CE 402: Part A Shallow Foundation Design Lecture No. (4): Combined Footing
Inddvidtual Footing
35
GEOTECHNICAL ENGINEERING LAB- II INDIVITUAL FOOTING GEOTECNICAL DESIGN CO-RELATION BETWEEN SPT-N VALU AND UNCONFINED COHESION,Cu BH-01 at depth= 8' SPT-N Valu= 4 Cu is found to be = 9.12/2 = 4.56 psi = ### psf = 0.66 ksf BH-02 at depth= 13' SPT-N Valu= 5 Cu is found to be= 10.88/2 5.44 psi ### psf 0.78 ksf N Cu Cu= 0.66/4 X N and Cu= 0.78/5 X N 4 0.66 Cu= 0.16 N Cu= 0.16 N 5 0.78 Rouding Cu= 0.78/5 X N Cu= 0.16 N Cu= N/6
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Transcript of Inddvidtual Footing
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
CO-RELATION BETWEEN SPT-N VALU AND UNCONFINED COHESION,CuBH-01at depth= 8'SPT-N Valu= 4Cu is found to be =9.12/2 = 4.56 psi = ### psf = 0.66 ksf
BH-02at depth= 13'SPT-N Valu= 5Cu is found to be= 10.88/2 5.44 psi ### psf 0.78 ksf
N Cu Cu= 0.66/4 X N and Cu= 0.78/5 X N4 0.66 Cu= 0.16 N Cu= 0.16 N5 0.78 Rouding Cu= 0.78/5 X N
Cu= 0.16 NCu= N/6
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
CO-RELATION BETWEEN SPT-N VALU AND UNCONFINED COHESION,Cu
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C1BH-02at depth, df 9 ft N = 10 Pu = ### kipUnconfined cohesion, Cu = 1.50 ksfLet, the footing si6'-0" X 6'-0" and F.S = 2.5
L = 6 B = 6 ftBearing Capacity,qu5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 10.95 ksfqall = qu/F.S = 4.38 ksf
Pressure from the column, qP/A = 5.56 ksfqa > qb is ok
qa= 4.38 > qb5.56So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 12.97 ft 2hi = 25.95 ftPu/(B+ha/2) X (L+ha/2) ha = 25.95 ft hc = 37 ft
ha = 2hi When hc > 2hi 0.556 37 > 25.95ha = hc 2hi > hc GWL= 0 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wa Po = 753.1 psf
X (Soil unit wt- water unit wt) Po = 0.75 ksfFrom BH-02Cc = 0.14 allowable settlement= 25 mm~32 mmeo = 0.67Sc = 6.26 inch
159.1 mmSc = 159.1<Sc(a)=32
so, footing size is sufisient for the settlement 3'-9"y
ECCENTRICITY CALCULATIONex = 0 ftey = 0.25 ft 3'-9"Ix = ### ft^4Iy = ### ft^4 7'-10"A = 36 3'-0" 3'-0"
Pu = 200 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 3'-3"qb = 6.02qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 6'-0"qb = 5.09
qb(max) < qa okqb(min) < 0 not okqb = 6.02 < qa = 4.38
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
6'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C2BH-02at depth, df =10 ft N = 5 Pu = ### kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing siz11'-0" X 7'-6"and F.S = 2.5
L = 19 B = 9 ftBearing Capacity,qu=5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.19 ksfqall = qu/F.S = 2.47 ksf
Pressure from the column, qbP/A = 1.24 ksfqa > qb is ok
qa= 2.47 > qb1.24So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 27.65 ft 2hi = 55.31 ftPu/(B+ha/2) X (L+ha/2) ha = 37 ft hc = 37 ft
ha = 2hi When hc > 2hi 0.205 37 < 55.31ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wat Po = 1511 psf
X (Soil unit wt- water unit wt) Po = 1.51 ksfFrom BH-02Cc = 0.10 allowable settlement= 25 mm~32 mmeo = 0.95Sc = 1.26 inch
31.957 mmSc = 31.957<Sc(a)=32
so, footing size is not sufisient for the settlementy
ECCENTRICITY CALCULATIONex = 0 ftey = 0.25 ft 3'-3"Ix = ### ft^4Iy = ### ft^4 7'-10"A = 171 3'-6" 3'-6"
Pu = 211.38 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 3'-9"qb = 1.25qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 7'-0"qb = 1.23
