Adding columns at mid span of crane girder

I’m working on adding a column on a crane runway beam at mid-span. Anyone have experience with this so I know what to look out for?


Fatigue is the issue. We once used 2-span crane girders for a new facility thinking we were saving both steel and erection costs.

Eight years later started having numerous end span connection failures with bolts, and could see tension when the crane was in the opposite bay, suffering fatigue failures.

Revised all of those connections and now at an additional 10 years in I expect to hear about fatigue problems at any time.

Dr. Fisher discusses the pros and cons of simple span vs continuous crane runway girders in AISC’s Design Guide No. 7. He recommends against continuous girders wherever fatigue needs to be considered:

AISC Design Guide 7 Industrial Buildings has been updated to its second edition. The guide is authored by Dr. James Fisher, Vice-President of Computerized Structural Design, and Chairman of the AISC Committee on Specifications. The updated guide provides complete coverage of structural considerations encountered in the design of conventional industrial buildings. The guide specifically addresses: Crane support Roof systems Roof truss framing Wall system design and support Framing schemes and systems Bracing systems Column anchorage Serviceability criteria and Fatigue concerns for crane supports

Above is a snippet.

@mtu1972, Thank you for the excellent reply and pointing this young engineer to the troubled spots.