Flexural Behaviors of Concrete Beams under Monotonic and Cyclic Loadings

In order to study the flexural behaviors of concrete beams under monotonic and cyclic loadings, three-point bending tests were performed on center-notched beams made of normal strength concrete (NSC) and high strength concrete (HSC) respectively. From the P-CMOD curves of the beams, it was found that nonlinear deformation occurred before the cracking load. The P-CMOD curves were further normalized to characterize the flexural performance of the beams by a nominal stiffness EIR. Based on the normalized EIR-CMODR curves, formulas for predicting the flexural behaviors of the beams were proposed. With these formulas, the P-CMOD curve of a specimen can be estimated if only the specimen dimension, E, Pmax and CMODun are known. Finally, the P-CMOD hysteresis curve was analyzed, a hysteresis loop model was proposed, and the hysteresis curve of XFEM was adjusted with Python to make it closer to the experimental results.