2. Chapter OneChapter One General definition of theGeneral definition of the
projectproject
Our project aims to analyze & design the foundations
of a seven story building in Nablus city.
3. Chapter two talks about literature review ofChapter two talks about literature review of
FoundationsFoundations
The lowest part of the structure generally is referred
to as the foundation.
It’s function is to transfer the load of the structure to
the soil on which it’s resting.
A properly designed foundation transfers the load
throughout the soil without overstressing the soil.
Thus, geotechnical and structural engineers who
design foundations must evaluate the bearing capacity
of the soil.
5.
Depending on the structure and soil Characteristics,Depending on the structure and soil Characteristics,
various types ofvarious types of
foundations are usedfoundations are used::
1- Isolated or single
footings are used to
support single columns.
This is one of the most
economical types of
footings and is used
when columns are
spaced at relatively long
distances.
6. 2-Combined
footings
usually support two
columns, or three
columns. Combined
footings are used
when two columns
are so close that
single footings
cannot be used or
when one column is
located at or near a
property line.
7. 3-Raft or mat foundation
consists of one footing
usually placed under the
entire building area.
They are used, when soil
bearing capacity is low,
column loads are heavy,
single footings cannot be
used, piles are not used
and differential
settlement must be
reduced.
8. 4-Pile foundation
Piles are used to
transmit the load to
underlying bedrock or a
stronger soil layer. Piles
are used when the soil
too weak, when
subjected to horizontal
forces… etc, the cost is
more than shallow
foundations.
9. Settlement of foundationSettlement of foundation
The settlement of a structural foundation consists of three
parts:
1- Immediate settlement: takes place during application of the loading as a result
of elastic deformation of the soil(no change in water content).
2- Consolidation settlement takes place as a result of volume reduction of the
soil caused by extrusion of some of the pore water from the soil.
3- Creep or secondary settlement occurs over a very long period of years after
completing the extrusion of excess pore water.
Figure below Settlement stages with time.
10. Chapter 3:Summary of laboratory test resultsChapter 3:Summary of laboratory test results
1-Natural moisture content (N.M.C): ranges between 6% -
33%.
2-Liquid limit (L.L): ranges between 22% - 70%.
3-Plastic limit (P.L): ranges between 17% - 44%.
4-Plasticity index (P.I): ranges between 2% - 34%.
5-Undrained cohesion (Cu): 0.42 Kg/cm2
.
6-Unit weight = 1.7 gm/cm3
7-Preconsolidation pressure: ranges between 2 – 4 g/cm2
.
8-Compression index (Cc): ranges between 0.4 – 0.45.
9-Initial void ratio (eo): ranges between 0.74 – 0.87.
10-Swelling pressure: ranges between 2 – 4 Kg/cm2
.
11-Swelling potential = 10%.
12-Specific gravity = 2.65.
13-Allowable bearing capacity = 2 Kg/cm2
.
14-modulus of elasticity ranges between 500 - 700 Kg/cm2
12. Chapter 4:Loads analysisChapter 4:Loads analysis
In order to calculate the loads that applied on each column we used
tributary area method, we obtained the following results:
Column
No.
Dimensions
m
Service load
ton
Ultimate load
ton
1+7 0.8*0.2
43.12 53.40
2+6 0.8*0.2
78.19 98.87
3+5 0.8*0.2
55.92 72.27
4 0.8*0.2
80.22 101.81
8+11 0.8*0.2
81.90 103.91
13+14 0.8*0.3
196.49 250.35
10+9 0.8*0.3 201.88
256.54
12+15 0.8*0.2 87.85
110.88
16+21 0.8*0.2 50.40
63.84
17+20 0.8*0.2 63.63
80.67
18+19 0.6*0.2 48.86
62.10
13. Chapter 5Chapter 5
Is the Basic part of this project; it handles with theIs the Basic part of this project; it handles with the
analysis, design and settlement calculations of isolated,analysis, design and settlement calculations of isolated,
wall, mat, and pile foundations.wall, mat, and pile foundations.
15. ( )Total load including self-weight
Area of footing
allowable soil pressure
=
*The area of footing can be determined from the actual external loads such that
the allowable soil pressure is not exceeded.
*Determining the depth using:
11--Design of one-way shearDesign of one-way shear..
u u
2 2
L c
V q b d
= − − ÷
The ultimate shearing force at
section m-m can be calculated
ΦVc = 0.75*0.17 √fc *b*d
If no shear reinforcement is to be
used, then d can be checked
16. 2-Design of two-way shear2-Design of two-way shear
The shear force Vu acts at a section that
has a length
b0 = 4(c+d) or 2(c1+d) +2(c2+d)
and a depth d; the section is subjected to a
vertical downward load Pu and vertical
upward pressure qu.
