CONSULTING Engineering Calculation Sheet E N G I N E E R … · · 2015-08-22Factor for SPT, N...
Transcript of CONSULTING Engineering Calculation Sheet E N G I N E E R … · · 2015-08-22Factor for SPT, N...
Job No. Sheet No. Rev.
Job Title
XX
Material Properties
Characteristic strength of concrete, fcu (≤ 60N/mm2; HSC N/A) 40 N/mm
2 OK
Yield strength of longitudinal steel, fy 460 N/mm2
Yield strength of shear link steel, fyv 460 N/mm2
Type of concrete and density, ρc 24 kN/m3
Factor of Safety
Factor of safety (overall base (effective) bearing and shaft (effective) friction), FOS2.0
Factor of safety (base (effective) bearing), FOS2 (usually 3.5) 3.0
Factor of safety (shaft (effective) friction), FOS3 (usually 1.0 to 1.5) 1.5
Loading factor, K (between 1.40 and 1.60 depending on DL to LL ratio) 1.50 BS8110
Note loading factor K multiplies SLS loads for ULS loads for section (reinforcement) design; cl. 2.4.3.1.1
Soil Description
Water unit weight, γw = 9.81kN/m3 9.8 kN/m
3
Soil name
Dry bulk unit weight, γdry 20.0 kN/m3
Saturated bulk unit weight, γsat 20.0 kN/m3
Undrained shear strength, Su(z) 22.5 + 22.5z kPa
Note that S u can be obtained from SPT (Stroud) or SPT (Fukuoka) values; Tomlinson
Effective cohesion, c' 0.0 kPa
Effective angle of shear resistance, φ' 38.0 degrees
Note that φ ' can be obtained from SPT (Peck) or CPT (Durgunoglu and Mitchell) values; Tomlinson
Effective angle of friction on shaft, δ' 25.1 degrees
SPT, N(z) 5 + 5.0z
Factor for SPT, N value (base effective bearing), KSPT,b 250
Pile (drilled shaft) in sands with L ≤ 10m, Q b ' ≤ 2900kPa 57.5L/10 Quiros and Reese
Pile (drilled shaft) in sands with L > 10m, Q b ' ≤ 2900kPa 57.5 Quiros and Reese
Pile (drilled shaft) in sands with L ≥ 10m, Q b ' ≤ 2900kPa 100 Shioi and Fukui
Pile in undrained cohesive soils 200 Neoh
Pile (driven displacement) in non-plastic silts 38L/D ≤ 300
Pile (driven displacement) in sands and gravels 38L/D ≤ 380 Meyerhof
Pile in drained cohesionless soils 400 Neoh
Factor for SPT, N value (shaft effective friction), KSPT,s 2.0
Pile in undrained cohesive or drained cohesionless soils 2.0 Neoh
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Analysis Method
Undrained, drained or empirical analysis ?
For clays, perform undrained, drained and empirical analyses;
For sands / gravels, perform drained and empirical analyses;
For rocks, perform drained and empirical analyses;
Gross (effective) bearing capacity limit, qflimit(z=L-L0) or qflimit'(z=L-L0) 10166 kPa
Note that the base gross (effective) bearing capacity is limited to values up to 15000kPa Tomlinson
because Vesic showed that at penetration depths greater than 20 pile diameters, a peak value
of base resistance is reached which is not exceeded at greater penetrations depths;
Note that this limiting value is D- and L- dependent, thus affecting the multi-D multi-L pile
capacity charts which has thus been set to be limited by the automatically calculated value;
qflimit(z=L-L0) or qflimit'(z=L-L0) = Nq,strip.σv'(z=20D-L0) ≤ 15MPa 10166 kPa
48.9
σv'(z=20D-L0) = psurface+γdry.(Lc+20D) Invalid kPa
cl. 2.4.3.1.1 σv'(z=20D-L0) = psurface+(γsat-γw).(Lc+20D-zu)+γdry.zu 208 kPa
σv'(z=20D-L0) = psurface+(γsat-γw).(Lc+20D) Invalid kPa
Shaft adhesion limit or shaft effective stress limit, Salimit(z) or τalimit'(z) 89 kPa
Note that the shaft adhesion or the shaft effective stress is limited to 110kPa because Vesic Tomlinson
showed that at penetration depths greater than 20 pile diameters, a peak value of skin friction
is reached which is not exceeded at greater penetrations depths;
Note that this limiting value is D- and L- dependent, thus affecting the multi-D multi-L pile
capacity charts which has thus been set to be limited by the automatically calculated value;
Quiros and Reese Salimit(z) or τalimit'(z) = Ks.tanδ'.σv'(z=20D-L0) ≤ 110kPa 89 kPa
Quiros and Reese σv'(z=20D-L0) = psurface+γdry.(Lc+20D) Invalid kPa
Shioi and Fukui σv'(z=20D-L0) = psurface+(γsat-γw).(Lc+20D-zu)+γdry.zu 208 kPa
σv'(z=20D-L0) = psurface+(γsat-γw).(Lc+20D) Invalid kPa
Include or exclude base resistance ?
