Abstract

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Abstract

• Our project is about ( Foundation Design of
  Al-Maslamani Mall) which is located in the
  village of Beit Eba Nablus governorate.
• The total plan area of this mall is about 3500
  m2
• The number of stories is 6 4 stories above the
  ground surface 2 stories are below the ground
  surface.

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Literature Review

• Site Investigation is the first important step in
  any engineering work to determine type depth
  of foundations , to evaluate bearing capacity ,
  to identify construction methods for many
  things
• Foundations are the part of an engineered system
  to receive transmit loads from superstructure
  to the underlying soil or rock .
• There are two types of foundations shallow
  deep foundations.
• Many factors should be taken into consideration
  in choosing foundation types such as soil
  properties , economic factors, engineering
  practice, ....etc

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Isolated footings
Piles
Mat
Combined Foundations
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 Isolated 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.
• Its function is to spread the column load to the
  soil , so that the stress intensity is reduced .

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Mat or Raft Foundations

• are used to spread the load from a structure
  over a large area, normally the entire are of the
  structure .
• They often needed on soft or loose soils with low
  bearing capacity as they can spread the loads
  over a larger area.
• They have the advantage of reducing differential
  settlements.

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Combined Foundations

• Are used in the following cases
• 1) When there are two columns so close to each
  other in turn the two isolated footing areas
  would overlap.
• 2) When the combined stresses are more than the
  allowable bearing capacity of the soil.
• 3) When columns are placed at the property line.

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Strap or Cantilever Footings

• Cantilever footing construction uses a strap beam
  to connect an eccentrically loaded column
  foundation to the foundation of an interior
  column .
• Are used when the allowable soil bearing
  capacity is high, and the distances between the
  columns are large .

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Pile Foundations

• They are long slender members that are used to
  carry transfer the load of the structure to
  deeper soil or rocks of high bearing capacity,
  when the upper soil layer are too weak to support
  the loads from the structure.
• Piles costs more than shallow foundations so the
  geotechnical engineer should know in depth the
  properties conditions of the soil to decide
  whether piles are needed or not.

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Classification of the piles

• According to load transmission functional
  behavior
• 1) End / Point bearing piles
• 2) Friction piles
• 3) Compaction piles
• According to type of material
• 1) Steel piles
  2) Timber piles
• 3) Concrete piles 4)
  Composite piles
• According to effect on the soil
• 1) Driven piles
• 2) Bored piles

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Bearing Capacity Settlement

• Bearing Capacity is the ability of a soil to
  support the loads applied to the ground .
  Ultimate bearing capacity is the theoretical
  maximum pressure which can be supported without
  failure Allowable bearing capacity is the
  ultimate bearing capacity qu divided by a factor
  of safety (F.S).
• There are three modes of failure that limit
  bearing capacity general shear failure, local
  shear failure, and punching shear failure.
• Any structure built on soil is subject to
  settlement. Some settlement is inevitable,
  depending on the situation, some settlements are
  tolerable.
• When building structures on top of soils, one
  needs to have some knowledge of how settlement
  occurs how fast settlement will occur in a
  given situation.

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Geotechnical Investigation

• The studied area is approximately flat with
  slight difference in the three existing
  elevations. The general soil formation within the
  depths of the borings consists mostly of wadi
  deposits of boulders silty clay followed by
  successive layers of hard boulders mixed with
  very little filling silty clay. The whole site is
  covered by grass.

• The geotechnical engineer decided to drill four
  boreholes trying to cover the whole construction
  area.

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The depths of the drilled boreholes were as
follows
Borehole No. Location Depth (m)
1 South-west 7.0
2 East 7.0
3 West 6.0
4 North 10.0

• Summary of lab. test results

• 20 KN/m³
  w 7.6 (avg.)
• C 0 KN/m² (average) LL
  44.5
• ط 25
  PI 25
• qall. 3.0 kg/cm2
  G 2.73
• a-Coefficient of active earth pressure
  KA 0.405
• b- Coefficient of passive earth pressure
  KP 2.464
• c- Coefficient of pressure at rest Ko
  0.577

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• After doing check on the bearing capacity value
  using FOUND software by using Terzaqi and
  Meyerhoff formulas, the value was ranging
  between 3.2 and 4.3 Kg/ cm2 respectively, SO we
  decided to use a value of 3.5 Kg/ cm2 in our
  project.

