ST350 Strain Transducer


The ST350 Strain Transducer has been designed to quickly and accurately measure strain on a variety of structures in harsh field environments. This 350Ω full Wheatstone bridge strain transducer is very accurate, rugged, and waterproof. Providing roughly 3.5 times the output of a typical foil strain gage, these reusable sensors are ideal for measuring live-load strain on structures and can be installed within minutes in all weather conditions.


  • Cost-effective
  • Installs in 5 minutes or less
  • Reusable, lasts for >10 years
  • Waterproof to 20ft (6 m)
  • Industrial cable, custom lengths
  • Standard millivolt output
  • N.I.S.T traceable calibration



  • Steel
  • Pre-stress/post-tension concrete
  • Reinforced concrete
  • Timber
  • Fiber Reinforced Polymer (FRP)
  • Live-Load testing & monitoring
  • Laboratory testing
  • Fatigue monitoring
  • Tension rod forces








CIRCUIT Full Wheatstone bridge with 4 active 350Ω strain gages
EXCITATION VOLTAGE +1.0 to +10.0 Vdc
OUTPUT mV level, ratiometric to Excitation Voltage
STRAIN RANGE  ±4,000 µε (Calibrated to ±2,000 µε)
EFFECTIVE GAGE LENGTH 3.0 in (76.2 mm) [Gage Extensions available for R/C structures]
HOUSING Machined 6061 Aluminum Alloy
CORROSION PROTECTION Hard Anodized Clear (MIL-A-8625 Type III)
WEATHER PROTECTION Designed to exceed IP67
Optional 100 ft (30 m), waterproofing available
TEMPERATURE RATING2 -58° to +176 °F (-50° to +80 °C)

1 Accuracy defined at the calibrated ±2,000 µε range.
2 Temperature limit based on instrumentation cable operating temperatures, call BDI for wide temperature range cable options.


Repair & Recalibration Services: BDI offers repair and recalibration services for all BDI Strain Transducers using our NIST-traceable Automated Strain Transducer Calibration System (ASTCS) that insures high-quality strain measurements.

Options & Accessories

Intelliducer Connector: Required for use with STS Intelliducer Nodes, cable is connected and potted for a weatherproof seal.
Integrated Thermistor: Temperature range of -55 °C to +220 °C, ±0.5 °C accuracy.
Reusable Mounting Tabs: ¼-20 or M6, zinc plated steel mounting tab.
Tab Jig: Machined aluminum jig for safely attaching mounting tabs to the strain transducer. Includes either 7/16″ or M10 end wrench.
Gage Extension: Machined aluminum 24 in (610 mm) gage length extension with 3.0 in (76 mm) increments
Extension Jig: Aluminum mounting jig for safely attaching gage extensions
Installation Jigs: Welding or concrete drilling jigs
Protective Covers: Insulated aluminum protective covers.