Motivation: Overweight vehicles can cause harm to the structural health of bridges. Thus, more attention should be paid to these types of live loads which may produce comparably high strain values.

Resensys’s Unique Solution: Resensys offers a combination of two devices to monitor and detect instances of overweight loads (e.g., heavy truck, dump truck, etc.) on bridges. These two devices are the Wireless Strain Guage SenSpot^TM and the Wireless Solar-Powered Camera.
‍
Wireless Strain Gauge SenSpot™:This SenSpot^TM continuously monitors and reports strain in load bearing members. Once the baseline reading is established, the maximum strain produced by legal loads is found using controlled test trucks. The estimated strain on load bearing members by the legal loads will be used as the threshold to screen for overweight loads and to detect potential load rating violations.

Wireless Solar-Powered Camera:The Wireless Solar-Powered Camera is used to take pictures after detecting loads which exceed the rated limits (source of overweight loads, e.g., heavy trucks). The camera is solar powered and it is not connected to any external source of electricity. The camera is powered off unless wireless strain gauges detect unusual strain at which point the camera takes a photo.
‍

Wireless strain gauge SenSpot™ at a truss of a bridge
‍

Wireless strain gauge SenSpot™ at a truss of a bridge

Resensys wireless solar-powered camera installed on a pier bridge

Resensys System Benefits: The Resensys system offers an accurate and wireless solution to the problem of monitoring instances of overweight loads on bridge (including obtaining strain measurements and getting visual feedbacks) with a wide variety of cost-effective benefits:

*Wireless Strain Gauge SenSpot™: No need for wiring, Minimal lane closure for installation
*Wireless Solar Powered Camera:  No need for electricity power to run
*10+ Years Battery Life sensors: Without battery replacement, maintenance and calibration in the field
*Easy Installation: Self-adhesive (e.g., steel) or flange-mount (e.g., concrete)
‍*Small in Size and Lightweight
* Quick Testing: Can be installed for short-term testing, easy to remove and reuse on other structures
*Long-term monitoring: Designed to be used for long-term monitoring (e.g., several years).
‍*Usable in Different Kind of Materials: Can be used on steel, concrete, steel, timber, and composites
*Rugged, Weather Proof and Corrosion Resistant:  Can operate in rain, snow, ice, high humidity, salty environment and extreme weather (-40°C to +65°C or -40°F     to +150°F).
‍*Infrastructure Less: Battery Operated, Energy self-sufficient, No need for communication infrastructure at the bridge
‍*Provide Data Visualization and Data Analysis
*Very High Resolution for Wireless Strain Gauge SenSpot™: 1 microstrain
‍*High Sampling Rate for Wireless Strain Gauge SenSpot™:  Typically, 20-100 samples per second
*Quick and Complete Assessment of Conditions after high strain event‍
‍
This system reduces installation cost and time for owners/authorities to get the accurate data and detailed visual feedback they need for load-rating violation on bridges. A unique capability of Resensys wireless strain gauge SenSpot™ sensors is to measure at a high sampling rate and resolution, while providing ultra-low power usage.

‍

These are the photos of the overweight trucks captured by the camera on a highway bridge. The time tags from the camera match the time of the high strain events.
‍

Above is a graph of strain spikes detected on a few selected members on a truss bridge. Peak strain change is close to 100 microstrain.
‍

This is the photo of the truck captured by the camera on a truss bridge. The time tag from the camera is 08/06/21 at 08:03:00am, which matches the time of the high strain event (graph above).
‍

Illustration of Resensys Structural Health Monitoring (SHM) System: A typical Resensys system for monitoring instances of overweight loads on bridges includes the following components:
‍Wireless Strain Gauges SenSpot™:are attached on critical elements as determined by inspection, finite element modeling, load rating model or authority’s/client’s suggestion. The number of gauges required per structure is usually dependent upon the design, existing issues on members and project needs.
SeniMax™: Is a wireless data logger gateway that is connected to the cellular or satellite networks; it collects SenSpot™ data at the site and sends it to a cloud database server (one SeniMax™ can cover as many as 100 SenSpot™ sensors and devices within its wireless communication range). 

Wireless Solar Powered Cameras:‍‍Are installed on top of the piers or light posts to detect and capture the source/picture of overweight load/truck in high strain events. So, it is placed towards the locations/sides that vehicles come to the piers or light posts. Required number of cameras are determined according to project requirements. Camera can be integrated with SeniMax™. Thus, separate SeniMax™ is not needed for data acquisition.
‍SenScope™:Software for data analysis and visualization, data export, automated alert/threshold management, thermal analysis, and obtaining sources/pictures of overweight loads/trucks..

Figure below shows a picture of a practical Resensys SHM system, which can be used for monitoring instances of overweight loads on bridges.