"COMBINED PILE RAFT FOUNDATION GEOTECHNICAL CALCULATION -Rolf Katzenbach

Apmācību semināru cikls
"Būvkonstrukciju kvalitatīva
projektēšana" ID Nr. EM 2019/105
05.12.2019. seminārs "Kombinēto
pāļu un seklo pamatu ģeotehniskie
aprēķini/Combined Pile Raft
Foundation Geotechnical
Calculations" 1
«Būvkonstrukciju kvalitatīva projektēšana»
ID Nr. EM 2019/105
Rīga, 2019
Training seminar / Apmācību seminārs
Combined Pile Raft Foundation Geotechnical Calculations
Kombinēto pāļu un seklo pamatu ģeotehniskie aprēķini
December 05, 2019, Riga
Prof.Dr.-Ing. Rolf Katzenbach (Germany)

Calculations" 2
NETWORK: LU WIFI
USERNAME: wlan50
PASSWORD: buvnieciba
3EM iepirkums „Apmācību semināru cikla “Būvkonstrukciju kvalitatīva projektēšana” organizēšana un norises nodrošināšana” ID Nr. EM 2019/105
WIFIWIFI
Introduction
•Pile deformations and load bearing capacity
mobilization at various deformations
•Calculation methodologies
Agenda / 10:00 - 11:30Agenda / 10:00 - 11:30

Calculations" 3
Coffee break / 11:30 - 12:00Coffee break / 11:30 - 12:00
•Additional issues in pile group calculations
•Shallow foundations
Agenda / 12:00 - 13:30Agenda / 12:00 - 13:30

Calculations" 4
Lunch break / 13:30 - 14:30Lunch break / 13:30 - 14:30
•Pile – raft foundations
•Manual calculation of combined pile-raft foundation
(CPRF)
Agenda / 14:30 – 16:00Agenda / 14:30 – 16:00

Calculations" 5
Introduction. Pile Deformations and Load Bearing Capacity
Mobilization. Calculation Methodologies.
Ievads. Pāļu deformācijas un pāļu nestspējas mobilizācija pie
dažādām to deformācijām. Aprēķina metodikas.
Prof. Dr.- Ing. Rolf Katzenbach (Germany)
10
Prof. Dr.-Ing. Rolf Katzenbach
• Managing Director of the International Consulting Office Professor Katzenbach
• Past Chairman of the TC 212 “Deep Foundations“ of ISSMGE
• Board Member of the German Tunnel Association (STUVA)
• Past Board Member of the German Geotechnical Society (DGGT)
• Board Member of DFI Europe
• Publicly Certified Official Expert and Independent Checking Engineering (ICE)
Anastasia Bychkova, M.Sc.
• Project Manager
Ingenieursozietät Professor Dr.-Ing. Katzenbach GmbH Tel.: (+49) 61 51 – 130 13 10
Robert-Bosch-Straße 9 Fax: (+49) 61 51 – 130 13 20
64293 Darmstadt Mob.: (+49) 171 – 8959809
Germany E-Mail: sekretariat@katzenbach-ingenieure.de
EM iepirkums „Apmācību semināru cikla “Būvkonstrukciju kvalitatīva projektēšana” organizēšana un norises nodrošināšana” ID Nr. EM 2019/105
About the speaker

Calculations" 6
11
Skin friction pile
Base pressure
Foundations
Shallow Foundations Pile Foundations
Combined Pile-Raft
Foundation (CPRF)
Foundation systemsFoundation systems
12
1
1 Pile-Soil-Interaction
2 Pile-Pile-Interaction
2
3
3 Raft-Soil-Interaction
4 Pile-Raft-Interaction
4
Combined Pile-Raft Foundation (CPRF)Combined Pile-Raft Foundation (CPRF)

Calculations" 7
13
  dydxy,x,s)s(R k,raft
     

m
1j
k,raftj,k,pilek,tot sRsRsR
     sRsRsR j,k,sj,k,bj,k,pile 
Total resistance of the CPRF:
Pile resistance:
Raft resistance:
, ,
1
,
( )
( )
m
pile k j
j
CPRF
tot k
R s
R s
 


CPRF coefficient:
14
Circular Raft Single Pile “1-Pile-Raft-Model”
l = 30.0 m
D = 1.5 m
Dslab = 12.0 m
d = 1.0 m
Three foundation types:

Calculations" 8
15
Single pile foundation
s = settlement
s
16
Axial Force
Settlement
5 MN
8 MN
13 MN
s = settlement
s
Single pile foundation

Calculations" 9
17
18
“1-Pile-Raft-Model” → Pile-Raft Interaction
s = settlement
s

Calculations" 10
19
s
Axial Force
Settlement
4 MN
6 MN
12 MN
s = settlement
20

Calculations" 11
21
Combined Pile Raft
Foundation
Spread Foundation Pile Foundation
Thickness of raft: d = 1.0 m
Diameter of pile: D = 1.5 m
Variations of pile center distance: e/D = 3.0 / 6.0 / 8.5
Variations of pile length: l/D = 10 / 20 / 30
Numerical Studies
Basic studies on the pile-pile interactionBasic studies on the pile-pile interaction
22
d = 1.0 m
D = 1.5 m
e = 3 · D = 4.5 m
l = 20 · D = 30 m
Configuration of the model with 25 piles (e/D = 3)

Calculations" 12
23
d = 1.0 m
D = 1.5 m
e = 6 · D = 9 m
l = 20 · D = 30 m
Configuration of the model with 9 piles (e/D = 6)
24
e / D = 6.0e / D = 3.0
Load settlement behaviour

