Name of the River: Teesta Cl. 703.1 Design Discharge of Foundation: Catchment area = 12500 % increase in discharge = 19.2 % Q, Actual discharge = 19820 cumecs Design discharge for foundation design = 23619 cumecs Cl. 703.2 Mean Depth of Scour: Theoretical effective linear waterway = 1002.8 m Actual effective linear waterway = 947.8 m HFL = 86.288 m 20.9 0.425 mm 1.15 9.7 m Mean Scour Level = 76.573 m Cl. 703.3 Maxm. Depth of Scour for Design of Foundation: Cl. 703.3.1.1 Flood without seismic combination: 19.4 m ii) For abutments: 12.3 m 19.4 m Cl. 703.3.1.2 Flood with seismic combination: 17.5 m ii) For abutments: 11.1 m 17.5 m Cl. 703.3.1.3 Without flood with seismic combination: 15.5 m ii) For abutments: 9.9 m 15.5 m km 2 Db, Design dischrg for foundn/m width at eff linear wat dm, weighted mean dia of bed material = Ksf, Silt factor = 1.76 (dm) 1/2 = dsm, mean depth of scour below HFL = 1.34 (Db 2 /Ksf) 1/3 = i) For Piers = 2.0 dsm = (a) Approach retained/ lowest bed level whichever is deeper = 1.27 d (b) With scour all around = 2.0 dsm = i) For Piers = 2.0 dsm = (a) Approach retained/ lowest bed level whichever is deeper = 1.27 d (b) With scour all around = 2.0 dsm = i) For Piers = 2.0 dsm = (a) Approach retained/ lowest bed level whichever is deeper = 1.27 d (b) With scour all around = 2.0 dsm =
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Name of the River: Teesta
Cl. 703.1 Design Discharge of Foundation:Catchment area = 12500% increase in discharge = 19.2 %Q, Actual discharge = 19820 cumecsDesign discharge for foundation design = 23619 cumecs
Cl. 703.2 Mean Depth of Scour:Theoretical effective linear waterway = 1002.8 mActual effective linear waterway = 947.8 mHFL = 86.288 m
20.9
0.425 mm
1.15
9.7 mMean Scour Level = 76.573 m
Cl. 703.3 Maxm. Depth of Scour for Design of Foundation:Cl. 703.3.1.1 Flood without seismic combination:
19.4 mii) For abutments:
12.3 m
19.4 m
Cl. 703.3.1.2 Flood with seismic combination:
17.5 mii) For abutments:
11.1 m
17.5 m
Cl. 703.3.1.3 Without flood with seismic combination:
15.5 mii) For abutments:
9.9 m
15.5 m
km2
Db, Design dischrg for foundn/m width at eff linear waterway =
dm, weighted mean dia of bed material =
Ksf, Silt factor = 1.76 (dm)1/2 =
dsm, mean depth of scour below HFL = 1.34 (Db2/Ksf)1/3 =
i) For Piers = 2.0 dsm =
(a) Approach retained/ lowest bed level whichever is deeper = 1.27 dsm =
(b) With scour all around = 2.0 dsm =
i) For Piers = 2.0 dsm =
(a) Approach retained/ lowest bed level whichever is deeper = 1.27 dsm =
(b) With scour all around = 2.0 dsm =
i) For Piers = 2.0 dsm =
(a) Approach retained/ lowest bed level whichever is deeper = 1.27 dsm =
(b) With scour all around = 2.0 dsm =
Design of Pier With Well Foundation
Basic Input Data
Left span on Pier = 110.00 m 10000Right span on Pier = 110.00 m 800Total width = 13.50 m
Carriageway width = 9.50 m 2400 4000Pier cap Rectangular top Dimension = 5.50 m x 11.00 m
Straight height of Pier cap = 1.00 m
Slant height of pier cap = 1.00 m 6000Pier wall Dimension = As per figure beside CS Area of Annular pier wall = 19.56 SqmFinished road level = 112.00 m Moment of Inertia = 36.95 m4Existing ground level = 82.00 m
EGL to FRL = 30.00 m
Superstructure depth = 7.50 m Volume of Pier Cap = 121.0 m3
Wearing course thickness = 0.10 m
Height of bearing & pedestal = 0.50 m
Bearing level = 104.40 m
Pier Cap top level = 103.90 m
Height of Pier column = 19.90 m
Depth of well foundation below well ca = 40.00 m
Well cap top level = 82.00 m
Depth of well cap = 2.50 m
Founding level = 39.50 m 45.42 m
HFL = 88.08 m
Scour Level(Normal) = 69.08 m Level of plane of rotation i.e, 0.2*D above base
Scour Level(Seismic) = 70.98 m
1.1 Dead Loads1.1.1 Dead Load of the superstructure
The longitudinal eccentricity is measured from the centre line of the pier to the centre of the bearing.
