Experimental and numerical research on cracking characteristics of medium-reinforced prisms under variable uniaxial degrees of elongation

The main objective of this research is to study the phenomenon of cracking in reinforced concrete (R/C) structural elements, particularly the columns and walls (especially the extreme regions of walls, namely the boundary columns). Various parameters affecting cracking phenomena were studied, e.g. load influence, tensile strain, etc. It has to be noted that load application is a monotonic axial tensile loading that simulates the strain condition taking place at the boundary edges of reinforced concrete seismic walls. Specifically, this type of loading simulates the tensile loading that takes place during the first semi-cycle of loading under dynamic seismic events. Experimental research was carried out by the construction and usage of a group of 4 experimental specimens, subjected to different degrees of elongation. This test group examined the tensile parameters and how they affect the cracking. The test specimens in question were all reinforced with the same medium longitudinal reinforcement ratio (2.68 %) and subjected to tensile degrees 10%0, 20%0, 30%0 and 50%0. Significant conclusions are reached on cracking, e.g. its extent, the size of the cracks, their positions, minimum crack width, maximum crack width, average crack width, and number of cracks.