Calculations" 13
25
Pile
Foundation
e = 3 · D
CPRF
e = 3 · D
26
Pile
Foundation
e = 6 · D
CPRF
e = 6 · D

Calculations" 14
27
.
.
. Details:
www.issmge.org/tc212International
CPRF-Guideline
ISSMGE · Technical Committee TC 212 Deep FoundationsISSMGE · Technical Committee TC 212 Deep Foundations
28
Bridge pier
foundation types
Option 1:
Spread Foundation
Option 2:
CPRF with 6 Piles
Option 3:
Pile Foundation with
12 Piles
Numerical studies: Comparison between different foundation typesNumerical studies: Comparison between different foundation types

Calculations" 15
29
Soil Investigation
30
Loam /
Debris
Rock
Loam / Debris Rock
Bulk mass weight g kN/m³ 20.0 22.0
g´ kN/m³ 10.0 12.0
Water content w % 14.5 -
Liquid cimit wL % 30.5 -
Plastic cimit wP % 18.5 -
Uniaxial strength qu kN/m² 175 - 220 500
Friction angle j´ ° 25 35
Cohesion c´ kN/m² 5 100
Modulus of stiffness Es MN/m² 20 150
Soil investigation
results

Calculations" 16
31
Numerical model of
the whole system
32
Option 1:
Spread foundation
Option 2:
CPRF with 6 piles
Option 3:
Pile foundation with 12 piles
Numerical models of the
foundation systems

Calculations" 17
33
Option 1:
Spread foundation
34
1: Edge Pile P1
2: Corner Pile P2
Option 2:
Combined Pile-Raft
Foundation (CPRF)

Calculations" 18
35
1: Center pile P1
2: Edge pile P2
3: Edge pile P3
4: Corner pile P4
Option 3:
Pile foundation
36
Bending moment
Pile foundation
Spread foundation
CPRF

Calculations" 19
37
Pile foundation
Spread foundation
Combinded Pile-Raft Foundation (CPRF)
Settlement
[cm]
Resistance [MN]Working Load: 30 [MN]
1.2
3.6
11.1
38
Settlement
Costs of pile production
(Assumption: 400 EUR per meter)
Spread foundation 11.1 cm -
CPRF (6 Piles) 3.6 cm 36,000 EUR
Pile foundation
(12 Piles)
1.2 cm 120,000 EUR

Calculations" 20
39
→ Combined Pile-Raft Foundation (CPRF)
Settlements calculated for a shallow
foundation: s > 40 cm
z = 0 - 20 m → 75 - 80 %
Messeturm · Frankfurt am Main,
Germany
Settlements:
z
s0
(z)
s dz
E (z)

 
Messeturm · Frankfurt am Main, GermanyMesseturm · Frankfurt am Main, Germany
40
Quaternary
sand and gravel
Frankfurt Clay

Calculations" 21
41
Quaternary
sand and gravel
Frankfurt Clay
Settlement isolines [cm]
42
Average pile load: 11.3 MN

Calculations" 22
43
Total building load: = 1,570 MN
αCPRF = 0.46
Ultimate pile load: 64 x 11.3 MN = 725 MN
Load transfer by raft: = 845 MN
Contact pressure: 250 kN/m2
44
Accomplished: CPRF of 64 piles (laverage = 30 m)
Costs of pile production:
64 piles of 30 m at 600 €/m  1.2 Mio. €
Pile foundation: 316 piles (l = 30 m)
316 piles of 30 m at 600 €/m  5.7 Mio. €
Savings in costs of
pile production 4.5 Mio. €
CO2 reduction: 2,500 t
Comparison of costs for the piles

Calculations" 23
QUESTIONS AND ANSWERS
Coffee break / 11:30 - 12:00Coffee break / 11:30 - 12:00

Calculations" 24
Additional Issues in Pile Group Calculations.
Shallow Foundation Deformations. Best Calculation Methods.
Dažādas problēmas pāļu aprēķinos.
Plātņu pamatu deformācijas, piemērotākās aprēķina metodikas.
48
Optimised geotechnical data aquisitionOptimised geotechnical data aquisition

Calculations" 25
49
Interpretation of the results of the soil investigation for the definition of the
three-dimensional soil profile (interpolation of stratigraphy)
BK 2BK 1
z
BK 2BK 1
z
BK 2BK 1
z
Geometric difficulties
Soil investigationSoil investigation
50
Physical difficulties:
Natural variance of the soil
mechanical parameters
0
5
10
15
20
25
30
0 10 20 30 40 50 60
Wassergehalt [%]
Plastizitätsindex Ip
Depth under surface [m]
p
w
[%]
water content w
plasticity index Ip

Calculations" 26
51
Possible situation of the stratigraphic
boundaries based on punctiform soil
information
Kriging Method (stochastic approach) Variant 2
Variant 3
Variant 1
52
In-situ analysis
Geotechnical investigation
methods
Laboratory analysis In-situ load tests

Calculations" 27
53
indirect exploration
probing, i.e.
• dynamic probing
• pressure probing
geophysical measurement
• seismic measurement
• geoelectric measurement
calibration on
direct exploration!
direct exploration
• excavation
• borehole
• groundwater level
• field parameter, i.e.
- subsoil
temperature
- dissolved oxygen
- pH-value
in-situ analysis
• grain-size distribution
• shear strength
 j , c
• compression test
 stiffness modulus ES
• water permeability
 permeability k
• thermal analysis
 l, c
• chemical analysis
analysis in
laboratory
Geotechnical investigation
methods
54
Allowable geometry of an
investigation dith without any
retaining/support structure
Attention: Stability of the investigation ditch!?!
Investigation ditch to detect the geometry of an
existing foundation
≥ 0.60 m
 1.25 m

