foundations under static loads

1Jean Louis BRIAUD1

TEXAS A&M UNIVERSITY

Deeyvid SAEZ BARRIOS2

1. President of ISSMGE, Professor and Holder of The Buchanan Chair, Texas A&M University

2. PhD Graduate Student and Research Assistant, Texas A&M University

April 2010THEORY PRACTICE

1. Load Resistance Factors Design (LRFD) Approach

2. Site Investigation

3. Design of Shallow Foundation for Vertical Loads

4 P I

CONTENT OUTLINE

4. Pile Instalation

5. Design of Single Piles for Vertical Loads

6. Design of Pile Group for Vertical Loads

7. Design of Piles for Horizontal Loads

8. Special Cases (Shrink-Swell Soils, Downdrag andScour)

9 The Role of Load Testing9. The Role of Load Testing

10. Conclusion

Jean Louis BRIAUD TEXAS A&M UNIVERSITY

1

2LOAD RESISTANCE FACTOR DESIGN (LRFD)

WORKING STRESS DESIGN

RL FS 2 0 3 0

LOAD RESISTANCE FACTORS DESIGN (LRFD)

= 1.0 to 2.0RL

FSL = FS 2.0 to 3.0


L= Load = Load Factor

R= Resistance = Resistance Factor =FS

1.0 to 2.0 = 0.30 to 0.90

RL =

IMPORTANT LOAD FACTORS IN FOUNDATION ENGINEERING

=n n iiii RL

LOAD RESISTANCE FACTOR DESIGN (LRFD)

= =i i

iiii1 1

i Li= 1.25DL + 1.75LL For Ultimate Load

i Li= 1.0DL + 1.0LL For Settlement in Sand & Immediate Settlement in Clays


i Li= 1.0DL Long Term Settlement in Clays

i Li= 1.25DL + EQLL+1.0EQ For Earthquake Analysis

2

3 IMPORTANT RESISTANCE FACTORS FOR SHALLOW FOUNDATION

= =

=n

i

n

iiiii RL

1 1


i R= 0.35R For Friction Angle Approach ---SANDS

i R= 0.45R For SPT Approach ---SANDS

i R= 0.55R For CPT Approach---SANDS


i R= 0.60R For Su Approach---CLAYS

i R= 0.50R For CPT Approach---CLAYS

Su= Undrained Shear Strength

IMPORTANT RESISTANCE FACTORS FOR DRIVEN PILESUNDER COMPRESSION LOADS

=n n RL


= =

=i i

iiii RL1 1

i R= 0.56R to 0.70R (Verif.) For Su Method---CLAYS

i R= 0.36R to 0.45R (Verif.) For SPT Method ---SANDS

R 0 44R 0 55R (V if ) F CPT M h d SANDS


i R= 0.44R to 0.55R (Verif.) For CPT Method---SANDS

Use 0.85(compression) for (uplift)


3

4 IMPORTANT RESISTANCE FACTORS FOR BORED PILESUNDER COMPRESSION LOADS.

=n n RL


= =

=i i

iiii RL1 1

i R= 0.65R For Su Method---CLAYS SIDE

i R= 0.55R For 9Su Method ---CLAY POINT

R= 0 65R For Method SANDS SIDE


i R= 0.55R For 0.057N Method---SANDS POINT

Use 0.85(compression) for (uplift)


i R= 0.65R For V Method---SANDS SIDE




4 P I

CONTENT OUTLINE

4. Pile Instalation



7. Design of Single Pile for Horizontal Loads



10. Conclusion


4

5http://www.earth-engineers.com/DSC01903.JPG

SITE INVESTIGATION WHY IS BORING IMPORTANT?


MAYNE, P., CHRISTOPHER, B., & DEJONG, J. (2002).

SITE INVESTIGATION STANDARD PENETRATION TEST (SPT)


5

6Advantages

1) Sampling Is Possible

MAYNE, P., CHRISTOPHER, B., & DEJONG, J. (2002)

SITE INVESTIGATION STANDARD PENETRATION TEST (SPT)

2) Simple

3) Suitable in many soil types

Disadvantages

1) Sample Disturbance

2) Not applicable for very soft or very loose soils

3) High Variability



SITE INVESTIGATION CONE PENETRATION TEST (CPT)


6

7Advantages1) Fast and continuous

profile

Disadvantages1) Required skill

operator to run


SITE INVESTIGATION CONE PENETRATION TEST (CPT)

profile.