Note that in general, the contribution of base resistance in bored piles should be ignored due Gue
to difficulty of proper base cleaning, especially in wet hole (with drilling fluid); The contribution and
of base resistance should only be used if it is constructed in dry hole, if proper inspection of Partners
the base can be carried out or if base grouting is implemented; Furthermore, a relatively larger
base movement is required to mobilise the maximum base resistance as compared to the
displacement needed to fully mobilise shaft resistance; The base displacement of approximately
5% to 10% of the pile diameter is generally required to mobilise the ultimate base resistance
provided that the base is properly cleaned and checked;
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Pile Group Dimensions
Width of pile group (pile cap) in x, Bcap 3.000 m
Length of pile group (pile cap) in y, Lcap 3.000 m
Pile Dimensions
Pile section shape
Pile shaft diameter (circular) or width (square), D 750 mm
Pile shaft cross sectional area, Aps = πD2/4 (circular) or D
2 (square) 441786 mm
2
Pile base diameter (circular) or width (square), Db 750 mm OK
Pile base cross sectional area, Apb = πDb2/4 (circular) or D
2 (square) 441786 mm
2 OK
Depth of pile cap base from ground level, Lc (>= 0.000m) 2.500 m OK
Depth of pile z=0 level from pile cap base, L0 (>= 0.000m) 0.000 m OK
Depth of pile founding level from pile cap base, L (>=L0) 60.000 m OK
Note that L 0 accounts for poor ground near surface level where no contribution of shaft skin
friction capacity is adopted, in fact negative skin friction is considered over L 0 length if requested;
Depth of water table from ground level, zu 3.000 m
Note that the soil beneath the water table has an effective submerged unit weight of about
half of the soil above the water table, thus reducing the drained overall pile effective capacity;
Hence use the highest water table forseeable;
Enter a negative z u value for water table above ground level, this representing a flood event
or a bridge pier within a sea or river with the ground level being the sea or river bed;
However, a water table above ground level may unconservatively decrease the overall pile
(effective) capacity utilisation, thus consider also the case when the water table is at ground level;
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L
L0
z
zu
Lc
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Pile Reinforcement
Pile type 40 N/mm2
Precast Driven Square RC Pile or Insitu Bored Circular RC Pile
Pile compression capacity design method
Cover to all reinforcement, cover4 (usually 75) 75 mm
Longitudinal steel reinforcement diameter, φp 32 mm
Longitudinal steel reinforcement number, np 12
Longitudinal steel area provided, As,prov,p = np.π.φp2/4 9651 mm
2
Shear link diameter, φlink,p 10 mm
Number of links in a cross section, i.e. number of legs, nlink,p 2
Area provided by all links in a cross-section, Asv,prov,p = nlink,p.π.φlink,p2/4 157 mm
2
Pitch of links, Sp 150 mm
Estimated steel reinforcement quantity 171 kg/m3
[ 7850 . A s,prov,p / A ps ]; No laps; Links ignored;
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Precast (Pretensioned Spun) Driven Circular RC Pile
Effective area of concrete, Aeff 33694 mm2
Effective prestress, fpe 6.3 N/mm2
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Insitu Bored Circular RC Pile (API Micropile)
Yield strength of API pipe, fy,API 552 N/mm2
Outer diameter of API pipe, ODAPI 177.8 mm
Wall thickness of API pipe, tAPI 9.19 mm
Cross sectional area of API pipe, AAPI = π.[ODAPI2-(ODAPI-2.tAPI)
2]/4 N/A mm
2
Cross sectional area of grout, Ac,API = Aps-AAPI N/A mm2
Elastic modulus of concrete, Ec = 5500.(fcu/1.5)0.5 28402 N/mm
2 BS8110
Elastic modulus of steel, Es 210000 N/mm2 cl. 2.5.3
API PIPE SIZES FOSstr = 2.0
Grade N80 ( fy = 80,000 PSI / 552 MPa )
OD (mm)Thickness (mm)ID (mm) Qult (kN) Qall (kN)
114.3 7.37 99.56 1,367 683
7.52 111.96 1,558 779
9.19 108.62 1,878 939
11.19 104.62 2,247 1,124
12.7 101.6 2,517 1,259
7.72 124.26 1,767 883
