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April 1989
by Michael A. Jordan
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.
March 1995
by Arun Bhimani
Case studies of three crane upgrade and relocation projects demonstrate the practicality and effectiveness of using present cranes in new settings. Procedures for undertaking a crane modification are discussed, and guidelines for the cost are presented.
May 1997
by Arun Bhimani and Simo Hoite
New cranes are replacing old cranes, especially at the larger and older European, U.S., and Asian ports. Increasingly, these older cranes are put up for sale, and buyers are finding some good bargains. This paper looks at some of the typical characteristics of available used cranes, discusses modification options and their costs, and looks at the issues crane buyers and sellers need to consider when entering the used crane market.
Original: February 1999
Reprinted: May 2008
by Michael A. Jordan
Since 1975, the development and use of structural maintenance programs have improved the reliability of heavily used container cranes. The programs, based on the principles of fracture mechanics and probabilistic methods, are designed to locate and detect fatigue cracks.
The paper 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. The paper also gives recommendations for what to do and what not to do when cracks are detected, describes typical crack patterns and good and bad fatigue details, and presents three specific examples of typical cracks and remedies based on actual occurrences.
April 2001
by Kenton Lee, Feroze Vazifdar, and Simon L. H. Wong
Useful structural life is the remaining time a crane can be operated with an acceptable risk of failure. This time can be extended using a structural maintenance program. This paper and presentation present the methods used to develop a structural inspection program and to evaluate useful life using statistical analysis and the principles of fracture mechanics. A theoretical overview is followed by a case study of useful structural life assessment of eight dockside container cranes for Hong Kong International Terminals.
January 2002
by Feroze Vazifdar
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.
Liftech’s techniques of predicting and prolonging the structural life of used cranes are discussed in this paper. Liftech provided this service for quayside container cranes and rail mounted gantry cranes in Hongkong International Terminals, Hong Kong. These cranes will be presented as case studies.
February 2003
by Feroze Vazifdar and C. Davis Rudolf
Presented at the 2003 TOC Asia in Hong Kong.
August 1996
by Michael A. Jordan
Sooner or later, duty cycle container cranes develop fatigue cracks.
This paper explains what is happening to the world's older cranes and what ports must do to deal with the problem.
April 1993
by Arun Bhimani
Container crane owners and operators often find they must modernize their cranes to keep existing tenants or attract new ones. However, modernizing cranes can be disruptive to the shipping operations. Many owners look for alternates to avoid the disruptions or defer the modernization until a suitable time.
In order to seize an opportunity to expand their business, the Port of Oakland modernized their cranes with minimal disruption to the operator. This paper describes the Oakland project and offers some information that may help you make an objective evaluation of your situation.
June 1992
by Michael A. Jordan
When operations demand more than an existing dockside container crane can provide, the choices are to buy a new crane or rejuvenate a middle aged one. Which is more profitable? Finding the answer requires investigation and objective evaluation.
This paper offers some information that will help you make your investigation and choose.
January 2005
by Patrick McCarthy
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.
For a crane structure, maintenance includes frequent visual inspection, periodic non-destructive testing (NDT), and repairing any cracks or damage caused by regular usage or accidents. Regular maintenance is not only essential for a reliable crane but is recommended to justify the allowable stresses. The crane is not designed to last forever with no limits on its fatigue life. This is impossible. Cranes will experience fatigue crack growth and if used indefinitely without inspection will eventually fail. The designer and operator must recognize this.
This article discusses the rationale behind structural maintenance programs for quayside container cranes.
March 2005
by Feroze Vazifdar
Presented at the TOC Asia 2005 conference in Hong Kong, China.
This presentation discusses fatigue design philosophy, useful life analysis, structural maintenance, and shows repair examples.
Fatigue cracks occur and can be catastrophic if not repaired in time. Cracking can be controlled with proper design, workmanship, quality control, and a proper structural maintenance program. Structural useful life analysis can be used to predict future cracking so the owner can decide the best course of action.
This article discusses the rationale behind structural maintenance programs for quayside container cranes.
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