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Home > Application Notes > Bearing Monitoring
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 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 has a wireless and accurate monitoring the bearing and expansion joints of bridges. Our sensors have 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 the bearings and expansion joints on bridges. A unique capability of Resensys wireless SenSpot™ sensors is to measure at high precision, while providing ultra-low power usage to allow for 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:
Measured response to temperature for tilt gauges would be obtained from regression analysis:
By this way, it is found whether there are excessive movements of bearings or not. Furthermore, it can be seen bearings are responsive or non-responsive (frozen bearings).
A typical Resensys system for Wireless Monitoring of Bearing/Expansion Joint of Bridge includes the following components:
Wireless SenSpot™ Sensors:These 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™: This 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™:This is the software used for data analysis, visualization, data export, automated alert/threshold management, thermal analysis, comparative analysis (regression analysis), and graphs.
The 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.
Home > Application Notes > Bearing Monitoring
A bridge bearing is a component of a bridge which typically provides a resting surface between bridge piers and the bridge deck. The purpose of a bearing is to allow controlled movement of the structure and thereby reduce the stresses involved. Possible causes of movement are thermal expansion and contraction, creep, shrinkage of/within the structure, or fatigue due to the properties of the material used for the bearing. For instance, abnormal movements in the bearing/expansion joint may cause abnormal movement in the piers of a bridge.
An expansion joint or movement joint is an assembly designed to hold parts together while safely absorbing temperature-induced expansion and contraction of building materials, and vibration, or to allow movement due to ground settlement or seismic activity. They are commonly found between sections of buildings, bridges, sidewalks, railway tracks, piping systems, ships, and other structures. Bridge expansion joints are designed to allow for continuous traffic between structures while accommodating movement, shrinkage, and temperature variations on reinforced and pre-stressed concrete, composite, and steel structures. They stop the bridge from bending out of place in extreme conditions, and also allow enough vertical movement to permit bearing replacement without the need to dismantle the bridge expansion joint.
The Resensys Wireless Displacement and Tilt SenSpot sensors data analysis can be used for bridge bearing/expansion joint monitoring. Resensys wireless displacement and tilt sensors are designed to provide accurate small scale displacement/tilt measurements over long periods of time, allowing them to provide base-level data and also continuously monitor for changes that could indicate changes in the effectiveness of these important bearings or joint functionality. Ensuring that these bearings/joints are functioning as designed can pre-empt expensive repairs or structural failures or other structural damage. This can allow for improved asset management decisions. By utilizing ultra-low power, wireless technology, Resensys decreases installation and maintenance costs of monitoring these elements.
The applicable, measurable and monitorable quantities for bridge bearing and expansion joint measuring are displacement, tilt and ambient temperature. Resensys SenSpots are able to monitor these structural quantities in concrete, steel and composite materials under wet, humid and extreme weather conditions. The product is corrosion resistant and can withstand salty environments.
A Resensys Bridge Bearing/Expansion Joint Monitoring solution comprises wireless Displacement SenSpot sensor and/or wireless Tilt SenSpot sensor on the location of bearings/expansion, a SeniMax Gateway to transmit data away from the site and the SenScope display user-interface.
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Address: 6517 Mid Cities Ave.
Beltsville MD 20705
USA
E-Mail: info@resensys.com
Phone: (301) 477 3075