9.17 121.36 2,076 1,038
10.54 118.62 2,361 1,180
8.94 150.42 2,471 1,235
10.59 147.12 2,896 1,448
12.06 144.18 3,268 1,634
8.05 161.7 2,370 1,185
9.19 159.42 2,687 1,344
10.36 157.08 3,008 1,504
11.51 154.78 3,319 1,660
12.65 152.5 3,623 1,811
13.72 150.36 3,904 1,952
9.52 174.66 3,041 1,520
10.92 171.86 3,461 1,731
12.7 168.3 3,986 1,993
14.27 165.16 4,440 2,220
15.86 161.98 4,891 2,446
11.43 196.24 4,116 2,058
12.7 193.7 4,546 2,273
14.15 190.8 5,029 2,515
10.03 224.44 4,078 2,039
11.05 222.4 4,473 2,237
11.89 220.72 4,796 2,398
13.84 216.82 5,536 2,768
11.43 250.14 5,185 2,592
12.57 247.86 5,677 2,838
298.4 12.42 273.56 6,160 3,080
339.7 13.06 313.58 7,398 3,699
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127.0
219.1
244.5
273.0
139.7
168.3
177.8
193.7
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Pile SLS Loading (Including Negative Skin Friction)
Surcharge at surface, psurface 0 kPa
Pile SLS vertical load, Fpile,v,n 3000 kN
Pile group (pile cap) SLS vertical load, Fpilecap,v 15000 kN
Note that F pile,v,n and F pilecap,v can be positive (downward) or negative (upwards);
Pile SLS vertical (compressive) NSF load, Fpile,v,NSF 0 kN
Note NSF = negative skin friction; Note F pile,v,NSF = ( πD or 4D).L 0 . β .[ σ v '(z=-L 0 )+ σ v '(z=0)]/2;
Consideration of NSF ? Not Considered
NSF reduction factor, β 0.30 Meyerhof
Clay
0.20-0.25 Garlanger
Silt
0.25-0.35 Garlanger
Sand
0.35-0.50 Garlanger
Effective vertical stress at z=-L0 level, σv'(z=-L0) 50 kPa
Case when (z u −−−− L c ) >= MAX (B cap , L cap ) Invalid
σv'(z=-L0) = psurface+γdry.Lc N/A kPa
Case when 0 < (z u −−−− L c ) < MAX (B cap , L cap ) Valid
σv'(z=-L0) = psurface+γdry.Lc 50 kPa
Case when (z u −−−− L c ) = 0 Invalid
σv'(z=-L0) = psurface+γdry.Lc N/A kPa
Case when (z u −−−− L c ) < 0 and z u >= 0 Invalid
σv'(z=-L0) = psurface+(γsat-γw).(Lc-zu)+γdry.zu N/A kPa
Case when z u < 0 Invalid
σv'(z=-L0) = psurface+γsat.Lc+γw.(-zu)-γw.(Lc+(-zu)) N/A kPa
Note that the above equation reduces to σ v '(z=-L 0 ) = p surface+( γ sat - γ w ).L c ;
Effective vertical stress at z=0 level, σv'(z=0) 50 kPa
Case when (z u −−−− L c −−−− L 0 ) >= MAX (B cap , L cap ) Invalid
σv'(z=0) = psurface+γdry.(Lc+L0) N/A kPa
Case when 0 < (z u −−−− L c −−−− L 0 ) < MAX (B cap , L cap ) Valid
σv'(z=0) = psurface+γdry.(Lc+L0) 50 kPa
Case when (z u −−−− L c −−−− L 0 ) = 0 Invalid
σv'(z=0) = psurface+γdry.(Lc+L0) N/A kPa
Case when (z u −−−− L c −−−− L 0 ) < 0 and z u >= 0 Invalid
σv'(z=0) = psurface+(γsat-γw).(Lc+L0-zu)+γdry.zu N/A kPa
Case when z u < 0 Invalid
σv'(z=0) = psurface+γsat.(Lc+L0)+γw.(-zu)-γw.(Lc+L0+(-zu)) N/A kPa
Note that the above equation reduces to σ v '(z=0) = p surface+( γ sat - γ w ).(L c+L 0 );
Total pile SLS vertical (compressive) load (per pile), Fpile,v,comp 3000 kN
Note F pile,v,comp = MAX(0, F pile,v,n )+F pile,v,NSF ;
Total pile SLS vertical (tensile) load (per pile), Fpile,v,tens 0 kN
Note F pile,v,tens = ABS(MIN(0, F pile,v,n ));
Pile ULS Loading (Including Negative Skin Friction)
Total pile ULS vertical (compressive) load (per pile), Fpile,v,comp,uls = K.Fpile,v,comp 4500 kN
Total pile ULS vertical (tensile) load (per pile), Fpile,v,tens,uls = K.Fpile,v,tens 0 kN
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Executive Summary
Undrained overall pile capacity N/A N/A
Drained overall pile effective capacity N/A N/A
Empirical overall pile effective capacity 89% OK
Pile axial compression capacity 68% OK
Pile axial tension capacity 0% OK
Pile detailing requirements
Undrained overall pile group capacity N/A N/A
Drained overall pile group capacity N/A N/A
Empirical overall pile group capacity N/A N/A
Overall utilisation summary 89%
% Vertical reinforcement in pile 2.18 %
Estimated pile steel reinforcement quantity 171 kg/m3
[Note that steel quantity in kg/m3 can be obtained from 78.5 x % rebar];
Material cost: concrete, c 300 units/m3 steel, s 3500 units/tonne
Reinforced concrete material cost = c+(est. rebar quant).s 900 units/m3
OK
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Undrained Overall Pile Capacity
