Compliance Testing of a Bullnose Median Barrier System; NCHRP Report 350

Abstract

A new bullnose guardrail system for the treatment of median hazards was developed and successfully crash tested according to the safety criteria set forth in NCHRP Report 350. The new system consists of a nose section 4500 mm wide by 4824 mm long, comprising three sections of curved thrie beam guardrail attached to parallel sides of thrie beam guardrail 4500 mm apart. The nose section was designed to safely capture and contain vehicles impacting the nose. Two 6 × 25 steel cables were attached behind the top two humps of the nose section to ensure vehicle capture in the event the thrie beam ruptured. Additionally, the first five sections of guardrail had horizontal slots cut in the valleys of the rail to improve vehicle capture and reduce the formation of large kinks that could pose a threat to a vehicle as the system deformed to absorb an impact. The research study included computer simulation modeling using LS-DYNA and full-scale vehicle testing using 2000-kg pickup trucks and 820-kg small cars in accordance with the Test Level 3 safety performance requirementd specified in NCHRP Report 350. Nine full-scale crash tests were performed on the new system. Several changes were made to the bullnose system to improve its safety performance during the course of the testing and development.