Development of Transition Between Free-Standing and Reduced-Deflection Portable Concrete Barriers

Portable concrete barriers (PCBs) are often used in applications where limited deflection is desired during vehicle impacts, such as bridge decks and work zones. In an earlier study, a reduced deflection, stiffening system was configured for use with non-anchored, F-shape portable concrete barriers and was successfully crash tested under Manual for Assessing Safety Hardware (MASH) safety performance criteria. However, details and guidance for implementing this barrier system outside the length-of-need, including within transitions to other barrier systems, was not provided. The focus of this study was to develop a crashworthy transition design between the reduced deflection, F-shape PCB system to free-standing, F-shape PCB segments using engineering analysis and LS-DYNA computer simulation. First, the continuous steel tubes in the reduced deflection system were tapered down to the surface of the free-standing PCB segments to reduce the potential for vehicle snag. In addition, steel tube spacers were added at the base of the two joints upstream from the reduced deflection system to increase the stiffness of adjacent freestanding PCBs. Simulations were performed to determine the critical impact points for use in a full-scale crash testing program. It was recommended to conduct three full-scale crash tests, two tests with a 2270P pickup truck vehicle and one test with an 1100C passenger car to evaluate the proposed design system impacted at the recommended critical impact points.