Undrained shear strength at z=0 level, Su(z=0) N/A kPa
Undrained shear strength at z=L-L0 level, Su(z=L-L0) N/A kPa
Base bearing capacity, Qb = (πDb2/4 or Db
2).qf(z=L-L0) N/A kN
Gross bearing capacity, qf(z=L-L0) = Nc.Su(z=L-L0) (<=qflimit(z=L-L N/A kPa Terzaghi
Note gross bearing capacity set to 0.0kPa if base resistance excluded;
Bearing capacity factor, Nc = 9.0 N/A Meyerhof
Shaft friction capacity, Qs = (πD or 4D).(L-L0).Sa N/A kN
Average shaft adhesion, Sa = [Sa(z=0)+Sa(z=L-L0)]/2 N/A kPa
Sa(z=0) = F.α(z=0).Su(z=0) (<=Salimit(z)) N/A kPa
Sa(z=L-L0) = F.α(z=L-L0).Su(z=L-L0) (<=Salimit(z)) N/A kPa
Note that S a (z=0) is the shaft adhesion at z=0 level and S a (z=L-L 0 )
is the shaft adhesion at z=L-L 0 level;
Shaft adhesion factor, α(z=0) 0.80 McClelland, Nordlund
Shaft adhesion factor, α(z=L-L0) 0.80 McClelland, Nordlund
Shaft adhesion length factor, F = function (L/D) 1.00
Note that α is 0.30 (under-reamed base piles); Tomlinson
Note that α is 0.30-0.60 (stiff over-consolidated clays); Whitaker and Cooke
Note that α is 0.30 (heavily fissured clay); Tomlinson
Note that α is 0.45 (very stiff clays, S u >= 150kPa); Neoh
Note that α is 0.45-0.60 (firm to stiff clays, eg. London Clay); Tomlinson
Note that α is 0.45 (bored piles), 0.80 (driven piles); Sutton
Note that α is 0.50 (firm to stiff clays, S u >= 70kPa); API
Note that α is 1-[(S u -25)/90] (soft to firm clays, 25kPa < S u < 70kPa); API
Note that α is 0.80-1.00 (soft Malaysian Clay); Gue and Partners
Note that α is 1.00 (very soft clays, S u <= 25kPa); Neoh, API
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Compressive
Compressive and Tensile
Compressive
Compressive
McClelland, Nordlund
McClelland, Nordlund
Whitaker and Cooke
Gue and Partners
Note that B in the term L/B above is D;
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Pile weight minus soil weight removed, Fpile = Aps.L.(ρc-γdry) N/A kN
Note under-reamed base dimensions ignored in calculation of F pile as deemed negligible;
Note conservatively, dry bulk unit weight assumed for density of displaced soil;
Combined base bearing and shaft friction capacity, Pf = Qb + Qs N/A kN
Base and Shaft Capacity Factored Individually
Compressive Undrained pile base capacity (factored), Qb / FOS2 N/A kN
Compressive and Tensile Undrained pile shaft capacity (factored), Qs / FOS3 N/A kN
Compressive Undrained pile base and shaft capacity (factored), Qb / FOS2 + Qs N/A kN
Base and Shaft Capacity Factored Together
Compressive Undrained pile base and shaft capacity (factored), Pf / FOS1 N/A kN
Tensile Undrained pile base and shaft capacity (factored), Qs / FOS1 N/A kN
Undrained overall pile capacity for vertical (compressive) load, MIN (Qb / FOS N/A kN
Undrained overall pile capacity for vertical (tensile) load, MIN (Qs / FOS3, Qs / FOSN/A kN
Undrained overall pile capacity utilisation = MAX (Fpile,v,comp / (MIN (Qb / FOS2 N/A N/A
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0
1000
0 5 10 15 20 25 30 35 40 45 50 55
Undrained Overall Pile (Compressive) Capacity, MIN (Qb/ FOS2+ Q
s/ FOS3, Pf/ FOS1) -Fpile(kN)
Length of Pile, L (m)
Undrained Overall Pile
(Compressive) Capacity Chart
D = Db = 300mm D = Db = 450mm D = Db = 600mm D = Db = 750mm
D = Db = 900mm D = Db = 1050mm D = Db = 1200mm D = Db = 1350mm
D = Db = 1500mm D = Db = 1650mm D = Db = 1800mm D = Db = 1950mm
D = Db = 2100mm
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Drained Overall Pile Effective Capacity
Effective vertical stress at pile top z=0 level, σv'(z=0) N/A kPa
Case when (z u −−−− L c −−−− L 0 ) >= 0 N/A
σv'(z=0) = psurface+γdry.(Lc+L0) N/A kPa
Case when (z u −−−− L c −−−− L 0 ) < 0 and z u >= 0 N/A
σv'(z=0) = psurface+(γsat-γw).(Lc+L0-zu)+γdry.zu N/A kPa
Case when z u < 0 N/A
σv'(z=0) = psurface+γsat.(Lc+L0)+γw.(-zu)-γw.(Lc+L0+(-zu)) N/A kPa
Note that the above equation reduces to σ v '(z=0) = p surface+( γ sat - γ w ).(L c+L 0 );
Effective vertical stress at water table z=zu-Lc-L0 level, σv'(z=zu-Lc-L0) N/A kPa
Case when z u >= 0 N/A
σv'(z=zu-Lc-L0) = psurface+γdry.zu N/A kPa
Case when z u < 0 N/A