Calculations" 28
55
Drilling
machine
Usual core diameter
d = 101 mmCore drilling
56
Falling weight
Sounding rod
Sounding rod point
Height to
fall
Ramming a sonde into the soil using a falling
weight with a constant height to fall, counting
the number of hits for a defined penetration
depth
 Measurement of the number of hits:
N10 = numer of hits for the penetration
of 10 cm into the subsoil
Number of hits
N10
z
T
S
Obstacle, e.g.
stones
Influence of the
skin friction
Dynamic probing - heavy - DPH (indirect investigation method)
Only in combination with
direkt investigation (e.g. driven
core sampler)

Calculations" 29
57
Cone penetration test CPT (indirect investigation method)
58
Depth under surface
[m]
Point pressure
[MPa] Soil layers
0.0
Middle sand
9.0
11.5
12.0
16.5
Gravel
Fine sand
Clay, alternating
with sand
1.2
Filling
0 10 20 30 40 50

Calculations" 30
59
Geotechnical Categories (GC):
define the minimum requirements on extent and quality of geotechnical
investigations, analysis and supervision of the construction (EC 7-1, 2.1 (8))
• Geotechnical Category GC 1
Project with low complexity factor
Project with medium complexity factor
Project with high complexity factor
increasing
complexity
factor
• deep excavations
• high-rise buildings
• tunnels, embankment dams, etc.
Geotechnical Categories Eurocode EC 7Geotechnical Categories Eurocode EC 7
60
Classification of the project into a
Geotechnical Category GC
GC 2, GC 3GC 1
Preliminary investigation
Main investigationInvestigation
Investigation during
construction
Observational
method
new
classification
if necessary
new
classification
if necessary Development of the main investigation
Scheme of soil investigationScheme of soil investigation

Calculations" 31
61
Type of construction/structure Horizontal distance / adjustment
(EC 7-2)
Normal buildings and industries Grid space of 15 m to 40 m
Extensive structures (storage site etc.) Grid space of max. 60 m
Long structures (road, railway track etc.) Distance of 20 m to 200 m
Special constructions (bridge, chimney etc.) 2 to 6 exploration points per
foundation
Long dams, embankments etc. Distance of 25 m to 75 m
Long retaining structures for watertightness Distance of 25 m to 50 m
In general:
• difficult subsoil conditions = tight grid
• steady suboil conditions = wide grid
Optimised geotechnical data aquisition
Scheme of soil investigationScheme of soil investigation
62
strip foundation
za
bB
za
15 - 40 m
za
 3,0×bF
and za  6 m
h
za
za
 1,5×bB
0,8×h < za < 1,2×h
and za  6 m
bF
za
bB
za
20 - 200 m
za

 6 m
Investigation
depth za
Investigation grid
raft foundation
dams
Interaction between soil investigation and design (EC 7-2)

Calculations" 32
63
Interaction between soil investigation and ground water conditions (EC 7-2)
za
 0,4× h  t + 2 mza
za
 1,0×H + 2 m resp. t + 2 mza

za
t + 5 m
GW-table beneath
maximum excavation
za
t
h
za
t
H
resp.za
0,4 h za
za
 H + 2 m resp. t + 2 mza

za
t + 5 m
za
t
h
za
t
H
Excavation pits
resp.
GW-table above
maximum excavation
Depth of
investigation za
If GW-aquifer is bigger, than:
64
Investigation depth za for piles, pile groups and CPRFs (EC 7)
za ≥ 3 ∙ Df
za ≥ 5.0 m
Pile groups and CPRFs:
za ≥ 1.0 ∙ bg
Piles:
Lpile = ?

Calculations" 33
65
Enhanced pile load tests using Osterberg Cells
Pile load tests in-situPile load tests in-situ
66
Type of Pile
Diameter
[m]
Depth
[m]
Bored Pile 1.2 11.0
- Load tests of piles with Osterberg Cells (O-Cells) –
Airport Frankfurt am Main, GermanyAirport Frankfurt am Main, Germany

Calculations" 34
67
68

Calculations" 35
69
Pile head load [MN]
Shaft Resistance
Total Resistance
Base Resistance
Pile head
movement
[cm]
70
Skin friction pile
Base pressure
Foundations
Combined Pile-Raft
Foundation (CPRF)

Calculations" 36
71
Influence of the stress levelInfluence of the stress level
72
M A I N
Flößerbrücke
80 kN/m2
800 kN/m2
200 400 600 800
Ultimate skin friction [kN/m2]
Commerzbank
Frankfurt am Main,
Germany
Frankfurt Limestone
Pile load tests in-situPile load tests in-situ

Calculations" 37
73
Frankfurt am Main, GermanyFrankfurt am Main, Germany
74
Quaternary
Frankfurt Clay
Frankfurt Limestone
Commerzbank Frankfurt am Main, GermanyCommerzbank · Frankfurt am Main, Germany

Calculations" 38
75
Construction Time: 1994 - 1997
Height: 299 m
Foundation: Pile Foundation
Settlement: 2.1 cm
76

Calculations" 39
77
78
PalaisQuartier Frankfurt am Main, GermanyPalaisQuartier · Frankfurt am Main, Germany

