Dynamic Impact Testing of S76X8.5 (S3X5.7) Steel Posts for Use in Cable Guardrail Systems
REPORT NUMBER
TRP-03-186-07
AUTHORS
Cody Stolle, Ronald Faller, Karla Lechtenberg (Polivka)
PUBLICATION DATE
2007-12-19
ABSTRACT
Dynamic impact testing of S76x8.5 (S3x5.7) steel posts at various embedment depths has been detailed, and the results presented. A total of 10 bogie tests were performed, with post lengths varying from 1,778 mm (5 ft-10 in.) through 2,286 mm (7 ft-6 in.). For each bogie test, raw acceleration data, obtained from the accelerometers, was filtered and used to create force-displacement and energy-displacement plots. From the energy-displacement graphs, the average post-soil forces were calculated for a 1,016-mm (40-in.) displacement at the center cable height. Post-soil forces were then compared to the post capacity of the standard 1,778-mm (70-in.) long cable post with an attached soil plate, and the post-energy relationships analyzed to determine if a suitable length of S76x8.5 (S3x5.7) steel post could replace the more costly standard cable post with attached soil plate. From these comparisons, it was determined that the 1,981-mm (78-in.) long post with 1,067 mm (42 in.) embedment depth had comparable performance to the standard cable post. Therefore, and in order to verify, it was recommended that the S76x8.5 (S3x5.7) cable post with a total length of 1,981 mm (78 in.) be crash tested in a cable barrier system.
KEYWORDS
Highway Safety, Steel Cable Post, Roadside Appurtances, Bogie Crash Testing, Cable Guardrail System