Lightweight Deflectometer (LWD)

Quality Assurance & Quality Control of Earthwork Projects

Measure in-situ soil modulus to ensure soil compaction requirements are met project wide or subgrade, subbase and roadbase. Designed and engineered at Olson Instrument's corporate office in Colorado, USA, the deflectometer conforms to ASTM E2835-11 standard for plate deflection measurement due to an impulse load.

Importantly, the Deflectometer LWD-1 measures the actual impulse force in order to calculate stiffness (peak force ÷ peak displacement) and modulus based on soil type (granular, clay, or mixed).

The LWD-1 is offered with an optional sunlight viewable touchscreen tablet.


Hands-on training is available for all of our NDE test methods at our Wheat Ridge, Colorado (USA) location, which is a suburb located approximately 15 minutes northwest of downtown Denver. Training may be available at your location by one of our agents/engineers upon special arrangement.

Scroll down the page to see Key Features and Specifications in the chart below.

Contact Olson Instruments if you need more information on any of our products.

For a quote, call our toll free number at 1-888-423-1214 or fill out our

Contact Form

Features & Benefits

Embedded load cell measures actual impact force Calibrated geophone receiver measures plate deflection
Simple design embeds spring assembly inside falling weight Add-On Impact Weights available (5kg and 10kg)
Multiple plate diameters available (300, 200, 150 and 100 mm (~ 12, 8, 6 and 4 inch) Two additional external geophones can be added to the system for deflection basin or Spectral Analysis of Surface Waves (SASW) layer moduli determination
Durable stainless steel design/construction Transport Cart (included)
Quick and easy onsite testing; can be performed with little or no special certification with immediate results displayed in either english or metric units Portable and lightweight - single person operation


27 kg (60 lb) total unit weight 1.25 m (50 in) total unit height
600 mm (2 ft) drop height 6.9 kN (1,550 lb) impulse loading
15 - 20 millisecond impulse duration 10 kg (22 lb) impact weight

Custom Systems Available - Call for Details! 1 Yr. Warranty Available on All Equipment Purchased