This study developed socketed foundations for two cable guardrail posts, the S335.7 and the Midwest weak post (MWP). The design efforts focused on developing cylindrical, reinforced concrete foundations with a steel tube embedded in the top center to create a socket. Foundations were designed to minimize damage and limit foundation displacements to less than 1 in. Satisfying these criteria ensured that damaged barrier posts could be replaced without the need for repairing or resetting the foundation. The foundations were evaluated for three soil types (weak soil, strong soil, and an asphalt mow strip) to gain an understanding of the link between soil conditions and foundation performance. Four-teen dynamic component tests were conducted on socketed foundation designs. Three socketed foundation options were developed for use with S335.7 posts: a 12-in.-diameter foundation in soil, a 15-in.-diameter foundation in soil, and a 12-in.-diameter foundation in asphalt. The S335.7 post foundations in soil with 12-in.-diameter sockets were found to be susceptible to concrete shear cracking and fracture, but they remain an option for those who can accept the risks of minor damage during severe impacts. The 15-in.-diameter foundations and those placed in asphalt had no indication of damage. Further, the reduced strength of MWPs resulted in no visible damage to 12-in.-diameter foundations. Guidelines based on site soil conditions and frost line depth were developed for the embed-ment depth of each foundation–post combination required for resistance to excessive displacements.
ASJC Scopus subject areas
- Civil and Structural Engineering
- Mechanical Engineering