Statnamic Pile Load Testing - Accueil | CFMS · · 2012-01-19Disadvantages: Difficult to ... STN Cyclic Load Displacement Diagram Displacement [mm] Load ... preparation European

www.fugro.com www.fugro.frDate

Statnamic Pile Load Testing

Flip Hoefsloot, Fugro The NetherlandsJanuary 2010


Contents Menu

Load Testing Methods

Description Statnamic

Video of TestApplication

Interpretation

GuidelinesConclusion


Load Testing Methods

STATIC

100 %

Load

Displacement

DYNAMIC

1-2 %

STATNAMIC

5-10%

High pressure gas

High pressure gas

Strain

Acceleration

Load

Displacement


Description Stanamic

1 2

3 4

A = Pile B = Load cellC = Cylinder D = Piston with chamberE = PlatformF = SilencerG = Reaction massH = Gravel ContainerI = GravelJ = LaserK = Laser beamL = Laser sensor


Fugro Profound

Knowledge and experienceStatnamic(Peter Middendorp)

ClientsWord wide



Hydraulic Catching Mechanism

Containers filled with local material (gravel or equivalent)

4 test a day

Simple inspection ignition system

Transport on one trailer



Equipment:

80 tons reaction mass

7 trailers for transport2 to 3 days a test

one cycle of testing



Video of Test


Application, Static Load Test

Advantages:

•Static behaviour

•Separation of:

•End Bearing

•Shaft Friction

Disadvantages:

•Cost

•Selection of Test Piles


Application, Dynamic Load Test

Advantages:

•Low Cost

•Test on all Piles

Disadvantages:

•Dynamic Pile-Soil behaviour

•High stresses in Pile

•Requires advanced analyzingTechniques

•Applicable only for Steel PipePiles


Application, Statnamic Load Test

Advantages: Relatively low Cost

Free selection of test Piles

Disadvantages: Difficult to determine Bearing Capacity

Difficult to distinguish between End Bearing and Shaft Friction

Application: Re-use of existing Piles

Load-Settlement behaviour

Condition: Tf Duration of rapid loadL pile lengthcp stress wave velocity test pile

1000/

10 ≤≤p

f

cL

T


Interpretation

Fstn = statnamic force, measuredFst = static resistanceu = displacement, measuredv = du/dta = d2u/dt2

m = pile massC = damping coefficient

)()()()( tvCtamtFtF ststn ⋅+⋅+=

M

Fstn

u F stn

k C

m


Interpretation

Load Cell

Laser Sensor

Accelerometer

0

5

10

15

200 50 100 150 200 250 300

Time [ms]Lo

ad [M

N]

0

10

20

30

40

50

60

0 50 100 150 200 250 300

Time [ms]

Dis

plac

emen

t [m

m]


Interpretation

Estimated damping parameter C (hyperbolic curve)

0

10

20

30

40

50

60

0 5 10 15 20

Load [MN]D

ispl

acem

ent [

mm

] .

Fstn(t)

Fstatic(t)

UP

)()()()( tvCtamtFtF stnst ⋅−⋅−=


Interpretation

Simplified input ofdynamics boundary conditions withMicrosoft notepad

Dynamic Analysis, PLAXIS


Interpretation

Dynamic Analysis, PLAXIS

Calibration model with static behaviourAverage damping parameter selected based on hyperbolic curve

Statnamic Test Numerical Simulation PLAXIS


Interpretation

Extrapolation according toMiddendorp and Bakker

Correction for “rate effects”:

Undrained behaviour

0

20

40

60

80

100

120

140

160

180

200

0 5 10 15 20 25

Load [MN]

Dis

plac

emen

t [m

m]

.

Fstn(t)

Fu(t)

Hyperbolic F=u/(p+q.u)

Hyperbolic F=Fref(u/uref)^0.5 0 0,05 0,10 0,15 0,20

-5000

-4000

-3000

-2000

-1000

0

|U| [m]

Fy [kN/rad]

Drained analysis

Undrained analysis

“Rate effect”


30

25

20

15

10

5

0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Bochum, Pfahl 57STN Cyclic Load Displacement Diagram

Dis

plac

emen

t [m

m]

Load [MN]

Cycle 1 Cycle 2 Cycle 3

30

25

20

15

10

5

0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Bochum, Pfahl 57STN Static Cyclic Load Displacement Diagram

Dis

plac

emen

t [m

m]

Load [MN]

Cycle 1 Cycle 2 Cycle 3 Hyp. Appr. Static QuickHyp. Appr. Static Long Term

Interpretation


Guidelines

The Netherlands

� CUR-comittee H410 “Rapid load tests”� goal: preparation European Codes� Fugro is member (Maarten Profittlich)

European Codes

� Draft standard Rapid Load Testing procedure� Working group 4 of TC 341� (Testing of geotechnical structures; Testing of piles: rapid load testing (reference

EN-ISO 22477-# version: 3.3, 23 April 2008)

� Guideline on the interpretation of Rapid Load test on piles� 7 November 2008


Conclusion

Statnamic provides alternative in case

� Static load tests are not feasible

� Re-use of existing Piles

� Determine Load-Settlement behaviour


Thank You

Documents

Statnamic Pile Load Testing - Accueil | CFMS · · 2012-01-19Disadvantages: Difficult to ... STN Cyclic Load Displacement Diagram Displacement [mm] Load ... preparation European