Base Plate on Steel Beam (not Concrete)

[TheManWithoutAPlan]

Quick question (hopefully):

I have a long beam, with an adequate flange width. On this beam, I have several posts connected using a base plate with 4 bolts.

Should I design these base plates (axial and moment) using the guidelines in AISC Design Guide 1 for your standard base plate bearing on concrete? If so, do I just replace the concrete strengths for steel strengths or is there an entirely differently procedure?

Thanks!

 

[slickdeals]

Are these posts subjected to moments? Or only axial loads?
You need to give more information on the framing..

 

[msquared48]

TYou also should check to see if you need bearing stiffeners between the flanges of the beam at each post location.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[ahmedhegazi]

As quick answer, no you can not design using this way as if they are resting on concrete ,strain stress compatibility is different and force transfer mechanism is different ,you need to check guide lines for design of moment connections

 

[weab]

I don't find that the "base plate" matters much. The load will transfer through the stiff points.

If the web of the column matches the beam web, then you need to determine if the beam needs stiffeners below the column flanges, especially if this is a moment connection about strong axes. Load can travel from column to beam via the web and the flanges. There is a procedure for determining stiffener need somewhere in Blodgett.

If the webs don't line up, assume that all the load transfers through the column web and add beam stiffeners below the column web. Either way, a nominal base plate should suffice, say 3/8" or 1/2". At this point, the base plate and bolts are mostly construction tools.

 

[gottemewrong]

I would add, you have to make sure that your anchorage can withstand the moments transfer from shearing and pull-out...

 

[EngineeringAdam]

As others have stated, designing a steel base plate to a steel beam is not the same as a steel base plate to concrete.

AISC 360-05 Section J10 covers "Flanges and webs with concentrated forces". This section applies to your problem. In some instances stiffener or doubler plates are not required.

However, it usually is considered good detailing practice to add stiffeners to steel beams that are receiving column loads.