Assessment of the Structural Integrity of the Portal Crane Elements After Long-Term Operation

Abstract

Evaluating the current technical condition and residual life of structures that may have reached or exceeded the end of their design life is a challenging issue in many industrial sectors. This paper focuses on the assessment of the structural integrity of structural elements of a seaport portal crane after operation for about 33 years. Test specimens were extracted from two crane elements, a jib (element A) as the most seriously loaded unit and, for comparison, a boom (element B) as the less loaded one, and machined in two different orientations, longitudinal and transversal. Both crane elements were made of a low-carbon rolled steel. The analysis was performed according to the FAD approach of FITNET Procedures. The basic level of analysis was used. For this purpose, the strength and fracture toughness characteristics of the steel from tested elements were determined experimentally. The strength and plasticity properties of the steel of both elements were similar. At the same time, the fracture toughness characteristics differ for the elements A and B and for the longitudinal and transverse specimen directions. The results of the FAD (FITNET) analysis performed for the elements containing a central crack loaded by tensile stress showed that they are not susceptible to failure. The relative length of cracks for which the critical state will be reached is also estimated.