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Performance Characteristics of Posts Embedded in Soil




Brandt Humphrey, Karla Lechtenberg, John Reid, Ronald Faller, James Holloway




The primary objective of this research study was to determine the post-soil impact reaction of W6x8.5 (W150x12.6) steel posts and 6-in. x 8-in. (152-mm x 203-mm) Southern Yellow Pine (SYP) posts, specifically along the weak axis. Five bogie tests were conducted on W6x8.5 (W150x12.6) A992 steel posts with a length of 72 in. with embedment depths ranging between of 24 and 40 in. (610 and 1,016 mm). Four bogies tests were conducted on 6-in. x 8-in. (152 mm x 203 mm) SYP posts embedded at depths ranging between 30 and 40 in. (735 and 1,016 mm). The target impact conditions were an impact speed of 20 mph (32.2 km/h) and an impact angle of 0 degrees creating weak-axis bending. The posts were impacted 24? in. (632 mm) above the groundline and perpendicular to the web of the post. A compacted, coarse crushed limestone material as recommended by the Manual for Assessing Safety Hardware (MASH) was utilized for all tests. For each test, acceleration data was used to determine force vs. displacement and energy vs. displacement and failure mechanisms of the post-soil system were noted. Conclusions and recommendations were made that pertain to the embedment depth of posts impacted along the weak axis.


Highway Safety, Crash Test, Roadside Appurtenances, Compliance Test, MASH, Steel Post, Southern Yellow Pine, SYP, Weak Axis, Impact Testing

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