Continued Development of a Non-Proprietary, High-Tension, Cable End Terminal System
Jennifer Schmidt, Bob Bielenberg, John Reid, Ronald Faller
A non-proprietary, cable guardrail system is currently under development for the Midwest States Pooled Fund Program. A cable guardrail end terminal was necessary to accompany the cable guardrail system. The objective of this research project was to develop design recommendations for the cable end terminal. Bogie testing that was previously completed on a design concept indicated delayed cable release, which was an undesired performance that led to vehicle instabilities. Several design changes were recommended for better end terminal performance and to reflect the changes made to the cable median barrier. An LS-DYNA model of the modified cable end terminal was developed. Simulations of 0- and 15-degree impacts on the end of the cable anchor bracket with a bogie model indicated that the cables would release easily and not induce vehicle instabilities. This behavior still needs to be verified through bogie and full-scale crash testing. Simulations of a 25-degree reverse impact between post nos. 2 and 3 with small car models indicated that cables did not release easily and may interlock around the car resulting in excessive vehicle decelerations or instabilities. Simulations of various line post designs found that the MWP and weakened MWP have lower forces and energies during impact than the S3x5.7 posts used in previous three-cable end terminals. This finding would suggest improved performance with respect to vehicle override and instability. However, vehicle simulations with multiple line posts impacted were inconclusive. Further design modifications, evaluation, and testing are recommended.
Highway Safety, Roadside Appurtenances, MASH, LS-DYNA, Computer Simulation, Cable End Terminal, High Tension