foundation design and case studies

The University of the West Indies Organization of

American States

PROFESSIONAL DEVELOPMENT PROGRAMME:

COASTAL INFRASTRUCTURE DESIGN, CONSTRUCTION AND MAINTENANCE

A COURSE IN

DESIGN OF MARINE STRUCTURES

CHAPTER 5

FOUNDATION DESIGN AND CASE STUDIES

By DEREK GAY, PhD Lecturer, Civil Engineering Department

Faculty of Engineering University of the West Indies

St Augustine Campus Trinidad, West Indies

Organized by Department of Civil Engineering, The University of the West Indies, in conjunction with Old Dominion University, Norfolk, VA, USA and Coastal Engineering Research Centre, US Army, Corps of Engineers, Vicksburg, MS, USA.

Trinidad and Tobago, West Indies, September 24th – 28th, 2001

Dr Derek GayDepartment of Civil Engineering

UWI.

Typical Mature Volcanic Deposits Deep Ash/Tiff (Tarish) over volcanic

boulder/rock formations

CDCM Sept 24-28 2001

3

Woodford Hill Formation Dominica

0

5

10

15

20

25

30

0 50 100 150SPT (blows/ft)

Dep

th (m

)


4

Dominica Woodford Hill formation

0

50

100

150

200

250

300

10+12

410

+508

10+6

5010

+758

11+0

8311

+088

11+1

9411

+495

11+9

3312

+222

12+24

812

+352

12+5

8612

+778

13+2

6113

+432

Station (m)

Elev

atio

n (m

)

Boulders/Rock Ash/Tiff weathered

Leeward Sea Port in Typical Swamp over Deep Alluvial Deposits


6

16.8

3.0

7.7

2.5

20.0

Fill (working surface)-ve frictional contribution

Soft-very soft silty clays, peat and organics

Loose - medium dense/stifff sands, silts, clays in lenses/pockets and mixed, variable

30.0

Dense/Stiff - very dense/stifff sands, silts, clays in lenses/pockets and mixed, uniform

piezometersplatessettlement


7

Loma Prieta Acceleration Strong Motion Record Diamond Heights

-0.12

-0.08

-0.04

0

0.04

0.08

9 10 11 12 13 14

Time (secs)

Acc

eler

atio

n (%

g)


8

Caricom Wharf AreaAmplification Spectrum (Loma Prieta)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0.01 0.1 1 10

Period (sec)

Spec

tral

Am

plifi

catio

n (s

urfa

ce/ro

ck)


9

Caricom Wharf AreaSeismic Acceleration Spectrum

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.01 0.1 1 10

Period (sec)

Spec

tral

Acc

eler

atio

n - g

Loma Prieta Zone 3 Zone 2b

Liquefaction Analysis from SPT and grainsize distribution results.


11

Old Harbour Bay JamaicaSummarised SPT Results

0

5

10

15

20

25

30

35

40

1 10 100

SPT N (blows/ft)

Dept

h (m

) BH A

BH B

LAND BHs


12

LIQUEFACTION POTENTIALLab Triaxial Shear method

(Seed et. al. 1971)

0

5

10

15

20

25

30

35

40

0 50 100

Shear Stress (kN/m^2)

Dep

th (m

)

.20g

.25g

.30g

.35gFailure Stress


13

LIQUEFACTION POTENTIALSPT N Field correlation method

(Seed et. al. 1985)

0

5

10

15

20

25

30

35

40

0 50 100

Shear Stress (kN/m 2̂)

Dep

th (m

)

.20g

.25g

.30g

.35gFailure Stress

Zone of potential,Liquefaction,Settlement,Shear Deformation

0.20g

.25

.30.30

.35

Problems of soft compressible soils with boulder/gravel inter-layering

influenced by tidal fluctuations, alluvial deposition and river flows.


15

-0.5

-0.3

-0.1

0.1

0.3

0.5

0.7

0.9

1.1

1.3

1.5

1.7

Wat

er T

able

Ele

vatio

n (m

)

1 2 3 3A 4 5 6 7 8 9Borehole

Water Table Ground Surface

Water Table Conditions Grenada


16

SPT vs Depth Grenada

0

6

12

18

24

0 50 100 150 200 250

SPT (Blows/ft)

Dep

th (m

)

very soft - soft silts & claysvery loose - loose sands & gravelsPrincipal contributor to observed settlement related cracking


17


18

BH98-12

BH98-6

BH98-5BH98-13

BH98-9

BH98-10

BH98-8

BH98-7

BH98-16BH98-15

BH98-14

BH98-11

POINTE SERAPHINE

BH93-1

BH93-2

BH93-3

BH93-4

1

CH1

CH2CH3

CH4

CH5

CH6

CH4A

CH5A

TP96-1

TP96-2

TP96-3

TP96-7TP96-8

TP96-4

TP96-9

TP96-6

TP96-5

Limits

of dre

dgin

g

Lim

i ts o

f dr e

dgin

g


19

BH98-12

BH98-6

BH98-5BH98-13

BH98-9

BH98-10

BH98-8

BH93-3

BH93-4

TP96-3

TP96-7


20

Very de nse sands & weath ered be drockN >> 100 blow s/ft.

Ve ry soft silts and claysN = 0-2 blows/ft

Wate r

+10

0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

-110

elev

atio

n ft

.

BH98-12 BH 98-6 BH 93-3 BH 98-5 B H98-13

Bottom ele v. of "H" piles

West Support Area Eastern Cantilever

14-15 17-18 20-21 25-26 31-32


21

+10

0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

-110

elev

a tio

n ft

.

BH98-13 BH 93-4BH98-9

Rock fill

Cross-section of Berth at eastern end.


22


23

PPGPL Docking FacilityCompressive Pile Capacity

0

5

10

15

20

25

30

35

40

0 100 200 300 400

Qa = Qb/3 + Qs/1.5 (Tons)

Dep

th b

elow

MSL

(m)

600 mm concrete 914mm steel dredged


24

PPGPL Docking FacilityCompressive Pile Capacity

0

5

10

15

20

25

30

35

40

0 100 200 300 400

Qa = Qb/3 + Qs/1.5 (Tons)

Dep

th b

elow

MSL

(m)

600 mm Concrete 914 mm Steel


25

Caribbean Tides 1

-100

-80

-60

-40

-20

0

20

40

60

80

100

0 100 200 300 400 500 600 700 800

Kingston Ponce Antigua Dominica


26

Caribbean Tides 2

-100

-80

-60

-40

-20

0

20

40

60

80

100

0 100 200 300 400 500 600 700 800

Castries Grenadines Barbados Tobago


27

Caribbean Tides 3

-100-80-60-40-20

020406080

100

0 200 400 600 800 1000

Nariva Gasparee Erin


28

Derek Gay B.Sc.(UWI), M.Sc.(London) PhD. (Texas)

• Academic

• Dept. Civil Engineering • University of the West Indies• St. Augustine• Phone: 868 645 3232 ext. 2504

• Email: [email protected]

• Consulting

• Earth Systems Engineering Limited

• 5B The Mews• 69-71 Cascade Road• Port of Spain • Trinidad West Indies• Phone 868 627 0980• Fax: 868 627 0981• Email: [email protected]

foundation design and case studies

Documents