Title: Dynamic Parameter Similitude for Concrete Models

Author(s): Charles R. Farrar, William E. Baker, and Richard C. Dove

Publication: Structural Journal

Volume: 91

Issue: 1

Appears on pages(s): 90-99

Keywords: damping; experimental modal analysis; mode shapes; reinforced concrete; resonant frequencies; scale models; similitude; vibration; Design

DOI: 10.14359/4500

Date: 1/1/1994

Abstract:
Reports the results of a series of experimental model analyses that were performed to examine the similitude of the dynamic parameters (resonant frequencies, mode shapes, and modal damping) of reinforced concrete replica models. Also reported are the similitude requirements for damping forces that were developed as part of this study. Although damping is typically considered a material property, the similitude analysis shows that both material properties and system geometry must be considered when scaling the damping forces. Results of the experiments show that the modal frequencies and the mode shapes of a prototype structure can be accurately predicted from tests on scale-model structures. Variations in equivalent viscous damping ratios identified on models and prototype were greater than variations for the other measured dynamic parameters. However, all damping ratios were less than 2 percent of critical, and the observed variations would not significantly alter the dynamic response of the structures.