Performance Evaluation of Strong Post Double-faced W-beam Guardrail and Strong Post Doubled-faced Thrie-Beam Guardrail at MASH Test Level 4 (TL-4) and Test Level 5 (TL-5) conditions

The main objective of the proposed research is to evaluate the performance of the strong post double-faced W-beam and Thrie-beam guardrails at MASH Test Level 4 (TL-4) and Test Level 5 (TL-5) conditions. Both the W-beam and Thrie-beam guardrails will be based on North Carolina Department of Transportation (NCDOT) design specifications and evaluated at two rail heights, i.e., 29 and 31 inches. Finite element modeling and simulation will be employed to evaluate all the guardrails under impacts of a small passenger car (2,400 lbs or 1,090 kg), a pickup truck (5,504 lbs or 2,499 kg), a single-unit truck (22,046 lbs or 10,000 kg), and a tractor-trailer (80,000 lbs or 36,287 kg). The proposed research will provide a summary of the effectiveness of the strong post double-faced W-beam and Thrie-beam guardrails at 29- and 31-inch rail heights under MASH TL-4 and TL-5 conditions. NCDOT engineers and officials will gain insights on the guardrails' performance (including any redirection characteristics and system deflections) when impacted by a single-unit truck and tractor-trailer combination. They will use the research results to make informed design and installation decisions for the placement and use of doubled-faced W-beam and Thrie-beam guardrails. NCDOT officials may use the research to evaluate and communicate their efforts to enhance safety on the prevention of cross-median crashes. The results can also be used to evaluate the effectiveness of providing safety hardware at higher standards than those currently recommended by the Federal Highway Administration (FHWA) Office of Safety.