Load Due toMoment(Kn-m)
Long Trans
PSC Box 5113.5 0 0
Hence, total vertical load due to superstructure = 5114 T
1.1.2 Super imposed dead load on superstructure
Load Due to No. Weight (T)
2 1 220
1 1.98 217.8
3. Footpath 2 0.66 145.24. FPLL 2 0.6 132
Hence, total load due to super imposed dead load = 715 T
1.1.3 Dead load of the substructure
Weight of pedestals 6 no.s x 0.800 m x 0.800 m x 0.500 m x 2.5 T/m3 = 5 T
Weight of Pier Cap 1 no.s x 121.00 m3 x 2.5 T/m3 = 303 TWeight of Pier Column 1 no.s x 19.90 m x 19.56 m2 x 2.5 T/m3 = 973 T
Hence, total vertical load due to substructure = 1281 TAt Steining stress check level
1.1.4 Dead load of the Well foundation Normal SeismicDepth of well foundation = 40 m 15.88 17.02Dia of well = 11 m 11 11
2.087 m 2.087 2.087Say = 2 m 2 2
Dredge hole dia = 7 m 7 7Well Curb height = 3.894 m 3.894 3.894
Weight of Well cap = = 594 T 594.0 594.0Weight of Steining = = 5104 T 1695.1 1855.8
Vertical Load (T)
The super imposed dead load on the structure comprises of the Crash barriers, Railings, Footpath & Wearing course loading from the deck.
Unit Weight (T/m)
1. Crash Barriers +Railing
2. Wearing Course
The substructure comprises of bearing, pedestal, pier cap & pier shaft. Summary of loads due to self weight of the substructure :
Steining thickness, h = Kd Öl =
Weight of Bottom plug = = 571 TWeight of Well curb = = 289 TWeight of Top plug = = 42 T 42.3 42.3Weightdue to sand fill = = 2446 T 775.2 853.9
Weight of water above well = = 459 T 458.9 458.9
= 4743 T 2388.8 2499.7
= 4150 T 1795.1 1906.1
= 5356 T = 1770 T = 1899 T
= 4762 T = 1177 T = 1305 T
Moments due to tilt & ShiftMoment due to shift = 1114.0 TmTilt moment of well cap = 178.7 TmTilt moment of Steining = 671.9 TmTilt moment of bottom plug = 4.16 TmTilt moment of well curb = 4.11 TmTilt moment of top plug = 12.19 TmTilt moment sand fill = 241.9 TmTilt moment DL+SIDL+SUB = 3777 Tm
TOTAL = 6004.1 TmTilt moment LL 168 Tm
Depth of grip below scour level = 29.58 m
Well foundation Bouyancy wrt HFL =
Well foundation Bouyancy wrt LWL =
Total dead weight of well
in LWL Condition =
Total dead weight of well
in HFL Condition =
At Steining stress check level
IRC: 78-2000For well in cement concrete, Kd = 0.03
For One Lane 70R loading::
Determination of Maximum reaction Case ::
Impact Factor = 8.80 % Impact Factor C/C of expansion gap 110 C/C of expansion gapOverhang on both side 1.2 Overhang on both sideSpan 107.6 Span.
