MASH Test No. 3-10 of a Non-Proprietary, High-Tension, Cable Median Barrier for Use in 6H:1V V-Ditch (Test No. MWP-9)
Date of this Version
Asadollahi Pajouh, M., Lechtenberg, K.A., Faller, R.K., Holloway, J.C. Bielenberg, R.W., Rosenbaugh, S.K., and Reid, J.D. (2018.) "MASH Test No. 3-10 of a Non-Proprietary, High-Tension, Cable Median Barrier for Use in 6H:1V V-Ditch (Test No. MWP-9)" NDOT Research Report #TRP-03-360-18.
The Midwest Pooled Fund Program has been developing a prototype design for a non-proprietary, high-tension, cable median barrier for use in a 6H:1V median V-ditch. This system incorporates four evenly spaced cables, Midwest Weak Posts (MWPs) spaced at 8 to 16 ft (2.4 to 4.9 m) intervals, and a bolted, tabbed bracket to attach the cables to each post. Full-scale crash testing was needed to evaluate the barrier’s safety performance. According to the Manual for Assessing Safety Hardware 2016 (MASH) testing matrix for cable barriers installed within a 6H:1V median V-ditch, a series of eight full-scale crash tests are required to evaluate the safety performance of a system.
Several previous tests have failed due to the posts penetrating into the occupant compartment. In order to mitigate the floor pan tearing, a modified MWP was designed. Test no. MWP-9 was conducted on the modified barrier system, consisting of MWPs with 3⁄4-in. (19-mm) diameter weakening holes at the ground line. Additionally, a two-part cap with a single retainer bolt was added to the top of the posts. The cap shielded the free edges of the MWPs during the post-to-vehicle contact. This test was conducted according to MASH 2016 test designation no. 3-10 and utilized an 1100C small car impacting the barrier on level terrain. The vehicle was contained by the system. The two-piece cap mitigated the floor pan tearing. However, one cable (cable no. 3) snagged on the cap retainer bolt and caused two cables (cable nos. 3 and 4) to become interlocked with the left-side A-pillar on the impact side of the vehicle, which resulted in excessive A-pillar crush. Therefore, test no. MWP-9 was deemed unacceptable. However, the two-part cap demonstrated that a closed-section post should be capable of mitigating floor pan tearing.