MR87-1_REDUCED.pdf

((SECTION 9-109-) 0. \ GENERAL Drainage structures are located anddesigned /0 adequately handle runoff across improvementsand to handle runoff from the improvement The locationof cuJvcns i ~ covered in Chapter IV of this Manual ThehydrauliC design of culverts and othel drainage faci litiesis discussed in preceding sections In rhis section criteri~peltaining to the selection of culver[ and storm sewermaterial and appurtenances are presented.9- 10 2 lyr ES Permissible culvert types are concrelebox, remforced concrete pipe, vitrified clay pipe ,corrug3 red metal pipe. corrugated aluminum alloy pipe,and cOHugared metal pipe-arch In general. there are IWOmerhods of ~p ecifying the permissible culvert Iypesdependent upon !he design traffic and rhe surface type.TIle first method is· to specify one particular culvert typeand Ihe second melhod is ro specify a group of culvertIypes as deH:·ibed in succeeding sections. The finalselection of the structure type is based on requirementsin the Standard Specifications, on good engineeringjudgmen' , and economy with consideration of 5ervice andmaintenance cosrs(I) ROADWAYS WITH LESS mAN 400 ADTAND ENTRANCES, Permissible types of culveltsacceplable for use under all loadway~ with less than 400ADT and all ent rances regardless of traffic or pavemenlsurface type are concre te box, reinforced concrete pipe,corr ugated metal pipe, cOJlugated aluminum alloy pipe.and cOIJugared melal pipe·arch. Concrete box structuresare considered for structures larger 'han 60 inches indiameter The most economical sr.ucture type may beused Corrugated metal pipe arch suuctures in sizes 8 -Sand larger are used where necessary because of limitedallowable srruc ture height The T ype 8 ·1 through 8-4corrugated melal pipe arch is nor acceptable A balleryof round pipe 0' $Ingle elliptical reinforced concrete pipemay be conside·ed in lieu of B· I through 8 -4 cOfluga tedmelal pipe arch Twelve· and fift een ·rnch pipes ale nOIu ~e d for cro~sroad culverts. cxcepr whe:e the use of anI S-inch pipe will creale an umightly or implaclicabledrainage condllion lJeveted · ends ale specified forcorrugated melal pipes la.ger rhan 4S·inch dianlelerCOllugared metal pipe·arches are not beveled In general.Ihe bevel ohould nOI be flatter .han 2'1 nor should 'heskew exceed I S degrees If these controls are exceeded.special con$ideration i~ given to Ihe use of headwalls.dplap. 'or slope pavement fa stiffen the strUClure againstuneven loading from the embankment and Ihe dynamicforces of the walel Proposed designs fOl .hese conditionsare ~ub mlHed to Ihe ~bln Office for approvalCHAPTER IXHYDRAULICS AND DRAINAGENON-HYDRAULIC ASP ECTS OF DRAINAGE DESIGNIn general. full circle pipes are specified on the plans by"Groups" These groups give the contraclor the permissiveoption of furnishing anyone or a combination of the ptpeIypes within Ihe specified group One group of pipe(Group II) is provided for crossroad culvens for roads withdesign ADT of less !han 400 and for side drainage suchas under enl/ances legaldless of the tramc Concrcte pipeis used fo r locations where high acidity or alkallllllY ofsoil s or waters or other cOHosive elements are plesent.The pennissi\'e pipe Iypes in Group II are (I) reinforcedconClele. (2) corrugated melal. (3) cOHug:lIed aluminumaUoy When Group II pipe is specified hyd.aultc designcomputations should be based on corrugated meTal pipeIn, special cases as described in a subsequent seclion "hereone pipe type has a peculiar advan1age over olhc. pipetypes, the particular pipe Type may be speciiied in lieuof $pecify ing groups(2) ROADWAYS WITH 400 OR MORE ADT WITHSURF ACE TYPE OTHER THAN ASPHALTICCONCRETE OR PORTLAND CEJl.I ENT CONCRETE.Permissible types of culve ll s accepTable for use unde!roadway~ with 400 ADT or mOle with surface Iypc orherthan asphaltic concrele O! portland cement conCICle arcconcrete box. reinforced concrete pipe. cOllugated mel~~pipe, and vjllified clay pipe (exII:! stlengl h) Box culveilsmspecified only when it is mOle economlC3l ro bUIldIhe box than it is to prov.de an equivalenr p.pe cui vel •in general. full circle pipes are spec. lied on Ihe plans by"Group" The gTOUp designation gives 'he COntraCfOl .hepermi5sive oplioll of furnishing anyone o r a combinaTionof Ihe pipe types wilhin Ihe specified group One groupof pipes (Group [) i5 prOvided. The permissive pipe Iype~in Group I a!e ( I) reinforced con'crete. (~) co. ruga redmetal. (3) vi r"fied clay (exIra ~ Irenglh) When Group Ipipe is specified hydraulic design compura.ions should t.ebased on corrugated mela] pipe In spec.al rases asdescribed in a subsequenr secrion where one pipe Iypehas a peculiar advantage over other pipe Iypes. thepaflicular Iype may be ~pec ified In lieu ot speCIfYing Ihegroup 12" and 15" pipes ale nOI used e.'(cepl as outlersfrom drop inlets Elhplrcal reinforced concrele prpe maybe used in special case~. u~ually fOl SIOfTn sewer ~. \\lterenecessary b\!cau$e or' Ijntil~d allowable "Tucture height(3) ROADWAYS WITH SU RFACE TYPE OFASPHALTiC CONC RETE O R PORTLAND CE~IENTCONC RETE PelmiSSlblc types 01 culveJls accepTable fOIuse under roadways wrrh sur(ace type of a~ph a l"c concrereor ponland cemenl conClete are conClete bOx. andreinforced concrete 01 vlfllfled day pipe lextra stlength)- 39 -Rev J·16·81