Culvert Wall Torsion Block

TORSION BLOCK DESIGN TORSION BLOCK DESIGN - CULVERT WALLS culvert wall torsion block.qpw 2 SPAN BOX CULVERT OPTION clear span of box: 8 ft Design Span: 8.75 ft wall thickness of box: 9 inches Overall culvert length: 18.25 ft top slab thickness: 9.5 inches Arm from CL top slab f'c: 3000 psi H soil: 70.00ft lbs/ft 1.063ft fs: 24 ksi H surch: 140.00f t lbs/ft 1.396 ft (soil: 120 pcf H wind: 60.00ft lbs/ft 3.896ft EFP active: 35 pcf P impact: 1111.11 ft lbs/ft 5.396 ft surcharge: 2 ft traffic impact load: 10 kips screen wall height: 3 ft retaining wall height: 2 ft screen wall thickness: 10 inches wind force on screen: 20 psf length of application for impact force: 9 ft RETAINING/SCREEN WALL DESIGN Load Combi nation 1: Earth + Surcharge + Impact at 100% H1 = 1321 plf M1 = 6265 ft lbs/ft Load Combination 2: Earth + Wind at 125% H2 = 104 plf M2 = 247 ft lbs/ft Load Combi nat ion 3: Ear th + Surcharge + Impact + 30% of Wind at 125% H3 = 1071 plf M3 = 5068 ft lbs/ft H design: 1321 plf M design: 6265 ft lbs/ft d wall = 7.625inches b = 12inches Try #6 12: As = 0.44 in**2/ft D = 0.004809 k = 0.254 j = 0.915 fv = 14 psi OK fc= 927 psi OK fs= 24483psi OK n = 9 Check Minimum Reinforcing 1.2 Mcr = 8.22 ft kips NMn = 14.24ft kips OK USE #6 12 for screen wall TORSION BLOCK LOADS Try Torsion Block Size: b = 19 inches h= 19 inches Distance from t op of t orsion block to top of wall: 4.208333 w wall = 0.684 k/ft w soil = 0.141 k/ft w block = 0.489 k/ft w total = 1.314 f/ft V at center wall = 7.19kips x distance to d away: 1.71 ft Vu at d away: 4.94kips Unit torsion loads to block: t soil = 97 ft lbs/ft Assuming .75 probability factor of collision: t surch = 430ft lbs/ft t impact= 9.89ft kip t impact = 13190 ft lbs/ft tu total= 10419 ft lbs t total = 13716 ft lbs/ft Tu at center wall = 56.98 ft kips Tu at d away: 39.18 ft kip Check Adequacy of torsion block size: ph = perimeter of hoop steel = 58 inches Ao = 178.5 in**2 d = 16 inches Aoh = 210 in**2 Alpha = 0.364 Beta = 0.466 Is Alpha<= Beta? block is adequately sized STIRRUP DESIGN At/s req'd= 0.0258228 for 1 leg of closed stirrups For two legs of stirrups: 0.051646 NVc = 14.15> Vu = 4.94kips Try #4 stirrups: At=1 leg= 0.2 in**s 2At = 0.0516456 * spacing 0.4 = 0.051646 * spacing spacing required = 7.75 inches Say = 6 inches 2*At des = 0.310 2*At min = 0.095 At design OK Check Maximum Spacing of Stirrups permitted ph/8 = 7.25 inches OK Use 6inches CHECK TORSIONAL CAPACITY OF SECTION NTn = 50.58 ft kips torsional capacity is OK LONGITUDINAL STEEL REQUIRED FOR TORSION At/s = 0.0333333 OK greater than minimum Al req'd = 1.93 Al min = -0.29 in**2 Al req'd is OK USE Al = 1.93 in**2 FLEXURAL DESIGN OF TORSION BLOCK DUE TO VERTICAL LOADS Mu design: 12.58 ft kips at center wall of culvert As req'd = 0.18 in**2 D req'd = 0.000579 D min = 0.00220256 As design: 0.23 in**2 Atotal = 2.17 in**2 Use 8 #6s: 3.52 in**2 ANCHORAGE OF TORSION BLOCK TO CULVERT WALLS 0.00030805 For Horizontal Forces: Ph = 30644 lbs As req'd= 0.57 in**2 For bending in culvert wall due to block torsion Tu = Mu = 56.98 ft kips = 683.74 in kips d for horizontal block bending = 16.5 inches b = 9 inches As req'd= 0.82 250682446.xls.ms_office

Culvert Wall Torsion Block

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