Investigation and Dynamic Testing of Wood and Steel Posts for MGS on a Wire-Faced, MSE Wall
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ABSTRACT
This study was performed to support the development of a non-blocked version of the Midwest Guardrail System (MGS) for use on wire-faced, MSE walls. The dynamic post-soil behavior for standard wood and steel posts placed in various soils with sloped and level terrain and using different installation methods was investigated. A total of twenty-six dynamic component tests were performed within four distinct rounds of testing - two tests conducted at 25 mph (40 km/h), twenty tests conducted at 20 mph (32 km/h), and four tests conducted at 15 mph (24 km/h). Dynamic testing was performed on 6-in. x 8-in. (152-mm x 203-mm) wood posts as well as on W6x8.5 (W152x12.6), W6x9 (W152x13.4), and W6x16 (W152x23.8) steel posts. The posts were embedded in strong soil conforming to AASHTO Grading B for all tests except one, in which the post was embedded in larger wall-facing limestone rock material. For each bogie test, force versus deflection and energy versus deflection curves were prepared. From this component testing program, a non-blocked version of the MGS with W-beam backup plates was recommended for installation, crash testing, and evaluation using 6-ft (1.8-m) long, W6x8.5 (W152x12.6) or W6x9 (W152x13.4) steel posts driven at the slope break point of a 3H:1V fill slope adjacent to and on top of an MSE wall.
KEYWORDS
Roadside Safety, Wood Posts, Steel Posts, Guardrail Posts, Bogie Testing, Impact Testing, MSE Wall, Wire-Faced, Fill Slope, and MGS