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Load Calculations
Service Load (ton) Ultimate Load (ton) Footing Column
44.5 60 F1 C21 ,C28
89.0 120 F2 C8 ,C9
135.7 183 F3 C3 ,C38
180.3 243 F4 C1,C2,C7,C23,C30,C32,C43
257.4 347 F5 C10,C15,C31,C37,C39,C4,C16
287.8 388 F6 C5,C6,C22,C29,C33, C41,C42,C24,C36,C40
387.2 522 F7 C11,C12,C13,C14,C17,C34,C35
429.5 579 F8 C18,C19,C20,C25,C26,C27
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Isolated Footing Design

• Manual Design steps
• Area of footing Total service loads on column
  / net soil pressure
• Determine footing dimensions B H .
• Assume depth for footing.
• Check soil pressure.
• Check wide beam shear FVc gt Vult
• Check punching shear FVcp gt Pult, punching
• Determine reinforcement steel in the two
  directions.
• Check development length .
• Check load transfer from column to footing .
• Then, we compare manual design with SAP design in
  footings F4 F8 .

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• The solution of SAP is always smaller than
  manual one, since SAP uses Finite Element Method.
• There is no need to calculate the settlement of
  the isolated footings since the soil is gravelly
  soil , has a qall. of 3.5 kg/cm2 .
• The final results of isolated footings design are
  in the next table

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As , B (mm2) As , H (mm2) Depth (m) B (m) H (m) Columns Dimension ( m) F Column
816 816 0.4 1.1 1.1 D 0.5m F1 C21 ,C28
1548 1548 0.5 1.6 1.6 0.50.2 F2 C8 ,C9
1710 1710 0.45 2 2 C3 0.70.4 C38 D 0.8 m F3 C3 ,C38
2614 2614 0.52 2.5 2.5 C1, C2, C30 1.10.4 C7 0.650.3 C23 0.750.75 C32 0.80.8 C43 0.60.3 F4 C1,C2,C7,C23, C30,C32,C43
5330 5330 0.90 2.85 2.85 C10 0.750.75 C15 , C37 0.60.3 C31 1.10.4 C39 D0.8m C4 0.40.65 C16 0.750.75 F5 C10,C15,C31,C37,C39,C4, C16
4930 4930 0.80 3 3 C5,C6,C40,C41,C42 0.8 0.65 C22 , C29 0.60.3 C24 0.750.75 C33 1.10.4 C36 D0.8 m F6 C5,C6,C22,C29, C33,C41,C42, C24,C36,C40
6540 6540 0.90 3.5 3.5 C11,C12,C13,C14,C35 D 0.8 m C17 , C34 0.750.75 F7 C11,C12,C13, C14,C17,C34, C35
7530 7530 0.95 3.8 3.8 C18,C19,C20,C26,C27 D0.8 m C25 0.80.8 F8 C18,C19,C20, C25,C26,C27
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Wall Stair Footing
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Dimensions and Reinforcement Details of Wall
Stair Footing

• Depth of wall footing 60 cm.
• Width of wall 20 cm.
• Width of footing (B) 2 m.
• Reinforcement
• 6 f16 / m in short direction
• 14 f16 in long direction

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Elevator Wall Footing
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Dimensions and Reinforcement Details of Elevator
Wall Footing

• Depth 33cm, h40cm
• 4 f16 / m
• For positive moment negative moment
• In both directions.