G = Gust factor = 2CD = Drag Co-efficient 1.44A1 = Exposed area of Deck Superstructure as seen in elevation
Exposed area 957 m2
Hence, transverse wind force on Deck Superstruct 3734.4 kNActing at 26.75 m from pier base
Wind load on Live Load ::
Exposed Area 198G=Gust factor 2
1.2
Hence, transverse wind forces 643.85 kNActing at 31.5 m from pier base
Longitudinal force on LL 160.96 kNActing at 31.5 m from pier base
Wind load on Pier ::
For Pier Cap porrtion
Exposed Area 9.5 m2
0.8G = Gust factor = 2
m2
CD= Drag co-efficient
CD = Drag Co-efficient =
Hence, transverse wind force on Pier cap 19.9 kNActing at 20.9 m from pier base
For Pier column (Height from 15-20m)
Exposed Area 19.8
1.4G = Gust factor = 2
Hence, transverse wind force on Pier 70.08 kNActing at 17.43 m from pier base
For Pier column (Height from 10-15m)
Exposed Area 19.8
1.4G = Gust factor = 2
Hence, transverse wind force on Pier 65.23 kNActing at 12.48 m from pier base
For Pier column (Height Upto 10m)
Exposed Area 40
1.4G = Gust factor = 2
Hence, transverse wind force on Pier 119.22 kNActing at 5 m from pier base
Total Transverse wind load on the pier 465.3Total transverse moment at pier base due to wind forces 12322.3Total transverse moment at Well Base due to wind forces 32096
CD = Drag Co-efficient =
CD = Drag Co-efficient =
CD = Drag Co-efficient =
Bridge situated In ( for 50 m/s basic wind speed )Terrain with obstructions
T Longitudinal force 16.10 TTmLongitudinal moment well base 11912 Tm TmLongitudinal moment pier base 5071 Tm
Forces and Moments due to Seismic Force:
i) The span is less than 15 meter.
ii) The total length of the bridge is less than 60 meter.
Zone = V
Span Length = 30.00 > 15
Total Length = 90.00 > 60
Soil Condition at Pile Cap Bottom Level = Hard
Seismic Analysis Required - "Yes", "No" = YES
Hence the bridge is to be designed for Seismic Forces.
Since the bridge is in Zone- V ,vertical component of the seismic force is to be considered to act simultaneously for the design.
= 0.666667
Horizontal seismic force =
Where = Seismic Force to be resisted
D.L = DL of the from the superstructure & substructure upto the scour level
L.L = Live Load
= Horizontal Seismic Coefficient
= (z/2) x (Sa/g) / (R/I)
Z = Zone Factor
I = Importance Factor
= 1.50 Important Bridge
= 1.00 Other Bridge
R = Reduction Factor
= 4.00
(Considering ductile detailing)
F applied at centre of mass of superstructur L =
Dist. of top of pier cap where 1mm x =
deflection required
DL from superstructure:
S.No Item Vertical Load (t)
1 Longitudinal Girders 5114.00
2 Crash Barrier 220.00
3 Wearing Coat 217.800
4 Deck Slab + Cross girder 0.00
5 Hand rail 0.00
5 Footpath 145.20
As per IRC :6-2010 included for seismic force calculation, no calculation of seismic force is required for structures in Zone -II & Zone -III, if the two conditions stated below are satisfied simultaneously.
AV x Ah
Feq Ah x (D.L + L.L)
Feq
Ah
5697.00
Youngs Modulus E = 5000 x (40) ^ 0.5 / 1000
Moment of Inertia I =
F = 6 * E * I / (x^2 * (3L - x))
F =
Fundamental time period T = 2 x (D / (1000 x F)) ^0.5
where D =
= DL from the superstructure =
= Live Load =
T =
Average Response Acceleration Coefficient Sa/g = 1.36 / T
For medium soil Sa/g = 2.5 (0.00 <= T <= 0.55)
= 1.36/T (0.55 <= T <= 4.00)
Taking Sa / g = 1.288
Horizontal Seismic Coefficient = 0.18 x 1.28753099728255 x 4 / 1.5
Vertical Seismic Coefficient Vh =
F req. to produce 1mm 'd' at top of pier
D1 + D2
D1
D2
Ah
Since the bridge is in Zone- V ,vertical component of the seismic force is to be considered to act simultaneously for the design.