2) Applicable for soft soils.

3) Strong Theoretical basis in interpretation.

operator to run

2) No soil sample can be obtained.

3) Unsuitable for very hard or dense soils and large particles.



SITE INVESTIGATION SEISMIC PIEZOCONE TEST


7

8MAYNE, P., CHRISTOPHER, B., & DEJONG, J. (2002).

SITE INVESTIGATION PRESSUREMETER TEST (PMT)


Advantages

1) Theoretically sound in determination of soil parameters


SITE INVESTIGATION PRESSUREMETER TEST (PMT)

soil parameters.

2) Applicable for larger zone of soil mass than any other in-situ test.

3) Develop complete stress vs strain curve

Disadvantages

1) It requires trained personel .

2) Time consuming (8 tests per day).

3) Delicate equipment.


8

91. Clays and Silts:

LABORATORY TESTS

Classification Tests, Undrained Shear Tests, Drained Shear Tests, Consolidation Tests

2. Sands and Gravels: Classification Tests





4 P I

CONTENT OUTLINE

4. Pile Instalation






10. Conclusion


9

10

BEHAVIOR OF SANDS AND CLAYS UNDER LOAD CONDITIONS

DESIGN OF SHALLOW FOUNDATION

FSQu Qu Q (Load)

CLAYS

FSQu

SANDS

Q(Load)QuallSS >

FS QallSS p

'p=maximum past pressure experience by the soil

+ ovrc e '0

g1

++

+= pvv

cv

prc

oCCe

Hs '''

'

'

0

0 loglog1

0

--TIME RATE OF SETTLEMENT--SETTLEMENT OF SHALLOW FOUNDATION

v

drv

CHTt

2

= ( )maxH

HU tave

=

H1

H2

HZi

50% 90% Time, t

Hdr=Smallest Drainage Path

Uave= Average Degree of Consolidation

H3

H4

Settlement, H

Hmax


16

17

--ELASTIC SOLUTION--Q

SETTLEMENT OF SHALLOW FOUNDATION

( )21;

I q BS

E= BL

Qq =

B

E100 Su for clays E750 N(SPT) for clean sands E450 N(SPT) for silty sands

I=0.88 I=/45.0

88.0

=BLI

SHAPE FACTOR


B

PLAN VIEWB

B B

L D

--LOAD SETTLEMENT CURVE METHOD--SETTLEMENT OF SHALLOW FOUNDATION

PMT

P

2Ro

R

P P


R/Ro

PLLimit Pressure

17

18

0 . 2 4

O

s RB R

=


--LOAD SETTLEMENT CURVE METHOD--

pdeBLf PffffP .... ,/ = ( )Bef e /33.01 = Eccentricity

( ) 1.0, /18.0 BDf DB += Slope Proximity( )LBf BL /2.08.0/ += Shape

( ) 2190

/tan1

=

vh FFf Inclination





18

19





19

20

FIVE LARGE SPREAD FOOTINGS TESTS IN SANDS


LABORATORY TESTS

Water Content & Unit Weight

Atterberg Limits

IN-SITU TESTS

Borehole Shear Test & Cross-Hole

Wave Tests


Atterberg Limits

Relative Density

Triaxial Test

Resonant Column Test

PiezoCone Penetration Test

Dilatomer Test

Pressuremeter Test

Step Blade Test

Standard Penetration Test & Cone

Penetration TestPenetration Test


20

21





21

22


n

tt

SS

=

11

Creep Model




22

23



IMPORTANT FINDING

Pu (kPa) = 75 N

THE GENERAL BEARING CAPACITY DOES NOT WORK IN THIS CASE


DEVELOP ED THE LOAD SETTLEMENT CURVE METHOD

23

24

Comparison between Bearing Capacity Predictions and Measured Pressure at 150 mm of Se.


