Long-term bridge vibration monitoring of a full-scale bridge using a permanent accelerometer array

This study investigates the long-term behavior of a full-scale bridge using a permanent strong motion accelerometer array. The test structure consists of a recently constructed twenty-five span bridge. It is an overpass bridge on the 21st South Interchange of I-15 in Salt Lake City, Utah. The bridge is a connector from westbound I-80 to westbound SR201. The test section of the S-shaped bridge spans four concrete bents over a total length of 183.5 meters. The spans are constructed of a transversely post-tensioned concrete deck, supported by three steel girders. The soils consist of extremely deep soft sediments. The array of accelerometers consists of three free field channels and 18 structural channels that are wired to two recorders at an adjacent free field site. The long-term behavior of the bridge is monitored using this permanent array of instrumentation. Changes in the dynamic characteristics of the bridge are of primary concern. These changes are due to such things as environment, maturing of the structure and foundation, cure or deterioration of concrete strength, or damage to the structure. The intent of this monitoring is to get a very accurate statistical baseline of the bridge dynamics. This monitoring will continue for at least several years.