STRUCTURAL HEALTH MONITORING OF A CURVED GIRDER BRIDGE SUBJECTED TO DIFFERENT BOUNDARY CONDITIONS

摘要

A curved, three-span continuous, steel I-girder bridge in Salt Lake City, Utah was tested in order to determine its dynamic and static response to forced vibration. The bridge supports were altered and its response was monitored for three different boundary condition states. For each of the three boundary condition states, two dynamic forced vibration methods were applied to the bridge in order to determine the feasibility of structural health monitoring. The first forced vibration method used an eccentric mass shaker capable of imparting a horizontal sinusoidal force of up to 89 kN (20,000 lbs). The second method involved horizontally striking the side of the bridge with a 2.47 kN (556 lb) impact hammer. An array of 1-Hz velocity transducers and 1-g accelerometers were utilized to record response of the bridge. The recorded dynamic response of the bridge was analyzed and resulted in mode shapes and natural frequencies for each boundary condition state for both the sinusoidal and impact testing. This paper discusses the resulting changes in relevant dynamic.