Cable barrier guardrail system with steel yielding support posts

Abstract

In accordance with a particular embodiment of the present invention, a guardrail system includes at least one cable operable to contain and redirect an errant vehicle. The guardrail system also includes a plurality of guardrail support posts spaced apart in relation to one another. Each support post includes a lower portion, a mid portion, and an upper portion. The lower portion is for installing below grade adjacent the roadway. The mid portion lies substantially adjacent the grade and includes a weakened section operable to weaken the support post about a longitudinal axis. The upper portion is releasably coupled to the at least one cable such that the upper portion is uncoupled from the at least one cable when the support post is displaced.

Description

TECHNICAL FIELD OF THE INVENTION [0001] The present invention relates generally to guardrail systems and more particularly, to a cable barrier guardrail system with steel yielding support posts. BACKGROUND OF THE INVENTION [0002] Guardrail systems are widely used along heavily traveled roadways to enhance the safety of the roadway and adjacent roadside. For example, guardrail systems may be used to accomplish multiple tasks, such as containing and redirecting an errant vehicle upon impact. One such system includes a guardrail beam, such as a “W-beam” (named after its characteristic shape), and corresponding support posts. Other systems may utilize cables and corresponding support posts. [0003] Support posts may be made of metal, wood, plastic, composites, or other materials. The material(s) forming the support posts may depend upon design and / or economical factors. For example, wood posts may be more readily available and more economical than metal posts in some geographical areas. ...

AI Technical Summary

Benefits of technology

[0007] Technical advantages of particular embodiments of the present invention include a guardrail support post that has sufficient lateral strength to redirect vehicles that collide along the length of the guardrail system at an angle to the flow of traffic with limited deflection and reduced longitudinal strength that mitigates the severity of the interaction (snagging) between an impacting vehicle and the post. Accordingly, a guardrail system of the present invention may provide benefits in terms of space (reduced deflection for a given post spacing) and cost savings (as a result of fewer posts required to achieve a desired deflection).

[0008] Other technical advantages may include increased flexibility with respect to design requirements of support posts. For example, wood support posts may be utilized in a cable guardrail system, in particular embodiments. Where wood support posts include a modified section, larger posts may be used than in conventional guardrail systems using wood posts. As a result of the increased lateral stiffness of the larger posts, the spacing between support posts may be increased, and less support posts may be required in the overall guardrail system without a resulting increase in deflection. Accordingly, a further technical advantage may include reduced costs associated with the installation and repair of the cable guardrail system. Similarly, if the spacing between support posts is left unchanged, the increased lateral stiffness of the larger posts may result in reduced lateral deflection. Accordingly, the cable guardrail system can be used at more restrictive locations.

[0009] Additional advantages may be realized by the mechanical coupling of the guardrail support posts to one or more cables used to contain and redirect errant traffic. In particular embodiments, a modified slot may releasably secure the cables with respect to the support post. A first portion of the modified slot may maintain the cables at a desired elevation with respect to the ground. The first portion may also maintain one or more cables in a position that is resistant to release from the support post. A second, generally U-shaped portion may similarly maintain a cable at a desired elevation with respect to the ground. However, the U-shaped portion may increase the strength of the web of the support post and thus provide resistance to the yielding of the support post. Accordingly, the second portion may reduce deflection of the support post.

Problems solved by technology

Many such prior attempts require substantial time, money, and resources during fabrication, modification, and / or installation, however.

Furthermore, wood posts may not provide sufficient strength to limit lateral deflections to desired levels.

Such posts may also deteriorate rapidly from exposure to the elements.

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