Due to the complex environment and high load risk, there are many difficulties in the installation of steel supports during high-altitude operations. Targeted solutions need to be developed, as follows:
1、 Difficulty 1: Low precision in lifting and positioning high-altitude components
Difficulty performance: Components (such as steel uprights and heavy-duty crossbars over 6m in length) are prone to shaking in the air, with large docking deviations (exceeding 20mm), making it difficult to accurately insert into connecting nodes, and the lifting process is prone to collision with already erected structures.
Solution:
Adopting "segmented lifting+temporary fixation": the long component is divided into units within 3m, and the position is fine tuned with a tower crane and a chain hoist (bearing capacity ≥ 5t). Temporary ear plates are set at both ends of the component, and pre fixed with bolts (tightened when the deviation is ≤ 5mm).
Set up an aerial positioning platform: Set up a temporary operating platform (with a scaffold board and protective fence) 2 meters below the working level, and use a pry bar to assist in aligning bolt holes on the worker's platform, reducing errors in suspended operations.
2、 Difficulty 2: Poor stability and high safety risks in high-altitude operations
Difficulty performance: Operators lack a stable foothold and are prone to imbalance due to wind loads (wind speed ≥ 10.8m/s) or component shaking, and unsecured steel supports are prone to falling.
Solution:
Mandatory safety protection: Workers are required to wear double hook safety belts (with hooks connected to fixed poles and safety ropes), and the working layer is covered with anti slip scaffolding boards (tied with iron wire and crossbars). A 1.2m high guardrail and a 200mm high toe board are installed on the outside.
Wind load control: In the event of strong winds above level 5, operations will be suspended. Unfixed components that have been installed will be temporarily tied with cable wind ropes (12mm steel wire ropes) (with 2 directions for each component and a tension of ≥ 5kN) to prevent overturning.
3、 Difficulty 3: Insufficient tightness of high-altitude connection nodes
Difficulty performance: Bolts and fasteners are difficult to tighten with standard torque at high altitude (such as M20 bolts requiring 300N · m torque), and are prone to loosening due to vibration, leading to support slippage.
Solution:
Tool adaptation: Use an electric wrench with torque display (error ≤ ± 5%), calibrate the tool before operation, and recalibrate every 10 bolts tightened to ensure that the torque meets the standard.
Node enhancement: Key parts are equipped with "double nut anti loosening" (tighten and then tighten by 1/3 turn), or anti loosening glue (such as thread locking agent) is applied to the bolt thread. After connection, the fastening position is marked with paint for easy inspection.
4、 Difficulty 4: High altitude measurement calibration is difficult
Difficulties: Verticality and levelness are affected by high-altitude visual obstruction, and the total station measurement error is large (exceeding 15mm), making it difficult to adjust in real time.
Solution:
Layered benchmark control: Permanent benchmarks are set up on the ground, and during the installation of each vertical pole, a laser projector (with an accuracy of ± 1mm/10m) is used to project the axis, and a 2m ruler is used to calibrate the verticality of each pole (with a deviation of ≤ 2mm/m).
Dynamic monitoring: Install a tilt sensor (with an accuracy of ± 0.1 °) on a stable frame, transmit real-time data to the ground terminal, and immediately stop and adjust when the tilt exceeds the standard (tilt>1 °).
Through the above measures, the accuracy, safety, and stability issues of high-altitude steel support installation can be effectively solved, ensuring that the installation quality complies with the "Technical Specification for Safety of High altitude Construction Operations" and reducing the risk of accidents.
