Crash Testing and Evaluation of the Modified G4(1S) W-Beam Guardrail on 2:1 Slope (405160-4-1)

The objective of this study is to assess the performance of the modified G4(1S) guardrail system when placed on a slope equal to 2H:1V. This guardrail system is to be evaluated under the conditions and criteria of NCHRP Report 350 TL-3. The guardrail system needs to be placed on the slope with such an offset that the face of the W-beam rail is aligned with the slope break. The first step was to evaluate the performance of guardrail posts with various embedment lengths when impacted by a bogie vehicle. The next step was to build and calibrate finite element models of selected posts and then use them in full-scale simulations of candidate guardrail systems. Based on the results of the cases simulated, the candidate design chose for testing was a W-beam (12 gauge) guardrail system with 8-ft posts placed on a 2H:1V slope. The posts are placed 1-ft off the slope break and spaced at 3 ft-1.5 inches (half the standard spacing for a strong-post W-Beam guardrail). In the full-scale crash test, the 2000P vehicle was contained and redirected. However, after exiting the installation, the vehicle rolled onto its left side. Due to this rollover, the guardrail on 2H:1V slope did not meet the criteria for NCHRP Report 350 test 3-11.