How to evaluate the reliability of outdoor column LED display screens can be mainly carried out from the following three aspects:
Firstly, conduct identification and testing on the foundation of the pillar LED display screen.
There are mainly two basic forms and layouts of it:
1. One is the balanced gravity type, where the upper load is mainly balanced by the gravity of the large volume foundation, usually a concrete foundation. This basic form is suitable for use in soft soil and open construction sites.
2. Another type is pile foundation type, which mainly uses expanded hole piles. This type of foundation form can be adopted in situations where the construction site is limited. When identifying the foundation of an advertising screen, it is necessary to first check its original drawings and construction materials. Then, if conditions permit, the foundation must be excavated to determine whether the foundation form, burial depth, size, and other conditions are consistent with the drawings. The strength of the advertising LED screen foundation concrete should be sampled and tested. In addition, during on-site investigation, special attention should be paid to whether there is any soil uplift or loosening around the steel column root of the advertising screen that uses a balanced gravity foundation. If there is any, it indicates that the foundation’s anti overturning ability cannot meet the requirements and there is a risk of collapse under strong winds at any time. Immediate reinforcement treatment must be carried out. In general, this situation is less common when using deep pile foundation advertising screens.
Secondly, inspect and identify the material of the column.
1. Inspection of the quality of the connection between steel columns and foundations.
The steel pipe columns and foundations of advertising screens are generally connected by bolts or welded. For bolted connections, it is necessary to check for missing bolts during inspection, and the bolts must not be deformed, slip, or loose; For those with design drawings, the specifications and models of bolts must meet the design requirements; Bolts should be treated with rust prevention measures. If they are severely corroded, they must be replaced immediately. Bolts should be tightened firmly and reliably; For high-strength bolts, the exposed thread should be 2-3 threads, and 10% of the bolt threads are allowed to be exposed by 1 or 4 threads; The burial depth of bolts should meet the requirements of the specifications.
2. Inspection of steel columns.
Firstly, the inclination of the advertising screen steel column must be measured. The inclination of the steel column cannot exceed 1000/H and must be measured in two directions; Next is the inspection of the quality of steel for advertising screen steel columns. The appearance quality inspection of steel can be divided into uniformity, whether there are interlayers, cracks, non-metallic inclusions, and obvious segregation. When there is doubt about the quality of steel, samples can be taken from the components to test the mechanical properties and analyze the chemical composition of the steel, but the safety of the structural components should be ensured. Finally, it is necessary to check whether there is rust on the steel pipe columns and the quality of the protective coating for the steel structure. The quality of steel structure protective coatings should be tested according to the current national product standards for coating quality.
Thirdly, inspect the upper steel frame member system.
At present, there are two common forms of connection between steel columns and upper steel frame member systems:
1. One type is T-shaped, with its main skeleton consisting of steel columns and an upper transverse main beam fixed in a T-shaped manner. The advertising screen is connected to the T-shaped rigid frame structure through various hanging parts and diagonal braces.
2. Another type is the spatial truss type, whose main frame is welded from an independent steel column and several parallel horizontal main beams at the top. The main beams are connected by horizontal and diagonal supports to form a spatial truss system, and the advertising screen is directly installed on the main frame.
Therefore, outdoor column LED display screens may have some safety hazards after a period of use, which requires us to regularly inspect and maintain the main structure of the advertising screen, and take measures such as rust prevention for the steel components, in order to ensure the reliability and quality of the column LED display screens.
