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Testing of W152x23.8 (W6x16) Steel Posts-Soil Embedment Depth Study for the Midwest Guardrail System (Non-Proprietary Guardrail System)




Beau Kuipers, John Reid




Dynamic impact testing of W152x23.8 (W6x16) steel posts at various embedment depths has been detailed and the results stated. The results are consistent within each group of tests as can be seen by the near equal profile of the force-deflection curves. The soil used conformed to AASHTO M 147-65 Gradation "B" specifications. Failure of the post was dependent upon embedment depth. In tests where the embedment depth was 101.6 cm (40 in.) or deeper, the soil failed with occasions of slight yielding within the post. When the embedment depth was 93.98 cm (37 in.) or less, the post pulled out of the ground. Based on the results presented herein, it appears that the 101.6 cm (40 in.) embedment depth is the depth of choice for the Midwest Guardrail System (MGS), sometimes referred to as the non-proprietary guardrail system (NPG). The force levels and energy absorbed at an embedment depth of 101.6 (40 in.) was comparable to the current W-Beam guardrail system standard embedment depth of 109.2 (43 in.). Force levels and energy absorption were significantly reduced when the embedment depth was reduced further to 94 cm (37 inches).


Highway Safety, Strong Steel Posts, Roadside Appurtenances, Bogie Crash Testing

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