qb(max) < qa okqb(min) < 0 not okqb = 1.25 < qa = 2.47
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
7'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C3BH-01at depth, df 10 ft N = 5 Pu = ### kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing si7'-0" X 7'-0" and F.S = 2.5
L = 7 B = 7 ftBearing Capacity,qu5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.56 ksfqall = qu/F.S = 2.62 ksf
Pressure from the column, qP/A = 2.16 ksfqa > qb is ok
qa= 2.62 > qb2.16So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc = hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2 hi = 15.14 ft 2hi = 30.27 ft
Pu/(B+ha/2) X (L+ha/2) ha = 30.27 ft hc = 32 ftha = 2hi When hc > 2hi 0.216 32 > 30.27ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wa Po = 1309 psf
X (Soil unit wt- water unit wt) Po = 1.31 ksfFrom BH-01Cc = 0.20 allowable settlement= 25 mm~32 mmeo = 1.00Sc = 2.41 inch
61.12 mmSc = 61.12<Sc(a)=32
so, footing size is sufisient for the settlementy
ECCENTRICITY CALCULATIONex = 0.33 ftey = 0.50 ft 4'-0"Ix = ### ft^4Iy = ### ft^4 3'-10" 4"A = 49 ft² 3'-4" 6" 3'-8"
Pu = 105.7 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 3'-0"qb = 2.60qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 7'-0"qb = 1.72
qb(max) < qa okqb(min) < 0 not ok 3'-6"qb = 2.60 < qa = 2.62
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po
ΔP =ΔP =
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
7'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C4BH-02at depth, df =10 ft N = 5 Pu = ### kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing siz12'-6" X 9'-0"and F.S = 2.5
L = 12.5 B = 9 ftBearing Capacity,qu=5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.24 ksfqall = qu/F.S = 2.49 ksf
Pressure from the column, qbP/A = 1.55 ksfqa > qb is ok
qa= 2.49 > qb1.55So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 22.84 ft 2hi = 45.67 ftPu/(B+ha/2) X (L+ha/2) ha = 37 ft hc = 37 ft
ha = 2hi When hc > 2hi 0.205 37 < 45.67ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wat Po = 1511 psf
X (Soil unit wt- water unit wt) Po = 1.51 ksfFrom BH-02Cc = 0.10 allowable settlement= 25 mm~32 mmeo = 0.95Sc = 1.26 inch
31.901 mmSc = 31.90<Sc(a)=32
so, footing size is sufisient for the settlementy
ECCENTRICITY CALCULATIONex = 0 ftey = 1.25 ft 3'-3"Ix = ### ft^4Iy = 759.38 ft^4 1'-3"A = 112.5 4'-6" 4'-6"
Pu = 174.42 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 5'-9"qb = 1.66qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 12'-6"qb = 1.44
qb(max) < qa okqb(min) < 0 not okqb = 1.66 < qa = 2.49
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
9'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C5BH-02at depth, df =10 ft N = 5 Pu = ### kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing size12'-6" X 12-6"and F.S = 2.5
L = 20 B = 10 ftBearing Capacity,qu= 5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.10 ksfqall = qu/F.S = 2.44 ksf
Pressure from the column, qbP/A = 2.07 ksfqa > qb is ok
qa= 2.44 > qb2.07So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 30.00 ft 2hi = 60 ftPu/(B+ha/2) X (L+ha/2) ha = 37 ft hc = 37 ft
ha = 2hi When hc > 2hi 0.378 37 > 60ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wate Po = 1511 psf
