What are the requirements for constructing bolted scaffolds?

Key points for erecting bolted scaffolding: (1) For floor-standing external scaffolds, place wooden boards or steel formwork measuring 400mm×300mm×50mm at the vertical poles. Vertical and horizontal ground rods are installed 200 mm above the bottom end of the scaffold poles, and are firmly connected to the poles to maintain the integrity of the scaffold’s base. (2) The vertical poles of the scaffold should be erected in a staggered pattern using steel pipes of different lengths, with adjacent joint connections placed at different heights, so as to offset the weak sections under load. (3) On the outside of the scaffold, a set of diagonal bracing shall be installed every 7 vertical poles; the angle between the diagonal bracing and the ground should be between 45° and 60°. The horizontal projection width of the diagonal rods should be 3 to 4 spans, with a maximum of 8 meters. The diagonal rods must be securely connected to the scaffold poles using fasteners. In addition to the ends, 2 to 4 additional fastening points should be installed along the length of the diagonal rods, with the distance between adjacent fastening points not exceeding 60d (i.e., 2.88 meters), in order to enhance the stability of the scaffold. (4) Two guardrails and toe boards shall be installed on the outside of the scaffold; the height of the guardrails shall be greater than 1.1 m, and dense safety nets shall be installed across them. The external scaffold must be raised in sync with the construction of the structure, and must always be one level higher than the working level. The operating level of the external scaffold shall be fully covered with scaffold planks over a height of not less than three steps. The construction load on the scaffold shall not exceed 3 KN/m2. (5) The grounding of the scaffolding is installed at the four corners of the building or every 30 meters; the grounding electrodes used are three angle irons of L50×5 size. L=1500 mm, buried underground; the grounding electrode is a 40´4 galvanized flat steel bar that is connected to the scaffolding. A lightning protection device must be installed on the exterior scaffold, with a grounding resistance not exceeding 4Ω. (6) The scaffold is connected to the structure longitudinally at each floor level; horizontally, a connection point is provided every 3.6 meters, and vertically as well, with a connection point every 3.6 meters. The tie point uses Ф25 rebar, with one end welded to the embedded component in the structural floor and the other end connected to the scaffold uprights. Steel pipes with a diameter of Ф48 can also be used at the columns to form clamps that connect to the scaffolding. (7) Parallel chord truss structures are used at the building entrances and exits, and the scaffolding at these locations is reinforced. Double vertical poles are used on both sides of the opening, and safety fasteners are installed at the lower ends of the suspended vertical poles; the connections at these points must be tight, and such fasteners must be provided at each step. A double-layer protective canopy is installed above the access scaffold, covered entirely with bamboo fences, to ensure the safety of those entering and exiting. See the diagram for the scaffolding method at the building’s entrances and exits. Comprehensive safety protection facilities must be in place; safety nets, protective railings, and toe boards must be installed as required, and the working level must be fully covered with scaffolding planks.

Requirements for the erection of fastener-type scaffolds: When constructing steel pipe fastener scaffolds, it is necessary to ensure that the foundation is level and solid, to install bases and pads, and to have reliable drainage measures to prevent water accumulation from soaking the foundation. The longitudinal spacing between the vertical poles: when arranged in a single row, the poles are placed 1.2 to 1.4 meters away from the wall ； When arranged in two rows, the inner row of vertical poles is placed 0.4 to 0.5 meters away from the wall, with a distance of around 1.5 meters between the vertical poles in the inner and outer rows. The joints of adjacent vertical poles should be offset from each other; when joining them, joint fasteners should be used, or steel pipe sleeves with a length of 400 mm, an outer diameter equal to that of the vertical pole’s inner diameter, and flanges welded in the middle can also be employed for connection. The vertical deviation of the upright pole shall not exceed 1/200 of the height of the scaffold. The distance between adjacent upper and lower horizontal bars is about 1.8 meters. The connections between the large horizontal members should be offset from each other, and joined using butt fasteners. If lap joints are used, the lap length must be at least 1 meter, with three rotational fasteners used to secure them in place. It should be connected to the vertical pole using right-angle fasteners, and the longitudinal horizontal height difference should not exceed 50 mm. The spacing between the small crossbars shall not exceed 1.5 m. When arranged in a single row, one end of the smaller crossbar should be set at least 240 mm into the wall, while the other end should rest on the larger crossbar, extending at least 100 mm outward ； When arranged in a double row, the distance from the end of the small crossbar to the wall is 50 ~ 100 mm. The small crossbars are connected to the large crossbars using right-angle fasteners. The small crossbars every three steps should be extended, and care should be taken to secure them to the wall. The angle between the diagonal brace of the vertical support and the ground should be in the range of 45° to 60°. The erection of diagonal braces involves using swivel fasteners to attach one diagonal brace to the vertical pole, and another diagonal brace to the extended portion of the horizontal bar; this prevents the steel pipes from bending when the two diagonal braces intersect. The connection joint at which the diagonal bar is fastened to the scaffold with fasteners shall be no more than 200 mm away from the scaffold node (i.e., the intersection of the vertical and horizontal bars). In addition to fastening at both ends, 2 to 4 additional fastening nodes need to be added in the middle. To ensure the stability of the scaffold, the lowest connection point of the diagonal braces should not be more than 500 mm above the ground. The extension of diagonal members should be achieved through butt joints using butt fasteners; when lap joints are used, the lap length must be no less than 400 mm, and these joints should be secured with two swivel fasteners. http://www.scutde.net/t14courses/1412-efmdljiaif/jiaoshoujia/pic/7.1-2.jpg Construction of steel pipe scaffolds