What type of washers are used on guard rail bolts?

The use of spring washers on guard rail bolts is significant because they provide a specific function in ensuring the integrity and stability of the rail system. Spring washers exert a continuous preload on the bolt after it has been tightened, which is essential for maintaining clamping force, especially in environments subject to vibration. This helps to prevent loosening over time, which is particularly crucial in rail operations where safety and stability are of utmost importance.

The design of spring washers allows them to absorb shock and accommodate movement or expansion in the materials, which is vital in outdoor conditions where temperature fluctuations could affect bolted connections. Their ability to keep the fasteners tight initially counters the tendency of materials to shift or settle over time.

Other types of washers, while useful in different applications, do not provide the same level of dynamic support and prevention of loosening. Flat washers primarily distribute the load but do not help maintain tension. Fender washers are used for larger surface areas but lack the mechanical advantage in vibration resistance. Lock washers offer some resistance to loosening as well, but spring washers are specifically designed for high-stress, high-vibration applications like guard rail systems, making them the preferred choice in this context.