Outdoor Billboard Inspection

 

(2) Applicable types

Single column billboard, double column billboard, truss billboard, wall mounted billboard, roof mounted billboard, floor standing billboard, LED display billboard (steel structure main body).

 

(3) Core principles of testing

Non destructive testing is the main approach, with minor damage testing as a supplement, to avoid secondary damage to the structure caused by testing;

Prioritize the detection of key stress areas;

Combining static detection and dynamic wind load review, taking into account the current state and bearing capacity under extreme weather conditions;

 

 

(1) Basic and Dependent Object Detection

Basic appearance and defect detection

Check for cracks, looseness, corner loss, and exposed reinforcement in the concrete foundation, and record any voids or settlement cracks at the contact point between the foundation and the ground; Detect cracks, leaks, and structural damage in the walls/roof abutments, and investigate the damage to the main building caused by the additional load of billboards.

 

Basic Geometry and Deformation Detection

Using a level to detect the overall settlement and uneven settlement of the foundation, measuring the elevation of the top surface of the foundation, and calculating the settlement difference

Foundation bolt/anchor system testing: testing specifications, quantity, burial depth, and verifying consistency with design values; Check the status of bolt connections: loose bolts, rust, and damaged threads;

Basic concrete strength testing;

 

(2) Main steel structure inspection

Appearance and damage detection of components

Inspect the surface cracks, pits, deformations, and scratches of columns/beams/trusses;

Corrosion and section loss detection of steel

Testing the integrity of anti-corrosion coatings: peeling, flaking, powdering, and bubbling range; Detect the actual wall thickness/section size of the corroded area of the steel and calculate the section loss rate;

Main geometric dimensions and deformation detection

Steel grade review;

 

(3) Connection node detection

Welding node detection

Testing locations: connection welds between columns and beams, truss node welds, connection welds between panel supports and main bodies, connection welds between ladders and main bodies;

Appearance inspection: defects such as weld excess height, undercutting, incomplete welding, porosity, slag inclusion, etc;

Non destructive testing: Ultrasonic testing (UT) is used to detect internal defects in key welds under stress.

 

High strength bolt node detection

Testing parts: truss node bolts, crossbeam fixing bolts, column splicing flange bolts, panel support bolts;

Appearance inspection: Check for bolt corrosion, thread damage, and missing gaskets, identify bolt fractures, thread slippage, and flange surface tightness

Check the specifications, quantity, and burial depth of expansion bolts/chemical anchor bolts, and verify their consistency with the design values; Detect the pull-out resistance of anchor bolts; Identify the risk of billboard detachment from walls/roofs caused by loose anchor bolts.

 

(4) Advertising panel and lighting facility inspection

Although advertising panels and lighting facilities do not bear the main load, they directly affect public safety and are additional load points that require special testing

 

Advertising panel detection

Detect the damage, aging, and deformation of the panel, and investigate the risk of being lifted up under strong winds;

Check the fixing status of the lighting fixtures, identify any looseness or corrosion; Check the welding/bolt connection reliability of the lamp bracket, as well as the bending and instability of the bracket itself; Check the fixation and protection of cables, and investigate the risk of leakage caused by cable wear and exposure.

 

(5) Electrical system testing

Insulation and leakage detection; Detect the insulation resistance of the circuit,; Lightning protection and grounding system testing; Check the reliability of the connection of lightning arrester (top cap, lightning rod); Detect the connection between the grounding down conductor and the main body of the billboard, and measure the grounding resistance value;

 

(6) Overall performance and bearing capacity verification

Based on the actual component parameters, connection status, and material properties detected on site, combined with the current load, professional software (PKPM, MIDAS/GEN) is used for modeling and verification, which is the core of the overall safety assessment:

 

Load calculation:

Dead load, live load, special load

Core verification items: compressive and flexural bearing capacity of the main steel structure, review the stress ratio of each component; Basic anti pull, anti overturning, and anti slip bearing capacity; Overall wind resistance stability verification, investigating the risk of being blown down under strong winds; The attached billboard needs to verify the connection strength with the main building.