Design and Testing of a MASH TL-3 Thrie-Beam System for Roadside and Median Applications (614341/Task Order DX)


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Final Report Link: Design and Testing of MASH TL-3 Thrie-Beam System for Roadside and Median Applicaitons


TTI Research Supervisor:
Maysam Kiani, Ph.D.
Associate Transportation Researcher
Texas A&M Transportation Institute
TAMU 3135
College Station, Texas 77843-3135
(979) 317-2693
[email protected]
Pooled Fund Technical Representative:
James Danila
Assistant State Traffic Engineer
Massachusetts Department of Transportation
10 Park Plaza, Room 7210
Boston, MA 02116
(857) 368-9640
[email protected]


Thrie-beam guardrail systems are used when enhanced Test Level 3 (TL-3) protection above what is typically provided with W-beam guardrail is desired. Currently, an AASHTO Manual for Assessing Safety Hardware (MASH) compliant Thrie-beam guardrail system for roadside applications exists, but a median version has yet to be developed. (1) Furthermore, the currently available roadside system incorporates components that are more costly to fabricate and install and create a wider footprint than conventional W-beam barrier alternatives. Therefore, the Roadside Safety Pooled Fund prioritized a project to develop MASH compliant cost effective Thrie-beam guardrail systems for both roadside and median applications. These systems were crash tested to MASH specifications. Lastly, transition designs from these newly developed systems to standard W-beam systems were developed through computer simulation.

The developed Thrie-beam Guardrail system (TGS) utilizes all MGS standard components with the exception of the Thrie-beam itself. TGS has a thrie-beam rail mounted at 34-inches to top as opposed to MGS with a W-beam rail mounted at 31-inches. The two systems are attached together using symmetric W-beam-to-thrie-beam transition segments.

*Based on the results of the three successful full-scale crash tests and the computer simulation effort, both roadside and median TGS configurations met all safety requirements for MASH TL-3.

*the opinions/interpretations identified/expressed in this section of the report are outside the scope of the TTI Proving Ground A2LA Accreditation