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c9/c;~~ <br /> RIPRAP STILLING BASINS FOR CULVERTS - FHWA PROCEt)uKt <br /> PROJECT GCC Rio Grande <br />EFERENCE: USDOT, 19 STATION: Rd 34+75 DATE 5!2312002 <br />75. Hydraulic Design of Engergy Dissipators (or Culverts <br /> and Channels. HEC N o. 14 <br /> VARIABLE S: <br />trs =Height of swur hole, ft <br />Yn = normal depth, ft <br /> <br />' <br /> Ls =Length of scour hok;, ft <br />Ws =Width of scour hole, R , tps <br />Vn =normal depth veb <br />An =normal depth area, sq. ft <br /> dm =mean rode diameter, d50, ft <br />O =Culvert discharge, cis TW = Talwater depth, ft <br />D =Culvert diameter, ft <br /> Ao =brink area Ye = equivak:m outlet depth for ro und wNerts. <br /> Yo =brink depth, ft <br /> <br /> RECOMME NDED VALUES: <br /> 1 NJ/Yo = taihvater to brink depth ratio kiss than 0.7 5. Higher tailwater requires veloary depy assesmeM <br /> 2 hs/dm =scour depth to median rode diameter greater than 2.0 and less than 4.0 <br /> 3 For best results, dm/Ye should be between 025 and 0.45 <br /> <br /> GNEN INFORMATION: <br />Discharge O = <br />440 <br />cfs <br />RCBC: D= <br />ft <br />SPAN = <br /> <br />N <br />1 <br />ft <br />R <br /> Tyy . q ft rmnnal depth = ft critical d = #D <br />/0 <br /> fkrvr is #ON/01 <br /> Culvert Dia. = 8 ft critical d = 5.4 Fg I1F4 <br /> normal depth= 8.0 R flow's SUBCRITIC AL <br /> COMPUTATIONS (boxes indicate additional input variables): <br />ROUND CULVERT <br />O/D^2.5 = 2.43 <br />TW/D = 0.50 <br />RECTANGULAR CU <br />Yo = Ye = 0.0 <br />Vo = #DN10! <br />LVERT <br />ft <br />ips <br /> Yo/D = 0.57 Fig IIF10 Fr = #DN/0[ <br /> Yo = 4.56 ft Tw/Ye = #DN/0! #DN/01 <br /> TWIYo = 0.88 Extend Ripra <br /> Ao = 29.6 Sq ft TRIAL SVJ NG <br /> Vo = 14.9 fps dm = 1.5 n <br /> Ye = 3.85 ft dm/Ye = #DN/0! #DNI01 <br /> Fr = 1.34 hs/Ye = 0.5 Figure XF2 <br /> <br />TRIAL SIZING hs = <br />hs/dm = o.o <br />0.0 n <br />OUTSIDE R <br />ANGE <br /> dm = 1.25 ft <br /> dm/Ye = 0.32 OK ADJUSTE D VALUES <br /> hsNe = 0.35 Figure XL dm = 1.5 ft <br /> hs= <br />hsldm = 1.3 <br />1.1 ft ~ <br />OUTSIDE <br />RANGE dm/Ye= <br />hsfYe = #DN/0! <br />0.5 #DNI01 <br />Fgure X1-2 <br /> hs = o.o n <br /> ADJUSTED VALUES Frs/dm = 0.0 OUTSIDE RANGE <br /> dm= <br />dmfYe = 1 <br />0.26 ft <br />OK <br />MINIMUM <br />BASIN S¢ <br />E <br /> hslYe = 0.5 Figure XI-2 10•hs = 0 ft <br /> hs= 1.9 ft 3•Wo= 0 ft <br /> hsldm = 1.9 OUTSIDE RANGE is = 0 n <br /> 15•hs = 0 ft <br /> MINIMUM BAS IN SIZE 4•Wo = 0 ft <br /> 10`hs = 19 ft -- Lb = 0 ft <br /> 3•Wo = 24 ft <br /> is = 24 ft <br />• 15'hs = <br />4•Wo = 29 <br />32 ft <br />ft <br /> Lb = 32 ft <br />