Review and Assessment of Past MnDOT Bridge Barrier Types

Many Minnesota bridges have older barriers or parapets that met the design code at the time of construction in the 1950s. Many of these bridge barriers no longer meet current strength and performance requirements of NCHRP Report 350 or the Manual for Assessing Safety Hardware (MASH). As the Minnesota Department of Transportation (MnDOT) begins to rehabilitate older existing bridges, a determination needs to be made as to whether the existing older type of barrier can remain in place or if it should be rehabilitated or replaced with a newer style barrier. This research documented the number of bridges in Minnesota that have One-Line Rails and type G, J, and F barriers and when they were built. Evaluations were then performed for both the structural strength and crashworthiness of each type of barrier and recommended guidance and evaluation criteria were developed to determine when an existing barrier should be upgraded or replaced. The main report is availale from the MnDOT web site at https://www.dot.state.mn.us/research/reports/2020/202024.pdf To obtain a copy of the appendices, contact research.dot [at] state.mn.us.