how much of the structure needs to be below ground

huangyhg

how much of the structure needs to be below ground?
i'm trying to help a co-worker determine how deep in the ground to the following: (5)-8" sch std pipe x 30'-0" long.  these are going to be poles for a netting to keep softballs from flying out of the field into the highway...crash!  i'm sure there has to be a standard for stuff like this somewhere, or at least a rule of thumb.
i was thinking like a 24" diamter hole 6 feet deep and fill it up with concrete would do it, but might be overkill, so i figured someone here would know.  thanks.
brian
brian,
try this out and i think you will be o.k.your pipe should be in the ground at least 1/4 the over all length of the pipe and your base hole needs to be 3 times the diamater of the pipe.concrete is very much needed here.it's not overkill due to wind shear and you need to factor the weight of netting it self
good luck
ed
ed,
many thanks.
brian
whoa, hold it there. lets skip the rule of thumb and consult the code. i have nothing against rules of thumb when it is in dd, but when you get to designing you should really crunch the numbers.
ibc 2003 section 1805.7 deals specifically with pole embedments. if you haven't converted to ibc, then ubc 97 section 1806.8 will do it.
i would suggest creating a simple spreadsheet because it is an iterative and irritating process.
sedre,
i do not make a habit of giving advise based on guessing.
  if you do the math you will see that may design is well with in the very standards you have cited.
i already know that size pole is more than adequate as that is what was up before...no codes involved here, no "official" job, just putting up some poles to hold some netting at a softball field...
thanks again.
brian
should there be a spacing of the pole affecting the size of pole and concrete caisson?
waskilly-
i mean this kindly- this forum is not usually used to solicit specific structural designs. we share approaches and experience in a general way, mostly.  requesting confirmation of embedment depth for your poles based on a brief post in this forum isn't really a fair thing to ask. there are several factors that need to be considered in answering this question, not least of which is site conditions.  
your project could get "official" really fast if the poles and nets blow down onto somebody's car or worse. suggest you talk to a geotechnical engineer in your area.  regards.
if you read the initial post, all i asked for was a standard or a rule of thumb to look at, not to "solicit a specific structural design" or a "confirmation of embedment depth".  i just provided the basic information to give a general idea of what the structure was to be.
thanks for the replies and motherly lectures folks. ;0)
brian