X (Soil unit wt- water unit wt) Po = 1.51 ksfFrom BH-02Cc = 0.10 allowable settlement= 25 mm~32 mmeo = 0.95Sc = 2.21 inch
56.0782 mmSc = 56.08<Sc(a)=32
so, footing size is Combaind for the settlementy
ECCENTRICITY CALCULATIONex = 0 ftey = 0 ft 3'-3"Ix = 6666.67 ft^4Iy = 6666.67 ft^4 7'-10"A = 200 3'-6" 3'-6"
Pu = 414.67 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 3'-9"qb = 2.07qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 7'-0"qb = 2.07
qb(max) < qa okqb(min) < 0 not okqb = 2.07 < qa = 2.44
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
7'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C6BH-01at depth, df 10 ft N = 5 Pu = ### kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing si11'-0" X 9'-0"and F.S = 2.5
L = 11 B = 9 ftBearing Capacity,qu5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.26 ksfqall = qu/F.S = 2.50 ksf
Pressure from the column, qP/A = 2.43 ksfqa > qb is ok
qa= 2.50 > qb2.43So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 21.48 ft 2hi = 42.96 ftPu/(B+ha/2) X (L+ha/2) ha = 32 ft hc = 32 ft
ha = 2hi When hc > 2hi 0.356 32 < 42.96ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wa Po = 1359 psf
X (Soil unit wt- water unit wt) Po = 1.36 ksfFrom BH-01Cc = 0.20 allowable settlement= 25 mm~32 mmeo = 1.00Sc = 3.88 inch
98.53 mmSc = 98.53<Sc(a)=32
so, footing size is sufisient for the settlementy
ECCENTRICITY CALCULATIONex = 0 ftey = 0 ft 3'-3"Ix = ### ft^4Iy = ### ft^4A = 99 3'-6" 3'-6"
Pu = 240.3 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 3'-9"qb = 2.43qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 11'-0"qb = 2.43
qb(max) < qa ok 5'-0"qb(min) < 0 not okqb = 2.43 < qa = 2.50
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
9'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C7BH-02at depth, df 10 ft N = 5 Pu = ### kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing si9'-6" X 8'-0" and F.S = 2.5
L = 9.5 B = 8 ftBearing Capacity,qu5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.38 ksfqall = qu/F.S = 2.55 ksf
Pressure from the column, qP/A = 2.02 ksfqa > qb is ok
qa= 2.55 > qb2.02So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 18.83 ft 2hi = 37.66 ftPu/(B+ha/2) X (L+ha/2) ha = 37 ft hc = 37 ft
ha = 2hi When hc > 2hi 0.206 37 < 37.66ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wa Po = 1511 psf
X (Soil unit wt- water unit wt) Po = 1.51 ksfFrom BH-02Cc = 0.10 allowable settlement= 25 mm~32 mmeo = 0.95Sc = 1.27 inch
32.17 mmSc = 32.17<Sc(a)=32
so, footing size is sufisient for the settlement 4'-7"y
ECCENTRICITY CALCULATIONex = 0 ftey = 0 ft 4'-0"Ix = ### ft^4Iy = ### ft^4A = 76 4'-9" 4'-9"
Pu = 153.2 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 4'-0"qb = 2.02qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 9'-6"qb = 2.02
qb(max) < qa okqb(min) < 0 not okqb = 2.02 < qa = 2.55
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
8'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C8BH-01at depth, df =10 ft N = 5 Pu = ### kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing siz12'-6" X 12'-6and F.S = 2.5
L = 12.5 B = 12.5 ftBearing Capacity,qu=5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.03 ksfqall = qu/F.S = 2.41 ksf
Pressure from the column, qbP/A = 2.35 ksfqa > qb is ok
qa= 2.41 > qb2.35So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 27.03 ft 2hi = 54.06 ftPu/(B+ha/2) X (L+ha/2) ha = 32 ft hc = 32 ft
