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TL-5 Development of 42-and 51-in. Tall, Single-Faced, F-Shape Concrete Barriers




Ronald Faller, Dean Sicking, Jordan Larsen, John Rohde, Bob Bielenberg, Karla Lechtenberg (Polivka)




A review of tractor-trailer impacts into rigid barrier systems was conducted in order to study the dynamic lateral vehicular loads imparted into common barrier systems. For a selected number of crash tests, researchers performed two linear regression analyses on the estimated lateral peak load versus impact severity. This analytical investigation resulted in a peak lateral design load ranging between 681 to 689 N (153 to 155 kips) and 1,081 to 1,103 N (243 to 248 kips) for the AASHTO PL-3 and NCHRP 350 TL-5 impact conditions, respectively. Researchers then determined the redirective capacities of four existing barrier designs using the standard yield-line analytical procedures. It was determined that the standard yield-line analytical procedures likely underestimate the redirective capacity of solid, reinforced concrete parapets, since other factors likely contribute to the redirective capacity of reinforced and non-reinforced concrete barrier systems. Since a "modified" yield-line analysis procedure is currently unavailable, the standard yield-line analysis procedure was used but in combination with a scaled-down design impact load. The new barrier systems were developed using a peak design impact load ranging between 939 N (211 kips) to 996 N (224 kips) or based on an average design impact load of approximately 965 N (217 kips). Two single-faced, F-Shape concrete barrier systems were designed to meet the TL-5 impact safety standards using the existing yield-line analysis procedures and for 1,067-mm (42-in.) and the 1,295-mm (51-in.) top-mounting heights. Attachment options were provided for anchoring the barriers to generic reinforced concrete slabs and a median foundation. The barrier and foundation systems were based on a conservative design approach where full-scale vehicle crash testing would not be required. Three research projects were recommended that would advance the state-of-the art for concrete barrier designs and provide new, more economical and innovative barrier and anchorage support systems.


Highway Safety, Analysis, Design, Roadside Appurtenance, Longitudinal Barrier, Concrete Barrier, Median Barrier, and Bridge Rail

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