Laserfiche WebLink
k'"- Assume each of the pipes is equally deflected un<Jerads required to achieve that result, The tangential <br />-',..._. .drface strain developed in th(i thick\&ail pipe'is muchgreater than the sur{ace strain in the thinweill pipe. <br />the tangentiat strain varies din:ctly a$ the wail ' <br />thickness (i.e.: clistarrce kom il"re neutralaxis) and isproportional to the arnount r:f ring rjeflection.'For agiven ring deffection, the thickerlhe wall, rne nigher <br />the strain. <br />Alternately, a$sume that each of ilre pipes issubjected to loadssuch that tfre tangential surface <br />strain in the pipe's wall surface is equal for lcoth pipes.For.equal surface strain" the degree of verticaldetlection of the pipe ring is diff6rent forthe twoptpes, unoer tnese circumstances;, ttre degree ofrJeflection would be less for the thickrvalf pibe anO'greater for the thinwall pipe. <br />The percentage ring deflection t>ased upon strain fora given SDR piBe can &re calcr.rtabd as iollows: <br />NVf =, 1o.es) t"lr{lt <br />AY** =, (0.2s) (e)(SDH) <br />;**. = ("0025)(sDFt) <br />Where: e, ,; Tangential strain in the surface of thepipe ring duer to cJeflection <br />- (conservativerly 0.01 for Driscopipe)D = Pipe OD, inchbst * pipe wallthicknerss" inchesSDR = Standard Dinrension Catio, DltAy * Vertical deflection, inches <br />Driscopipe recognizes a tangontial surfacer strainvalue of 0.01 due to.ring deflec;tior-r as, a conssnrl;u,,yet respon$ibre design param*ter: Tiiis varue is basedupon the following: <br />' Most of the deflection of a flexible pipe occurswithin a few hours or a few d;ays aftrii finalbackfilling and increases very litile theieafter. Thisresufts in the development ol,'the soil arcrrover thepipe which relieves ihe pipe of rnucA oithe verticalsoit load lry the arcfring'action of the soilonuefofJ',19- nV the developmeht of soit restrainiat the sides<lf the pipe. <br />-soilsystenr <br />OD <br />Dr. Fleynofcl K. <br />buckle under <br />ordinary is comrraclelcl <br />and is in full with the pipe.virtual fail-safe <br />installation can bb assured if soil is generall'y <br />over B57o of Proctor T-99) Densrity. <br />With lhe backfill of.standard <br />density, the deptlir of laying for is alrnost <br />unlimit'ed, HoweJer, in lhe thinner series, tlue tcr <br />achieve the: <br />of the pipe <br />backfill <br />rnaterialother <br />adequate if <br />installations. <br />is relatively <br />would cover <br />Howeven B5?, <br />shoukj be <br />39