An investigation into the design and manufacture of FRP composite W-beam guardrail

This paper discusses the design and manufacture of highway guardrail of W-shape with fiber-reinforced polymer (FRP) composite material and its testing. As a first approximation, laminate theory was used for the layup decision of the initial batch, and then the design was refined through a series of trial runs before the target 482 MPa (70,000 psi) tensile strength was achieved. The manufacturing process was done by the vacuum assisted resin transfer molding process. The test results showed that while the FRP W-beam tensile strength was of the same order of magnitude as that of steel, the flexural stiffness was approximately one-third that of the standard AASHTO steel Wbeam guardrail. Also, under flexure, even a fractured FRP W-beam bounces back to a linear shape after the load is removed, which suggests that, perhaps, in highway installations, post-damage replacement could be delayed longer than for the steel W-beams. The study showed that it is feasible to manufacture W-beam profile guardrails of different thickness to obtain the desired strength, stiffness, and impact characteristics.