1. Wind pressure resistance performance

The wind resistance performance is primarily affected by the flexibility and overall strength of the unit board material, followed by the strength of the overall frame.

Sound barriers are typically affected by wind loads and pulsating loads generated by vehicles passing through. The deflection, residual deformation, and damage are commonly used to evaluate whether the sound barrier unit panels have experienced functional failure. According to national standards, the elastic deflection of the unit panels should not exceed one percent of the panel length, and the residual deformation should not exceed one half of one percent of the panel length.

2. Impact Resistance Performance

Impact resistance is related to the strength and brittleness of the surface material of the unit board.

During operation, sound barriers may detach due to impacts from external moving objects, posing a risk to driving safety. Therefore, the sound barrier units must possess robust shock resistance. In accordance with national standards, when the unit panel withstands an impact of (30±1J) energy, damage is limited to the surface portion of the unit panel structure and must not cause damage or translational fractures to the internal components.

3. Bend and fracture resistance load

The bending resistance and tensile load are related to the overall strength and toughness of the unit panel.

The bending and tensile load resistance refers to the surface pressure that the sound barrier unit panels must be able to withstand, which is a technical indicator for controlling the structural strength of the sound barrier. The testing method and requirements are as follows: The sound barrier unit panels are supported at both ends in a parallel manner, with one end fixed and the other set as a rolling pivot support. Apply a load not exceeding 30% of its own weight, at least five times, until fracture occurs, and record the total load from the first level to the fifth level as the test result.

4. Fatigue Resistance Performance

Fatigue resistance is related to the overall strength and toughness of the unit board.

The fatigue resistance specification for sound barriers dictates the number of fatigue impacts the barrier panels can withstand over their service life, considering the number of trains passing. It is a critical indicator for ensuring the safety of sound barrier products during their service life under certain speeds and train counts. According to national standards, a fatigue test machine applies a constant force at a frequency of 4Hz, undergoing 4 million sine wave cycles. The overall structure of the sound barrier should not exhibit any signs of cracks, panel damage, bonding failure, or loose hardware after the test. Additionally, the internal and external structures, as well as the sound-absorbing materials, should not show any deformation, damage, cracking, delamination, or loosening that would affect their use.

5. Corrosion Resistance Properties

Corrosion resistance is related to the anti-corrosion treatment of the metal frame of the unit board.

Corrosion resistance is used to measure the service life of metal materials for noise barriers. According to TBT 3122-2010 "Technical Requirements and Testing Methods for Acoustic Components of Railway Noise Barriers," the corrosion resistance is demonstrated by the results of a 4000-hour salt spray test, with the difference in performance among all test pieces serving as the basis for the test. In the 2019 version of the technical requirements and testing methods for acoustic components of railway noise barriers, corrosion resistance is indicated by salt spray resistance or coating adhesion. The coating adhesion is first evaluated by scoring with a grid knife according to the standard, then firmly sticking with tape and peeling it off to check the surface appearance of the scored area.

6. Fire-resistant properties

Fire resistance is related to the internal material of the unit board.

Fire performance testing determines whether the materials used in acoustic barrier panels meet the standard requirements. According to relevant standards, non-metallic acoustic barrier panels generally require a fire rating of B1 (flame retardant) or above, while metallic acoustic barrier panels typically require a fire rating of A (non-combustible) or above. The testing method involves using a small flame to directly strike the vertically placed sample to measure its combustibility.