DL of the from the superstructure & substructure upto the scour level
Zone No. Zone factor
V 0.36
IV 0.24
III 0.16
II 0.10
= 29.9 m
= 21.9 m
As per IRC :6-2010 included for seismic force calculation, no calculation of seismic force is required for structures in Zone -II &
5000 x (40) ^ 0.5 / 1000 = 31622777 KN/m^2
= 36.95 m^4
6 * E * I / (x^2 * (3L - x)) = 215584 KN/m
= 215.58 KN/mm
2 x (D / (1000 x F)) ^0.5
56970.00 KN
3163.89 KN
= 1.056 sec
= 1.288
(0.00 <= T <= 0.55)
(0.55 <= T <= 4.00)
0.18 x 1.28753099728255 x 4 / 1.5 0.087
0.058
Seismic cases for pier base Check Seismic cases for Foundation CheckSeismic Case :: Longitudinal Direction
Sl. No. Load due to
1 Dead load of Superstructure 444.92 104.4
2 SIDL 50.72 104.4
3 Pedestal+Cap 26.74 95.3
4 Pier Column 84.67 91.95
Total seismic force (Longitudinal Direction) 608.00 102.10 Total seismic force (Longitudinal Direction)
Seismic Case :: Transverse Direction
Sl. No. Load due to
1 Dead load of Superstructure 444.92 108.15
2 SIDL 50.72 112.00
3 Pedestal+Cap 26.74 95.3
4 Pier Column 84.67 91.95
5 Live load (Max. Re.) 5.51 113.2
Total seismic force (Transverse Direction) 613.00 105.64 Total seismic force (Transverse Direction)
Sl. No. Load due to
1 Dead load of Superstructure 444.92 108.15
2 SIDL 50.72 112.00
3 Pedestal+Cap 26.74 95.30
4 Pier Column 84.67 91.95
5 Live load(Max. Long) 3.56 113.20
Total seismic force (Transverse Direction) 611.00 105.62 Total seismic force (Transverse Direction)
Sl. No. Load due to
1 Dead load of Superstructure 444.92 108.15
2 SIDL 50.72 112.00
Horizontal load (T)
Acting at (m)
Horizontal load (T)
Acting at (m)
Horizontal load (T)
Acting at (m)
Horizontal load (T)
Acting at (m)
3 Pedestal+Cap 26.74 95.30
4 Pier Column 84.67 91.95
5 Live load(Max.Trans) 4.64 113.20
Total seismic force (Transverse Direction) 612.00 105.65 Total seismic force (Transverse Direction)
Seismic Case :: Vertical Direction
Sl. No. Load due to
1 Dead load of Superstructure 296.61
2 SIDL 41.47
3 Pedestal+Cap 17.82
4 Pier Column 56.45
5 Live load (Max. Re.) 3.67
Total Vertical seismic force 417.00
Sl. No. Load due to
1 Dead load of Superstructure 296.61
2 SIDL 41.47
3 Pedestal+Cap 17.82
4 Pier Column 56.45
5 Live load (Max.Long) 2.37
Total Vertical seismic force 415.00
Vertical load (T)
Vertical load (T)
Sl. No. Load due to
1 Dead load of Superstructure 296.61
2 SIDL 41.47
3 Pedestal+Cap 17.82
4 Pier Column 56.45
5 Live load (Max Trans) 3.10
Total Vertical seismic force 416.00
Vertical load (T)
Seismic cases for Foundation CheckSeismic Case :: Longitudinal Direction
Sl. No. Load due to Acting at (m)
1 Dead load of Superstructure 556.15 104.40
2 SIDL 63.40 104.40
3 Pedestal+Cap 33.42 95.30
4 Pier Column 105.84 91.95
Total seismic force (Longitudinal Direction) 759.00 102.24
Seismic Case :: Transverse Direction
Sl. No. Load due to Acting at (m)
1 Dead load of Superstructure 556.15 108.15
2 SIDL 63.40 112.00
3 Pedestal+Cap 33.42 95.30
4 Pier Column 105.84 91.95
5 Live load (Max. Re.) 6.88 113.20
Total seismic force (Transverse Direction) 766.00 105.67
Sl. No. Load due to Acting at (m)
1 Dead load of Superstructure 556.15 108.15
2 SIDL 63.40 112.00
3 Pedestal+Cap 33.42 95.30
4 Pier Column 105.84 91.95
5 Live load(Max. Long) 4.45 113.20