Comparison between Predicted and Measured Load at 25 mm of Settlement


San Jacinto Monument Houston (1936)

LOADING:

Gross Pressure = 224 kPaMax Pressure (Dead + Wind) = 273 kPa

EXAMPLE - SAN JACINTO MONUMENT

Excavation= - 83 kPaNet Pressure=141 kPaNet Pressure after Mat Poured = 10 kPaPressure from Terraces = 34 kPa & 84 kPa


24

25

STRATIGRAPHY - SAN JACINTO MONUMENT


SOIL INDEX PROPERTIES


25

26

CONSOLIDATION CHARACTERISTICS


STRESS DISTRIBUTION


26

27

CONSOLIDATION CHARACTERISTICS


ACTUAL SETTLEMENT


27

28

ACTUAL SETTLEMENT

DESCRIPTION S(m)

CASE 8 (I l di R b d) 0 607CASE 8a (Including Rebound) 0.607

CASE 7a (Not including rebound) 0.370

DAWSONS PREDICTION 0.187


MEASURED SETTLEMENT 0.329




4 P I

CONTENT OUTLINE

4. Pile Instalation






10. Conclusion


28

29

BORED PILES Concrete (dry drilling

or mud drilling), timberor steel piles.

Use in harder soils or

DRIVEN PILES Timber , Concrete, and

Steel.

Use in softer soils.

DESIGN OF DEEP FOUNDATION-TYPES OF PILES

Use in harder soils orfor high loads.

Nominal diametersranging from 0.40 to 4.0m.

Typical length rangingfrom 3 m to 45 m.

Nominal diametersranging from 0.30 to 3.0m.

Typical length rangingfrom 3.0 m to 60 m.

END BEARING PILES FRICTION PILES


WW

DRIVING ANALYSISN (bpf)

Set-Up

N (bpf)

W

I-II-

s

s

III-

End of Driving


29

30

http://www.vibropile.com.auhttp://www.coastalcaisson.com

DRILL DRY

INSTALATION OF BORED PILES

DRILL DRY

DRILL WET

USING CAISINGUSING CAISING


http://www.moretrench.com/~moretren/cmsAdmin/uploads/thumb2/Drilled_Shafts_001.jpg

DRILL DRY - BORED PILE INSTALLATION


30

31

http://www.kbtech.com/images/photos/Anderson%2022%20Cobble%20on%20Auger%20Pilot.jpg

DRILL WET - BORED PILE INSTALLATION


INSTALLATION OF BORED PILE WITH CAISING

http://www.agrafoundations.ca/images/large/3.0-Bored-Piles/Thumb-2.jpg


31

32

WAK

BULB, STRONG LAYER FIXED END

V

NON-DESTRUCTIVE TESTING FOR BORED PILES

time

cLt 2=

at A

FL

A

COMP. COMP.

time

cLt 2=

at A


NECKING, WEAK LAYER FREE END

VWAK

NON-DESTRUCTIVE TESTING FOR BORED PILES

F

time

cLt 2=

at A

L

A

COMP. TENS.

time

cLt 2=

at A


32

33

PILE DRIVINGhttp://images.google.com/imgres?imgurl=http://www2.dot.ca.gov/hq/esc/geotech/projects/t


h

W

PILE DRIVING ANALYSIS FOR DRIVEN PILES( )

3 0 0( ) 2

U De W h m mR c

N b p f

=+

L R

st

st

Load, Q

sb


Settlement, s

33

34

PILE DRIVING ANALYSIS FOR DRIVEN PILES

RUD

RUD

RUDTotal

EnergyElastic Energy

max( )

2.5UDeWh mmR =

Np(bpf)75e=efficiency of the hammerW= hammer weight

Scs


gh= drop heightNp= number of blow per footC= elastic compression (5mm?)RUD= ultimate resistance of the pileat the end of driving.