ha = 2hi When hc > 2hi 0.452 32 > 54.06ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wat Po = 1359 psf
X (Soil unit wt- water unit wt) Po = 1.36 ksfFrom BH-01Cc = 0.20 allowable settlement= 25 mm~32 mmeo = 1.00Sc = 4.79 inch
121.66 mmSc = 121.66<Sc(a)=32
so, footing size is sufisient for the settlementy
ECCENTRICITY CALCULATIONex = 0 ftey = 0.25 ft 3'-3"Ix = ### ft^4Iy = ### ft^4 7'-10"A = 156.25 3'-6" 3'-6"
Pu = 367.32 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 3'-9"qb = 2.40qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 7'-0"qb = 2.31
qb(max) < qa okqb(min) < 0 not okqb = 2.40 < qa = 2.41
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
7'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C9BH-01at depth, df 10 ft N = 5 Pu = ### kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing si11'-0" X 8'-0"and F.S = 2.5
L = 11 B = 8 ftBearing Capacity,qu5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.35 ksfqall = qu/F.S = 2.54 ksf
Pressure from the column, qP/A = 2.43 ksfqa > qb is ok
qa= 2.54 > qb2.43So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 20.20 ft 2hi = 40.41 ftPu/(B+ha/2) X (L+ha/2) ha = 32 ft hc = 32 ft
ha = 2hi When hc > 2hi 0.33 32 < 40.41ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wa Po = 1359 psf
X (Soil unit wt- water unit wt) Po = 1.36 ksfFrom BH-01Cc = 0.20 allowable settlement= 25 mm~32 mmeo = 1.00Sc = 3.63 inch
92.19 mmSc = 92.19<Sc(a)=32
so, footing size is sufisient for the settlementy
ECCENTRICITY CALCULATIONex = 0 ftey = 0 ft 4'-0"Ix = ### ft^4Iy = ### ft^4A = 88 5'-6" 5'-6"
Pu = 214.1 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 4'-0"qb = 2.43qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 11'-0"qb = 2.43
qb(max) < qa ok 6'-6"qb(min) < 0 not okqb = 2.43 < qa = 2.54
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
8'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C10BH-02at depth, df 10 ft N = 5 Pu = 84.44 kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing si6'-0" X 6'-0" and F.S = 2.5
L = 6 B = 6 ftBearing Capacity,qu5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.76 ksfqall = qu/F.S = 2.70 ksf
Pressure from the column, qP/A = 2.35 ksfqa > qb is ok
qa= 2.70 > qb2.35So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 12.97 ft 2hi = 25.95 ftPu/(B+ha/2) X (L+ha/2) ha = 25.95 ft hc = 37 ft
ha = 2hi When hc > 2hi 0.235 37 > 25.95ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wa Po = 1190 psf
X (Soil unit wt- water unit wt) Po = 1.19 ksfFrom BH-02Cc = 0.10 allowable settlement= 25 mm~32 mmeo = 0.95Sc = 1.25 inch
31.69 mmSc = 31.69<Sc(a)=32
so, footing size is sufisient for the settlement 4'-7"y
ECCENTRICITY CALCULATIONex = 0 ftey = 0 ft 3'-0"Ix = ### ft^4Iy = ### ft^4A = 36 3'-0" 3'-0"
Pu = 84.44 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 3'-0"qb = 2.35qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 6'-0"qb = 2.35
qb(max) < qa okqb(min) < 0 not okqb = 2.35 < qa = 2.70
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
3'-10"x
6'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C11BH-02at depth, df =10 ft N = 5 Pu = ### kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing siz12'-0" X 8'-0"and F.S = 2.5
L = 12 B = 8 ftBearing Capacity,qu=5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.34 ksfqall = qu/F.S = 2.54 ksf