Total seismic force (Transverse Direction) 764.00 105.59
Sl. No. Load due to Acting at (m)
1 Dead load of Superstructure 556.15 108.15
2 SIDL 63.40 112.00
Horizontal load (T)
Horizontal load (T)
Horizontal load (T)
Horizontal load (T)
3 Pedestal+Cap 33.42 95.30
4 Pier Column 105.84 91.95
5 Live load(Max.Trans) 5.81 113.20
Total seismic force (Transverse Direction) 765.00 105.65
Determination of Capacity Of Well Foundation as per IRC 45-1972 ::
Check for Case Number Case 11Input Data:
Total Vertical Load acting at the Base of the WellNet External horizontal load acting on the well at Scour levelNet applied external moment about the base of the wellBulk Density of soilAllowable Bearing Capacity of soil
Angle of Internal Friction ( Φ ) Angle of Wall Friction (δ)
Coefficient of Active Earth PressureCoefficient of Passive earth Pressure
CHECK:Applied horizontal load on Well = 999.1 TH > M ( 1+ µµ')/r - µW
r = 16.59 mµ = tan Φ = 0.5774
therefore, H should be greater than - 2339.6 T OK
&
L = Projected width of the soil mass offering resistancce multiplied by appropriate value of shape factor
Iv = Moment of inertia of the projected area in elevation of the soil mass offering resistance
Ib = Moment of inertia of base about the axis normal to direction of horizontal forces passing through its CG
m = KH/K
I = Ib + m. Iv ( 1+ 2µ'α)
&
H < M ( 1- µµ')/r + µW
Therefore, H should be less than = 10555.1 T OK
Check for elastic state:
RHS Value 4.65LHS Value 2.79 OK
Determination of base pressure :
= (W-µ'P)/A + M B/(2I)
= (W-µ'P)/A - M B/(2I)
P = M/r = 4107.74A= Area of base of well = 95.03 m2
Therefore, = 133 T/m2 OK
& = 102 T/m2 OK
mM/I < γ (Kp-Ka)
σ1
σ2
σ1 =
σ2
OK OK
Case Vertical Load (T) Horizontal Load (T)
Case 1 12782 362= 12662.2 T Case 2 12670 356= 999.1 T Case 3 12733 357= 68146.9 Tm Case 4 12782 362= 1.8 T/m3 Case 5 12670 356= 170 T/m2 Case 6 12733 357
Case 7 12685 111930 Case 8 12685 100120 Case 9 13303 624
Case 10 12662 11180.297 Case 11 12662 9996.105 Case 12 13026 623
Case 13 12675 1118Case 14 12675 1000Case 15 13039 623
Determination of Capacity Of Well Foundation as per IRC 45-1972 ::
Check for Case Number Case 15Input Data:
Total Vertical Load acting at the Base of the WellNet External horizontal load acting on the well at Scour levelNet applied external moment about the base of the wellBulk Density of soilAllowable Bearing Capacity of soil
Angle of Internal Friction ( Φ ) Angle of Wall Friction (δ)
Coefficient of Active Earth PressureCoefficient of Passive earth Pressure
Ultimate Resistance Method:
Check that:
LHS Value = 151.83 T/m2RHS Value = 751.00 T/m2 OK
D/B = 2.69 Q = 0.64
= 35188.1 Tm
Side resisting moment
= 121220.2 Tm
= 18507.4 Tm
Hence, Total Moment about the plane of rotation
W/A < σu/2
Determination of Base resisting moment Mb at the plane of rotation
Mb = Q W B tan Φ
Hence, Base resisting moment Mb = ( For circular well, a shape Factor of 0.6 Should be multiplied)
Ms = 0.10 γ D3 (Kp-Ka) L
Ms =
Determination of resisting moment due to friction at front & back faces (Mf) about the plane of rotation
Mf = 0.11 γ (Kp-Ka) B2 D2 sinδ
Mf =
= 0.7* (Mb+Ms+Mf)
D28
As per geotech report
Therefore total resisting moment = 122441 TmApplied moment = 49733 Tm
Determination of Capacity Of Well Foundation as per IRC 45-1972 ::Ok 72708