by K. Romstad, B. Maroney and M. Chajes
Romstad, K., B. Maroney and M. Chajes (1989). Interpretation of Rio Dell Freeway Response During Six Recorded Earthquake Events
SMIP 89 Seminar on Seismological and Engineering Implications of Recent Strong-Motion Data, p. 8-1 - 8-13.
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Six earthquakes have ken recorded since 1980 on the overpass of Highway 101 at Painter Street in Rio Dell, California, just
south of Eureka. Finite element models of the bridge have been constructed and the natural frequency results compared with the
recorded motions. Analysis of the experimental data tends to identify the first six modes of vibration. Modeling the
backfill-abutment-superstructure interaction is key to the analytical modeling to describe response. Torsional modes of
vibration of the individual spans appear heavily influenced by the skew implying use of very simple bridge models should he
approached cautiously for such short spans.