Calculations" 40
79
100
80
60
40
20
0
-20
Load [MN]
Displacement [mm]
Upper Osterberg Cell
Lower Osterberg Cell
Top ground surface 102.02 msl
Concrete 70.60 msl
59.00 msl
0 5 10 15 20 25 30
D = 1.7 m
5 m
Pile load tests with Osterberg Cells (O-Cells)
80
0 5 10 15 20 25 30
-20
-10
0
10
20
30
40
50
60
70
80
90
oberes Pfahlsegment
Maximum skin friction
qs = 830 kN/m²
Upper segment
0 5 10 15 20 25 30
90
80
70
60
50
40
30
20
10
0
-10
-20
Intermediary and lower segment
Load [MN]
Displacement [mm]
Pile load tests with
Osterberg Cells
(O-Cells)

Calculations" 41
81
0 5 10 15 20 25 30
40
20
0
-20
-40
-60
-80
Load [MN]
Top ground surface 102,02 msl
Concrete 70,60 msl
59,00 msl
Displacement [mm]
D = 1.7 m
5 m
Pile load tests with Osterberg Cells (O-Cells)
82
0 5 10 15 20 25 30
-70
-60
-50
-40
-30
-20
-10
0
10
20
30
40
mittleres Pfahlsegment
unteres Pfahlsegment
Last [MN]
Maximum skin friction (improved)
qs = 1,040 kN/m²
Maximum base pressure
qb = 7,000 kN/m²
0 5 10 15 20 25 30
40
30
20
10
0
-10
-20
-30
-40
-50
-60
-70
Displacement [mm]
Intermediary segment
Lower segment
Load [MN]Sum of load: 78 MN
Pile load tests with
Osterberg Cells
(O-Cells)

Calculations" 42
83
Fill
Silt and sand layers
Silty sand
Silt
Clay and marl layers
140 m
International Business Center Solomenka · Kiev, UkraineInternational Business Center Solomenka · Kiev, Ukraine
84
Silt and sand layers: qs,k = 65 kN/m²
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Load [MN]
Pile segments 2 und 3
Pile segment 1
Vertical
displacement
[cm]

Calculations" 43
85
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Load [MN]
Pile segment 3
Pile segment 1Phase B1
Phase B2
Vertical
displacement
[cm]
Clay and marl layers: qs,k = 80 kN/m²
qb,k = 3,000 kN/m2
86
Foundation system
Classic pile
foundation with piles
and barrettes
Load tests
Foundation design
33 % higher bearing
capacity
Realised foundation
≈ 25 % less of
piles/barrettes length

Calculations" 44
87
more than 800 m high
Burj Khalifa· Dubai, UAEBurj Khalifa· Dubai, UAE
88
Analyses with Finite-Element-Method at Institute and Laboratory of Geotechnics,
Technische Universität Darmstadt (TUD)
0
10
20
30
40
0 10 20 30 40 50 60
Pile head load [MN]
Pile head movement
[cm] 4.0
3.0
2.0
1.0
10
60 MN
Result of in-situ load test presented by Bunce/Ibrahim, Hyder Consulting:
max. load: 60 MN
max. movement: 2.2 cm
2.6 cm

Calculations" 45
89
Measured settlements
(Ibrahim, Hyder Consulting): s  5.0 cm
Pressure under raft: 0  2,200 kN/m2
Equivalent base geometry: A  3,600 m2
b  60 m
90
Young´s modulus from soil report for
weak sandstone/siltstone:
E = 78 MN/m2
Load test:
- max. 32 MN
- max. settlement of pile head: 0.7 cm
Business Bay District · Dubai, UAEBusiness Bay District · Dubai, UAE

Calculations" 46
91
Young´s modulus from back-analysis for
weak sandstone/siltstone:
E = 5,500 MN/m2
92
E = 31,000 MN/m2
A = 1.3 m2
F = 32 MN
s = 0.7 cm
used pile length ≈ 18 m
F L
2s
E A



 


s E A
L
0.5 F

Calculations" 47
93
full length
of test pile:
40 m
used length
of test pile:
18 m
94
Skin friction pile
Base pressure
Foundations
Combined Pile-Raft
Foundation (CPRF)

Calculations" 48
95
Messeturm
MAINTOWER
Commerzbank
ECB
West East
Es(z) = 15 - 50 MN/m2
Es(z) > 250 MN/m2
z
Subsoil in Frankfurt am Main, GermanySubsoil in Frankfurt am Main, Germany
96
AfE-Building · Frankfurt am Main, GermanyAfE-Building · Frankfurt am Main, Germany

Calculations" 49
97
AfE-Building · Frankfurt am Main, GermanyAfE-Building · Frankfurt am Main, Germany
98
Construction time: 1973 - 1976
Height: 162 m
Foundation: raft foundation
max. settlements: 34 cm (!!)
Marriott-Hotel · Frankfurt am Main, GermanyMarriott-Hotel · Frankfurt am Main, Germany

Calculations" 50
99
Retaining wall
Joint
Main core
Core 4 Core 2
Core 3
Core 2
Main core
Core 4
Compensation of the differential settlements
100
Stiff concrete
cells (hotel area)
Flexible steel
construction
(office area)
Hinged
connections
Jacks
Jacks
Compensation of the differential settlements

Calculations" 51
101
Foundation:
raft foundation
Height:
155 m
Settlements:
min. 10 cm
max. 22 cm
Δ 12 cm
Deutsche Bank · Frankfurt am Main, GermanyDeutsche Bank · Frankfurt am Main, Germany
102
Measured settlement isolines

Calculations" 52
103
Compensation system in the joint between high-rise building and
the adjacent building
high-rise building
adjacent building
jacks
104
geometry = “banana“
deflection ~ 6 cm
at twintowers of Deutschen Bank umax
Reaction to the tilting of a structure:
 construction above the lot point
using laser measurements
b
s
H
n
u








