05-SUPER PASSAGES



SUPER PASSAGES

I.SITE SURVEY:

1 Site survey should be furnished as per check slip for CM & .CD works with the following details.(check slip enclosed)

a i) Report accompanying the Site survey

ii) H.Ps of canal & drain / river.

b Site plan with flow direction of canal & drain along with b net levels @ 10m interval & contours.(IS ; 7784 (Part I) : 1993)

LS of drain / river

i) covering 500 metres on U/S & D/S with levels @ 10minterval.

ii)The L.S with levels @10m to 20m interval with cross sections of drain on U/S, D/S @ centre line,10m,25m,50m,100m,& @100m interval beyond for a length of 500m.

iii)The cross section levels shall be @ 3m to 5m interval in the gorge portion and 10m intervals in the flanks extended up to MFL touching the ground.Observed MFD may be computed from the observed MFL and shown on the LS & CSs.

d)The catchment area shall be marked on the Topo sheet for all the C.A's more than 2.5sq. Km. If the C.A. is less than 2.5sq.Km.,the C.A. is to be traversed on ground and to be

The MFD may be computed as per the following formula.

Dicken's Formula, Q = CM3/4

1.IN UPLAND AREAS:

Q = Discharge in Cusecs

CA upto 1 Sq.mile.C=1400

CA from 1 Sq.mile to 30 Sq.milesC=1200

CA more than 30 Sq.milesC=1060

(2) IN DELTAIC AREAS :

Ryve's Formula Q = CM2/3

C = 1000 for Q more than 500 cusecs

For deltaic catchment of Krishna & Godavari the formula shall be Ryve's formula adopting 'c' value as per the Mitra Committee Report for Upland & Deltaic Catchments.(Mitra Committee Report)

g)Observed MFD may be computed from the observed MFL and shown on the LS & CSs.

h)Details of Tank such as FTL, distance from the structure etc., if there is any tank on D/S on Vagu course.

Bore hole data /TPs upto Hard strata or for min. depth of 2m for shallow foundations & upto 1/3rd embedment depth below maximum scour depth along the Centre line @ suitable intervals depending upon the importance of structure with minimum 5 Nos covering both the Drain & Canal @centre, U/S & D/S sides.(Table I & II of APERL for test resultsof foundation soils enclosed.IRC 78 : 2000)

2.DESIGN:

Note on Principles of Design, the assumptions made & the general features  of the structure.

HYDRAULIC DESIGN

1.MFL computations adopting Step by Step method. 2.(a)Design of ventway(or size of pipe) for the Drain/river limiting  allowable velocity.(Design of Small Dams by USBR. 

(b). For small discharge of Drain, pipes can be proposed limiting the velocity .(IS:7784(part ii / section 2))

(c)The Drain bed level can be raised upto 600mm above the natural bed level to achieve vertical clearance in the canal.(IS 458 -1988 IS :783 - 1985 )

3. Design of Tail channel & approach channel keeping in view the Lacey's formula for Wetted perimeter & velocity limits depending on stratification.(IS ; 7784 (part 2/sec2)

4. Transition lengths on U/S & D/S of drain(IS : (7784 (part - I) - 1993)

5. TEL calculations for the Drain considering eddy loss coefficients as per IS code along with flow diagram with dimensions and levels.(IS : 7784 (part - 2 / sec 2) - 2000)

6.Scour depth calculations of Drain: R= 1.34 (q2/f)1/3 with relevant factor of safety.

7. Checking of Thickness of Apron(IS : 7784 (part - I) - 1993 )

8.Exit gradient calculations: GE = (H/d)x[1/(π√λ)] ; Where λ = [1+ √(1+α2)]/2 ; α= b/(IS : (7784 (part - I) - 1993 )

9. Proposal sketch (IS : 7784 (part - I) - 1993 )

3.STRUCTURAL DESIG

i)SUPER STRUCTURE

a. Design of trough 

b. Design of head wall on U/S & D/S by adopting TVA procedure / Coulomb's Theory/ Rankine's theory with a top width of 500mm.  

ii)SUB STRUCTURE

1. Design of pier

2.Design of Abutmen

3. Abutment and  Pier foundations shall be isolated footing/ RCC raft as the case may be(IS 458 : 1988 , IS 783 - 1985)

a) Design of wing walls & return wall both on U/S & D/S of drain - The walls  are to be designed  adopting TVA procedure /Coulomb's Theory / Rankine's Theory with a top width of  500mm(TVA Hand book ; IS 1904 - 1966)

b)  Tabulation of stress table :- A consolidated stress table has to be furnished indicating the stress on concrete & stress on soil for the Abutment, Piers, Wings &Returns

c) Minimum grade of PCC shall be M10 Grade, unless otherwise specified.(IS-456:2000)

d) Minimum grade of concrete for RCC shall be M20 Grade,unless otherwise specified.

4.MISCELLANEOUS ITEMS :-

a) Water stops(IS-456:2000)

b) Weep holes in the Retaining walls (IS : 7784 :1993)

c) Bearings(IS : 7784 :1993)

d) Expansion , Contraction & Construction Joints (IS : 7784 :1993)

e) Cut & Ease waters(IS : 3370  - 1965 IS:7784)

DRAWINGS

a)General Layout on net level plan duly showing contours.

b) General plan,Sectional elevation & End View - Plan indicating  Half plan @Top &Half plan @ bottom & Sectional Elevation along the LS of the drain & End View along the cross section of the drain.

c)Wall Sections, RCC Details & Details of miscellaneous items.(Scale : 1:50, 1:100, (or) 1:200)

The Drawings shall contain assumptions made, TPs, Specifications,HPs of canal,Hydrology of the Drain, Bar bending schedule,Stress table etc.((i)Scale : 1:50,(or) 1:100 for sectionsii)Scale : 1:25 (or) 1:20 for Rcc details.)

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