From a safety perspective, based on decades of domestic practical experience and research on domestic scaffolding, ground-supported scaffolding with single-pipe vertical poles is generally limited to a height below 50m; heights exceeding 50m are prone to risks. When the required erection height is greater than 50m, more prudent strengthening measures shall be taken, such as using double-pipe vertical poles, segmental load unloading, and segmental erection.
Specifications for Erection of Ground-Supported Scaffolding
I. Specifications for Setting Vertical Pole Foundations
1.The foundation shall be leveled, tamped, and its surface shall be hardened with concrete. Vertical poles shall be placed vertically and stably on metal bases or solid backing plates.
2.Longitudinal and transverse sole plates (ground sweep rods) shall be installed at the bottom of vertical poles. Longitudinal sole plates shall be fixed to vertical poles at a distance not exceeding 200mm from the base using right-angle couplers; transverse sole plates shall be fixed to vertical poles immediately below the longitudinal sole plates using right-angle couplers. When vertical pole foundations are at different heights, the longitudinal sole plate at the higher level shall extend two spans towards the lower level and be fixed to vertical poles. The height difference shall not exceed 1m, and the distance from the axis of vertical poles on the upper side of the slope to the slope edge shall not be less than 500mm.
3.A drainage ditch with a cross-section not less than 200×200mm shall be installed outside the vertical pole foundation to keep the foundation free of standing water. The area within 800mm outside the foundation shall be hardened with concrete.
4.External scaffolding shall not be supported on parts such as roofs, canopies, and balconies. If it is really necessary, the structural safety of such parts (roofs, canopies, balconies, etc.) shall be checked and verified, and details shall be clearly specified in the special construction plan.
5.If there are equipment foundations or pipe trenches under the scaffolding foundation, no excavation shall be carried out during the use of the scaffolding. If excavation is required, reinforcement measures shall be adopted.
II. Specifications for Erection of Vertical Poles
1.The first-step distance of steel pipe scaffolding shall not exceed 2m, and the step distances of other steps shall not exceed 1.8m. The longitudinal spacing of vertical poles shall not exceed 1.8m, and the transverse spacing shall not exceed 1.5m (preferably 0.85m or 1.05m).
2.When the erection height exceeds 25m, double vertical poles or spacing reduction shall be adopted for erection. The height of the auxiliary vertical poles in the double-pole setup shall not be less than 3 steps (and not less than 6m).
3.Longitudinal and transverse sole plates must be installed for the first row of vertical poles. Longitudinal sole plates shall be fixed to vertical poles at a distance not exceeding 200mm from the top of the base using right-angle couplers; transverse sole plates shall also be fixed to vertical poles below the longitudinal sole plates using right-angle couplers.
4.The first row of vertical poles, sole plates, and scissors braces shall all be painted with alternating yellow-black or red-white paint.
III. Specifications for Setting Scaffold Members
1.Transverse horizontal poles shall be installed at the intersections of vertical poles and longitudinal horizontal poles of the scaffolding, with both ends fixed to vertical poles to ensure safe force bearing.
2.Except for the top step of the top layer, the splicing of vertical poles in all other layers and steps must be connected using butt couplers. The lap length shall not be less than 1m and shall be fixed with no fewer than 3 swivel couplers.
3.During the use of the scaffolding, it is strictly forbidden to remove the longitudinal and transverse horizontal poles at the main nodes.
4.Longitudinal horizontal poles shall be installed on the inner side of vertical poles, with a length not less than 3 spans.
5.Splicing of longitudinal horizontal poles shall be done using butt couplers or lap joints. When using butt couplers, the butt couplers of longitudinal horizontal poles shall be arranged in a staggered manner. When using lap joints, the lap length of longitudinal horizontal poles shall not be less than 1m, with 3 swivel couplers fixed at equal intervals. The distance from the edge of the coupler cover plate at the end to the end of the lapped longitudinal horizontal pole shall not be less than 100mm.
6.The edge length of the coupler cover plates at both ends of horizontal poles shall not be less than 100mm, and shall be kept as consistent as possible.
7.Lap and butt joints of adjacent members must be staggered by one span, and the number of joints in the same plane shall not exceed 50%.
