Experimental and Numerical Analysis of Fracture in Prestressed Concrete

This work examines the crack initiation and propagation in Prestressed Concrete (PC) beams by a combined experimental and numerical approach. Four-point bending tests performed on PC sleepers lead to the formation of multiple cracks, in a number that depends on the specimen. The location of each fracture and its growth with time is monitored by Digital Image Correlation (DIC). The experiments are simulated by a finite element approach, reproducing the concrete response by a smeared crack model. The model parameters are calibrated to match the experimental moment deflection curve. In this study, only the beam segment enclosing one crack is discretized. The effect of the external load is simulated by applying the horizontal displacements returned by DIC at the vertical boundaries of the analyzed region. Thus, uncertainties are reduced since there is no need to discretize the PC element in its whole length, to include the supports and the loading plates, and to simulate the interactions between the different components.