Development of a new energy-absorbing roadside/median barrier system with restorable elastomer cartridges.

PDFTech ReportTRP-03-281-13NDOR DPU-STWD (94)Median barriersEnergy absorbing materialsElastomersFinite element methodHighway safetySimulationImpact testsRubberDeflection testsUnited StatesNebraska. Dept. of RoadsSchmidt, Jennifer D.Faller, Ronald K.Sicking, Dean L.Reid, John D.Lechtenberg, Karla A.Bielenberg, Robert W.Rosenbaugh, Scott K.Holloway, Jim C.Midwest Roadside Safety FacilityUnited States. Federal Highway AdministrationNTL-HIGHWAY/ROAD TRANSPORTATION-DesignNTL-SAFETY AND SECURITY-Highway SafetyUS Transportation CollectionA Manual for Assessing Safety Hardware (MASH) Test Level 4 (TL-4) energy-absorbing, urban roadside/median barrier was developed to reduce lateral vehicle accelerations below those observed during similar crashes into permanent concrete barriers. Several types of energy absorbers were evaluated for use in this barrier. Elastic polymers, or elastomers, have superior restorability, reusability, compressibility, and resistance to environmental effects. Finite element analysis simulations were used to further study the energy absorption and deflection of conical-shaped, cylindrical-shaped, and shear fender elastomer shapes. Component tests were conducted on rubber cylinders and marine shear fenders.The proposed design consisted of an open concrete rail with shear fender rubber posts that are anchored to a concrete foundation. The precast concrete beams measured 22 in. (559 mm) wide, 20 in. (508 mm) tall, and 20 ft (6.1 m) long and were spliced on top of 16-in. (406-mm) high, 14-in. (356-mm) wide, and 22-in. (559-mm) long shear fender posts, which were spaced at 10 ft (3 m) on center. Finite element analysis simulations also demonstrated that lateral vehicle accelerations were reduced by up to 33 percent for a MASH TL-4 small car impact into the new barrier as compared to a rigid concrete barrier. Simulations also demonstrated that the new barrier had adequate capacity to contain the MASH TL-4 single-unit truck. The cost of the barrier was estimated to be $175/ft ($574/m). The barrier should be further evaluated using finite element simulations and full-scale crash testing