Standards

ASTM E2583-07“Measuring Deflections with a

Light Weight Deflectometer (LWD)”

NOW….

ASTM E2835-11 “Measuring Deflections using a Portable Impulse

Plate Load Test Device

SCOPEASTM D 2583-07

ASTM D 2835-11

SUMMARY OF TEST METHOD

ASTM D 2583-07

ASTM D 2835-11

No possibility to investigate the material stress dependancy

SIGNIFICANCE OF USEASTM D 2583-07

ASTM D 2835-11

Different way to measure deflection

ASTM D 2583-07

Changing drop height and drop weight is possible to simulate the real stress applied by the design wheel load.

The standard 2583-07 recommend to be careful to the volume of soil involved but not to the stress level applied

ASTM D 2835-11

APPARATUSASTM D 2583-07

ASTM D 2835-11

-2.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0

ms

kN

Load Dynatest

Load Zorn

Dynatest – Load cell output. Zorn – from a series of 15 kg laboratory test on load cells.

APPARATUS

ASTM D 2583-07

ASTM D 2835-11

APPARATUS

ASTM D 2583-07

ASTM D 2835-11

…………

APPARATUS

ASTM D 2583-07 – Signal condition and Record System

ASTM D 2835-11 – Reagents and Materials

ASTM D 2583-07 - Calibration

……………

ASTM D 2835-11 - Sampling

ASTM D 2835-11 – Sampling + Verification

VERY LONG PROCEDURE

SAMPLING + VERIFICATION

ASTM D 2835-11 – Maintenance and handling

d

rfE

21

f=2, r=150 mm,

σ=100 kPa ν=0.4

E(d=0.2mm)= 126 MPa Upper limit

E(d=3.0mm)= 8 MPa Lower limitBoussinesq Equation

UNIVERSITY OF PISA RESEARCH

PRECISION AND BIASASTM D 2835-11

UNIVERSITY OF PISA RESEARCH

NO CORRELATION!

ASTM D 2583-07

ASTM D 2835-11

IAN 73/06 Revision 1 2009

PRECISION AND BIAS

LWD DYNATEST LOADING

Loading Plate 100 mm 200 mm 300 mm

Drop weight mass 10 kg 15 kg 20 kg

Loading range >15 kN peak load using 20 kg

Pulse duration 15-30 ms

Drop height Variable depending to load level to be achieved

LOAD CELL

Range 0-25 kN

Accuracy 2% ± 2 kPa

Precision 0.0003 kN

DEFLECTION SENSOR

Type of sensors Velocity transducers-Geophone

Number 1 in a hole under the plate, additional 2 sensors

Range 0-2200 μm

Sampling period 60-120 ms, set by user

Accuracy 2% ± 2 μm

Precision 0.1 μm

PRECISION AND BIASASTM D 2835-11

Additional error due to the absence of the load cell…

Performance Foundation Group UK

• LWD Best Practice Guide

– The LWD is considered in general to be relatively rapid and cost effective tool

• Guide aims to provide a useful reference to LWD users, specifically to explain three key aspects:

– Principle of operation

– Use for construction testing

– Protocols for measurements and reporting

LWD Best Practice Guide

LWD Best Practice Guide