1
2
1
max
with n: number of storeys
H: height of building [m]
Δs: differential settlement [m]
b: width of foundation raft [m]

Calculations" 53
105
Construction time: 1975 - 1978
max. settlements: 20 cm
Bohrpfahlwand Baugruben-
sicherung
Pressure cushion
h = 0.4 m
Bored pile wall
Retaining wall
Raft thickness: 3.0 – 4.0 m
~ 7.0 m
~ 5.0 m
Old Dresdener Bank · Frankfurt am Main, GermanyOld Dresdener Bank · Frankfurt am Main, Germany

Calculations" 54
Lunch break / 13:30 - 14:30Lunch break / 13:30 - 14:30
Pile - Raft Foundation Design Procedures as a United
Foundation Structure
Pāļu un plātnes pamatu kopdarbība vienotā pamatu
konstrukcijā

Calculations" 55
109
• Piles have to be set directly under the load of the superstructure. The centre of the
pile group should be under the centre of the loads.
• Few long piles are better than many short piles.
• The length of the piles has to be adapted to the loads. At the edge and the corners
of the raft shorter piles and in the inner part of the raft longer piles are
recommended.
• By applying pile centre distances of e/D ≥ 4.5 the piles of a CPRF are used in a very
cost-effective way.
• Optimum of the CPRF-coefficient: αCPRF = 0.5 … 0.7
, ,
1
,
( )
( )
m
pile k j
j
CPRF
tot k
R s
R s
 


CPRF coefficient:
Recommendations for the design of a CPRFRecommendations for the design of a CPRF
110
Construction Period:
2001 - 2003
Foundation: CPRF
Height: 120 m
City Tower · Offenbach am Main, GermanyCity Tower · Offenbach am Main, Germany

Calculations" 56
111
112
36 piles of  30 m at 600 €/m  0.6 Mio. €
113 piles of 30 m at 600 €/m  2.0 Mio. €
Savings in costs of
pile production: 1.4 Mio. €

Calculations" 57
113
Service load
Skyper · Frankfurt am Main, GermanySkyper · Frankfurt am Main, Germany
114

Calculations" 58
115
46 piles of 35 m at 600 €/m  1.0 Mio. €
320 piles of 30 m at 600 €/m  5.8 Mio. €
Savings in costs of
116
57 piles of 40 m at 600 €/m  1.4 Mio. €
246 piles of 30 m at 600 €/m  4.4 Mio. €
Savings in costs of
Opernturm · Frankfurt am Main, GermanyOpernturm · Frankfurt am Main, Germany

Calculations" 59
117
40 piles of 30 m at 600 €/m  0.7 Mio. €
180 piles of 30 m at 600 €/m  3.2 Mio. €
Savings in costs of
Westend · Frankfurt am Main, GermanyWestend · Frankfurt am Main, Germany
118
112 piles of 30 m at 600 €/m  2.0 Mio. €
277 piles of 30 m at 600 €/m  5.0 Mio. €
Savings in costs of
Maintower · Frankfurt am Main, GermanyMaintower · Frankfurt am Main, Germany

Calculations" 60
119
Height: 170 m
Construction time:2011 - 2014
High-rise building
and living tower: CPRF
Underground parking: Foundation raft with
micro piles against buoyancy
Total building load ≈ 2,000 MN
Quaternary
sand and gravel
Frankfurt Clay
Frankfurt Limestone
Taunsturm · Frankfurt am Main, GermanyTaunsturm · Frankfurt am Main, Germany
120
Living tower:
 piles: 12
 foundation raft: 1.2 m
High-rise buildings:
 piles: 46
Underground parking:
 piles: 65

Calculations" 61
121
122

Calculations" 62
123
46 piles of 25 m at 600 €/m  0.7 Mio. €
230 piles of 30 m at 600 €/m  4.1 Mio. €
Savings in costs of
124
European Central Bank · Frankfurt am Main, GermanyEuropean Central Bank · Frankfurt am Main, Germany

Calculations" 63
125
126

Calculations" 64
127
97 piles of 30 m at 600 €/m  1.7 Mio. €
490 piles of 30 m at 600 €/m  8.8 Mio. €
Savings in costs of
pile production 7.1 Mio. €
128
Project Area
River Dnjepr
200 m
2.200 MN
Tower A
Tower B
Mirax Plaza Tower A · Kiev, UkraineMirax Plaza Tower A · Kiev, Ukraine

Calculations" 65
129
130
“Pull-out Test”:
d = 0.82 m, l = 10 m
displacement
[cm]
“Compression Test”:
d = 0.82 m, l = 44 m

Calculations" 66
131
Foundation systems
Realised foundation
CPRF:
64 Barrettes
l = 33 m
2.8 x 0.8 m
Load tests
Foundation design
Invention of a numerical
model
Barrette foundation:
120 Barrettes
l = 40 m
2.8 m x 0.8 m
First CPRF
in Ukraine (αCPRF = 0.88)
132
Accomplished: CPRF of 62 barretts (l = 33 m)
Costs of barrett production:
62 barretts of 33 m at 920 €/m  1.9 Mio. €
Barrett foundation: 120 barretts (l = 40 m)
Costs of barrett production:
120 barretts of 40 m at 920 €/m  4.4 Mio. €
Savings in costs of
barrett production: 2.5 Mio. €
Comparison of costs of the barretts

Calculations" 67
133
Federation Tower · Moscow, RussiaFederation Tower · Moscow, Russia
134
360 m
243 m