( )3 0 0( ) 2

U De W h m mR c

N b p f

=+

WAVE EQUATION ANALYSIS

2

2

2

2

tU

ER

AED

zU

=

Ec = Wave Velocity

WAK

RUD

=mass density of the pile

E=elastic modulus

A=cross sectional area of the pile

RUD= ultimate resistance of the pile at the end ofdriving

D


Np

L

34

35

WAVE EQUATION ANALYSIS

WAK WAK

D D


L L

+-

+

+

Soft Hard

Software: CAPWAP Driving ProcessPile CapacityPil I i

PILE DRIVING ANALYZER

h

W

Pile IntegrityStresses along the Pile

STRAINL R

Strain and

AccelerationTransducers

st


ACCELERATIONsb

time

35

36




4 P I

CONTENT OUTLINE

4. Pile Instalation






10. Conclusion


pufuu QQQ +=ApAfQ +

QuQu

Working

ULTIMATE BEARING CAPACITY OF A SINGLE PILE

pusuu ApAfQ +=fu= Ultimate Skin Friction (kPa)

As= Surface Area

L fu QfuUltimate

Load

Working Load

pu= Ultimate Point Pressure (kPa)

Ap= Point Areapu Qpu


36

37

Short and Long TermULTIMATE POINT RESISTANCE FOR DRIVEN PILES

For Clays -Short Term.uSq 9max =For Clays Long TermN'

( ) ( ) 5.0max 1000 NkPaq = For Sands (Short & Long Term)

For Clays -Long Term (Nq from API)

For Sands -Short & Long Term

qvo Nq max =

qvo Nq'

max =

Others Methods are based on Pressuremeter and Cone Penetration Test

Frank, R. (1997), Calcul des Fondations Superficielles et Profondes, Presses de LEcole Nationale des Ponts et Chaussees, pp141


(Nq from API)

Short and Long TermULTIMATE FRICTION FOR DRIVEN PILES IN CLAY

uu Sf =max 'max vuf =


37

38

ULTIMATE FRICTION FOR DRIVEN PILES IN SAND

For Piles in Sand

Short and Long Term'

max vuf =

( ) ( ) 7.0max 5 NkPafu =N=SPT blow count

For Bored Piles Usefumax=0.75fumax (Driven)


For Clays:KPaSSuf 275550 =

Reese & ONeilNc

S

Square

ULTIMATE BEARING CAPACITY OF A BORED PILE

KPaSSuf uu 27555.0 =

92.016;

+==

bcucu B

LNSNP

0.5' ; 1 .5 0.135( ( )) ;f z ft = =

D/B

Strip

For Sands:; 1 .5 0.135( ( )) ;

0.25 1.2; 200u v

u

f z ftf kPa


Pu(kPa)=57 NSPT for 0 NSPT75 blows per footPu= 4300 kPa for NSPT 75 blows per foot

38

39

FOR MORE INFORMATION ON DOWNDRAG VISIT:

PILNEG, free software

http://ceprofs.tamu.edu/briaud/


http://ceprofs.tamu.edu/briaud/

Briaud J.-L., Tucker L.M., 1998, Design guidelines for downdrag on uncoated and bitumen coated piles, NCHRP Report 393, National Academy of Sciences.

Qu

Qu

CRITICAL DEPTH OF A SINGLE PILE

Nc

St i

Square9.0

SKEMPTONS CHART

L1 fu

Dc=4B

LAYER 1

D/B

Strip7.0

4.0Jean Louis BRIAUD TEXAS A&M UNIVERSITY

pu

B

4B LAYER 2

39

40

Qtop

Stop

SETTLEMENT FOR SINGLE PILES

GENERAL APPROACH

L

Stop

fu

AELPSS avebottomtop +=

0 .6 (? )a v e to pP Q=

q SbottomJean Louis BRIAUD TEXAS A&M UNIVERSITY

( )EBpIs bottom

21 =

QtopQ

QwTf1

1111 21

sp AfAqP += AEPLww += 12

SETTLEMENT FOR SINGLE PILES

P3

Qtop

P2

L1 f1

L2

w3

wT

f2

w

f

f2

w

w q1

P1

q

L3

w1

w2f3 f1

w

q


40

41




4 P I

CONTENT OUTLINE

4. Pile Instalation






10. Conclusion


QusingleQugroup

ULTIMATE LOAD CAPACITY OF A PILE GROUP

L L

Zone of Influence

gleuugroup enQQ sin=e=overall efficiency factor 1.0


41

42

BLOCK FAILUREANALYSIS OF A PILE GROUP FOR CLAYEY SOILS

Qugroup

L

D


( ) BLSNDLBSQ ucuublock ++= 2( )min ,ugroup usingle ublockQ nQ Q=

B L

LOAD TRANSFER FOR A PILE GROUP ANALYSIS

Qugroup Qugroup

2/3L L L

Hard Layer


Transfer the Load to 2/3 L if the Soil is uniform (Friction Piles)

