ABSTRACT
At least five known radial gate failures are caused by trunnion bearing seizure. The radial gate arms are normally designed to withstand bending moments from nominal friction on the bearings. Experience has shown that lack of lubrication and years of deterioration leads to increased friction and even seizure of the bearings. The bending moments produced by bearing friction imposed on the gate arms are beyond the moment capacity, resulting in collapse. Norconsult has developed a method for measuring trunnion bearing friction while the gates are in service. By means of strain gauges attached to the gate arms, the strain caused by the bearing friction is measured during gate movement. The signals from the strain gauges and a gate position transmitter are logged digitally, allowing direct presentation of test results. The method gives objective and precise verification of measuring results, and the risk of subjective and wrong assessments is minimized.