σv'(z=zu-Lc-L0) = 0 N/A kPa
Effective vertical stress at critical depth z=20D-L0 level, σv'(z=20D-L0) N/A kPa
Case when (z u −−−− L c −−−−20D) >= 0 N/A
σv'(z=20D-L0) = psurface+γdry.(Lc+20D) N/A kPa
Case when (z u −−−− L c −−−−20D) < 0 and z u >= 0 N/A
σv'(z=20D-L0) = psurface+(γsat-γw).(Lc+20D-zu)+γdry.zu N/A kPa
Case when z u < 0 N/A
σv'(z=20D-L0) = psurface+γsat.(Lc+20D)+γw.(-zu)-γw.(Lc+20D+(-zN/A kPa
Note that the above equation reduces to σ v '(z=20D-L 0 ) = p surface+( γ sat - γ w ).(L c+20D);
Effective vertical stress at pile base z=L-L0 level, σv'(z=L-L0) N/A kPa
Unit weight, γ' N/A kN/m3
Case when (z u −−−− L c −−−− L) >= MAX (B cap , L cap ) N/A
σv'(z=L-L0) = psurface+γdry.(Lc+L) N/A kPa
γ' = γdry N/A kN/m3
Case when 0 < (z u −−−− L c −−−− L) < MAX (B cap , L cap ) N/A
σv'(z=L-L0) = psurface+γdry.(Lc+L) N/A kPa
γ' = zu/MAX(Bcap, Lcap) . [γdry - (γsat - γw)] + (γsat - γw) N/A kN/m3
Case when (z u −−−− L c −−−− L ) = 0 N/A
σv'(z=L-L0) = psurface+γdry.(Lc+L) N/A kPa
γ' = γsat - γw N/A kN/m3
Case when (z u −−−− L c −−−− L ) < 0 and z u >= 0 N/A
σv'(z=L-L0) = psurface+(γsat-γw).(Lc+L-zu)+γdry.zu N/A kPa
γ' = γsat - γw N/A kN/m3
Case when z u < 0 N/A
σv'(z=L-L0) = psurface+γsat.(Lc+L)+γw.(-zu)-γw.(Lc+L+(-zu)) N/A kPa
Note that the above equation reduces to σ v '(z=L-L 0 ) = p surface+( γ sat - γ w ).(L c+L);
γ' = γsat - γw N/A kN/m3
Structure, Member Design - Geotechnics Piles v2015.01.xlsx
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14
Engineering Calculation Sheet
Consulting Engineers jXXX
Structure, Member Design - Geotechnics Piles
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L
L0
z
zu
Lc
Job No. Sheet No. Rev.
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Base effective bearing capacity, Qb' = (πDb2/4 or Db
2).qf'(z=L-L0) N/A kN
Gross effective bearing capacity, qf'(z=L-L0) (<=qflimit'(z=L-L0)) N/A kPa Terzaghi
= sc.dc.Nc,strip.c' N/A kPa
+ sq.dq.Nq,strip.σv'(z=L-L0) N/A kPa
+ sγ.dγ.Nγ,strip.Db/2.γ' N/A kPa
Note gross effective bearing capacity set to 0.0kPa if base resistance excluded;
Note for piles bored in rock, s c .d c = 1.2, s q .d q = 1.0 and s γ .d γ = 0.7; Gue and Partners
Note for piles bored in rock, q f ' = 0.3q uc , where Neoh
q f ' for weak rock 1500 kPa Neoh
q f ' for medium rock 2400-7300 kPa Neoh
q f ' for strong fresh rock 10000 kPa Neoh
Note typically for driven piles, N q = 20 (loose sand) to 100 (very dense sand), Neoh
and for bored piles N q = 12 (loose sand) to 40 (very dense sand);
Equations for bearing capacity factors
+20D); Cohesion Factors
Shape factor, N/A EC7
Depth factor, N/A
Note D and B in the above equation are L c+L and D b , respectively;
Bearing capacity factor, Nc,strip N/A
Soils Nc,strip = (Nq,strip-1).cotφ' N/A EC7 (Prandtl)
Rocks Nc,strip N/A Kulhawy and Goodman
Surcharge Factors
Shape factor, N/A EC7
Note B' and L' in the above equation are D b and D b , respectively;
Depth factor, dq N/A
Note D and B' in the above equation are L c+L and D b , respectively;
Bearing capacity factor, Nq,strip N/A
Soils N/A EC7 (Reissner)
Rocks Nq,strip N/A Kulhawy and Goodman
Self Weight Factors
Shape factor, N/A EC7
Note B' and L' in the above equation are D b and D b , respectively;
Depth factor, N/A
Bearing capacity factor, Nγ,strip N/A
Soils Nγ,strip = 2.0(Nq,strip-1).tanφ' N/A EC7 (Hansen)
Rocks Nγ,strip N/A Kulhawy and Goodman
Structure, Member Design - Geotechnics Piles v2015.01.xlsx
Structure, Member Design - Geotechnics Piles 19-08-15
Engineering Calculation Sheet
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Shaft effective friction capacity, Qs' = (πD or 4D).Σ(∆L.τa') N/A kN
Equation for shaft effective stress
Soils / Rocks τa'(z=0) = Ks.tanδ'.σv'(z=0) (<=τalimit'(z)) N/A kPa
τa'(z=zu-Lc-L0) = Ks.tanδ'.σv'(z=zu-Lc-L0) (<=τalimit'(z)) N/A kPa
τa'(z=20D-L0) = Ks.tanδ'.σv'(z=20D-L0) (<=τalimit'(z)) N/A kPa
τa'(z=zu-Lc-L0) = Ks.tanδ'.σv'(z=zu-Lc-L0) (<=τalimit'(z)) N/A kPa
Gue and Partners τa'(z=L-L0) = Ks.tanδ'.σv'(z=L-L0) (<=τalimit'(z)) N/A kPa
Note that τ a '(z=0) is the shaft effective stress at z=0 level and τ a '(z=L-L 0 )
