FALLING WEIGHT DEFLECTOMETER -FWD- mastrad logohome







FALLING WEIGHT DEFLECTOMETER (FWD)

FALLING WEIGHT DEFLECTOMETER (FWD)

DEFINITION

The FWD produces a load pulse which simulates the effect of a moving wheel load in magnitude. A mass is dropped from a chosen height generating a dynamic load.

The applied load is measured by a heavy duty load cell and the load is transmitted to the pavement through a plate (300 mm dia) resulting in a deflection of the pavement surface.

The deflection is measured by gephones simultaneously providing a picture of the deflection bowl which makes evaluation of multi-layer pavement structure possible.

DATA COLLECTION

The measured set of data (peak load, deflection values, distance from start point, air and surface temperatures) is displayed on the micro computer for direct visual inspection, and is printed out and stored on disk when accepted by the operator.

PAVEMENT ANALYSIS AND DESIGN

Information about layer thicknesses and expected traffic load during the desired period combined with the FWD generated data enable calculation of the E-moduli of the pavement.


Structural analyses to determine the bearing capacity and to estimate expected service life and required overlay are easy and fast with the Design Computer Program.

TECHNICAL SPECIFICATION

 

TECHNICAL SPECIFICATIONS:

 

PRI2100 FWD Test  System

 

 

 

 

 

 

Trailer Version:

L x W x H

Weight:

 

4.30 x 1.85 x 1.30  m (excl. of warning lights)

1200 kg

Distance Meter Counter :

Accuracy:

 

 

Better than 0.001 % integrated in data collection software

No. of axles:

2

 

 

 

 

System:

 

Built-in Version:

L x W x H

Weight:

 

4.75 x 1.85 x 1.94 m (excl. of warning lights)

2300 kg

Capacity:

Up to 65 test pints per hour (depending on distance between test points)

 

 

Operation:

may be operated by one person

Load Characteristic:

Load range:

 

10-250 kN

Temperature range:

(measurement)

0° C to +45° C

 

Load pulse duration:

Load pulse shape:

Load pulse rise time:

20-30 msec

half -  sine

approx. 10 msec

 

Temperature range (transport):

Safety:

- 25° C to +60° C

Complies with EC regulations for mechanical and electronic devices (EC-marking)

Load Cell :

Load cell accuracy:

Load resolution:

Load plate:

 

2% +/- 0.2 kN

0.1 kN (1 kPa)

4-split 300 mm transverse

 

Power Supply (FWD):

Trailer:

 

 

24 VDC petrol generator mounted on trailer

Deflector Sensor :

Sensor type:

 

Seismic Velocity Transducer

Built-in version:

24 VDC mounted on car engine (car: 12 VDC)

Number of geophones:

Geophone accuracy:

1-9 (optimum)

better than +/- 2%

Data Acquisition System:

Time History (real time):

 

on all geophones and loads

Geophone resolution:

Geophone range:

1 micron

2200 micron

Resolution:

16 BIT on all analog channels (load, geophones, temperature, falling height)

T-beam:

Geophone beam:

Rear 600 mm & transverse 450 mm

2500 mm from centre

Sampling:

Sampling period:

40 kHz (for 10 channels)

60/120 msec (chosen by user)

 

 

 

 

Temperature Sensor:

Sensor type:

 

PT 100

Data storage (peak value)

ASCII format

Number of sensors:

Temperature accuracy:

Temperature resolution:

3 - surface, air, manual

better than 1 %

0.1 ° C

Data storage (time history)

ASCII or binary compression (comp. software)

 

 

 

Optional Hard- and Software

·       Paint marker

·       Rear deflector extension bar (rear and transverse)

·       Stacking tower tester

·       450 mm load plate

·       Video monitor

·       Warning light (trailer and car)

·       Calibration software package for load, geophones and temperature as a

·       Integrated path for data collection software

·       Calibration package ready for operation consisting of hardware and

·        Software (Loudspeaker type with LVDT as reference)

 

 

Data Collection Software

System: Windows 3.11 or Windows 95

·       Easy setup pf data and sequence

·       Presentation of time history and peak value on same screen picture

·       Automatic loading of temperautre wuth alarm for correct measurement

·       Full manual made operation from PC

·       Easy setup of system configuration with save and load functions

·       Full FWD test module with all digital and analog I/O channels

·       Easy file handling module with view function

·       Integrated distance meter calibration module.