Help Using Hansens Bearing Capacity Equation

[shredator]

Hello,
I am trying to calculate pipeline thrust block sizes using Hansen's bearing capacity equation, which I found in Foundation Analysis and Design by Joseph E. Bowles, fourth edition, around page 189. My problem is that, even with small base tilt angles, the base factors (b sub q, and b sub gamma) completely blow up. Anyone have experience using this method?
thanks in advance.

 

[vulcanhammer]

An alternate source of information on this method is EM 1110-1-1905, which can be downloaded from

http://www.vulcanhammer.net/geotechnical/shallow-slope.php

http://www.vulcanhammer.net

http://www.vulcanhammer.info

 

[shredator]

Thank you for that source, the equation now returns believable values, up to a point. Increasing the tilt angle of the footing reduces the bearing capacity (as it should) up to about 50 degrees, then it begins to increases again for angles above about 50. Is this supposed to work this way? I am trying to use it for a tilt of 90 degrees. If anyone has a good reference on how to design thrust blocks, other than using an assumed bearing capacity, I would love to hear about it!
Thanks

 

[PEinc]

Did you try sizing the thrust block based on passive resistance to the horizontal load? You can pick a thrust block height and width that give the necessary passive resistance along with the required safety factor.