is the shaft effective stress at z=L-L 0 level;
Note τ a ' = σ h '.tan δ ' = K s σ v '.tan δ ';
Note effective cohesion, c' ignored due to disturbed soil adjacent to pile foundation;
Ks.tanδ' 0.43
Calculated Ks.tanδ' = kKs.K0.(OCR)0.5.tanδ' = kKs.(1-sinφ 0.22 Burland, Meyerhof
Coefficient of horizontal soil stress, kKs 1.25 Tomlinson
Overconsolidation ratio, OCR 1.0
Effective angle, δ ' for sandy gravel 40.0 degrees Neoh
Effective angle, δ ' for sand 32.0 degrees Neoh
Effective angle, δ ' for silts and clays 21.0-31.0 degrees Neoh
Effective angle, δ ' for bored pile residual angle degrees Neoh
Manual Ks.tanδ' 0.43
Pile bored in very loose to dense sands (Meyerhof)K s .tan δ ' = 0.10-0.35 Neoh, Meyerhof
Pile bored in loose sands (Davies and Chan)K s .tan δ ' = 0.15-0.30 Gue and Partners
Pile bored in dense sands (Davies and Chan)K s .tan δ ' = 0.25-0.60 Gue and Partners
Pile CFA in chalk K s .tan δ ' = 0.45 CIRIA574
Pile CFA in chalk with N >= 10, q uc >= 4MPaK s .tan δ ' = 0.80 CIRIA86
Pile bored or driven cast-in-place in chalkK s .tan δ ' = 0.80 CIRIA574
Pile driven in very loose to dense sands (Meyerhof)K s .tan δ ' = 0.44-1.20 Neoh, Meyerhof
Rocks τa'(z=0) = αβquc (<=τalimit'(z)) N/A kPa Gue and Partners
EC7 (Prandtl) τa'(z=L-L0) = αβquc (<=τalimit'(z)) N/A kPa Gue and Partners
Kulhawy and Goodman Note that τ a '(z=0) is the shaft effective stress at z=0 level and τ a '(z=L-L 0 )
is the shaft effective stress at z=L-L 0 level;
Reduction factor, α 0.30
Correlation factor, β 0.25
Unconfined uniaxial compressive strength, quc 1500 kPa
EC7 (Reissner)
Kulhawy and Goodman
Note typically τ a ' = 0.05q uc , where Neoh
τ a ' for weak rock 100-140 kPa Neoh
τ a ' for medium rock 700-1000 kPa Neoh
EC7 (Hansen) τ a ' for strong rock 1000-1400 kPa Neoh
Kulhawy and Goodman
Structure, Member Design - Geotechnics Piles v2015.01.xlsx
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Engineering Calculation Sheet
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Job No. Sheet No. Rev.
Job Title
XX
Burland, Meyerhof
Neoh, Meyerhof
Gue and Partners
Gue and Partners
Neoh, Meyerhof
Gue and Partners
Gue and Partners
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Structure, Member Design - Geotechnics Piles
Structure, Member Design - Geotechnics Piles v2015.01.xlsx
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Engineering Calculation Sheet
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Compressive
Compressive and Tensile
Compressive
Compressive
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Structure, Member Design - Geotechnics Piles v2015.01.xlsx
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Structure, Member Design - Geotechnics Piles
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Pile weight minus soil weight removed, Fpile = Aps.L.(ρc-γdry) N/A kN
Note under-reamed base dimensions ignored in calculation of F pile as deemed negligible;
Note conservatively, dry bulk unit weight assumed for density of displaced soil;
Combined base effective bearing and shaft effective friction capacity, Pf' = Q N/A kN
Base and Shaft Effective Capacity Factored Individually
Compressive Drained pile base effective capacity (factored), Qb' / FOS2 N/A kN
Compressive and Tensile Drained pile shaft effective capacity (factored), Qs' / FOS3 N/A kN
Compressive Drained pile base and shaft effective capacity (factored), Qb' / FOS N/A kN
Base and Shaft Effective Capacity Factored Together
Compressive Drained pile base and shaft effective capacity (factored), Pf' / FOS N/A kN
Tensile Drained pile base and shaft effective capacity (factored), Qs' / FOS N/A kN
Drained overall pile effective capacity for vertical (compressive) load, MIN (Q N/A kN
Drained overall pile effective capacity for vertical (tensile) load, MIN (Qs' / FOS N/A kN
Drained overall pile effective capacity utilisation = MAX (Fpile,v,comp / (MIN (Qb N/A N/A
Structure, Member Design - Geotechnics Piles v2015.01.xlsx
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Made by Date Chd.
