use of substandard components is prohibited. 4. Clean and level the site where the scaffolding will be erected, and ensure proper drainage. II. Technical Requirements for Erection (I) Foundation Treatment 1. To ensure that the foundation has sufficient bearing capacity, the construction of the pole foundations must meet the requirements specified in 5.4.1 as well as those outlined in the construction organization plan ； When the scaffold is erected on structural floors or cantilevered platforms, shims or pads should be placed under the base of the vertical poles, and a preliminary check should be carried out on the structure such as the floor or cantilevered platform. 2. On the scaffold foundation, the position lines for the tower columns of the portal frame should be marked, and the placement locations of the shims and bases must be accurate. (II) Procedure for erecting portal scaffolds: 1. Assembly of the scaffold: It should be constructed by extending from the left end toward the right end, layer by layer from bottom to top, with the direction of construction changed at each layer in order to reduce the accumulation of errors. It is not allowed to construct it by moving from both ends toward each other or in an alternating manner, as this can lead to misalignment at the joints and make connection difficult. 2. Sequence of scaffolding erection: Lay the padding (planks) → Install the base → Raise the frame from one end and attach cross braces immediately → Install the horizontal beams (or scaffold planks) → Install the steel ladder → Install horizontal reinforcement rods → Proceed upward layer by layer following the above steps → Install diagonal bracing at the specified positions → Assemble the top railing. 3. The erection of the scaffold must be carried out under construction supervision; the height erected at one time should not exceed three steps above the topmost wall connection element, or the free height should be less than 6 meters, to ensure the stability of the scaffold. (III) Precautions for erecting the frame and installing accessories 1. The installation of cross braces, horizontal beams, scaffold planks, connecting rods, and locking arms shall comply with the construction specifications. 2. The boom frames and accessories of different products must not be used together on the same scaffold. 3. Cross bracing, horizontal frames, and scaffold planks should be installed promptly following the setup of the portal frame. 4. The lock arms and hooks of each component must be in the locked position. 5. Horizontal frames or scaffolding planks should be installed continuously in the same step, and the planks should be fully covered. 6. The location of the steel ladder shall meet the requirements of the assembly layout plan; the lower-level steel ladder may cross two or three scaffold steps before turning. 7. Guard plates (fences) should be installed on both sides of the construction level of the scaffold, while guard rails (bars) should be placed on the outside of that level. The guardrails and guard plates shall be located on the inside of the vertical posts of the scaffold frame. (IV) Installation of horizontal reinforcement rods and diagonal bracing 1. The installation of horizontal reinforcement rods and diagonal bracing shall comply with the structural requirements, and it shall be carried out simultaneously with the erection of the scaffold. 2. Horizontal reinforcement rods should be securely connected to the frame on the inner side of the vertical rods using fasteners, while diagonal bracing members should be secured to the outer side of the frame’s vertical rods using fasteners. (5) Installation of connecting members 1. The installation of connecting members must be carried out simultaneously with the erection of the scaffold; it is strictly prohibited to install them after the scaffold has been built. 2. When the working level of the scaffold is two steps above the adjacent diaphragm members, temporary reinforcement measures should be employed to ensure stability, and these measures must be removed only after the diaphragm members have been installed. 3. The part of the wall connector that is embedded in the wall must be firm and reliable; it must be perpendicular to the wall surface, with no upward inclination allowed. 4. The wall connectors should be attached near the joints of the upper and lower gantries. 5. When a flexible diaphragm wall with one support and one pull point is used, the distance between the pull point and the support should not exceed 400 mm. (VI) Requirements to be met when fasteners are used to connect fixtures, wall connectors, etc., to the gate frame: 1. The specification of the fasteners should match the outer diameter of the steel pipes being connected. 2. The tightening torque value for the fastening bolts is 45 N•m to 60 N•m, and must not be less than 40 N•m. 3. The length of the end of each member extending beyond the edge of the fastener cover plate shall be not less than 100 mm.

