Probability calculation applied to potential failure zones of the bridge girder of metallurgical crane

This article addresses the examination of potential failure zones of metallurgical casting crane with 300 ton lifting capacity. Complex system of static loading applied to a 24-meter long and 3-meter high girder was regarded as the object of examination. Girder components were manufactured from steel Bст3сп5. Calculation was first performed using the “LIRA-SAPR” automatic design system to obtain the actual stresses and displacements. Probability density for limit and safe actual stresses was then built based on previously conducted research and simulation. It was established that further operation under such loads could result in a failure. After analyzing the level of loading applied to the crane girder components and assemblies, the decision was made to reinforce them with a truss bar. The recalculation demonstrated that such decision was adequate and that the crane could be further operated without failure. The presented information can be used in the technology related to extending the service life of metallurgical cranes most of which are operated after the expiry of their warranty period.