Development and Testing of a Concrete Barrier Design for Use in Front Slope or On MSE Wall (405160-00013-2)

The objective of this research was to restrict lateral deflection of a concrete barrier when placed adjacent to steep slopes or on top of Mechanically Stabilized Earth (MSE) walls, without using a concrete moment slab. The final design was required to incorporate 20-ft long single slope barrier segments with grouted rebar grid connection. The researchers first evaluated the performance of the free-standing barrier with grouted rebar-grid connection using a smaller scale bogie impact test and simulation analysis. It was determined that the grouted rebar-grid connection did not provide enough strength to restrict lateral deflections. The researchers then evaluated restricting the deflection of the barrier be embedding it 10 inches in soil. The barrier was placed in from of a 1.5H: 1V slope. The offset of the barrier from the slope break point was restricted to 2 ft. Another phase bogie testing and simulation analysis was performed to evaluate the performance of the grouted rebar grid connection in the embedded configuration. Results of the simulation analysis showed that the embedded barrier system will result in acceptably reduced lateral deflections. A 100-ft long installation of the embedded single-slope barrier in front of a 1.5H: 1V slope was subsequently crash tested under Manual for Assessing Safety Hardware (MASH) criteria. The design performed acceptably according to the requirements of MASH and the maximum static barrier deflection was 5.5 inches. While the barrier was tested in front of a 1.5H: 1V slope, due to a relatively small lateral deflection, it is also recommended for use on top of MSE walls as long as a minimum 2-ft lateral offset is maintained between the back of the barrier and the wall.