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AbstractAbstract

*Our project is about ( Foundation Design of Al-Maslamani Mall) which is located in the village of

Beit ba ! "ablus governorate#

$%he total plan area of this mall is about &' m

$%he number of stories is *+ , stories above the

ground surface stories are below the groundsurface#

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Literature ReviewLiterature Review

.ite /nvestigation is the first important step in an0 engineering

wor1 + to determine t0pe depth of foundations 2 to evaluate bearing capacit0 2 to identif0 construction methods for man0things3

Foundations are the part of an engineered s0stem to receive

transmit loads from superstructure to the underl0ing soil or roc1 #

%here are two t0pes of foundations 4 shallow deep foundations#

Man0 factors should be ta1en into consideration in choosing

foundation t0pes such as soil properties 2 economic factors2engineering practice2 ####etc

•  

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Isolatedfootings Piles

Combined Foundations

Mat

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Isolated FootingsIsolated Footings

Are used to support singlecolumns#

 %his is one of the mosteconomical t0pes of footings andis used when columns are spacedat relativel0 long distances#

/ts function is to spread thecolumn load to the soil 2 sothat the stress intensit0 isreduced #

 

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 are used to spread the load

from a structure over a large

area2 normall0 the entire are

of the structure #%he0 often needed on soft

or loose soils with low

 bearing capacit0 as the0 can

spread the loads over a larger

area#

%he0 have the advantage of

reducing differential

settlements#

Mat or Raft Foundations

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Are used in the following cases4

• 5) 6hen there are two columns soclose to each other in turn thetwo isolated footing areas would

overlap#

• ) 6hen the combined stresses aremore than the allowable bearingcapacit0 of the soil#

• &) 6hen columns are placed at the propert0 line#

 

Combined Foundations

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Cantilever footingconstruction uses a strapbeam to connect aneccentrically loaded column

 foundation to the foundation

of an interior column .

 Are used when the allowable

 soil bearing capacity is high,and the distances betweenthe columns are large .

Strap or Cantilever Footings

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Pile FoundationsPile Foundations

%he0 are long slendermembers that are used to carr0 transfer the load of the structureto deeper soil or roc1s of high bearing capacit02 when the uppersoil la0er are too wea1 to support

the loads from the structure#

7iles costs more than shallowfoundations+ so the geotechnical

engineer should 1now in depththe properties conditions ofthe soil to decide whether pilesare needed or not#

 

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Classification of the pilesClassification of the piles

According to load transmission functional behavior 4

5) nd 8 7oint bearing piles

) Friction piles

&) 9ompaction piles

According to t0pe of material4

5) .teel piles ) %imber piles

&) 9oncrete piles ,) 9omposite piles

According to effect on the soil4

5) Driven piles

) Bored piles

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Bearing 9apacit0 4 is the abilit0 of a soil to support the loads applied

to the ground # Ultimate bearing capacity is the theoretical ma:imum

 pressure which can be supported without failure+ Allowable bearing

capacity  is the ultimate bearing capacit0 ;u divided b0 a factor of

safet0 (F#.)#

%here are three modes of failure that limit bearing capacit04 general

shear failure2 local shear failure2 and punching shear failure#

An0 structure built on soil is subject to settlement# .ome settlement is

inevitable2 depending on the situation2 some settlements aretolerable#

6hen building structures on top of soils2 one needs to have some

1nowledge of how settlement occurs how fast settlement will occur

in a given situation#

Bearing Capacity & Settlement

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eotechnical Investigation%he studied area is

appro:imatel0 flat with slight

difference in the three e:isting

elevations# %he general soil

formation within the depths of the

 borings consists mostl0 of wadi

deposits of boulders silt0 cla0

followed b0 successive la0ers ofhard boulders mi:ed with ver0

little filling silt0 cla0# %he whole

site is covered b0 grass#

%he geotechnical engineerdecided to drill four boreholes

tr0ing to cover the whole

construction area#

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  < ="8m> w < ?#* @ (avg#)

 9 < ="8m (average) < ,,#' @

 C < ' 7/ < '

 ;all# < 1g8cm)  E < #?&

  a-9oefficient of active earth pressure4 =A < #,'

  b- 9oefficient of passive earth pressure4 =7 < #,*,

  c- 9oefficient of pressure at rest4 =o < #'??

