Design and Evaluation of Sleeve Nut through Tensile Testing
Karla Lechtenberg, Ronald Faller, Cody Stolle, Mojdeh Asadollahipajouh, Erin Urbank
The Midwest Pooled Fund Program has been developing a prototype of a non-proprietary, high-tension, four-cable, median barrier for use anywhere 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 2016) 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. Previous full-scale tests conducted on this system have indicated potential cable snag on the cable bracket nuts and exposed threaded studs. Cable snagging can limit vertical cable movement and post deflection, which could then lead to significant occupant compartment deformation and penetration, and therefore failed tests. Consequently, new nut designs were investigated for use with the cable brackets in attempt to eliminate cable snagging. Tensile testing was performed on multiple sleeve nut prototypes and all were deemed acceptable.
Highway Safety, Crash Test, Roadside Safety Appurtenances, MASH, Cable Barrier, Sleeve Nut, Closed-Section Post, Tensile Testing