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Job No. Sheet No. Rev.
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Compressive
Compressive and Tensile
Compressive
Compressive
Structure, Member Design - Geotechnics Piles 19-08-15
Structure, Member Design - Geotechnics Piles v2015.01.xlsx
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Engineering Calculation Sheet
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0
1000
0 5 10 15 20 25 30 35 40 45 50 55
Empirical Overall Pile Effective (Compressive) Capacity, MIN (Qb' / FOS2+ Q
s'/ FOS3, Pf' / FOS1) -Fpile
(kN)
Length of Pile, L (m)
Drained Overall Pile Effective
(Compressive) Capacity Chart
D = Db = 300mm D = Db = 450mm D = Db = 600mm D = Db = 750mm
D = Db = 900mm D = Db = 1050mm D = Db = 1200mm D = Db = 1350mm
D = Db = 1500mm D = Db = 1650mm D = Db = 1800mm D = Db = 1950mm
D = Db = 2100mm
Job No. Sheet No. Rev.
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Empirical Overall Pile Effective Capacity
SPT at z=0 level, N(z=0) 5
SPT at z=L-L0 level, N(z=L-L0) 305
Base effective bearing capacity, Qb' = (πDb2/4 or Db
2).qf'(z=L-L0) 0 kN
Gross effective bearing capacity, qf'(z=L-L0)=KSPT,b.N(z=L-L0) (<=q 0 kPa
Note gross effective bearing capacity set to 0.0kPa if base resistance excluded;
Shaft effective friction capacity, Qs' = (πD or 4D).(L-L0).τa' 6985 kN
Average shaft effective stress, τa' = [τa'(z=0)+τa'(z=L-L0)]/2 49 kPa
τa'(z=0) = KSPT,s.N(z=0) (<=τalimit'(z)) 10 kPa
τa'(z=L-L0) = KSPT,s.N(z=L-L0) (<=τalimit'(z)) 89 kPa
Note that τ a '(z=0) is the shaft effective stress at z=0 level and τ a '(z=L-L 0 )
is the shaft effective stress at z=L-L 0 level;
Pile weight minus soil weight removed, Fpile = Aps.L.(ρc-γdry) 106 kN
Note under-reamed base dimensions ignored in calculation of F pile as deemed negligible;
Note conservatively, dry bulk unit weight assumed for density of displaced soil;
Combined base effective bearing and shaft effective friction capacity, Pf' = Q 6985 kN
Base and Shaft Effective Capacity Factored Individually
Compressive Empirical pile base effective capacity (factored), Qb' / FOS2 0 kN
Compressive and Tensile Empirical pile shaft effective capacity (factored), Qs' / FOS3 4657 kN
Compressive Empirical pile base and shaft effective capacity (factored), Qb' / FOS 4657 kN
Base and Shaft Effective Capacity Factored Together
Compressive Empirical pile base and shaft effective capacity (factored), Pf' / FOS 3492 kN
Tensile Empirical pile base and shaft effective capacity (factored), Qs' / FOS 3492 kN
Empirical overall pile effective capacity for vertical (compressive) load, MIN (Q 3386 kN
Empirical overall pile effective capacity for vertical (tensile) load, MIN (Qs' / FOS 3492 kN
Empirical overall pile effective capacity utilisation = MAX (Fpile,v,comp / (MIN (Q 89% OK
Structure, Member Design - Geotechnics Piles 19-08-15
Engineering Calculation Sheet
Consulting Engineers jXXX
Structure, Member Design - Geotechnics Piles v2015.01.xlsx
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Structure, Member Design - Geotechnics Piles 19-08-15
Structure, Member Design - Geotechnics Piles v2015.01.xlsx
Engineering Calculation Sheet
Consulting Engineers
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0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 5 10 15 20 25 30 35 40 45 50 55
Empirical Overall Pile Effective (Compressive) Capacity, MIN (Qb' / FOS2+ Q
s'/ FOS3, Pf' / FOS1) -Fpile
(kN)
Length of Pile, L (m)
Empirical Overall Pile Effective
(Compressive) Capacity Chart
D = Db = 300mm D = Db = 450mm D = Db = 600mm D = Db = 750mm
D = Db = 900mm D = Db = 1050mm D = Db = 1200mm D = Db = 1350mm
D = Db = 1500mm D = Db = 1650mm D = Db = 1800mm D = Db = 1950mm
D = Db = 2100mm
Job No. Sheet No. Rev.
