Guardrail Support With Weakened Zone For Impact Separation
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Solution Overview
Problem
Current road safety barrier systems, particularly semi-flexible guardrails, face issues with maintaining height during impacts due to deformation of posts and spacer blocks, leading to inadequate containment and redirection of vehicles.
Innovation Solution
A barrier system with a support having a weakened zone around the connection region of the fastener, allowing the support to separate from the guardrail during deflection, ensuring the fastener remains attached and the guardrail remains elevated to function as a containment ribbon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the guardrail is directly attached to the support posts using conventional fasteners, then the guardrail is securely fixed in position, but the posts and spacer blocks plastically deform on impact causing the guardrail to be dragged down and under the vehicle
Solution Approach 1:
The support post is segmented into two functional zones: a connection region with sufficient strength to hold the guardrail during normal conditions, and a weakened zone that facilitates controlled separation during impact. This segmentation allows the post to transition from a rigid attachment structure to a separable connection, enabling the guardrail to maintain height while the post absorbs impact energy through controlled failure.
Solution Approach 2:
The mechanical properties of the support post are changed spatially by creating a weakened zone with reduced cross-sectional area or altered material properties around the connection region. This parameter change allows the post to exhibit different behavioral characteristics in different zones: strong attachment at the connection region and controlled deformation/separation at the weakened zone during impact events.
2Adaptability or versatility
If the guardrail is made flexible to redirect vehicles, then vehicle redirection is improved, but a considerable distance must be provided adjacent the roadway to arrest and redirect the vehicle
Solution Approach 1:
The guardrail system transitions from a static rigid structure to a dynamic system that changes its mechanical behavior during impact. The support posts are designed to dynamically transition from holding the guardrail in a fixed position to controlled separation, allowing the guardrail to become more flexible during impact events. This dynamic behavior enables effective vehicle redirection with reduced space requirements compared to fully flexible barriers.
Data Source
AI summary
A barrier system including a guardrail, a support to hold the guardrail in position and a fastener to attach the guardrail to the support, wherein the support has a weakened zone to facilitate the fastener releasing from the support when the support is subject to impact forces.