Transfer the Load to the bottom if there is a hard layer

(End Bearing Pile)

42

43

CASE HYSTORY NEW ORLEANS HOSPITAL10000 Timber Piles0.3 m diameter (average)16 Story-Building15 m Long

1500 MN

15 m Long Soft Clay at the top2m thick dense sand at 14.5 m

Su=20 kPa

H

H=2 m

H=14.5 m

SandLOAD

Load Test for a Single Pile


Su=30 kPa

H1

H2

H3

H4

H=83.5 m

H5

L

Weight of the Hospital=1500 MNRu for one pile = 300 kN10000 x Ru=3000 MN ----FS=2.0 ok.

1500 MN

CASE HYSTORY NEW ORLEANS HOSPITAL

Hi v Uo b a H=xHi

Ultimate Block Capacity= 1200 MN (PROBLEM)

Htotal = 0.50 m

H

H=2 m

H=14.5 m

H1

H2

H3

H4

H=83.5,

H5

43

44




4 P I

CONTENT OUTLINE

4. Pile Instalation




8. Special Cases (Shrink-Swell Soil, Downdrag andScour)


10. Conclusion


DESIGN OF SINGLE PILE FOR HORIZONTAL LOADS


44

45





45

46



ULTIMATE HORIZONTAL LOAD

oov lLforlD 34>

=


vlou BDpH 43=

ov lLforLD 3lo

Dv=L/3 for l

47

FIXED HEAD BEHAVIOR FREE HEAD BEHAVIOR

Houyo

M

Houyo

M


Ly'o=0 L

0' oy


L =length pile

Hou =ultimate horizontal load

M =moment at the top of the pile

yo = horizontal displacement at the top of the pile

y'o =deflection at the top of the pile

HORIZONTAL DISPLACEMENT @Hou/3


GENERAL CASE

oo lLfMH 322 L d Fl ibl

P li it f PMT

yo

oEK 3.2=

oo

o

o

oo lLforklKl

y 32 >+=( )

2

2 2 3o oo o

H L My for L l

KL += = L d Fl ibl

P li it f PMT

oo

o lLforKly 3>=

oo

o lLforLKHy 3lo

Dv = L/3 for l= L d Fl ibl

P li it f PMT

yo

oEK 3.2=

oo

o lLforKly 3>=

oo

o llforKLHy

49



( )( )

n

ooou

ou

tt

tHtH

= ( )( )

n

ooo

o

tt

tyty

=

LONG TERM LATERAL LOAD

n=0.01 to 0.03 in sands

n=0.02 to 0.08 in clays


Hou= ultimate horizontal load at time t

Hou= ultimate horizontal load at time to

yo = lateral deflection at time t

yo = lateral deflection at time to

49

50

( )( )

n

tt

tRtR

=

( )( )

= ot

tRtR

nlog

n VALUES FROM THE PRESSUREMETER TEST

n=0.01 to 0.03 in sandsn=0.02 to 0.08 in clays

( ) oo ttR

ottlog


R(t)= change in the radius of the cavity at time t

R(t0)= change in the radius of the cavity at time to

n VALUES FROM THE PRESSUREMETER TEST


50

51

aN Nyy 1=

a averages 0.1 for clays (one way and two way)

