Nebraska LTAP


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Meyer, D.T., Asadollahi Pajouh, M., Lechtenberg, K.A., Faller, R.K., Bielenberg, R.W., and Holloway, J.C. (2018). "Phase II Evaluation of Floor Pan Tearing for Cable Barrier Systems", NDOT Research Report TRP-03-359-18.


The objective of this research effort was to mitigate the potential for floor pan tearing and penetration into the occupant compartment by modifying the posts utilized in a prototype cable barrier system. A series of dynamic component tests were conducted on the modified Midwest Weak Post (MWP). A bogie vehicle was equipped with a simulated floor pan designed to replicate the height, thickness, and strength of the floor pan of a Kia Rio. Two methods of post modification were investigated, including edge protection on the top of the MWP as well as weakening of the MWP at the ground line.

Two methods of edge protection were tested, including a 31⁄2-in. x 21⁄2-in. x 3/16-in. (89-mm x 64-mm x 5-mm) thick steel tube cap and 21⁄8-in. x 13⁄8-in. x 7-gauge (54-mm x 35-mm x 5-mm) bent steel plates. Weakening of the MWPs was accomplished through two 3⁄4-in. (19-mm) diameter holes drilled through the weak-axis of the posts at the ground line. Both methods of edge protection showed potential for mitigating the propensity for floor pan tearing. In all but one test, the posts caused creasing on the simulated floor pan. In one test, test no. MWPFP-23, the edge protector connection bolt sheared and allowed the posts’ free edges to contact and tear the simulated floor pan, which would not be expected in full-scale crash testing with the 1100C vehicle. The bogie testing of MWPs with 3⁄4-in. (19-mm) diameter weakening holes with steel plate edge protectors mounted at the top of the posts resulted in only minor creasing on the simulated floor pan. Thus, a combination of weakening holes and edge protectors using steel bent plates at top of the MWP was recommended for further evaluation through full-scale vehicle crash testing.