Umnutzung von Bestandskranbahnen (Teil 1)

New usage of existing crane runways.

Strengthening of existing crane runways for future use is a common problem to be solved by structural engineers. After determination of their technical condition it has to be decided whether replacement of the crane runway is necessary or repair and further usage of the girder are possible. In the first part of the article a wide range of options is presented, that might be capable of creating conditions for the further use of the crane runway. To increase the cross section of the crane runway is an obvious way, but not the only one and in some cases not even the best. To enable a further usage of the crane runway, some details of the crane design can be changed or electronically the way the crane rolls and handles payloads.
The second part of the article focusses on the fatigue strength of crane runways. The material structure of crane runways with heavy fatigue loading may be pre-damaged due to the previous usage even if there are no cracks detected. Possibilities are shown on how to combine the fatigue damage caused by previous and further use to estimate the remaining life of the crane runway. In retrospect the assumptions concerning the severity of the fatigue loading, which have to be made during the planning process of the crane runway, sometimes turn out as to be too unfavourable. In those cases, a reclassification of the crane fatigue loading can be possible. A lower classification of the crane causes a longer period of use.