Numerical modeling of the effects of impact conditions, foundation stiffness, and cable pretension on the behavior of high-tension guard cable systems

Abstract

Cable barriers are one type of road restraint system commonly used on highways across the United States to contain and redirect errant vehicles and to prevent crossover accidents. These systems are typically tested under the provisions from safety manuals considering standard crash conditions (e.g., vehicle speed and impact angle). To understand the performance of cable barriers, it is important to evaluate the effects of non-standard crash and system conditions, including various vehicle speeds, impact angles, foundation material stiffness, and cable pretension loads. For that purpose, we created a set of full-scale finite element models in LS-DYNA to assess the effects of these non-standard conditions on the performance of high-tension cable barrier systems. The results from the models show that soft soils and under-tensioned systems yield higher cable deflections. Moreover, the results indicate that speeding vehicles colliding at non-standard angles increase cable tensions by up to 91% and cable deflections by up to 318%. These findings highlight the importance of evaluating cable barrier performance under more severe scenarios, which could lead to system failure and more severe collision consequences.