Pressure from the column, qbP/A = 1.71 ksfqa > qb is ok
qa= 2.54 > qb1.71So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 21.05 ft 2hi = 42.1 ftPu/(B+ha/2) X (L+ha/2) ha = 37 ft hc = 37 ft
ha = 2hi When hc > 2hi 0.203 37 < 42.1ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wate Po = 1511 psf
X (Soil unit wt- water unit wt) Po = 1.51 ksfFrom BH-02Cc = 0.10 allowable settlement= 25 mm~32 mmeo = 0.95Sc = 1.25 inch
31.6592 mmSc = 31.66<Sc(a)=32
so, footing size is sufisient for the settlementy
ECCENTRICITY CALCULATIONex = 0.67 ftey = 0 ft 6'-0"Ix = 512.00 ft^4Iy = 1152.00 ft^4A = 96 4'-0" 3'-7"
Pu = 164.03 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 6'-0" 0'-8"qb = 1.80qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix)qb = 1.61
qb(max) < qa ok 8'-0"qb(min) < 0 not okqb = 1.80 < qa = 2.54
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
3'-10"x
12'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C12BH-01at depth, df 10 ft N = 5 Pu = 79.59 kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing si5'-6" X 5'-6" and F.S = 2.5
L = 5.5 B = 5.5 ftBearing Capacity,qu5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 6.88 ksfqall = qu/F.S = 2.75 ksf
Pressure from the column, qP/A = 2.63 ksfqa > qb is ok
qa= 2.75 > qb2.63So footing size is sufisient for the column lood
SETTLEMENT CALCULATIONSc =
hi = 11.89 ft 2hi = 23.79 ftPu/(B+ha/2) X (L+ha/2) ha = 23.79 ft hc = 32 ft
ha = 2hi When hc > 2hi 0.263 32 < 23.79ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wa Po = 1122 psf
X (Soil unit wt- water unit wt) Po = 1.12 ksfFrom BH-01Cc = 0.20 allowable settlement= 25 mm~32 mmeo = 1.00Sc = 2.61 inch
66.31 mmSc = 66.31<Sc(a)=32
so, footing size is sufisient for the settlementy
ECCENTRICITY CALCULATIONex = 0 ftey = 0 ft 2'-9"Ix = 76.26 ft^4Iy = 76.26 ft^4A = 30.25 2'-9" 2'-9"
Pu = 79.59 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 2'-9"qb = 2.63qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 5'-6"qb = 2.63
qb(max) < qa okqb(min) < 0 not okqb = 2.63 < qa = 2.75
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
5'-6"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C5BH-02at depth, df =10 ft N = 5 Pu = ### kipUnconfined cohesion, Cu = 0.83 ksfLet, the footing size27'-6" X 12-0"and F.S = 2.5
L = 26 B = 12 ftBearing Capacity,qu= 5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 5.95 ksfqall = qu/F.S = 2.38 ksf
Pressure from the column, qbP/A = 2.36 ksfqa > qb is ok
qa= 2.38 > qb2.36 So footing size is sufisient for the column lood
SETTLEMENT CALCULATIONSc =
hi = 37.29 ft 2hi = 74.59 ftPu/(B+ha/2) X (L+ha/2) ha = 37 ft hc = 37 ft
ha = 2hi When hc > 2hi 0.543 37 < 74.59ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wate Po = 1511 psf
X (Soil unit wt- water unit wt) Po = 1.51 ksfFrom BH-02Cc = 0.10 allowable settlement= 25 mm~32 mmeo = 0.95Sc = 3.04 inch
77.1266 mmSc = 77.13<Sc(a)=32
so, footing size is Combaind for the settlementy
ECCENTRICITY CALCULATIONex = 0 ftey = 0 ft 3'-3"Ix = ### ft^4Iy = ### ft^4 7'-10"A = 312 3'-6" 3'-6"
Pu = 737 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 3'-9"qb = 2.36qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 7'-0"qb = 2.36
qb(max) < qa okqb(min) < 0 not okqb = 2.36 < qa = 2.38
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
