Testing And Evaluation Of Mash Tl 3 Transition Between Guardrail And Portable Concrete Barriers

Testing and Evaluation of MASH TL-3 Transition Between Guardrail and Portable Concrete Barriers

Development of a MASH TL-3 Transition Between Guardrail and Portable Concrete Barriers

Often, road construction causes the need to create a work zone. In these scenarios, portable concrete barriers (PCBs) are typically installed to shield workers and equipment from errant vehicles as well as prevent motorists from striking other roadside hazards. For an existing W-beam guardrail system installed adjacent to the roadway and near the work zone, guardrail sections are removed in order to place the portable concrete barrier system. The focus of this research study was to develop a proper stiffness transition between W-beam guardrail and portable concrete barrier systems. This research effort was accomplished through development and refinement of design concepts using computer simulation with LS-DYNA. Several design concepts were simulated, and design metrics were used to evaluate and refine each concept. These concepts were then analyzed and ranked based on feasibility, likelihood of success, and ease of installation. The rankings were presented to the Technical Advisory Committee (TAC) for selection of a preferred design alternative. Next, a Critical Impact Point (CIP) study was conducted, while additional analyses were performed to determine the critical attachment location and a reduced installation length for the portable concrete barriers. Finally, an additional simulation effort was conducted in order to evaluate the safety performance of the transition system under reverse-direction impact scenarios as well as to select the CIP. Recommendations were also provided for conducting a Phase II study and evaluating the nested Midwest Guardrail System (MGS) configuration using three Test Level 3 (TL-3) full-scale crash tests according to the criteria provided in the Manual for Assessing Safety Hardware, as published by the American Association of Safety Highway and Transportation Officials (AASHTO).

MASH TL-3 Transition Between Median Guardrail and Median Concrete Barrier

The purpose of this research was to develop a Manual for Assessing Safety Hardware (MASH) Test Level 3 (TL-3) compliant transition between a median guardrail and median concrete barrier, and then test the design according to MASH TL-3 crash testing guidelines. The design was developed using finite element computer simulations. This report provides details on the computer simulations, the Texas Department of Transportation (TxDOT) median transition system, the crash tests and results, and the performance assessment of the median transition for MASH TL-3 transition evaluation criteria. The TxDOT median transition met the performance criteria for MASH TL-3 transitions.