  The depths of the drilled boreholes were as follows: The depths of the drilled boreholes were as follows:

Borehole No. Location Depth (m)

5 .outh-west ?#

ast ?#

& 6est *#

, "orth 5#

Summary of lab. test results:

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 After doing chec1 on the bearing capacit0 value using FOUND

software  b0 using %era;i and Me0erhoff formulas2 the value

was ranging between and ,#& =g8 cm) respectivel02 SO we

decided to use a value of 3.5 Kg cm! in our project#

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"ol#mn $ Footing $ Ultimate Loa%

(ton)

 Ser&ice Loa%

(ton)

"!' "! F' *+ ,,.5

" "- F! '!+ -.+

"3 "3 F3 '3 '35.

"'"!""!3"3+"3

!",3

F, !,3 '+.3

"'+"'5"3'"3"3-

","'*

F5 3, !5.,

"5"*"!!"!-"33

",'",!"!,"3*",+ F* 3 !.

"''"'!"'3"',"'

"3,"35

F 5!! 3.!

"'"'-"!+"!5"!*

"!

F 5- ,!-.5

!oad Calculations

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Manual Design steps:

1) Area of footing = Total service loads on column / net soilpressure

) Determine footing dimensions ! " # $

%) Assume depth for footing$

&) 'hec( soil pressure$) 'hec( wide beam shear : +c , +ult 

-) 'hec( punching shear : +cp , .ult punching

0) Determine reinforcement steel in the two directions$

) 'hec( development length $

2) 'hec( load transfer from column to footing $

 Then we compare manual design with 3A. design in footings 4& "4 $

Isolated Footing "esign

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 %he solution of .A7 is alwa0s smaller than manualone2 since .A7 uses Finite lement Method#

%here is no need to calculate the settlement of theisolated footings+ since the soil is gravell0 soil 2 has a

;all# of ' 1g8cm) #

%he final results of isolated footings design are in the

ne:t table 4

"ol#mns Dimensions / s B

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"ol#mn $ F $

"ol#mns Dimension

( m)  (m) (m) (m)

(mm!)

(mm!)

95 29G F5 D< #'m 5#5 5#5 #, G5* G5*

9G 29H F #'$# 5#* 5#* #' 5',G 5',G

9& 29&G F& 9& 4 #?$#,

9&G 4 D < #G m

#,' 5?5 5?5

952929?29&2

9&29&29,&F,

952 92 9& 4 5#5$#,

9?4 #*'$#&

9& 4 #?'$#?'

9& 4 #G$#G

9,& 4 #*$#&

#' #' #' *5, *5,

95295'29&529&?29&H29,2

95*

F'

95 4 #?'$#?'

95' 2 9&? 4 #*$#&9&5 4 5#5$#,

9&H 4 D

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Wall Stair FootingWall Stair Footing

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Dimensions and 5einforcementDimensions and 5einforcement

Details of 6all 3tair 4ootingDetails of 6all 3tair 4ooting

Depth of wall footing = -7 cm.

6idth of wall = 7 cm.

6idth of footing 8!) = m.

5einforcement:

- 91- / m in short direction

1& 91- in long direction 

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Elevator Wall FootingElevator Wall Footing

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Dimensions and 5einforcementDimensions and 5einforcement

Details of levator 6all 4ootingDetails of levator 6all 4ooting

 Depth = %%cm h=&7cm

4 φ16 / m

4or positive moment " negative moment

;n both directions$

1einforcement %etails for ele&ator wall4

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Pile FoundationPile Foundation

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Design of pile foundationDesign of pile foundation

1-Estimating pile capacit

 The ultimate carrpressed b< :

?u = ?p @ ?s

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!-"etermination o# t$e point bearingcapacit

For piles in roc10 sand soil as in ourcase 2 the point bearing capacit0

ma0 be estimated as 4

I7 

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  %"etermination o# s%in resistance

;t can be calculated b< using the followingformula:

 ?3 =B C.*E*f F

6here:

 E : Eength of the pile. : .erimeter of the pile

f : 4rictional factor

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 The following table presents the dimensions The following table presents the dimensions

of piles and their capacities in 8GH)$of piles and their capacities in 8GH)$

length

(m)D(m) '+ '! ', '5 '* '

#' 5 5*, 5* ?G &5 &,H ,&

#* 5'? G ?5 &,' &G* ,& '*

#? 5H* '* &H ,5' ,*& '5, *?

