Technical Papers - Container Handling
When extreme winds blow, cranes sometimes collapse. If one tie-down fails, a crane can break loose and roll down the rails, destroying neighboring cranes. Although other crane structural failures can occur during extreme winds, crane to-wharf tie-down systems are often the weak link for full crane collapse, and thereby deserve more attention.
Kuenz has been working on rail mounted gantry (RMG) cranes for intermodal terminals and river harbor terminals for many decades. As the market leader throughout Europe and North America, Kuenz has installed several hundred cranes throughout the world. Kuenz engineers in 2014 recognized that designing a RMG had become harder for the following reason: The cranes had become bigger. The largest Kuenz Cranes have a main girder length of over 140 metres, stack one over five, and their weight is over 700 tonnes. They are also faster, as the gantry speed for such a crane is 120 metres per minute, and trolley speed is 150 metres per minute. The wind surface of the structures had increased because of new codes and regulations. Customers were operating the cranes with wind speeds up to 28 metres per second.
As volumes have found their way up again, and additional terminal capacity is not easily realized, terminals return to seeking improvements in their internal processes. Based on our experience, which covers over 50 terminals where we assisted in performance improvement programs, it is possible to make substantial performance gains for internal processes. This is also recognized by the terminals themselves. A recent survey by Navis indicates that 76% of the respondents put process improvement as a ‘number one priority’ for terminal operations. Process improvements may be seen through productivity increases, gains in service levels, for example the reliability of port stay, capacity enhancement due to using space more effectively, and cost reductions. Without a doubt, double digit improvements can be attained in the performance-cost index.