Calculations" 68
135
Pile load tests TP 15-1 and TP15-2 with Osterberg Cells (O-Cells)
136
-3,0
-2,0
-1,0
0,0
1,0
2,0
3,0
4,0
5,0
0 5 10 15 20 25 30 35 40
displacement [cm]
load [MN]
upper pile
segment
lower pile
segment
Pile load tests TP 15-1 and TP15-2
with Osterberg Cells (O-Cells)
TP 15-1 TP 15-2

Calculations" 69
137
Pile load test with Osterberg-Cells (O-Cells)
Back analysis for calibration of numerical simulations  Lagos, Nigeria
138
Numerical simulation
using Finite-Element-
Method (FEM)

Calculations" 70
139
optimised design of
the foundation
systems
Combined Pile-Raft Foundation (CPRF)
140
Excavation (2005)
Eastern fault of
the Rhein valley
Conference Center Darmstadtium · Darmstadt, GermanyConference Center Darmstadtium · Darmstadt, Germany

Calculations" 71
141
Eastern Rhein Valey Fault
• H-beam wall and
bored pile wall
• depth  16 m
• max. 4 layers of anchors
142
Cross section

Calculations" 72
143
144
Manual Calculation of
Combined Pile-Raft Foundation (CPRF)

Calculations" 73
145
Section A-A Section B-B
Soil conditions:
0 - 8 m: Sand, slightly gravel
Es,first = 40 MN/m²
Es,re = 60 MN/m²
γ = 19 kN/m³
γr = 20 kN/m³
8 - 54 m: Frankfurt Clay
Es,re = 50 MN/m²
γ = 20 kN/m³
γr = 21 kN/m³
from 54 m: Frankfurt Limestone
Es,Lst >> Es,Clay
Height: 178.80 m
Upper floors: 48
Basement floors: 3
Frankfurt Limestone
Frankfurt Clay
Project descriptionProject description
146
Design and discuss the foundation alternatives for the given building regarding the
following tasks:
a) Calculation of the loads:
Calculate the effective characteristic construction load Fc,eff
b) Calculations for a spread foundation:
 Calculate the settlement regarding the limit depth
 Calculate the maximum building deviation max u
c) Calculations for a pile foundation:
 Determine the needed amount and length of piles
d) Calculations for the Combined Pile-Raft Foundation (CPRF):
 Calculate the needed pile length to decrease the settlement about 50 %
compared to the spread foundation
 Calculate the estimated pile-raft coefficient αCPRF
Scope of workScope of work

Calculations" 74
147
a) Load calculation:
 Load for one floor including permanent load and traffic load: 14 kN/m²
 Specific weight for raft: gconcrete = 25 kN/m³
b) Spread foundation:
 Difference in settlement Δs caused by inhomogenous soil:
Δs = ±30 % of average settlement (given by measurements / experience)
c) Pile foundation:
 Pile diameter D = 1.5 m
 Minimum bonding depth in limestone = 3 × D
 Soil param.: Frankfurt clay:
- no skin friction assumed
Frankfurt limestone:
- characteristic maximum skin friction: qs,ult = 600 kN/m²
- characteristic maximum base resistance: qb,ult = 5000 kN/m²
Input DataInput Data
148
Area
Upper floors
AUF = 37.95 · 21.0 + ½ · 10.4 · 1.22
+ ½ · (7.81 + 9.23) · 10.99
+ 13.01 · 37.5 - ½ · 13.01 · 1.67
+ ½ · (3.5 + 2.5) · 8.0
= 1398 m2
Basement floors
ABF = 62.95 · 61.0 - ½ · (2.0 · 26.13 + 11.96) · 1.41
= 3795 m2
a) Calculation of the loadsa) Calculation of the loads

Calculations" 75
149
Fc = (nUF · AUF + nBF · ABF) · (g + q)
+ ABF · hraft foundation· gconcrete
= (48 · 1398 m2 + 3· 3795 m2) · 14 kN/m2
+ 3795 m2 · 4.5 m · 25 kN/m3
= 1525784 kN = 1526 MN
u = ∆ h · gw = (17.95 m - 6 m) · 10 kN/m3
= 120 kN/m2
Fc,eff = Fc - u · ABF = 1.526 · 103 kN - 120 kN/m2 ·
3795 m2
= 1071 MN
Uplift (Groundwater)
a) Calculation of the loadsa) Calculation of the loads
150
Skin friction pile
Base pressure
Foundations
Combined Pile-Raft
Foundation (CPRF)
b) Calculation for the shallow foundationb) Calculation for the shallow foundation

Calculations" 76
151
Calculation of the limit depth
Fc,eff = 1071 MN
Contact pressure:
σ0 = 1526 · 103 / 3795 m2 - 120 kN/m2
= 282 kN/m2
σ‘in-situ = gr · z = (21 kN/m³ - 10 kN/m³) · z
For i-chart:
a/b = 1.05
i = 0,2 σ‘in-situ/ σ0
From i-chart:
z/b = 0.7
z = 0.7 · 60 m= 42 m
But Limestone layer begins 36 m below the
foundation (with Es,Lst >> Es,Cl):
 Limit depth at the top of the limestone
layer
 z = 54 m – 17.95 m = 36 m
i-chart
Determination of Δ σ´z under the characteristic point
of a square load area
Limit depth z
z/b = 0.7
152
Calculation of the Settlements
Uplift: u = 120 kN/m2
Contact pressure:
σ0 = 1526 · 103 / 3795 m2 - 120 kN/m2
= 282 kN/m2
Soil excavation (Unloading / Reloading):
σRe = 6 · 19 + 2 · 10 + (17.95 – 8) · 11
= 243 kN/m²
Primary loading (first loading):
σfirst = 282 kN/m2 – 243 kN/m2
= 39 kN/m2
b = 3795 m2 / 62.95 m = 60 m
z = 54 m - 17.95 m = 36 m
 z/b = 0.60
a/b = 1.05
i-chart  i = 0.36
i-chart
Determination of Δ σ´z under the characteristic point
of a square load area
i = 0,36

