Location

Seattle, WA

Start Date

1-1-1996 12:00 AM

Description

This paper describes a new machine that has been developed for directly measuring the deflection of airfield pavements under a rolling load wheel. This rolling weight deflectometer (RWD) optically measures the maximum amplitude of the depression basin using a new type of laser sensor that operates on the principle of triangulation. Four sensors that are mounted on a beam make pavement measurements. The key to producing accurate results is the requirement that the sensors remain in a straight line. Previous attempts using the method were plagued with deflection errors caused by thermal and vibrational beam bending. The patented RWD uses a laser to monitor bending of the physical beam in realtime. The information is used with pavement sensor data to produce accurate deflection measurements in the presence of significant beam bending. The bending-compensated RWD produces a deflection measurement with an accuracy of 40 μm (0.0015 inch). The RWD consists of a horizontally transported beam, strategically placed pavement sensors, a subsystem that monitors beam bending, an odometer, and a data acquisition computer.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

15B

Chapter

Chapter 7: Infrastructure

Section

Concrete Structures

Pages

1823-1830

DOI

10.1007/978-1-4613-0383-1_238

Language

en

File Format

application/pdf

Share

COinS
 
Jan 1st, 12:00 AM

A Rolling Weight Deflectometer for Quantitative Pavement Measurements

Seattle, WA

This paper describes a new machine that has been developed for directly measuring the deflection of airfield pavements under a rolling load wheel. This rolling weight deflectometer (RWD) optically measures the maximum amplitude of the depression basin using a new type of laser sensor that operates on the principle of triangulation. Four sensors that are mounted on a beam make pavement measurements. The key to producing accurate results is the requirement that the sensors remain in a straight line. Previous attempts using the method were plagued with deflection errors caused by thermal and vibrational beam bending. The patented RWD uses a laser to monitor bending of the physical beam in realtime. The information is used with pavement sensor data to produce accurate deflection measurements in the presence of significant beam bending. The bending-compensated RWD produces a deflection measurement with an accuracy of 40 μm (0.0015 inch). The RWD consists of a horizontally transported beam, strategically placed pavement sensors, a subsystem that monitors beam bending, an odometer, and a data acquisition computer.