ANALYSIS BEARING CAPACITY AND FRACTURE IN BENDING ELEMENTS UNDER THE ACTION OF CYCLIC LOADINGS

Abstract

The influence of static and frequently repeated loads on the bearing capacity and crack resistance of diagonal sections of reinforced concrete beams on crushed stone and calcareous sand is investigated. Two types of fatigue failure were obtained: fatigue concrete shear fracture over the tip of diagonal crack and fatigue break of cross rods, with following concrete destruction over the tip of diagonal crack. The destruction process is based on multiple concentration of micro-cracks, which lead to the main crack. So we have the necessity to add with the new strength calculation methods, taking into account the laws of crack birth and crack development and new material characteristics that evaluate the stage of fatigue failure. It is necessary to know the influence of different factors on the rate of the main crack’s development. The dimension of cross distance, the level of cyclic loading and the coefficient of cycle asymmetry have the great influence on the main crack’s development and failure.