Calculations" 77
153
Settlement
i-chart
With Hooke‘s law of elasticity:
ε = σ / E and ε = Δl / l;
s = Δl = (σ · l)
E
sre = 36 m · ½ · (243 kN/m2 + 0.36 · 243 kN/m2)
50 · 103 kN/m2
= 0.118 m
sfirst = 36 m · ½ · (39 kN/m2 + 0.36 · 39 kN/m2)
30 · 103 kN/m2
= 0.032m
ssf = sre + sfirst = 0.118 m + 0.032 m = 0.150 m
= 15.0 cm
Youg‘s Modulus Clay
Es,re = 50 MN/m²
154
Tilting
Difference in settlement ∆s caused by inhomogenous soil:
30 % of entire settlement ssf:
∆s = ± 0.3 · ssf = 4.5 cm
max u = H · 2 · Δs / b
max u = (178.8 m + 17.95) · 2 · 0.045 m / 60 m
max u = 0.30 m (!)
H
(tilting at the top of the high-rise building)
either: spread foundation ist not possible due to the
requirements regarding serviceability
or: active measures are necessary to correct tilting
during (and after) construction of the high-rise
building

Calculations" 78
155
Skin friction pile
Base pressure
Foundations
Combined Pile-Raft
Foundation (CPRF)
c) Calculation for the pile foundationc) Calculation for the pile foundation
156
Characteristic construction weight Fc,eff = 1071 MN
Design
Minimum bonding depth in limestone 3 · D: 4.5 m
Pile diameter D: 1.5 m
 Length in clay: 54 m -18 m = 36.00 m
Length in limestone: = 4.50 m
Total length of piles: = 40.50 m
 skin surface per m : As = 1,5 · π = 4.71 m2/m
base surface: Ab = 1,52 · π /4 = 1.77 m2
Rult = Rb,ult + Rs, ult = Ab · q b, ult + ∑ q s, ult · As,i
= 1,77 m2 · 5000 kN/m2 + 4.71 m2/m · 4.5 m · 600 kN/m2
= 21567 kN = 21.5 MN
Rd = Rk / γ p = 21.5 MN /1.4 = 15.4 MN
Ed = Ek · γ Q = 1071 MN · 1.35 = 1446 MN
Number of piles: n = Ed / Rd = 1446/15.4 = 94
 Total pile meter: 94 · 40.5 = 3807 m
c) Calculation for the pile foundationc) Calculation for the pile foundation

Calculations" 79
157
Skin friction pile
Base pressure
Foundations
Combined Pile-Raft
Foundation (CPRF)
d) Calculation for the CPRFd) Calculation for the CPRF
158
Designt Decision: CPRF = 0.5 50 % of the load carried by the piles
50 % of the load are carried by contact pressure
SRpile = 0.5 · 1071 MN = 535 MN
Soil parameters of Frankfurt clay: drained: j‘ = 20°, c‘ = 20 kN/m²
undrained: j‘ = 20°, cu = 100 - 150 kN/m²
Characteristic maximum skin friction: qs,ult = 75 kN/m²
Characteristic maximum base resistance: qb,ult = 750 kN/m²

Calculations" 80
159
Ultimate pile capacity: Rult = Rb,ult + Rs,ult = Ab · qb,ult + qs,ult · As
Next design decision: chosen pile length: L = 30 m
chosen pile diameter: D 1.5 m
Rult = 1.77 m² · 750 kN/m² + 4.71 m²/m · 30 m · 75 kN/m² = 11925 kN
Rult = 11.9 MN
Number of piles: n = 535 MN / 11.9 MN = 45
Total pile meter: Slpile = 45 · 30 m = 1350 m
After this first pre-dimensioning of a numerical calculation with a full 3D model
(Finite Element Analysis) is necessary taking into account the position and the
amount of the loads and the pile-raft-interaction and the pile-pile-interaction, and in
order to calculate the settlements and the overall safety of the structure.
160
Estimated costs for a pile (boring and conreting): 1000 USD per m
•) Costs for the Pile Foundation: 1000 USD/m · 3807 m = 3 807 000.00 USD
•) Costs of the Piles of the CPRF: 1000 USD/m · 1350 m = 1 350 000.00 USD
Saving: 2 457 000.00 USD
+ less time for pile production
+ less CO2 emission
Comparison CRPF vs. Pile FoundationComparison CRPF vs. Pile Foundation

Calculations" 81
161
Commerzbank-Tower
Project FOUR (Photomontage)
MainTower
Frankfurt Banking CenterFrankfurt Banking Center
162
Frankfurt Clay
Frankfurt
Limestone
Marl
Cerithien
Skyper
Japan
Center
MainTower FOUR
West
Ost
0 mNN
20 mNN
60 mNN
100 mNN
from: Quick & Colleagues
Frankfurt Banking CenterFrankfurt Banking Center

Calculations" 82
163
Quarternary Sand and
Gravel
Frankfurt Clay
Frankfurt Limestone
3D Finite Element Model3D Finite Element Model
164
Core Walls
Raft
Tower 2
Piles for CPRF
Primary Piles for top-town method
Diaphragam
Wall
3D Finite Element Analysis Constructive elements3D Finite Element Analysis • Constructive elements

