Why Install Spacer Blocks Between Guardrail Panels and Posts?

highway guardrail

Why are spacer blocks installed between guardrail panels and posts? What benefits do they offer?

  1. Energy Absorption: Spacer blocks themselves act as energy-absorbing mechanisms. Upon impact, they allow the guardrail to deform gradually, promoting energy dissipation and reducing the risk of severe injury to vehicle occupants.
  2. Prevent Wheel Snagging: By securing the spacer block between the post and the guardrail panel, a gap is created. This prevents a vehicle’s front wheels from snagging on the post during a collision, which could lead to a more abrupt and dangerous impact.
  3. Enhanced Force Distribution: Integrating spacer blocks into the guardrail system distributes impact forces across a wider structural area. This results in a more even distribution of stress, leading to a smoother collision trajectory for the vehicle, improving its redirection, and enhancing the overall strength of the guardrail system.
  4. Mitigating Curb Impacts: When installing guardrails with spacer blocks in sections with curbs, the distance between the guardrail panel and the curb face is reduced. This minimizes or even eliminates the adverse effects of a vehicle hitting the curb and then vaulting into the guardrail.

Spacer blocks can be fabricated from various shaped steel sections. Two commonly recommended types are A and B. Type A, with its hexagonal structure, is suitable for round posts, while Type B, based on French standards, is designed for C-shaped or other structural steel posts.

In conclusion, the role of spacer blocks in guardrail systems is crucial and should not be overlooked. They significantly contribute to the system’s effectiveness in absorbing impact energy, preventing dangerous vehicle behavior during collisions, and enhancing overall road safety.

Scroll to Top