I have a project specifications review task for which I have a question regarding seismic drift limits for mill buildings with overhead bridge cranes. My associate insists that h/400 should be applied for the seismic drift limits, just as it would be for wind drift (measured at the crane rail elevation, per AIST TR-13). I say that an earthquake is an ultimate strength event, and this is too strict a limit. I believe that something more like h/60 is more appropriate. One isn't concerned with keeping a straight-tracking rail line during an earthquake. You only want to ensure that in addition to the building not collapsing, that the crane doesn't fall off the rails. This may take a lateral restraint or keeper to accomplish, but you still don't want to apply a limit that is too strict. What is the current thinking on this subject for mill buildings with heavy crane loads (100 tons, or more)?
Red Flag Submitted
Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action.
Reply To This Thread
Posting in the Eng-Tips forums is a member-only feature.
When was the last time you drove down the highway without seeing a commercial truck hauling goods?The ubiquity of these machines underscores the important roll they play in modern commerce. Download Now