The high level of wear of the fixed production assets of engineering constructions and metalwork as well as the operation of objects in beyond design basis terms could cause the damage emergency due to the great amount of damage and loss. The intensive accumulation of damageability and the long terms of operation with fatigue cracks are characteristic of subcrane beams of bridge cranes of the heavy operating modes under the conditions of cyclic loading. The article presents the results of numerical researches of the bearing ability of a subcrane beam in regular and emergency operation on the basis of the final element analysis of the stress-strain state. By the results of the calculations, the distributions of tension intensity of stresses arising at the upper zone of a subcrane beam wall along its length at various values of eccentricity of the loading caused by the rail displacement from a vertical axis of the beam section are obtained. It has been found that the increase of the loading eccentricity could lead to the accelerated development of the emergency situation with the sharp decrease of the load-bearing capacity of the subcrane beam. The consistent patterns of the stress-strain state of the beam wall due to a number of factors in normal and in emergency operation have been determined. It has been shown that the crack could lead to the redistribution of stresses in the subcrane beam wall. The dependence of a crack growth rate on the size of eccentricity of beam loading has been considered and intensity of stresses arising at the top of the crack. Based on the traditional methods of fracture mechanics, the analysis of the residual resource of subcrane beams with operational defects has been made.
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