IV. Specifications for Setting Scissors Braces and Transverse Diagonal Braces
1.Scissors braces shall be continuously installed from the bottom corner to the top along the length and height directions.
2.The diagonal rods of scissors braces shall be connected to the extended ends of vertical poles or transverse horizontal poles. Splicing of diagonal rods shall be done by lap joints, with an inclination angle of 45°～60° (45° is preferred). Each scissors brace shall span 5～7 vertical poles, with a width not less than 4 spans (and not less than 6m).
3.Transverse diagonal braces shall be installed at both ends of in-line or open-type double-row scaffolding, and additional transverse diagonal braces shall be installed every 6 spans in the middle.
4.The erection of scissors braces and transverse diagonal braces shall be carried out simultaneously with that of vertical poles, longitudinal and transverse horizontal poles, etc.
5.The lap length of scissors braces shall not be less than 1m, and shall be fixed with no fewer than 3 swivel couplers.
V. Specifications for Scaffold Planks and Guardrails
1.Scaffold planks shall be fully laid on each step of the external scaffolding.
2.Scaffold planks shall be laid horizontally or vertically against the wall, placed in position without leaving gaps.
3.The four corners of each scaffold plank shall be firmly bound in parallel with 18# galvanized wire. The joints shall be flat, and no overhanging planks (protruding planks) are allowed. Damaged scaffold planks shall be replaced in a timely manner.
4.The outer side of scaffold planks shall be enclosed with qualified dense-mesh safety nets, which shall be fixed to the inner side of the outer vertical poles of the scaffolding using 18# galvanized wire.
5.A 180mm-high toe board (or toe rod) shall be installed on each step of the outer side of the scaffolding, and guardrails of the same material shall be installed at heights of 0.6m and 1.2m. If an edge is formed on the inner side of the scaffolding, it shall be protected in the same way as the outer side of the scaffolding.
6.For flat roofs, the outer vertical poles of the scaffolding shall extend 1.2m above the eave; for sloped roofs, the outer vertical poles shall extend 1.5m above the eave.
VI. Specifications for Connecting Scaffold Structure to Building
1.Wall-attached members shall be installed close to the main nodes, with a distance not exceeding 300mm from the main nodes. If the distance exceeds 300mm, reinforcement measures shall be adopted. When a wall-attached member is located near 1/2 of the vertical pole step distance, adjustments must be made.
2.Wall-attached members shall be installed starting from the first-step longitudinal horizontal pole at the bottom layer. If installation at this position is difficult, other reliable fixing measures shall be adopted. Wall-attached members shall be arranged in a diamond pattern, or alternatively in a square or rectangular pattern.
3.Rigid wall-attached members shall be used to connect the scaffolding to the building.
4.Wall-attached members shall be installed horizontally. If horizontal installation is not possible, the end connected to the scaffolding shall be connected in a downward-sloping manner (upward-sloping connection is not allowed).
5.The spacing of wall-attached members shall comply with the requirements of the special construction plan: the horizontal spacing shall not exceed 3 spans, and the vertical spacing shall not exceed 3 steps (and not exceed 4m; for scaffolding with a height above 50m, the vertical spacing shall not exceed 2 steps). Wall-attached members shall be densely arranged within 1m of building corners and within 800mm of the top of the building.
6.Wall-attached members must be installed at both ends of in-line or open-type scaffolding. The vertical spacing of wall-attached members shall not exceed the floor height of the building, and shall not exceed 4m or 2 steps.
7.The scaffolding shall be erected in line with the construction progress, with a single erection height not exceeding two steps above the adjacent wall-attached members.
8.It is strictly forbidden to remove wall-attached members during the use of the scaffolding. Wall-attached members must be removed layer by layer along with the scaffolding; it is forbidden to remove all or multiple layers of wall-attached members first before dismantling the scaffolding. The height difference during segmental dismantling shall not exceed two steps; if the height difference exceeds two steps, additional wall-attached members shall be installed for reinforcement.
9.If it is necessary to remove existing wall-attached members for construction purposes, reliable and effective temporary connection measures shall be adopted to ensure the safety and stability of the external scaffolding.
10.When the scaffolding height exceeds 40m and wind eddy effects exist, wall-attached measures to resist upward overturning shall be adopted.
Post time: 2025-12-30 11:27:51