Sebastjan Bratina

Non-linear time-dependent analysis of cracked reinforced concrete bar:

A numerical model for analysis of crack appearance and propagation along reinforced concrete bar due to external load with the influence of aggregate bridging is presented. The governing equations are solved by a novel strain-based finite element method. The concrete cover and the reinforcing bar are each modelled separately. The tangential slip between the concrete and the reinforcing bar is fully accounted for, whereas the delamination is neglected. The discrete crack concept is employed, in which the aggregate bridging between two uncracked parts of concrete, separated by a crack, is accounted for by a non-linear spring. The adequacy, accuracy and the efficiency of the present model are verified in studies of reinforced concrete bar subjected to short-term tensile tests. It is found out that by the present numerical model, the spreading of cracks and varying of the length of reinforced concrete bar may be described relatively well. The model also enables the time-dependent analysis of the appearance and propagation of cracks due to restrained shrinkage and creep of concrete.