Circular Anchor Bolts 7

[macan1]

I am looking for Circular Anchor Bolts design software/handbook/technical papers/reference.
The circular anchor bolts are embedded in concrete pedestal, and subject to moment, shear, axial force.
Thanks,

 

[structuresguy]

Is the base plate raised up so that the bolts are exposed and taking the full compression loads? If so, the analysis by hand is fairly easy. Choose a neutral axis thru the base which results in worst case condition, usually thru an opposite pair of bolts. Then using a linear strain distribution across the neutral axis, you can calculate the contribution of each of the bolts at different distances from neutral axis to the moment resistance of teh assembly. I have not done one in a while, but I seem to remember that you have to solve an inequality, pretty easy with Excel. Once you have the bolt tensions and compressions due to bending, all that is left is a combined stress check due to bending, tension/compressio, and shear. Also check the bolts in compression for buckling. You could probably set up a spreadsheet in Excel easily to do this analysis for any number of bolts.

I know you were looking for something quicker and easier, sorry. Sometimes I prefer to write my own spreadsheets than use some obscure utility I downloaded from the net. Not to knock the many excellent utilities out there.

 

[rowe]

There is a PCA publication "Strength Design of Anchorage to Concrete" (by Ronald Cook) that has been adopted by the latest edition of ACI318 as an appendix. If you don't have the latest ACI318 you can get the publication from PCA for about $20.

 

[structuresguy]

IBC 2000 and later also has a section on anchorage to concrete which is quite good. I think it is similar to the PCA method which is now used by ACI.

 

[3dboy]

I've always done this buy summing up the I+Ad^2 of each bolt (about the neutral axis) and dividing by the distance from the N.A. to the furthest bolt to get the S of the bolt group. No inequality to solve. accurate if raised up, conservative if bearing on the concrete.

 

[J1D]

Simpler way to calculate the maximum tension in a bolt from bending is to imagine the anchor bolts form a thin-walled steel pipe, cross-sectional area of each bolt is then DBC*3.14*t/N (where DBC=diameter of bolt circle; t=wall thickness; N=number of bolts). By this way, you can quickly get the widely used equation:

T=4M/N*DBC

 

[arto]

Bednar's
Pressure Vessel Design Handbook has design info for columns/anchor bolts

 

[unclesyd]

Here is a program (BASEPLT) based on "Process Equipment Design" by Brownell & Young.

http://www.engineering-software.com/pr/sku27599.htm