Selecting Drainage Pipes

Are you talking about in effect just 3-1/2" of cover (where does 11,500 pound load come from?)

THE 11,500.00 LBS IS THE LOAD GOING TO ROLL OVER THE TRENCH

I guess what I am asking is how deep is the "trench"?

the trench is only 10" deep

Randy Conner-

I gave a "good answer" vote because your attachment was right to the point. I even saved the pdf file, knowing full well that I will probably never have need to use it but it caught my interest anyway.

Regarding the question and the problem, I see a 6" pipe in a 10" deep trench with a concrete cover. I think the designer of this needs to go back to the drawing board to come up with a more viable design. Much information is lacking in the question and follow-up clarifications to make any sense out of this problem.

Hi rpat312,

there's really no need for you to over-engineer your drainage pipe. it's just a drainage pipe and you can even use PVC for it (if PVC can handle the substance passing through it). you will need, however, to protect it from vehicles travelling over it by encasing it in a strong concrete trough.

use a 2"-thick steel plate running the length of the trough opening. that should be more than enough for a 6"-wide opening to protect your pipe and supporting the vehicles.

HTH!

You may be right, as the penalties of "over-engineering" can obviously be at least a little extra effort/time and/or money spent etc. However, we obviously do not really know what the risks of under-engineering or failure might be in this specific case (e.g. a drain for a very small low point in a cow pasture might admittedly represent much less concern if it were to say break and back up than an installation in a nuclear plant draining off radioactive material so it doesn't rain down on someone's head!)

[I guess it might have just as easily been said in the real life incident involving the small plastic pipes that somehow squirreled loose from whatever moorings they had that preceded the Taum Sauk Reservoir disaster (that in turn let loose basically all at once a flow reported roughly equivalent to the Mississippi River) that these were "just conduits" -- see http://www.missourinet.com/gestalt/go.cfm?objectid=8743F9ED-ABBE-EEC5-F07E6A5A82DA850C , http://www.associatedcontent.com/article/462284/worst_manmade_disaster_the_taum_sauk.html?cat=17 , http://web.mst.edu/~rogersda/dams/2_43_Rogers.pdf , I noticed now http://www.moenviron.org/News_Articles2008.asp and hundreds of other sites.]

Hi Randy,

I gave you a GA for your post #5. it directly addressed OP's question.

however, the Taum Sauk illustration is kinda out-of-context to the discussion at hand, as those conduits (that failed) that housed the instrumentation had no loads passing over them (as in OP's case), and were dislodged from their moorings by the rise and fall of the dam's water level (again not applicable to OP's case).

but I agree, that was an under-engineered job that could have been done better. cheers!

Thanks (was just curious though, where did you see the conclusion though in the Taum Sak case that the pipes were, "...dislodged from their moorings by the rise and fall of the dam's water level"?)

Hi Randy,

it was in the links you provided. those reports were very thorough.

I think it was here: http://web.mst.edu/~rogersda/dams/2_43_Rogers.pdf

Thanks!

Sir, You need to be more specific. Where is the 11,500 lbs coming from? Is it per square inch or what? Is the 11,500 lbs coming from what will be driving over it. If so the concrete needs to be a bit thicker and needs to be reinforced with rebar or mesh wire. Does the pipe need to be six inches. that will carry an enormous amount of water. What ever size or kind you use it needs to be it's diameter X 1.5 below the bottom of the concrete with a good packed base or the concrete will break parallel with the pipe.

Contech makes H-20 rated underdrain, A-2000, they also have minimum cover tables.