As the core support structure of a solar power station, PV racking is exposed to the natural environment for a long time, enduring multiple tests such as wind, snow, rain and corrosion. As the operating life of PV power plant increases, various damages may occur in the solar racking system, which directly affects the safety and power generation efficiency of the power plant.

I. First, metal corrosion: stent of the “invisible killer”  

1. Damage phenomenon:

- Rust spots, coating peeling and blistering appear on the surface.  

- In serious cases, it leads to the thinning of the thickness of the profile, and even perforation.  

2. Main causes:

-Environmental factors:

  - Coastal areas: high salt spray environment accelerates electrochemical corrosion.  

  - Industrial pollution areas: acid rain, sulfide and other corrosive gas erosion.  

  - High temperature and high humidity areas: moisture and oxygen together lead to corrosion.  

- Material problems:

  - Use of low-quality steel (e.g., Q235 without hot-dip galvanizing treatment).  

  - Insufficient thickness or poor adhesion of anti-corrosion coating (e.g. epoxy zinc-rich primer <60μm).  

- Design defects:

  - Pooling of water in structural gaps, forming corrosion “hot spots”.  

  - Failure to consider galvanic corrosion due to contact of different metals. 

II. Structural deformation: warning of load overrun*

1. Damage phenomena:

- Tilting of columns, bending of beams, overall structural instability.  

- Component mounting surface is uneven, affecting power generation efficiency.  

2. Main causes:

- Extreme weather:

  - Strong winds (>25m/s) resulting in excessive wind loads.  

  - Heavy snow (>0.5kN/m²) resulting in excessive snow loads.  

- Inadequate design:

  - Failure to check the loads according to local meteorological conditions (e.g. low values of basic wind pressure and snow pressure).  

  - Insufficient structural rigidity (e.g. column spacing too large, missing diagonal braces).  

- Construction problems:  

  - Foundation not compacted, resulting in uneven settlement.  

  - Unstandardized installation of connectors (e.g., untightened bolts, poor quality welds).

III. Third, the failure of the connectors: small parts of the big hidden trouble

1. Damage phenomenon:

- Loose bolts, fall off, resulting in structural instability.  

- Weld cracking, separation of the connection part.  

2. Main causes:  

- Vibration fatigue:

  - Long-term wind vibration causes the preloading force of bolts to drop.  

  - Micro-cracks in welds due to thermal expansion and contraction stresses.  

- Installation problems:  

  - The bolts are not tightened according to the standard torque (e.g. the torque of M16 bolts should be 200N-m).  

  - Welding process is unqualified (e.g. no beveling, no cleaning of welding slag).  

- Material defects:  

  - Use of low-strength bolts (such as 4.8 instead of 8.8).  

  - Mismatch of welding rod type (e.g. using E43 welding rod for Q345 steel).

IV. Foundation damage: a hidden but deadly threat

1. Damage phenomenon:

- Concrete foundation cracked and broken.  

- Anchor bolts are pulled out and brackets are separated from the foundation.  

2. Main causes:

- Soil problems:

  - Frozen areas without frost protection (e.g. insufficient foundation depth).  

  - Insufficient bearing capacity of soft soil foundation (<80kPa).  

- Design defects:

  - Insufficient overturning moment due to small foundation size.  

  - Insufficient anchor bolt depth (e.g. M20 anchor bolt depth should be ≥400mm).  

- Construction quality:  

  - Concrete strength is not up to standard (e.g. C25 is only C20).  

  - Anchor installation deviation is too large (>5mm).