Performance evaluation of low-tension three-strand cable median barriers

The primary purpose of longitudinal safety barriers, such as cable barriers, is to contain or redirect errant vehicles that depart the roadway and thereby keep them from entering opposing travel lanes or encountering terrain features and roadside objects that may cause severe impacts. In this study, finite element analysis, vehicle dynamics analysis, and full-scale crash testing were performed to study the effects of sloped terrain on the safety performance of cable median barriers. A detailed finite element model of a three-strand cable barrier was developed and validated against a previously conducted full-scale crash test. The full-scale crash test and simulation were set up for an impact of the cable barrier with a 2,000-kg (4,400-1b) pickup truck at an angle of 25 degrees and an initial velocity of 100 km/h (62 mph). This setup is in accordance with NCHRP Report 350 guidelines for Test Level 3 safety performance. With this model, computer simulations were performed to assess the performance of the barrier under different impact scenarios and with different terrain profiles. Vehicle dynamics analyses were also conducted to compute the trajectory and dynamics of the vehicle as it crossed the sloped terrain and struck the cable median barrier. On completion of the computer simulation analyses, full-scale crash testing was performed to validate the results.