Evaluation of concrete barriers with novel shock absorbers subjected to impact loading

Vehicle speeds have increased due to improved road condition. However, this increased speed can result in high energy collisions. Recently, a vehicle occupant in South Korea was killed by a fragment ejected from a concrete median barrier that was struck by a vehicle. The current design impact level of a concrete median barrier (CMB) is SB5-B (270 kJ). However, the impact level of the mentioned accident was estimated as over SB7 (2300 kJ). In the present work, a series of numerical analyses was conducted to reduce the fragmentations of CMB due to impact. Field test were utilized to verify the newly developed model of CMB in impact events. The wire-mesh reinforcements and increment of the cross section were considered as design modifications. In particular, a special device to absorb a significant collision energy has been developed without a dramatic increase in construction cost. This device consists of an empty space around the dowel bars which fix the barrier to the foundation. The empty space allows the dowel bars to deform to absorb collision energy. The performance of the new concrete median barrier equipped with the shock absorbing devices was verified by using carefully designed field test data.