X hits on this document

49 views

0 shares

0 downloads

0 comments

3 / 17

Statnamic load testing requires no reaction piles, no reaction beam, no hydraulic jack, and is set up in a fraction of the cost and time. The Statnamic device is set up on the pile top and includes a calibrated load cell and displacement measuring system.

During a Statnamic test, a high-speed data acquisition system scans and records the load cell, displacement transducers, accelerometers and embedded strain gages (if any). The test measurements provide a high degree of resolution fully defining the piles load and deflection response with as many as 100,000 data points recorded during a typical ½ second test. Because the duration of the axial Statnamic test is adequately longer than the natural period of the foundation element, the entire foundation remains in compression. Thus, stress waves do not exist and a simple model can be used to determine the static capacity. However, the measured Statnamic force is not simply the foundation capacity but must be corrected for inertia and damping forces through the fundamental equation of motion (below). The damping value is quantified using principles of the Unloading Point Method (UPM) proposed by Peter Middendorp of TNO Building and Construction Research. Please contact Applied Foundation Testing for detailed information regarding the UPM. The curves in Figure 2 illustrate the measured Statnamic data and the derived static response using the UPM.

FSTATIC=FSTN-ma-cv

Where

F S T A T I C = t h e d e r i v e d s t a t i c l o a ma cv d ( k x ) F S T N the measured Statnamic force (load cell) the measured inertia the foundation/soil damping = = =

and

m

=

a

=

c

=

v

=

mass of the foundation acceleration of the foundation foundation/soil damping coefficient velocity of the foundation

Load Cycle 4

0.00 0.00

  • -

    0.10

  • -

    50.00

  • -

    100.00

  • -

    150.00

  • -

    200.00

  • -

    250.00

  • -

    300.00

  • -

    350.00

  • -

    400.00

  • -

    450.00

  • -

    0.20

  • -

    0.30

  • -

    0.40

Displacement (Inches)

  • -

    0.50

  • -

    0.60

  • -

    0.70

Load (tons)

Statnamic

Static

Figure 2. Thin line shows Statnamic measured load (with inertia and damping). Thick line shows only static component of foundation behavior.

Document info
Document views49
Page views49
Page last viewedThu Dec 08 23:01:16 UTC 2016
Pages17
Paragraphs223
Words3837

Comments