Calculations" 83
165
T1
T2
T3
T4
0 cm
1,0 cm
2,0 cm
3,0 cm
4,0 cm
5,0 cm
6,0 cm
calculated settlement
3D Finite Element Analysis Calculated settlement3D Finite Element Analysis • Calculated settlement
166
0,0
2,5
5,0
7,5
10,0
12,5
15,0
0 500 1000 1500 2000 2500 3000 3500 4000 4500
G
G+Q
1,5(G+Q)
2(G+Q)
Diaphragm
wall Raft Piles Combined (=overall)
Resistence (CPRF)
Settlement
[cm]
Load [MN]
CPRF fulfills the safety requirements
Calculated Load-Settlement-Curve Tower 1 (3D FEM)Calculated Load-Settlement-Curve Tower 1 (3D FEM)

Calculations" 84
167
Quelle: QIG
Quelle: QIG
14.03.2019
14.03.2019
Diaphragam Wall Cutter
Frankfurt Clay in the Cutter
Diaphragam Wall Cutter only
applied in the Limestonefrom: Quick & Colleagues
Project FOURProject FOUR
168
Thermal
Energy 50%
Fuels 29%
Electric Power
21%
Final energy consumption by energy carriersFinal energy consumption by energy carriers

Calculations" 85
169
Lighting
1%
Cooking
4%
other electrical
appl.
7%
Heating
77%
Warm water
11%
Final energy consumption in Europe in the residential sectorFinal energy consumption in Europe in the residential sector
170
Specific heat
capacity cp [J/(kg*K)]
0
500
1000
1500
2000
0
500
1,000
1,500
2,000
Subsoil has ideal
thermal material
properties for the
storage of energy!
Subsoil for energy storageSubsoil for energy storage

Calculations" 86
171
For heating and cooling purposes
energy can be extracted from or
stored in the subsoil by e.g.:
• Borehole heat exchangers
• Energy piles
• Groundwater wells
“shallow“
“deep“
Geothermal use of the subsoilGeothermal use of the subsoil
172
Energy piles
and other foundation elements
Thermal function
for heating and cooling
Structural function
Heat exchanger tubes
Energy pile
Reinforcement
cage
• Heat exchanger tubes integrated in
the concrete
• Energy transfer through circulating
heat exchanger fluid
Deep foundation elements for geothermal energy supplyDeep foundation elements for geothermal energy supply

Calculations" 87
173
Drilling
Installation of the heat
exchanger tubes at the
reinforcement cage
Pressure control of the heat
exchanger tubes
Deep foundation elements for geothermal energy supplyDeep foundation elements for geothermal energy supply
174
Summer: solar thermal charging
Seasonal thermal storageSeasonal thermal storage

Calculations" 88
175
Some building are consuming heating power already, others are self-sufficient
Autumn: partly discharge of the storage
176
Bilance: energy stored in summer is consumed;
additional need is covered by the source of geothermal energy.
Winter: energy subtraction is dominant

Calculations" 89
177
Conduction Convection Dispersion Temporal change
Energy sources
l soil thermal conductivity [W/(m·K)]
Dl soil coefficient of heat dispersion [W/(m·K)]
T temperature of soil [K]
v mean velocity of fluid [m/s]
energy sources [W/m³]
t time [s]
r density [kg/m³]
c specific heat capacity [J/(kg·K)]
rc volumetric heat capacity [J/(m³·K)]
n pore volume [-]
(rc)w volumetric heat capacity of the fluid ground water [J/(m³·K)]
(rc)s volumetric capacity of the solid phase [J/(m³·K)]
       l

l r  r


iw
T
div gradT - c div v T +div D gradT +Q = c
t
    r r rw s
c = n c + 1-n c
iQ
Energy transport equationEnergy transport equation
178
A Seasonal Thermal Storage is the geothermally activated soil volume equipped with
heat exchanger elements for the storage of energy for heating and cooling.
Temperature in the
Seasonal Thermal Storage
Heat
injection
Summer
Heat
extraction
Winter
Heat
injection
Summer
heat pump or heat exchanger
building
subsoil:
energy
storage
coolingheating
Winter operation Summer operation
Time

Calculations" 90
179
• top-down method
• pile foundation in the
Frankfurt Limestone
PalaisQuartier · Frankfurt am Main, GermanyPalaisQuartier · Frankfurt am Main, Germany
180
Retaining wall
• D = 1.5 m,
length up to 38 m
• 130 of 543 piles built as energy
piles (almost every second
reinforced pile)
Foundation piles
• diameter up to 1.86 m,
length up to 27 m
• 262 of 302 piles built as energy
piles
Groundwater flow-direction
NW to SE in total: 392 energy piles

Calculations" 91
181
Winter operation: 2,350 MWh/a (heating)
Summer operation: 2,410 MWh/a (cooling)
Max. capacity: 913 kW
Power output of foundation-
and retaining wall piles [kW]
182
energy-fleece,
Austria
energypiles
energy-Tubbing,
Germany
Geothermal Energy in Traffic and TransportGeothermal Energy in Traffic and Transport

Calculations" 92
Thank you for attention!
+371 67013100www.em.gov.lv@EM_gov_lv,@siltinam /ekonomikasministrija Brīvības iela 55, Rīga, LV-1519, Latvia pasts@em.gov.lv

"COMBINED PILE RAFT FOUNDATION GEOTECHNICAL CALCULATION -Rolf Katzenbach

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"COMBINED PILE RAFT FOUNDATION GEOTECHNICAL CALCULATION -Rolf Katzenbach