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Proceedings Paper

Modal analysis of a three-span curved steel girder bridge
Author(s): Bryant G. Nielson; Kevin C. Womack; Marvin W. Halling
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Paper Abstract

The purpose of this study was to investigate the application of modal analysis to ascertain changes in the boundary conditions (or structural damage) of a complicated bridge structure. Reconstruction of the Interstate 15 corridor through Salt Lake City, Utah had provided an opportunity for destructive testing to be conducted on a three-span, continuous curved steel girder bridge. Forced Vibration testing using an eccentric mass shaker was conducted on the bridge in three phases. Each phase represented a change in boundary conditions. The initial testing was done with the bridge in the as-built condition with the continuous deck at the abutments and frozen bronze bearings. The second phase of testing occurred after the bridge deck was cut way from the approach slabs. For the third phase of testing, the bearings at the ends of the girders were replaced with teflon pads and the bearings over the two intermediate piers were jacked up and greased. The results of the study show that modal analysis is capable of determining changes in a structure's natural frequencies and mode shapes due to a change in the boundary conditions. By extrapolation this would indicate that modal analysis would work as an effective non-destructive evaluation tool.

Paper Details

Date Published: 9 June 2000
PDF: 7 pages
Proc. SPIE 3995, Nondestructive Evaluation of Highways, Utilities, and Pipelines IV, (9 June 2000); doi: 10.1117/12.387805
Show Author Affiliations
Bryant G. Nielson, Utah State Univ. (United States)
Kevin C. Womack, Utah State Univ. (United States)
Marvin W. Halling, Utah State Univ. (United States)

Published in SPIE Proceedings Vol. 3995:
Nondestructive Evaluation of Highways, Utilities, and Pipelines IV
A. Emin Aktan; Stephen R. Gosselin; Stephen R. Gosselin, Editor(s)

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