Hi all, first my background is structural. It’s the first time I have been requested to design an anchor block. I initially posted in the piping group and they advised me to post here instead due to the nature of the question. The piping is 48” dia. HDPE, all buried. Pipe rxn is 440 kips due to Poisson’s effect? (Not sure what that is but I leave that to the piping folks). We have a geotech report and the soils are primarily clay, with some layers of cohesionless material in there.
I have been following guidelines from PPI (see here: https://www.plasticpipe.org/common/...Division Publications/Anchor Block Report.pdf)
It has been helpful but not sure about some areas being applicable to my situation, so wanted to ask for some guidance. In that document, they use a 1.5 FOS to size the anchor block. They also consider only cohesionless soils in their report, and assume typical values of Ka, Kp, etc (vs. having the actual values in my case) to determine soil pressures acting on either side of the block. I am wondering where that 1.5 factor is derived, and whether it is being used to size the block due to some unknowns since they don’t have exact values and are providing generic guidance (and perhaps to cover any sliding effects?). If yes, does it make sense to include it in a situation where a geotech has provided those values in a report (and those factors therefore, inherently have margin built into them)?
I just want to make sure I am not being more conservative than I need to be since the block size is already quite large, but most importantly I want to make sure I am doing this correctly, so if the factor is reasonable and needed, I of course will include it in spite of the size. Any advice or guidance is appreciated.
I have been following guidelines from PPI (see here: https://www.plasticpipe.org/common/...Division Publications/Anchor Block Report.pdf)
It has been helpful but not sure about some areas being applicable to my situation, so wanted to ask for some guidance. In that document, they use a 1.5 FOS to size the anchor block. They also consider only cohesionless soils in their report, and assume typical values of Ka, Kp, etc (vs. having the actual values in my case) to determine soil pressures acting on either side of the block. I am wondering where that 1.5 factor is derived, and whether it is being used to size the block due to some unknowns since they don’t have exact values and are providing generic guidance (and perhaps to cover any sliding effects?). If yes, does it make sense to include it in a situation where a geotech has provided those values in a report (and those factors therefore, inherently have margin built into them)?
I just want to make sure I am not being more conservative than I need to be since the block size is already quite large, but most importantly I want to make sure I am doing this correctly, so if the factor is reasonable and needed, I of course will include it in spite of the size. Any advice or guidance is appreciated.