CYCLIC LATERAL LOADING

a averages 0.08 for sands under one way loading

a averages 0 for sands under two way loading

HoONE WAY CYCLIC

HoTWO WAY CYCLIC

y

LOADING

y

TWO WAY CYCLIC LOADING


aN NRR = R

R

a

Nlog1

a FROM THE PRESSUREMETER TEST

PMT ONLY APPLICABLE FOR ONE WAY

R 1 ( )Na log =

CYCLIC LOADING


51

52

THE PRESSUREMETER TEST


THE PRESSUREMETER TEST


52

53

LATERAL LOAD NEAR A TRENCH


trenchnotrench HH =LATERAL LOAD NEAR A TRENCH


53

54

FUTURE WORK IN RETAINING WALLS


EARTH PRESSURE COEFFICIENT VS MOVEMENT/HEIGHT


54

55

Hou Hou

FIXED HEAD BEHAVIOR

DESIGN OF PILE GROUP FOR HORIZONTAL LOADS

L L


( ) ( )gleougroupou enHH sin=n= number of piles

e=efficiency factor

Direction of the Load

4 DIAMETER PENETRATION AND 0.5- DIAMETER CLEAR SPACING

GROUP EFFICIENCY FOR HORIZONTALLY LOADED PILES

0.33 0.360.31

Fraction of the Load


55

56

0.20 0.18 0.14 0.20 0.28

8 DIAMETER PENETRATION AND 0.5 DIAMETER CLEAR SPACING

GROUP EFFICIENCY FOR HORIZONTALLY LOADED PILES


0.21 0.17 0.17 0.18 0.26


0.19 0.19 0.19 0.19 0.24





4 P I

CONTENT OUTLINE

4. Pile Instalation






10. Conclusion


56

57

Soil Movement

FOUNDATION ON SHRINK-SWELL SOILS

h=active zoneShrink Swell Soil w

Water Content Profile

d

w

i

wi

i

i

i wE

wfHH

=== 33.0


Shrink-Swell SoilShrinking

Qu

SwellingQu

FOUNDATION ON SHRINK SWELL SOILS

L

h=active zoneLOAD

Qu

Qp


Shrinking

Swelling )( hLDfL uLOAD = DhfL uLOAD =

4)(

2DphLDfL uuLOAD +=

57

58

STIFFENED SLAB ON PIERS


ELEVATED STRUCTURAL SLAB ON PIERS


THIN POST TENSIONED SLAB ON GRADE


STIFFENED SLAB ON GRADE


58

59

DOWNDRAG ON PILES


PILE POINT BEHAVIOR


59

60

2(1 )4

ppunch

s

Q Dv

AE =

PILE POINT BEHAVIOR

punch = Pile point movement

= Poissons ratio

Qp= Point resistance

A= Area of pile pointA= Area of pile point

D= Diameter of pile point

Es= Soil modulusFor clays = Es = 100 Su = EPMTFor sands=Es (kPa) = 750 N = 2 EPMT


EXAMPLE OF DOWNDRAG ON SINGLE PILES

Pile Ultimate Capacity

Qu = 706 + 1000

Q = 1706 kNQu 1706 kN


60

61

EXAMPLE OF DOWNDRAG ON SINGLE PILES


Qfn(group)Qfn(single)

DOWNDRAG FOR A GROUP OF UNCOATED PILES

LL

s s sCorner Piles

Side Piles

Internal Piles

( ) ( )glefngroupfn QQ sin5.0=

( ) ( )glefnsidefn QQ sin40.0=

( ) ( )glefnernalfn QQ sinint 15.0=

5.2=dsfor


61

62

SCOUR TYPES

Probable Flood Levelys(Abut) Applies ys(Cont) Applies

CL

Normal Water Level

ys(Abut)

y s(pier) y s(Cont)


is Abutment Scour Depthis Contraction Scour Depthis Pier Scour Depth

Where, ys(Abut)y s(Cont)y s(pier)

( )0.7( ) 1 ( ) ( )2.2 2.6's Pier w L sp pier c piery K K K K Fr Fra = 0.33

1 10.89 , for 1.43' 'w

y yK a a

=

1.0, for whole range of /LK L a=0.91

2.9 , for 3.42' '

1 0 elsesp

S SK a a

63

OBSERVED FAILURE MODES OF BRIDGE DUE TO SCOUR(based on failure photos in Briauds files)

