New Wide Flange Beam Bearing on Existing Concrete Pedestal

[AndEI]

The owner of a building is replacing a roof cooling tower that is currently supported on four 12"x12" concrete pedestals. The new cooling tower has a smaller footprint, and we were hired to provide structural steel support framing for the cooling tower. I was hoping to get some input on a couple of details for the attachment of a new steel W8x31 (controlled by bolt gage for the cooling tower attachment) to the existing concrete pedestals.

Option 1 is to D&E threaded rods into the pedestal, provide 2" of grout, and bear the W8x31 on the pedestal. We would provide hole sizes given in Table 14-2 in the W8x31 flange.

Option 2 is to post install a bent plate on top of the pedestal, with the anchors installed in the sides of the pedestal. We would then field weld the W8x31 to the bent plate. Someone else in the office used this detail with enough success, but I would like to avoid field welding since everything is galvanized.

Any and all thoughts welcome.

 

[phamENG]

Either one should work. If you really want to do the saddle, you can have that shop welded and galvanized after fabrication. Be mindful of your inside bend radius on the bent plate - you can't be tight to the side and top unless there's a chamfer on the pedestal.

 

[Once20036]

The first option seems much easier - what's the downside that you perceive to drive you toward the second option?
Aside from that, if you don't need grout in the second option, why do you need it in the first option?

 

[XR250]

The first option makes it tough to drill and install the bolts. The second option would be better with a grout layer to mitigate the bend radius.