NEHRP Clearinghouse

Seismic Response Characteristics of Meloland Road Overpass during 1979 Imperial Valley Earthquake.
Werner, S. D.; Levine, M. B.; Beck, J. L.
National Science Foundation, Washington, DC., March 1985, 264 p.
Identifying Number(s)
The Meloland Road Overpass (MRO), a two-span reinforced concrete bridge located near El Centro, California, survived very strong shaking during the 1979 Imperial Valley earthquake with virtually no damage. This shaking triggered a total of 26 strong motion accelerometers located on or near the bridge, providing the most extensive array of earthquake response measurements yet obtained for bridges in the United States. This report describes work directed toward using these data to gain insights that can enhance future design, analysis, and instrumentation of bridges in an earthquake environment. The work involved (1) special reprocessing of the original motions measured at the MRO, to correct for recorder stall and nonsynchronization problems that had arisen during the earthquake; (2) formulation of a new methodology for modal identification of structures with any number of support and response measurements; and (3) application of this new methodology to the reprocessed bridge motions, in order to assess the seismic response characteristics of the MRO.
; Dynamic response; Seismic waves; Graphs (Charts); Earthquakes; Measurement; Vibration; Overpasses; Shaking; California; Bridges (Structures); Motion