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Structural Monitoring Solutions for Wireless Bridge Bearing/Expansion Joint Monitoring - Monitoring and Testing
Purpose: this application note explains how Resensys wireless instrumentation can be used in different types of bearings and expansion joints to detect their functionality and responsiveness. Bearing malfunction can lead to excessive strain in bridge load bearing members, and it can cause damage to bridge piers and abutments. Resensys offers two types of wireless devices for long term remote monitoring of bridge bearings and expansion joints:
- Wireless Displacement SenSpot™ sensor:Helps monitor linear movements at expansion joints.
- Wireless Tilt SenSpot™ sensor:Helps monitor tilting on rotary bearing systems such as rocker bearings.
Both types of devices report temperature, which helps analyze the readings and compare the measured movements with expected thermal responses as a quick and reliable way to assess structural health of bearing systems.
Resensys offers well-suited way by wireless solution and sensors for accurate monitoring of bearing and expansion joints of bridges with a wide variety of cost-effective benefits:
- Wireless Tilt and Displacement Sensor: No need for wiring, Minimal lane closure for installation
- 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
- 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 Tilt Sensor: 0.01 degree
- Very High Resolution for Displacement Sensor: 0.01 mm or 0.4 mil resolution
This system reduces installation cost and time for owners/authorities to get the real time and accurate data they need for monitoring of bearings and expansion joints. A unique capability of Resensys wireless SenSpot™ sensors is to measure at high precision, while providing ultra-low power usage to allow short and long term monitoring.
Technical Note: Functionality of the bearings rotation and responsiveness of pier bearings are assessed by comparing measured responses rate (attained from regression analysis of Displacement/Tilt and corresponding temperature data during monitoring time period) with expected value (attained from effective length of spans and steel thermal expansion coefficient).
Expected response to temperature for a bearing would be obtained as follows:
Linear regression between tilt (bearing rotation) and temperature for a bridge bearing in a specific time period
A typical Resensys system for Wireless Monitoring of Bearing/Expansion Joint of Bridge includes the following components:
Wireless SenSpot™ Sensors:are attached on critical bearings/expansion joints as determined by inspection, finite element modeling, or authority’s/client’s suggestion. The number of gauges required per structure is usually dependent upon the design, existing issues on members and monitoring needs:
-Wireless Tilt SenSpot™ sensor -Wireless Displacement SenSpot™ sensor
SeniMax™: is a wireless data logger gateway that is connected to the cellular or satellite networks; it wirelessly 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).
SenScope™:software for data analysis and visualization, data export, automated alert/threshold management, thermal analysis, comparative analysis (regression analysis) and graphs.
Figure below shows a picture of a practical Resensys Structural Health Monitoring (SHM) system, which can be used for wireless monitoring of bearing and expansion joints.
