Frank Georg Schulz | TERRATEST

Light Weight Deflectometer: Cable vs. Bluetooth Technology

Mar 17th 2015 at 1:59 AM

An FWD or falling weight deflectometer is a highly useful type of testing device that helps civil engineers evaluate the physical properties of ground surfaces or pavements. The data that this device generates is mainly used to analyze and estimate the structural capacity of the ground surface either for overlay design or to determine if there is any overloading. FWDs are used in a wide range of construction and engineering applications, from designing and building highways to railway tracks, local roads, airport pavements, and even industrial and commercial establishments.

There are three major types of falling weight deflectometers, namely, the light weight deflectometer or LWD, the heavy weight deflectometer or HWD, and the rolling weight deflectometer or RWD. A light weight deflectometer is portable and used to test in situ bases. It is quicker than traditional isotope measuring methods and it doesn't require reference measurements, which makes it ideal for use during construction either to test bases or subgrade moduli or calculate the elastic moduli of different pavement layers in a multi-layer system, like a subgrade below a base course, below an asphalt concrete. Light weight deflectometers also don't require radioactive sources, which means they don't require safety courses to operate. Modern versions also don't require multiple operators and can independently collect and print out data files, which makes it easier to analyze collected data files on site.

HWDs or heavy weight deflectometers are designed for higher loads and are often used to test pavements that are to be subject to heavy weights, like airport pavements. RWDs on the other hand, are designed for collecting continuous deflection data instead of mere discrete deflection data.

Modern LWDs are available in a wide range of configurations and formats. The most advanced types come with many useful features, including in-built printers, which allow instant analysis of data output right on site. The best LWDs are even equipped with GPS systems and text input functions. Some can even be hooked up on computer devices for more in-depth data analysis. Manufacturers even offer cable and wireless options, both of which offer their own advantages. Wireless LWDs offer the convenience of better portability, especially when conducting tests on narrow spaces. Wireless capabilities are possible through bluetooth technology, which not only allows wireless operation, but access via smartphone and/or tablet apps as well. Other notable features of modern LWDs include USB drives for data transfer, screen display, and voice prompts.

About The Author:

TERRATEST GmbH is world leader in development and manufacturing of Light Weight Deflectometers for dynamic load plate test. They offer the world’s first light weight deflectometerTERRATEST 5000 BLU” with Bluetooth and voice navigation. For more information about their products visit their website!

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