In this study, non-linear finite element simulations were conducted to evaluate the performance of the current NCDOT cable median barrier (CMB) and two retrofit CMB designs (named “Sixth Design Retrofit” and “Four-cable Design Retrofit”) placed on a 6H:1V sloped median. The aim of this research was to investigate possibility of replacing the current CMB design with one of the two retrofit designs. All three CMB designs were evaluated under MASH TL-3 conditions, i.e., under the impacts of a 1100C passenger car and a 2270P pick-up truck at 100 km/hr (62 mph) and a 25-degree impact angle. The CMBs were impacted from both front-sides and backsides at two different impact locations: 1) on a post in the CMB mid-span, and 2) at the midpoint between two adjacent posts in the mid-span. The CMB performance was evaluated using vehicular responses specified in MASH, i.e., the exit-box criterion, MASH evaluation criteria A, D and F, exit angle, yaw, pitch and roll angles, and transverse velocities.
The simulation results demonstrated the effectiveness of each of the three CMB designs on a 6H:1V sloped median under vehicular impacts. The simulation results showed that cable heights and the number of cables played an important role in the effectiveness of CMBs when placed on sloped medians. The finite element modeling and simulation works were shown to be both effective and efficient and can be used to study crash scenarios that are difficult and/or extremely expensive to conduct with physical crash testing.
