How to ensure verticality and levelness during the installation of scaffolding steel supports?
When installing steel supports for scaffolding, ensuring verticality and levelness is the core of ensuring structural stability, which needs to be achieved through preliminary preparation, precise measurement, step-by-step control, and verification. The specific methods are as follows:
1、 Preliminary preparation: Establishing benchmark conditions
Foundation leveling and hardening
The foundation at the bottom of the pole needs to be leveled and compacted, and a C20 or above concrete cushion layer (thickness ≥ 100mm) should be poured. The surface should be calibrated with a level, and the flatness error should be ≤ 5mm. A full-length channel steel (10 # or above) or scaffold board should be added to the soft ground to disperse pressure and avoid settlement.
An adjustable base is set at the bottom of the pole, and the adjustment range of the base screw is controlled within 300mm (if exceeded, additional pads need to be added) to ensure that the initial support surface is level.
Setting out and positioning
Pop up the vertical and horizontal axis lines of the pole on the ground according to the drawing, mark the precise position with ink lines (deviation ≤ 5mm), and place a positioning steel plate (100 × 100mm) at the intersection of the axis lines to avoid installation deviation of the pole.
2、 Verticality control: step-by-step calibration of the upright pole
Single pole installation calibration
After the upright pole is erected, first use a 2m ruler to stick tightly to the pole body, adjust the adjustable base or top screw to ensure that the verticality deviation is ≤ 2mm/m; Re check the verticality of the entire height using a total station or a plumb bob (weighing ≥ 0.5kg), with a deviation of ≤ 10mm every 10m height (total deviation ≤ 15mm when the total height is ≤ 20m).
When the verticality direction of adjacent poles is opposite, priority should be given to ensuring overall straightness, and the deviation direction should not be concentrated on one side.
Horizontal bar connection auxiliary fixation
When installing the first step of the crossbar, first fix the two end uprights, calibrate the levelness of the crossbar with a spirit level (deviation ≤ 3mm/m), and then use this as a reference to fix the middle uprights. Use the crossbar tension to restrain the inclination of the uprights and form a stable unit.
3、 Levelness control: Layered verification of horizontal bars and sweeping rods
Leveling of sweeping pole and horizontal pole
The height of the sweeping pole from the ground should be ≤ 200mm. During installation, use a level to measure each point point to ensure that the height difference of the horizontal bars in the same plane is ≤ 5mm. When the height difference exceeds the standard, fine tune it with the screw of the pole base and prohibit cutting the pole.
Before installing the upper horizontal bar, use the lower horizontal bar as a reference to pull a straight line (with consistent tension on the nylon line) to ensure that each horizontal bar is in the same vertical plane and the horizontal deviation between layers is ≤ 10mm.
Auxiliary leveling of cross bracing and slant support
Each diagonal brace spans no more than 5 upright poles. During installation, fix the nodes at both ends first, then tighten them with flower basket bolts. Use diagonal force to correct the horizontal deviation of the frame, ensuring that the frame is not twisted in the plane (diagonal deviation ≤ 100mm).
4、 Review and Adjustment: Dynamic Control of Errors
After installing 3 layers of vertical poles, a total station should be used for overall review: the vertical and horizontal verticality deviation and the elevation difference of the horizontal pole should comply with the specifications. Any parts that exceed the standards should be adjusted immediately (loose connection nodes, adjust the verticality of the vertical pole with a jack, and then re tighten).
Recalibrate once after encountering strong wind and rainstorm to prevent deviation accumulation caused by foundation settlement or loose connection, ensure that the perpendicularity of scaffold steel support is ≤ 1/1000 of the total height and levelness is ≤ 5mm/2m in the whole cycle, and fundamentally avoid potential safety hazards caused by eccentric force.
