Analysis of the Seismic Records of a Suspension Bridge

A well-instrumented suspension bridge in Los Angeles, was shaken by the October 1, 1987 Whittier earthquake (M L = 5.9). This study addresses the following objectives: (1) three-dimensional modeling; (2) temporal and spectral analyses of the records; (3) modal identifications, including estimation of damping values; (4) a comparative study of analytical studies, the ambient vibration survey and the identified properties from the earthquake records; (5) envelopes of maximum earthquake-induced displacements and straining actions, and (6) recommendations for damping augmentation devices at critical zones. Finally, a reasonable agreement is found between the calculated and measured dynamic characteristics and response quantities.