Russian Bearing Plate Design 3

[dozer]

In section 8.6 of SP 16.13330.2017, they have some equations for moments in the base plate. I'm using an English translation. They actually call them bearing plates. Anyway, this refers you to Table F.2 to get the alpha values that you plug into the equations. This in turn has three variables, a, b, and d[sub]1[/sub] which they define as short side, long side, and length of free side respectively. I've attached a sketch showing my guess as to what these are, except for d[sub]1[/sub]. I'm actually have an HSS column so I don't think it matters but I would still like to know what that is. Is anyone familiar enough with this code to confirm or set me straight? The other thing I'm guessing on is what they mean by "supported on four sides" and "supported on three sides". I'm imagining that they are thinking of it as the bottom of the base plate has a pressure load and the column that connects to the base plate acts as a support. Of course, this is just conjecture on my part because they can't be bothered to include a diagram that would clear things up.

 

[HTURKAK]

The relevant table is E2 copy and pasted below to find α values of plates supported on four sides and three sides ( one side is free)

a :short side ; b :long side; d1:length of the free side;or diagonal of the rectangle supported on two neighbor sides a1:length of the side perpendicular to the free side.

Regarding your attached sketch,sorry if i disapointed you but your estimation is not correct....

I just write ( base plate with gussets ) and searched ..one of the outcome;

If you look type 9 , there are 8 perimeter plates, the corner plates are supported on two sides, the other perimeter plates supported on three sides.. when the RHS is large enough while cantilever lengths small , the interior plate could be assumed four side supported etc...

I will suggest you design as per AISC dg1 then confirm ur size with SP 16.13330.2017..

 

[dozer]

Hturkak, thanks for the response. So it sounds like I don't have the notion of number sides supported right but I still don't get what the variables a, b, and d[sub]1[/sub] are. Could you sketch them on my drawing. Thanks.

 

[HTURKAK]

If your case is without gusset plates , the applicable formula is (102) which is

M= 0.5 * q * c **2 ( c is cantilever length)

You are expected to check the cantilever moments for C1 and C2..

For info. only, if the same base plate has gusset plates ;

In this case,
P1 plate = three sides supported

P2 plate = two sides supported

P3 plate = four side supported etc...

 

[dozer]

Thanks Hturkak. Your second figure does a good job of explaining what they mean by number of sides supported. So in that figure, the a and b dimensions shown would be for checking P3, right?

 

[HTURKAK]

If b> a; ( apparently yes..) a and b dimensions shown would be for calculating the design moment for 4 sides supposrted plate..

assume b= 150 mm a= 100 mm b/a=1.5 α 1= 0.081 , α 2= 0.050

Ma =0.081*q*100**2
Mb= 0.050*q*100**2

etc..

If you provide base plate info. for one of the real cases, i would reply .. but tomorrow..

 

[dozer]

Hturkak, I appreciate the offer but I've got it now. Thanks again for the help.