Reinforcement details for elevator wall
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Pile Foundation
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Design 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 Qp Qs

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• 2-Determination of the point bearing capacity

For piles in rocky sand soil as in our case , the
point bearing capacity may be estimated as QP
Ap q' Nq Qlimit Where Ap Area of the pile
tip. q effective stress at pile tip. Nq
Factor depends on soil friction angle Qlimit
(0.5 Pa Nq tan ط ) Ap
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• 3-Determination of skin resistance
• It can be calculated by using the following
  formula
• QS ? P?Lf
• Where
• ?L Length of the pile
• P Perimeter of the pile
• f Frictional factor

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The following table presents the dimensions of
piles and their capacities in (KN).
18 16 15 14 12 10 8 length (m) D(m)
430 349 312 278 216 164 122 0.5
526 430 386 345 271 208 157 0.6
627 514 463 415 329 256 196 0.7
731 602 544 489 390 307 239 0.8
839 694 628 566 455 362 285 0.9
951 789 716 647 524 420 335 1
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Summary of piles sizes, number of piles needed,
cap dimensions
Cap dimension (m) of piles Pile size (L,D) (m,m) Service Load (KN) Column
2.22.2 4 (8 , 0.5) 445 2128 (F1)
2.22.2 4 (14 , 0.5) 890 89 (F2)
2.22.2 4 (16 , 0.5) 1357 338 (F3)
2.852.85 4 (15 , 0.7) 1803 127233032 43 (F4)
4.62.85 6 (15 , 0.7) 2574 1015313739 416 (F5)
5.23.2 6 (14 , 0.8) 2878 5622293341 42243640 (F6)
7.23.2 8 (14 , 0.8) 3872 1112131417 3435 (F7)
7.23.2 8 (15 , 0.8) 4295 1819202526 27 (F8)
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• The structural pile design depends on the nature
  of soil, which is either stiff or weak, the pile
  is to be designed as short column if the soil is
  stiff , and designed as along column if the soil
  is weak.
• The minimum area of steel is 0.5 of the gross
  area of the pile, also the ties are used starting
  with 5 cm spacing and ending by 30 cm spacing
  .the concrete cover must be not less than 7.5 cm.
• Asmin0.005Ag
•  

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Efficiency of pile group

• The efficiency of the load-bearing capacity of a
  group pile may be defined as
• M Qg(u ) / ?Qu
• Where
• Qg(u) ultimate load bearing capacity of the
  group pile.
• Qu ultimate load-bearing capacity of each pile
  without the group effect
• Using simplified analysis to obtain the group
  efficiency as shown in the following formula
• ? (2(mn-2) 4D) / (pmn)
• Where
• m of piles in the direction of Lg.
• n of piles in the direction of Bg.
• d Spacing between piles centers.
• D Diameter of the pile
• P Perimeter of pile cross section

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Design of a pile cap

• The minimum distance between two piles is 3D.
• Pile caps should extend at least 15 cm beyond the
  outside face of exterior face of exterior piles.
• The minimum thickness of pile cap above pile
  heads is 30 cm.
• The cover in pile caps commonly ranges between
  20 25 cm .
• Design Steps
• Assume depth (d)
• Check Punching shear FVcp gt Vult, punching
• Check wide beam shear FVc gt Vult
• Calculate area of steel needed
• Check ?min. lt ? lt ?max.

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Retaining Wall Design
The retaining wall is designed by PROKON Program
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Conclusions

• 1) From soil report, we note that PI is 25 and
  cohesion is zero and this can be explained by the
  following
• We have soil contains some clay between gravels,
  and when we take a sample of this soil to be
  tested for atterberg limits to determine PI,we
  use sieve 40 and we take the passing which are
  clay particles and in turn this leads to increase
  the magnitude of plasticity index.
• Cohesion is zero since the soil sample is almost
  gravel.
• 2) After designing the two alternative choices
  (single footings and piles system) surveying
  the quantities for concrete only, we find that it
  is more practical, realistic and economical to
  use single footings
• 3) there is no need to make settlement
  calculations for footings and piles ,since we
  have a gravely soil with B.C of 3.5 kg/cm2(the
  settlements in our situation are tolerable, so we
  can ignore them)..

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