Health monitoring and evaluation of structures have become more critical than ever. A large number of retaining walls, bridge abutments, dams and other geotechnical structures are designed with pre-stressed ground anchors. There is a growing trend in using re-stressable anchors. The engineer needs to know the force in the anchor to decide if anchor is performing as intended and if re-stressing is needed. Among available instruments strain gauges, load cells or fiber optics are pre-installed. Mounting of strain gauges and fiber optics are challenging. Load cells when used require larger block-out to stress and larger cap to protect the anchor. Most do not provide reliable data after few years in service. A sensor was developed based on elasto-magnetic characteristic of steel, which will not require any attachment to the steel element and will not be subjected to compression loading and have a similar service life to that of the surrounding structure. Its application in force monitoring in retaining wall, force transfer in bond zone and tie-back force monitoring in a tunnel is presented.
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