Development of a Transition Between Free-Standing and Reduced-Deflection Portable Concrete Barriers – Phase I
Mojdeh Asadollahi Pajouh, Jennifer Schmidt, Bob Bielenberg, Ronald Faller
The objective of this research effort was to develop a Manual for Assessing Safety Hardware 2016 (MASH) Test Level 3 (TL-3) transition between the recently developed non-anchored, reduced-deflection, F-shape, Portable Concrete Barrier (PCB) system and free-standing, F-shape PCB segments. The reduced-deflection PCB system consisted of a cap plate bolted across the PCB joint and continuous tubes running along the sides of the barriers, which was successfully crash tested under MASH 2016 TL-3. A transition was developed between the reduced-deflection PCB and free-standing PCB systems through engineering analysis and LS-DYNA computer simulation. First, the continuous steel tubes in the reduced-deflection system were tapered down to match the surface of the free-standing PCB segments at a 1:6 lateral-to-longitudinal rate to reduce the potential for vehicle snag. An HSS 3½x3½x⅜ steel tube was added between adjacent PCB segments at the base of two joints upstream from the reduced-deflection system to improve transition performance. Simulations were performed to determine the critical impact points (CIP) for full-scale crash testing of the selected design. It was recommended to conduct three full-scale crash tests, two tests with test designation no. 3-21 with a 2270P pickup truck vehicle, and one test with test designation no. 3-20 using an 1100C passenger car to evaluate the system. For test designation no. 3-21, two impact locations were deemed critical, one at 4.3 ft (1.3 m) upstream from the transition joint (i.e., upstream from the end of the free-standing PCB and upstream from the reduced-deflection PCB system), which is the MASH 2016 recommended CIP, and one at 55.7 ft (17 m) upstream from the transition joint. For test designation no. 3-20, the CIP was recommended to be 3.6 ft (1.1 m) upstream from the transition joint.
Highway Safety, Roadside Appurtenances, MASH, Computer Simulation, LS-DYNA, Temporary Concrete Barrier, Portable Concrete Barrier, Reduced Deflection, Transition