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XX
Pile Reinforcement Design
Precast Driven Square RC Pile or Insitu Bored Circular RC Pile
Pile Longitudinal Reinforcement Design
Percentage of reinforcement As,prov,p/Aps x 100% 2.18 %
Axial compression capacity, Ncap,pile,comp 4418 kN
SLS Design Ncap,pile,comp = 0.25fcu.Aps 4418 kN Gue and Partners
ULS Design Ncap,pile,comp = 0.35fcu.Aps + (0.67fy-0.35fcu).A N/A kN
Note alternatively, SLS design including steel reinforcement can be estimated by N cap,pile,comp BS8004
= 0.275f cu .A ps + 0.55f y .A s,prov,p with 0.55f y limited to 175N/mm2;
Total pile vertical (compressive) load (per pile), Fpile,v,comp,(uls) 3000 kN
SLS Design F pile,v,comp 3000 kN
ULS Design F pile,v,comp,uls N/A kN
Axial compression capacity utilisation = Fpile,v,comp,(uls)/Ncap,pile,comp 68% OK
Axial tension capacity, Ncap,pile,tens 2442 kN
SLS Design Ncap,pile,tens = 0.55fy.As,prov,p 2442 kN
ULS Design Ncap,pile,tens = 0.95fy.As,prov,p N/A kN
Total pile vertical (tensile) load (per pile), Fpile,v,tens,(uls) 0 kN
SLS Design F pile,v,tens 0 kN
ULS Design F pile,v,tens,uls N/A kN
Axial tension capacity utilisation = Fpile,v,tens,(uls)/Ncap,pile,tens 0% OK
Pile Shear Reinforcement Design
Note that pile shear design to be performed as per column design;
Pile Detailing Requirements
All detailing requirements met ? OK
Min longitudinal steel reinforcement number, np (>=6 circular; >=4 square) 12 OK
Min longitudinal steel reinforcement diameter, φp (>=12mm) 32 mm OK
Percentage of reinforcement As,prov,p/Aps x 100% (>0.4% and <5.0%) 2.18 % OK
Longitudinal steel reinforcement pitch (>=75mm+φp but >=100mm+φp for T40; <=300mm)143 mm OK
Circular pile bar pitch = π.(D-2.cover4-2.φlink,p-φp)/np 143 mm
Square pile bar pitch = 4.(D-2.cover4-2.φlink,p-φp)/np N/A mm
Min link diameter, φlink,p (>=0.25φp; >=8mm) 10 mm OK
Max link pitch, Sp (<=12φp, <=300mm, <=D) 150 mm OK
Require an overall enclosing link.
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Precast (Pretensioned Spun) Driven Circular RC Pile
SLS axial compression capacity, Ncap,pile,comp = 0.25.(fcu-fpe).Aeff N/A kN
SLS total pile vertical (compressive) load (per pile), Fpile,v,comp N/A kN
Axial compression capacity utilisation = Fpile,v,comp/Ncap,pile,comp N/A N/A
Insitu Bored Circular RC Pile (API Micropile)
Gue and Partners
SLS axial compression capacity, Ncap,pile,comp N/A kN
Reinforcement only Ncap,pile,comp = fy,API.AAPI/2.0 N/A kN
Composite section (strain compatibility) Ncap,pile,comp = 0.5fy,API.(AAPI+Ac,API N/A kN BS8004 cl. 7.4.6.3.1
Concrete filled CHS Ncap,pile,comp = (0.91fy,API.AAPI+0.45f N/A kN BS5400 cl. 11.3.7
SLS total pile vertical (compressive) load (per pile), Fpile,v,comp N/A kN
Axial compression capacity utilisation = Fpile,v,comp/Ncap,pile,comp N/A N/A
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Structure, Member Design - Geotechnics Piles v2015.01.xlsx
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Accounting for Tolerance in Pile Installation
BS8004 cl. 7.4.6.3.1
BS5400 cl. 11.3.7
Moment induced at head due to out-of-position, M = 0.075Fpile,v,comp,uls 338 kNm
Lateral force induced at head due to out-of-vertical, H = Fpile,v,comp,uls/75 60 kN
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Structure, Member Design - Geotechnics Piles v2015.01.xlsx
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Group Pile Design
Undrained Analysis
Consideration of NSF ? N/A
Total pile group SLS vertical (compressive) NSF load, Fpilegroup,v,NSF N/A kN Tomlinson
Note NSF = negative skin friction; Note F pilegroup,v,NSF = B cap .L cap . γ dry or sat .L 0 ;
Pile group capacity, N/A kN Tomlinson
Note D, B, L, s and s b in the above equation are L-L 0 , B cap , L cap , S a , S u (z=L-L 0 )
and D, respectively;
Undrained overall pile group capacity for vertical (compressive) load, QN/A kN
Undrained overall pile group capacity utilisation N/A N/A
Note utilisation is (F pilecap,v + F pilegroup,v,NSF ) / (Q u / FOS 1 );
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Structure, Member Design - Geotechnics Piles v2015.01.xlsx
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Drained Analysis
Note there is no risk of drained overall pile group failure if FOS of individual piles Gue and Partners
are adequate;
Empirical Analysis
Note perform undrained or drained analysis;
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Scheme Design (Cohesive Soils)
Gue and Partners
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Scheme Design (Non Cohesive Soils)
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