Modelling cracking in reinforced-concrete beams using beam finite elements with embedded discontinuity

This work presents a novel embedded discontinuity layered beam finite element with the ability to predict crack occurrence and development in reinforced-concrete beams. A transversal crack is embedded in an element in a manner that it opens at a predefined position when the tensile concrete strength at layer's mid-depth is reached. The use of layers allows the crack to propagate through the depth of the beam. The cracked layers involve discontinuity in the position vector of the layer's reference line as well as a discontinuity in the cross-sectional rotation, equal to the crack-profile angle. Reinforcement is treated as an additional layer of finite cross section and zero thickness with its own constitutive law implemented involving the standard beam kinematic hypotheses and a non-linear bond-slip relationship. The applicability of the new element is investigated on a four-point bending beam test for monotonically increasing loading.