Existing Crane Runway Beam

[baueng]

Have an existing W24x55 channel capped runway beam but must add A36 members to bring it up to same properties as a W24x76. How have you fellow engineers dealt with this issue. Add C's to the web, add bottom C ??
Thanks to all...

 

[Ron]

That depends on why you need it to reach those properties. If bending only, then plate on bottom flange will work. If other properties, tailor the location and type of add-on to the need, for instance if web crippling, add stiffeners....

 

[JAE]

Be careful of the details of what Ron suggests (which are all appropriate by the way). With a crane you have many cycles of loading and fatigue plays an important part in the design.

For example, if you cover plate the beam bottom flange, the welds connecting the cover plate should not be stitch welds but a continuous weld. The finish detail of the weld end at the ends of the cover plate can greatly affect the class of fatigue you fall under.

Check out the AISC Spec for the Fatigue section for more info.

 

[Ron]

JAE's right (He has a habit of that!). Must consider the fatigue aspect. Transverse welds are a particular problem, thus JAE's warning about terminations.