Representation of damage caused by fragmentation impact in design and analysis of reinforced concrete barriers

This paper presents methodology and calculation models that aim to enable a more realistic design of reinforced concrete (RC) protective barriers. The proposed methodology considers the global effect of fragmentation impact, which is commonly neglected in current design procedures. The analysis considers a non-uniform, two-zone damage model over the span, where the damage caused by fragment strikes is represented in the model in terms of reduced equivalent cross-section heights. It is shown that one of these zones, denoted ‘intense strip’, is significantly more damaged than the other zone. This representation of a damaged barrier, inside and outside the intense strip, should be considered for its global analysis. The proposed model was validated by comparison of its predictions with measured static load-deflection curves of plate specimens, which had been damaged by fragmentation impact in previously performed field tests. The models that are described in this paper, which provide an equivalent slab dimensions, can be used in further, more realistic dynamic analysis of the structural behavior of RC elements, subjected to combined blast and fragmentation loading.