Category: Cranes: Structural Maintenance

Published in World Port Development.

Published in World Port Development, Container Crane & Component Supplement

Presented at PEMA 2014 Annual General Meeting in Amsterdam

The booklet explains the fundamental principles of general yielding, fatigue crack growth, brittle fracture, the concepts of stress intensity and fracture toughness, fatigue design criteria, the statistical basis for fatigue criteria, and the selection of inspection intervals.

This presentation discusses fatigue design philosophy, useful life analysis, structural maintenance, and shows repair examples.

Structural maintenance is most efficiently, i.e., cost effectively, achieved through varying inspection intervals for the different crane components, depending on predicted cumulative “damage.” In this sense, cumulative damage refers to fatigue crack growth, not accidental damage.

So you have an older crane that has not undergone regular structural inspection—what are your options? You can do nothing and blindly use the crane, which, as we will explain later, is risky. Or you can assess its condition to find out how much structural life remains. Once you know the condition, you can decide how to best use the crane.

Welded steel structures always contain fatigue cracks, usually at welded joints. The behavior of fatigue cracks, basic fatigue design, and common misconceptions about fatigue loading are discussed in this paper.