Currently, most non-proprietary portable concrete barrier (PCB) systems in use on the nation’s highways are New Jersey safety shape or F-shaped barrier segments, composed of reinforced concrete and simple pinned connections that allow rotations between segments. Three problems exist with this basic design: (1) the stepped, sloped face of the barrier often allows impacting vehicles to climb and roll as they impact the barrier, causing vehicle instabilities that can result in rollover; (2) the segment connections allow significant rotations prior to loading the adjacent segment, resulting in high lateral deflections upon vehicle impact, up to 80 in. for impacts with pickup trucks. Where deflections must be limited, anchoring or pinning of the segments into the pavement is required, which impedes installation and removal, exposes workers to traffic hazards, and causes pavement damage and (3) the bottom toes of the barrier segments are often under-reinforced, which often results in the toes fracturing off the segments when loaded during impacts or even during transportation and placement of the segments. Significant damage to the toe of a segment impairs barrier performance, thus requiring segments to be replaced often.
In an effort to encourage state DOTs and hardware developers to advance their hardware designs, the Federal Highway Administration (FHWA) and AASHTO have collaborated to develop a MASH implementation policy that includes sunset dates for various categories of roadside hardware. The new policy will require that devices installed on federal-aid roadways after the sunset dates must satisfy MASH. Temporary work-zone devices, including portable barriers, let on projects after December 31, 2019, must have been successfully tested to MASH 2016. Devices used on projects let before this date may continue to be used throughout their normal service lives. Thus, an opportunity exists to develop a high-performance PCB system that meets the MASH safety criteria as well as address the deflection, stability, and durability concerns of most current PCB designs.
The objective of this research project is to develop a new, high-performing PCB design that is as economical as widely used PCB existing systems and meets the following criteria: (1) satisfy MASH Test Level 3 crash testing requirements; (2) reduce the potential for post-impact vehicle instability, specifically reduced roll and vehicle climb as compared to existing PCB systems; (3) minimize system deflections (less than current NCHRP 350 deflections and to the greatest extent practical); (4) are free-standing with no anchoring or connections to the ground required, but anchoring available; (5) ensure installation and removal times comparable to existing PCB systems; (6) transport and delivery comparable to existing PCB systems; (7) increase durability over existing PCB systems; and (8) are non-proprietary.