Bridge Modal Analysis Without Sensor Installation
Two field demonstrations show how Q2 delivers 65 simultaneous non contact velocity signals for rapid, repeatable mobile bridge vibration monitoring under live traffic and a train crossing without lane closures or user interference.
For a platform-level view of when to use Q2 versus QMini, Q1S or Q1, see the Q-series comparison reference.
Discuss the application
Application Overview
Usage of Ommatidia's Q2 Laser RADAR provides a fast, safe, repeatable measurement layer between visual inspection and fixed SHM systems.
- Operate from accessible standoff positions.
- Avoid contact with structures with degrading surface properties.
- Acquire enough spatial information during the same operational event to compare locations, extract local strain, and identify weak spots.
Q2 Approach: 65 Simultaneous Non-Contact Measurements
Position Q2 where there is a clear line of sight to the bridge area of interest. The instrument projects a line of laser beams across the structure, with each illuminated point acting as an independent Laser Doppler Vibrometry channel.
Outputs from one acquisition include:
- Time-domain vibration response during traffic or train passages.
- Displacement estimates obtained by integrating velocity signals.
- Frequency spectra and dominant vibration components.
- Point-to-point comparisons across the 65 measurement channels.
- Model-based strain estimates where applicable.
- Field quality checks using the internal accelerometer.
How It Works
Ommatidia Q2 is based on multichannel laser Doppler vibrometry, a non-contact technique that measures vibration by detecting the Doppler shift of laser light reflected from a moving surface.
Instead of installing accelerometers or strain gauges on the bridge, Q2 projects a line of 65 laser beams onto visible structural points from a safe observation position. Each beam acts as an independent vibrometry channel, recording line-of-sight surface velocity at the same instant.
This simultaneous acquisition is what makes the system different from single-point LDV: it captures how different parts of the bridge respond to the same event while keeping setup fast, remote, and repeatable.
Operational Benefits
Proof Points
- Operational events captured: elevated vibration levels during vehicle passages and the train crossing were clearly recorded.
- Spatial variation: different channels showed distinct responses, providing richer context than single-point measurements.
- Frequency-domain insight: recurring low-frequency components appeared across repeated road-bridge acquisitions, while railway spectra changed clearly before, during, and after crossing.
- Quality control: comparison with the internal accelerometer helped separate bridge-driven content from possible setup motion.
Talk to Ommatidia
Discuss how this measurement approach could support applications workflows with the Ommatidia team.
Ommatidia Upgrade & Trade-In Program
Upgrade to Ommatidia’s latest Laser RADAR technology and unlock more capability for your next measurement challenge. Whether you are expanding an existing setup or replacing an older system, we offer tailored upgrade options with discounts of up to 40%.
If you are currently using another manufacturer’s system, send us your model and measurement requirements. We will review your trade-in possibilities, identify the best Ommatidia configuration, and outline a practical upgrade path for your team.