Case 1 - Big Scour Hole

26% Observed Occurrence

Case 2 Settlement of Pier


Case 3 - Loss of Deck


Case 4 - Loss of Pier

37% Observed Occurrence Jean Louis BRIAUD TEXAS A&M UNIVERSITY


126

Case 1 - Big Scour Hole



63

64

Courtesy of the University of Kentucky at Louisville





64

65


129

Case 2 Settlement of Pier





65

66





66

67




134

Case 3 - Loss of Deck



67

68



Hatchie River Bridge, Tennessee



68

69




138

Case 4 - Loss of Pier



69

70





70

71





71

72





72

73


This distance should be made larger to decrease

the risk of collapse

145Jean Louis BRIAUD TEXAS A&M UNIVERSITY

STRUCTURAL

and

GEOTECHNICAL

THE ROLE OF SOIL STRUCTURE-INTERACTION

Qu Q

S

k1


73

74




4 P I

CONTENT OUTLINE

4. Pile Instalation




8. Special Cases (Shrink-Swell Soils and Downdrag)

9. Example Problems

0 T T10.The Role of Load Testing

11. Conclusion


Laboratory testing brings the problem of sampledisturbance . However, its application is valuable for theunderstanding of some properties that can not bedetermined using In-Situ Tests.

THE ROLE OF LABORATORY TESTING


74

75

THE ROLE OF IN-SITU TESTINGMAYNE, P., CHRISTOPHER, B., & DEJONG, J. (2002).

In-situ testing gives a good estimation of the soil properties byreducing the problem of sample disturbance.

Its application depends on the project magnitude and importance.


http://images.google.com/imgres?imgurl=http://

THE ROLE OF LOAD TESTING: SONIC INTEGRITY TEST

SONIC-INTEGRITY: is an in-situ test that helps to locatepotential problems in bored piles.


75

76

Hydraulic

Jack and Gauges

Q(Load)Qu Qu

LOAD

RXRX

THE ROLE OF LOAD TESTING: STATIC LOAD TEST FOR PILES

Q(Load)

0.1B

QuQuAEL

L

RX

SANDS

S(Settlement) CLAYS

AEQLBS e += 1.0

L

Reaction Piles


http://www.earth-engineers.com/Pile%20Load%20Test%20%281%29.jpg

THE ROLE OF LOAD TESTING: STATIC LOAD TEST FOR PILES

It provides the load curve of an installed pile. From that,the ultimate load resistance of the pile can be determined.


76

77

STATIC LOAD TEST FOR SHALLOW FOUNDATION(Texas A&M University Load Tests)


THE ROLE LOAD TESTING: STATNAMIC TEST www.statnamiceurope.com/

The Statnamic is another load test that provides a loadSettlement curve of an installed pile.


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STATNAMIC LOAD TEST FOR SINGLE PILES

Q(Top Load)BANG

Q( p )ChargeBIG MASS

LASER

Calibrated

Dynamic

stop


S(Top Settlement)

Ly

Load Cell

Sbottom

OCELL INSTALLATIONFROM: HTTP://WWW.LOADTEST.COMTransducers

HC

THE ROLE OF LOAD TESTING: OSTERBER CELL TEST

L

Load Cell

Hydraulic Control

Steel Plates

Tested Area

Load Cell

Reaction Area


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4 P I

CONTENT OUTLINE

4. Pile Instalation




8. Special Cases (Shrink-Swell Soils and Downdrag)

9. Example Problems

0 T T10.The Role of Load Testing

11. Conclusion


Foundation engineering requires:

1. A good understanding of site conditions including Geology

CONCLUSION

2. Proper use of theory in design

3. Safety against ultimate capacity

4. Allowable movements

5. Good experience and engineering judgementjudgement

6. Appropriate specifications

7. Quality control during construction


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MORE REFERENCES

BRIAUD, J.L., SALLOP: Simple Approach for Lateral Loadson Piles, Journal of Geotechnical and GeoenvironmentalEngineering, Vol. 123, No. 10, pp. 958-964, ASCE, NewYork, October 1997.

BRIAUD, J.L., The Pressuremeter, A. A. Balkema, Rotterdam,Netherlands, 1992.

ASSHTO LRFD (Load Resistance Factor Design).

BRIAUD J L GIBBENS R B h i f Fi S d


BRIAUD J.-L., GIBBENS R., Behavior of Five SpreadFootings in Sand, Journal of Geotechnical andGeoenvironmental Engineering, Vol. 125, No.9, pp. 787-797,September 1999, ASCE, Reston, Virginia.

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foundations under static loads

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