MASH Evaluation of Minnesota Department of Transportation Bicycle and Pedestrian Bridge Rail and Hybrid Bridge Rail

Abstract

The Minnesota Department of Transportation (MnDOT) currently uses two bridge rail systems that are configured with a concrete bridge rail and a steel beam and post rail. The first is a concrete bridge rail with an attached bicycle and pedestrian rail and the second is a hybrid concrete bridge rail with a lower brush curb and an upper steel beam and post railing structure. Both bridge railings were previously developed and successfully crash tested under the safety criteria of NCHRP Report 350. MnDOT desired to evaluate these bridge railings to the current safety standards of AASHTO’s Manual for Assessing Safety Hardware (MASH). The concrete railing with a bicycle and pedestrian rail was crash tested to MASH TL-3, and it satisfied all safety criteria for MASH test 3-11. The hybrid bridge railing was subjected to all three prescribed crash tests in the MASH TL-4 matrix. The two tests with passenger vehicles were conducted near the downstream end transition to a concrete end buttress to evaluate vehicle snag, while the single-unit truck test was conducted near the middle of the rail to evaluate the railing’s strength. The hybrid railing passed all safety performance criteria.