Q1 = 369.68 kipQ2 = 367.32 kipL3 = 13.5 ft L = 26 ft B =
X = (Q2*L3)/(Q1+Q2) A = B*L L2+X =L/2X = 6.77 A = 312 L2 =0.5*(L-2*X)
L2 = 6.23
L1 = L - (L2+L3)L1 = 6.27
x
7'-0"
12 ft
qb =(Q1+Q2)/AL2 =0.5*(L-2*X) qb = 2.36
L - (L2+L3)
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C1BH-02at depth, df 10 ft N = 6 Pu = 50.6 kipUnconfined cohesion, Cu = 1.00 ksfLet, the footing si7'-0" X 7'-0" and F.S = 2.5
L = 4.5 B = 4.5 ftBearing Capacity,qu5 X Cu(1+0.2 X Df/B)+(1+0.2 X B/L)
qu= 8.42 ksfqall = qu/F.S = 3.37 ksf
Pressure from the column, qP/A = 2.50 ksfqa > qb is ok
qa= 3.37 > qb2.50So footing size is sufisient for the column lood
SETTLEMENT CALCULATIONSc = (Cc*H)/(1+eo) X log X (Po+ P)/Po
hi = 9.73 ft 2hi = 19.46 ftP = Pu/(B+ha/2) X (L+ha/2) ha = 19.46 ft hc = 37 ft
ha = 2hi When hc > 2hi P = 0.25 37 > 19.46ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wa Po = 1002 psf
X (Soil unit wt- water unit wt) Po = 1.00 ksfFrom BH-02Cc = 0.10 allowable settlement= 25 mm~32 mmeo = 0.95Sc = 1.16 inch
29.42 mmSc = 29.42<Sc(a)=32
so, footing size is sufisient for the settlement 3'-9"y
ECCENTRICITY CALCULATIONex = 0 ftey = 0.25 ft 3'-9"Ix = 34.17 ft^4Iy = 34.17 ft^4 7'-10"A = 20.25 3'-6" 3'-6"
Pu = 50.6 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 3'-3"qb = 2.87qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 7'-0"qb = 2.13
qb(max) < qa okqb(min) < 0 not okqb = 2.87 < qa = 3.37
so, footing eccentricity is ok
hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
7'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
DESIGN OF FOUNDATION FOR COLUMN, C1BH-02at depth, df 10 ft N = 7 Pu = ### kipUnconfined cohesion, Cu = 1.17 ksfLet, the footing si7'-0" X 7'-0" and F.S = 2.5
L = 7 B = 7 ftBearing Capacity,qu5 X Cu(1+0.2 X Df/B)*(1+0.2 X B/L)
qu= 8.70 ksfqall = qu/F.S = 3.48 ksf
Pressure from the column, qP/A = 2.16 ksfqa > qb is ok
qa= 3.48 > qb2.16So footing size is sufisient for the column load
SETTLEMENT CALCULATIONSc =
hi = 15.14 ft 2hi = 30.27 ftPu/(B+ha/2) X (L+ha/2) ha = 30.27 ft hc = 37 ft
ha = 2hi When hc > 2hi 0.216 37 > 30.27ha = hc 2hi > hc GWL= 7 ft wt = ### pcfPo = water table X soil unit wt + (ha/2 - wa Po = 1315 psf
X (Soil unit wt- water unit wt) Po = 1.32 ksfFrom BH-02Cc = 0.10 allowable settlement= 25 mm~32 mmeo = 0.95Sc = 1.23 inch
31.2 mmSc = 31.2<Sc(a)=32
so, footing size is sufisient for the settlement 3'-9"y
ECCENTRICITY CALCULATIONex = 0 ftey = 0.25 ft 3'-9"Ix = ### ft^4Iy = ### ft^4 7'-10"A = 49 3'-6" 3'-6"
Pu = 105.7 kipqb(max) = (Pu/A)+(Pu*ex/Iy)+(Pu*ey/Ix) 3'-3"qb = 2.29qb(min) = (Pu/A)-(Pu*ex/Iy)-(Pu*ey/Ix) 7'-0"qb = 2.02
qb(max) < qa okqb(min) < 0 not okqb = 2.29 < qa = 3.48
so, footing eccentricity is ok
(Cc*H)/(1+eo) X log X (Po+ΔP)/Po hi ={SQRT(B²+38 X B X L+ L²)-B-L}/2ΔP =
ΔP =
ft²
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
x
7'-0"
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
CO-RELATION BETWEEN SPT-N VALU AND UNCONFINED COHESION,CuBH-01at depth= 8'SPT-N Valu= 4Cu is found to be =9.12/2 = 4.56 psi = ### psf = 0.66 ksf
BH-02at depth= 13'SPT-N Valu= 5Cu is found to be= 10.88/2 5.44 psi ### psf 0.78 ksf
N Cu Cu= 0.66/4 X N and Cu= 0.78/5 X N4 0.66 Cu= 0.16 N Cu= 0.16 N5 0.78 Rouding Cu= 0.78/5 X N
Cu= 0.16 NCu= N/6
GEOTECHNICAL ENGINEERING LAB- IIINDIVITUAL FOOTING GEOTECNICAL DESIGN
CO-RELATION BETWEEN SPT-N VALU AND UNCONFINED COHESION,Cu