#G &H &? &H ,GH ',, * ?&5

#H G' &* ,'' '** *G *H, G&H

5 &&' , ', *,? ?5* ?GH H'5

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Summary of piles si4es5 number of piles needed5 cap dimensionsSummary of piles si4es5 number of piles needed5 cap dimensions::

"ol#mn  $ Ser&ice Loa%

(KN)

2ile sie(LD)

(mm)

$of piles"ap

%imension

(m)

5JG  (F5) ,,' )G2#'( , #K#

GJH  (F) GH )5,2#'( , #K#

&J&G  (F&) 5&'? )5*2#'( , #K#

5JJ?J&J&J& J,&  (F,)

5G& )5'2#?( , #G'K#G'

5J5'J&5J&?J&HJ,J5*  (F')

'?, )5'2#?( * ,#*K#G'

'J*JJHJ&&J,5

J,J,J&*J, (F*)

G?G )5,2#G( * '#K

55J5J5&J5,J5?J&,J&'  (F?)

&G? )5,2#G( G ?#K

5GJ5HJJ'J*

J?  (FG)

,H' )5'2#G( G ?#K

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 %he structural pile design depends on the nature of soil2 which is either stiff or wea12 the pile is to be designed as short column if the soil is stiff 2 and designed as along column ifthe soil is wea1#

 %he minimum area of steel is #'@ of the gross area of the pile2 also the ties are usedstarting with ' cm spacing and ending b0 & cm spacing #the concrete cover must be notless than ?#' cm#

  Asmin=7$77Ag

 

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Efficiency of pile groupEfficiency of pile group

%he efficienc0 of the load-bearing capacit0 of a group pile ma0 be defineas4

M< Ig(u ) 8 LIu

6here4

Ig(u)< ultimate load bearing capacit0 of the group pile#Iu< ultimate load-bearing capacit0 of each pile without the group effect

sing simplified anal0sis to obtain the group efficienc0 as shown in the following

formula4

N < ((mJn-) J ,D) 8 (pKmKn)

6here4

 m4 of piles in the direction of g#

 n4 of piles in the direction of Bg#

 d4 .pacing between piles centers#

 D4 Diameter of the pile

74 7erimeter of pile cross section

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"esign of a pile cap"esign of a pile cap::  The minimum distance between two piles is %D$

.ile caps should e>tend at least 1 cm beterior face of e>terior piles$

 The minimum thic(ness of pile cap above pile heads is %7cm$

 The cover in pile caps commonl< ranges between 7 "

cm $

Design 3teps:

1) Assume depth 8d)

) 'hec( .unching shear : +cp

 , +ult punching

%) 'hec( wide beam shear : +c , +ult 

&) 'alculate area of steel needed

) 'hec( Imin$ J I J Ima>$

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Retaining *all "esign+Retaining *all "esign+

%he retaining wall is designed b0 7PO=O" 7rogram +

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&onclusions'&onclusions'1)From soil report2 we note that 7/ is ' and cohesion is ero and this

can be e:plained b0 the following4

6e have soil contains some cla0 between gravels2 and when we ta1e asample of this soil to be tested for atterberg limits to determine 7/2we

use sieve , and we ta1e the passing which are cla0 particles and in

turn this leads to increase the magnitude of plasticit0 inde:#

9ohesion is ero since the soil sample is almost gravel#

)After designing the two alternative choices (single footings and piles

s0stem) surve0ing the ;uantities for concrete onl02 we find that it is

more practical2 realistic and economical to use single footings

&)there is no need to ma1e settlement calculations for footings and

 piles 2since we have a gravel0 soil with B#9 of ' 1g8cm(the

settlements in our situation are tolerable2 so we can ignore them)##

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