Evaluation and Design of ODOT's Type 5 Guardrail with Tubular Backup Final rept

摘要

The purpose of this project was to assess the performance of both the ODOT GR-2.2 guardrail and the ODOT GR-3.4 transition system under NCHRP Report 350 test level 3 (TL-3) conditions, propose any modifications that would improve their crashworthiness and, ultimately ensure that the final designs qualify for use on the National Highway System (NHS) as TL-3 systems. Finite element analyses of the guardrail and transition systems were performed using the LS-DYNA finite element software to simulate NCHRP Report 350 Test 3-10 and Test 3-11 impact scenarios. The analysis results indicated that the original ODOT GR-2.2 guardrail would successfully meet all NCHRP Report 350 test level 3 safety criteria. The analyses also indicated that the performance of the system could be significantly improved with simple modifications to the guardrail. The integrated system of the Nested Type 5 Guardrail with Tubular Backup and the ODOT GR-3.4 transition was considered the most practical and feasible design improvement and was therefore recommended as a final design.