Flexural Behavior of a Cantilevered Slab Adjoined to a Crash Barrier on a Reinforced Concrete Bridge Deck

Existing structures require to be reassessed for resilience when subjected to evolving load conditions over the years. For example, in the case of a bridge deck, a sustained trend of increase in the weight of vehicles is translated into considerable increase in burden on the structure. The flexure of a cantilevered slab adjoined to the crash barrier is negatively affected because of the joint action of gravity and the transmitted dynamic action of an impact. The code-stipulated method of analysis used in the original design is based on applying an equivalent static force to represent an impact action. Many analytical investigations into the transmission of the impact force from the barrier to the adjoining deck slab as reported in the literature were also based on static analyses. As inertial resistance in dynamic conditions is not represented by static analyses, there are uncertainties regarding the margin of safety. The displacement-based method (DBM) features the use of algebraic expressions and was first introduced as a cost-effective tool to expedite dynamic analysis of rigid rockfall barriers. The effects of inertial resistance are accounted for, and predictions are consistent with numerical simulations. This study aims to adapt DBM to the design of vehicular crash barriers and the adjoining cantilevered slab on the bridge deck. The adaptation had to account for complications caused by crumbling of the vehicle and repeated contact on the barrier by the same vehicle in a collision event. The distinctive behavior of the angle of stress distribution within the cantilevered slab also needs to be taken into account. The accuracy of the model predictions is demonstrated by comparison against computer simulations of an experimentally validated numerical model in collision scenarios of a Test Level 4 truck.