III. Acceptance 1. Once the scaffolding has been erected in its entirety or in sections, an inspection of its quality must be carried out; it may only be put into use after passing this inspection. 2. For scaffolds with a height of 20m or less, the person in charge of the specific construction project shall organize technical and safety personnel to conduct inspections and acceptance ； For scaffolds with a height of more than 20 meters, the technical supervisor of the project shall, in line with the progress of the work, organize the person in charge of the respective construction unit along with relevant technical and safety personnel to conduct inspections and acceptance on a segmented basis. (1) The following documents shall be available at the time of acceptance: 1) Necessary construction design documents and assembly drawings ； 2) Factory certification or quality grading mark for the components of the scaffold ； 3) Construction records and quality inspection records for the scaffolding project ； 4) Major issues in scaffold erection and records of handling them ； 5) Construction acceptance report for the scaffolding project; (2) For the acceptance of the scaffolding project, in addition to reviewing relevant documents, on-site inspections should also be carried out. The spot checks should focus on the following items, which shall be recorded in the construction acceptance report. 1) Are the components for safety measures complete, and are the fasteners tight and of proper quality? ； 2) Are the safety nets properly installed and are the handrails in place? ； 3) Is the foundation level and solid? ； 4) Are there any omissions in the installation of wall connectors? Are they complete and meet the required standards? ； 5) Whether the verticality and levelness are acceptable. (3) Permissible deviation in the dimensions of the scaffold installation: 1) Verticality of the scaffold: The vertical deviation of the scaffold along the lengthwise direction relative to the wall shall be ≤ H/400 or 50 mm (where H is the height of the scaffold) ； The lateral vertical deviation of the scaffold shall be ≤ H/600 and 50 mm ； The vertical and horizontal deviation of each scaffold level should be ≤ h0/600. 2) Levelness of the scaffold: The longitudinal horizontal deviation of the bottom scaffold level along the wall should be ≤ L/600 (where L is the length of the scaffold). IV. Demolition: After the construction is completed, the scaffold can be demolished only after it has been inspected and verified by the person in charge of the specific project to confirm that it is no longer necessary. A plan must be developed for the dismantling of the scaffolding, and it can only be carried out after approval by the project supervisor. The dismantling of scaffolding shall comply with the following provisions: 1. Before dismantling the scaffolding, the materials, tools, and debris on it must be removed. 2. When dismantling the scaffolding, a safety zone should be established, warning signs should be placed, and a dedicated person should be assigned to oversee safety. 3. The dismantling of the scaffold shall be carried out in accordance with the principle of removing components installed later first, following these procedures: (1) Start by removing the top handrails and railing posts from the edge of the span, then remove the scaffold planks (or horizontal beams) and ladder sections, and finally take down the horizontal bars, reinforcing bars, and diagonal bracing. (2) Start removing the cross bracing from the top level across the edges, and simultaneously remove the top bracing wall connectors and the top-level frame. (3) Continue to synchronously remove the second stage gantry and its accessories. The free overhang height of the scaffold shall not exceed three steps; otherwise, temporary bracing shall be installed. (4) Remove sequentially and synchronously downward. For diaphragm rods, long horizontal rods, and diagonal bracing, they must be removed only after the scaffold has been taken down to the relevant span of the frame. (5) Remove the sweeping rod, the bottom frame, and the sealing rod. (6) Remove the base and take away the pads and shims. 4. The dismantling of scaffolding must comply with the following safety requirements: (1) Workers must stand on temporarily installed scaffolding planks while carrying out the dismantling work. (2) During demolition, it is strictly prohibited to use hard objects such as hammers to strike or pry. The removed connecting rods should be placed in bags, while the locking arms should first be taken to the ground and stored indoors. (3) When removing the connecting components, first turn the locking plate on the lock seat and the locking piece on the hook to the open position, then proceed with removal; do not pull forcefully, and hitting is strictly prohibited. (4) The removed gantries, steel pipes, and accessories should be bundled together and lifted mechanically or transported via a derrick to the ground to prevent collisions; throwing them is strictly prohibited.