Development of Guardrail to Bridge Rail Transition

摘要

The report describes the development and testing of a guardfence-to-rigid bridge rail transition. The transition consists of a tubular W-beam supported on 7 inch diameter round wood posts. It is designed to transition to a vertical wall or to the concrete safety shaped barrier. It can be used on new construction or as a retrofit for existing installations. Based on a full-scale vehicular crash test program, the design was judged to be in compliance with recommended impact performance criteria as presented in NCHRP Report 230. Also described is a tentative design for approach guardfence at bridge ends near an abutting roadway. The design consists of short radius, curved guardrail supported on weakened round wood posts. Tubular W-beam and nested W-beam elements were examined and both appear to offer acceptable performance for a design impact speed of approximately 40 mph.