Nondestructive Deflection Testing


Nondestructive Deflection Testing (NDT) is an integral part of the pavement evaluation, design and management programs used by engineers today. Large amounts of data is collected using NDT without effecting the condition of pavement. The most common method of NDT is the Falling Weight Deflectometer (FWD).

Falling Weight Deflectometer caltran4.jpg (62343 bytes)

The FWD is a device capable of applying dynamic loads to the pavement surface, similar in magnitude and duration to that of a single heavy moving  wheel load. The response of the pavement system is measured in terms of vertical deformation, or deflection, over a given area using seismometers. ERI currently maintains and operates two models of Falling Weight Deflectometers, the KUAB Two Mass FWD (2m-FWD) and Dynatest FWD.

NDT Services

ERI offers NDT services for use in the following investigations:

• Pavement structural evaluation
• Seasonal and historical variations
• Joint load transfer efficiency
• In-situ materials characterization
• Void detection   
• Variability of material properties
• Subgrade evaluation
• Layer moduli backcalculation
• Pavement overlay design
• Uniform pavement sectioning

Past Experiences

The staff of ERI has over 15 years of experience in testing a variety of pavement conditions and types including flexible, rigid, composite and unpaved surfaces. Our clients include airport authorities, state department of transportation, cities, counties universities, private agencies and research institutes. With a diverse background in pavement testing, design, evaluation, and management, ERI can conduct an efficient and economical NDT program customized to your organization's needs. For a short list of ERI's NDT projects please refer to Accomplishments.


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