huangyhg

pipe crushing load
i am working on a stacking of concrete cylinder piles four high. i am trying to make sure that the piles in the bottom row do not crush from the load above. can you suggest me any equation to check this condition. the piles will be supported on wood dunnage.
check out our whitepaper library.
look in the first site below, under pipes -> long.line loads -> 2 loads on dia.
prex
other options: check with the manufacturer, look in roark's formulas for stress and strain, which should have similar info to the xcalcs.
i am getting reasonable moment on the section. now the next point is what will be the length of the resisting section for this moment? thanks-
please elaborate: aren't you in a condition of longitudinally distributed line load (stacked pipes parallel to each other)?

prex
i would analyze the circle as a fixed-fixed beam with a length equal to the diameter. these fixed end moments are equal to pl/8. if the resisting moment of the plain concrete exceeds the pl/8 moment, you shouldn't see any cracks. the value of p is equal to the weight of the stack above the beam. you could be much more exact, but why bother?
prex, the piles are not continuously supported. they will be resting on timber pads at 18'-0" intervals. can the entire 18' be considered providing resistance?
are subsequent higher piles also supported at 18' intervals? if so, then the bearing capacity of the concrete compared to the load/dunnage area will govern. no flexure except self weight.
shin25fff">,
what i can suggest is that you use the 45° rule to determine the width of the resisting section. as the maximum bending moment is at 90° from the concentrated load, section width (or resisting length) would be πdfff">/2, dfff"> being the mid wall diameter.
it's a rough method, but is the only one excluding fem, and can tell you if you are comfortable in a safe condition or not.
prex
i think 45 degree rule may be more appropriate. but, i do not think that 'n' in nd/2 is applicable as the supports are right top of one another. therefore, the load has a chance to distribute only over a total width of one pile dia plus the width of the dunnage.
thanks all.

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