( )
2
u u uV P q c d= − +
( ) ( )u u u 1 2V P q c d c d= − + +
for square columns
for rectangular columns
Shear strength is the smallest of :
1) Vc =Φ Φ (1+ 2 ) √fc *bo*d
6 sβ
2) Vc =Φ Φ ( sα + 2 ) √fc *bo*d
12 bo/d
3) Vc = *0.33 √fc *b*dΦ Φ (3
17. Flexural Strength and Footing reinforcementFlexural Strength and Footing reinforcement
The bending moment in
each direction of the
footing must be checked
and the appropriate
reinforcement must be
provided.
calculated Rn = Mu / bd2
and determine
the steel percentage required ρ.
Determine As
As= *b*dρ
18.
19. Settlement of isolated footing :Settlement of isolated footing :
The settlement here is calculated based on elastic
theory and consolidation, the following table
summarized the results .
20. Combined footingCombined footing
Combined footings are used when two columns are so
close that single footings cannot be used or when one
column is located at or near a property line.
23. Dimensions and reinforcement details of wallDimensions and reinforcement details of wall
footingfooting
The depth is calculated using wide beam shear.
Should be Vu ≤ VcΦ.
Vc= *0.17*√fc*d*bΦ Φ
Depth of wall footing = 45 cm.
Width of footing=
b = 2.45 m
. .
all
D L L L
b
q
+
=
25. Dimensions and reinforcement details ofDimensions and reinforcement details of
elevator wall footingelevator wall footing
After analysis and design the following dimensions is
determined
depth = 40 cm, h=50cm
Reinforcement details for elevator wall
26. The settlement is acceptable and it’s as showing, InThe settlement is acceptable and it’s as showing, In
average =6 mmaverage =6 mm
28. Design of pile foundationDesign of pile foundation
1-Estimating pile capacity
The ultimate carrying capacity is equal to the sum of
the ultimate resistance of the base of the pile and the
ultimate skin friction over the embedded shaft length
of the pile, this expressed by :
Qu = QS + QP
29. 2-Determination of the point bearing capacity
For piles in saturated clay in
undrained cohesion as our case ,
the point bearing capacity may be
estimated as :
QP
= 9 Cu Ap
30. 3-Determination of skin resistance
The formula of skin resistance of the pile can be
expressed as :
QS =∑ {P*∆L*f }
31. This table presents the proposed dimensions of pilesThis table presents the proposed dimensions of piles
and there capacities in (KN).and there capacities in (KN).
We choose Pile diameter 0.5 m and the lengths were (8 , 10 , 18) m
32. Cap dimensionsCap dimensions
The minimum distance between two terraced piles is 2D.
Pile caps should extend at least 150 mm beyond
the outside face of exterior piles.
The minimum thickness of pile cap above pile heads is 300 mm.
The chosen dimensions as the following figure
2.4X2.4X0.45 m
33. The number of piles needed and cap dimensions areThe number of piles needed and cap dimensions are
summarized in the table below:summarized in the table below:
34. Reinforcement details of pilesReinforcement details of piles
The structural design for all piles is :
Pile diameter= 50cm.
Pile gross area=
)π/4)(502
)= 1962.5cm2
.
As min = 0.005Ag = 0.005*1962.5 =
9.82cm2.
Use 6 16 mmΦ .
36. Settlement of pilesSettlement of piles
Elastic settlement for single pile
Se = Se(1) + Se(2) + Se(3)
Se1:Elastic settlement of pile.
Se2:Settlement of pile caused by the load at the pile tip.
Se3:Settlement of pile caused by the load transmitted along the pile shaft.
37. Elastic settlement of group of piles:Elastic settlement of group of piles:
Se = S * √(Bg / D)
Se(rigid) = 0.93 * Se(elastic)
The following table presents the elastic settlement of group of piles
38. Consolidation settlement of pilesConsolidation settlement of piles
This table summarized the results of calculation of consolidation settlement of
piles:
40. Determine the depthDetermine the depth
To determine the depth of the mat we
should take the critical loads and positions.
The depth of mat determined by the
critical check which is punching shear
check.
We found it =60 cm.
41. Settlement of mat foundationSettlement of mat foundation
from 3mm to maximum 11.4 mm
42. Chapter 6Chapter 6
This chapter aims to do some comparisons, quantities
calculations, discusses the results of the project, and
it gives recommendations of what are the proper and
most economical type of foundation for this building.
43. As a result of the previous analysis of the quantities of
concrete and steel needed for the different types of
foundation, in addition to the calculations in chapter five,
especially settlement calculations for these types, we
recommend using isolated footing with (-the combined ,wall,
elevator- footing) instead of the other types. The following
table summarizes the comparison :