John D. Reid
Date of this Version
Bhakta, S.K., Anchoring and Stiffening Techniques for Portable Concrete Barriers, Thesis, University of Nebraska-Lincoln, Lincoln, Nebraska, November, 2017
Portable concrete barrier (PCB) systems are utilized on federal and state highways in circumstances such as placing adjacent to vertical drop-offs and in construction zones. PCB systems are most commonly used in a free-standing configuration, which are known to have relatively large deflections when impacted. Large deflections are undesirable when dealing with limited space. In order to allow PCBs to be used in space restricted locations, seven PCB anchoring and stiffening techniques were tested and evaluated as per Manual for Assessing Safety Hardware (MASH) testing standards. Results will allow the New Jersey Department of Transportation to update guidance for their use and installation of PCBs.
Techniques that restrict deflections included the use of anchorage and stiffeners on the PCBs. Pin and bolt anchor rods were used to anchor PCBs to road surfaces, and box beam rails and non-shrink grout wedges were used as stiffeners. Box beam rails were mounted on the back side of the system and non-shrink grout wedges were placed between barrier sections.
Full-scale crash tests indicated that anchoring of PCBs limits barrier deflection when impacted. Box beam stiffening of free-standing systems reduced dynamic barrier deflections from 40.7 in. to 33.0 in. The bolt anchored version of the PCB system had 4.9 in. of dynamic deflection, by far the least amount; additionally the vehicle was more stable than the pin anchorage systems.
Advisor: John D. Reid