DLRB At kM2.183

2. VENTWAY Depth of cut = + 219.795 - 213.878 = 5.917 m Width of canal at t= 6.50 + 1.5 x 5.917 x 2 = 24.251 m Provide 3 V of 7 m clear span. Thickness of deck + w.c. 0.650 + 0.1 = 0.750 m Width at bottom of deck 5.917 - 0.750 ) x 1.5 x 2 + 6.50 = 22.001 m Length of deck = 3x 7+ 2x 1+ 2x 0.37 = 23.740 m Balance width of cana 24.251 - 23.740 = 0.511 3. AFFLUX Width at FSL = 1.5 x 1.6 x 2+ 6.5 = 11.300 m Area of obstruction due to pie = 2 sq.m. Area of Normal sectio = (6.50 + 1.5 x 1.60 ) x 1.60 = 14.24 sq.m. Net Area = 14.24 - 2.000 = 12.240 sq.m. Afflux = + 0.01524 x A 2 - 1 17.86 a = 0.36 + 0.01524 x 14.240 2- 1 17.86 12.240 ( 0.02016 + 0.01524 ) x ( 1.35349652 - 1) = 0.0354 x 0.35349652 = 0.013 m or 1.300 cm < 2cm = Hence OK to be closed by providing Returns / parapets. v 2

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Transcript of DLRB At kM2.183

DESIGN OF TRESTLE PIER

ventway, afflux & scour depth2. VENTWAYDepth of cut=+219.795-213.878=5.917mWidth of canal at top=6.50+1.5x5.917x2=24.251mProvide3Vof7mclear span.Thickness of deck + w.c. =0.650+0.1=0.750mWidth at bottom of deck = (5.917-0.750) x1.5x2+6.50=22.001mLength of deck =3x7+2x1+2x0.37=23.740mBalance width of canal =24.251-23.740=0.511to be closed by providing Returns / parapets.3. AFFLUXWidth at FSL=1.5x1.6x2+6.5=11.300mArea of obstruction due to piers=2sq.m.Area of Normal section= (6.50+1.5x1.60) x1.60=14.24sq.m.Net Area=14.24-2.000=12.240sq.m.Afflux=v2+0.01524xA2-117.86a=0.36+0.01524x14.2402-117.8612.240(0.0201567749+0.01524)x(1.3534965184-1)=0.0353967749x0.3534965184=0.013mor1.300cm0.371Max. Comp. Stress=(22.97/2.400) x { 1 + (6 x0.371) /2.400}18.44T/ Sqm( Compression )Min. Stress=(22.97/2.400) x { 1 - (6 x0.371) /2.400}=0.69T/ Sqm( Compression )Which can be allowed.STRESS ON SOIL: ( Taking moments about 'B' )S.NODescriptionLoadL AMomentin Tonsin mtsin T.mW1As calculated6.2811.0556.626W20.75x0.300x2.5000.5630.9250.520W30.380x0.675x2.5000.6410.7400.475W40.5x1.000x2.945x2.4003.5341.4335.065W50.5x0.400x0.400x2.4000.1922.4330.467W60.750x2.945x2.4005.3010.9254.903W70.5x0.250x2.945x2.4000.8830.4670.412W80.5x0.250x2.945x2.1000.7730.3830.296W9(0.250x0.250x2.5000.250x0.725x2.100)0.5370.4250.228W102.000x0.400x2.4001.9201.3002.496W11x4.320x2.1000.0000.1500.000W123.000x0.600x2.4004.3201.5006.480Pv0.0384x (6.120 -1.200 ) x2.1002.904-----------V =27.84927.97Ph0.134x (6.120 -1.200 ) x2.10010.1341.96819.94T1As calculated1.6673.9456.575FrAs calculated0.0003.9450.000M =54.49Lever arm=M / V=54.49/27.85=1.957mEccentricity=1.957-3.000/2=0.457mPermissible 'e'=3.00/6=0.500>0.457Max. Comp. Stress=(27.85/3.000) x { 1 + (6 x0.457) /3.000}17.77T/ Sqm( Compression )Min. Comp. Stress=(27.85/3.000) x { 1 - (6 x0.457) /3.000}=0.80T/ Sqm( Compression )