Portal Frame with crane runway girder
Portal Frame with crane runway girder
(OP)
Fatique check is required when designing heavy duty crane runway girder. What about the main portal frame structure? The portal frame members and their connections would also undergo repetitive loading as the crane travels back and forth. Is it necessary to check the portal structure for fatique?






RE: Portal Frame with crane runway girder
Look at your building. Can the loads which rack the frames come from any direction? Determine the fatigue range for your frames and then apply the criteria for your building members
RE: Portal Frame with crane runway girder
RE: Portal Frame with crane runway girder
Unlike connections in normal structures, where forces and displacements reach their maximum value perhaps a few times in the structure's life, the elements supporting a crane runway girder are repeatadly subjected to near-maximum value forces, translations and rotations.
These elements should be detailed to prevent them undergoing a large amount of bending or stretching in service.
RE: Portal Frame with crane runway girder
My concern would be the connection of the bracket to the rigid frame column more than the column itself. I recall my college professors and experience tell us all that most failure occurs at the connections.
Having said that, I would determine the number of cycles and the approximate the welded connection and then compute the allowable stress based on AISC ASD or LRFD.
Regards
RE: Portal Frame with crane runway girder
So, in general, fatigue design of portal frames with cranes is required unless exempted by the code.