Development of a Socketed Foundation for the Midwest Weak Post (MWP) VI

摘要

Thousands of miles of cable guardrail have been installed on highways across the United States. Often, these installations incorporate socketed post foundations as opposed to simply driving barrier posts into the surrounding soil. Socketed foundation designs allow the posts to slide in and out of a ground socket for easy replacement in the event of system damage during a crash. Thus, the time and cost of system repairs can be minimized. However, multiple State DOTs have reported that real-world crashes into cable barrier installations have resulted in damage to their socketed foundation designs. Unfortunately, foundation damage requires repair crews to either replace the socketed foundation itself or drive a post into the soil adjacent to the damaged component. Either situation defeats the purpose of using sockets, greatly increases the time necessary to restore a damaged barrier, and results in higher maintenance costs and increased risk to repair crews working adjacent to high-speed facilities. The majority of existing socketed post foundation designs are constructed by coring a hole in the soil, placing a steel sleeve in the hole, and backfilling the hole with Portland cement concrete. Many of these designs do not have sufficient reinforcement to resist impact loads that are transmitted through the post and into the socket. Further, many of the foundations are too shallow to resist translation and rotation displacements when a post is impacted. Thus, a need exists to develop socketed foundation designs that perform as intended in the field.