The experimental organization and some preliminary results of a work in progress aimed at the dynamic characterization of the earth dam at Bomba (Chieti, Italy) are presented in this paper. The straight dam has a height of 57.5 m and a length equal to 681 m. The experimental studies include ambient vibration measurements using short-period seismic sensors, which are shown in this paper, ground base interferometry, installation and measurement of a local GPS network, spot ambient noise measurement with a compact SL06 SARA triaxial short period seismometer. Two different sensor layouts were realized. The first layout consisted of eight triaxial points of measurement, four along the crest of the dam, along its geometric axis, and four along the downstream slope. The second layout was intended to study the right abutment close to which there is a landslide; it was made of eight triaxial points of measurement, three on the crest close to the right abutment, one on the abutment and four along the front of the landslide, almost orthogonal to the dam. For each layout a 30 min recording at 200 sps was performed. Data were analyzed in time domain, amplitude in terms of RMS, and in frequency domain by means of cross spectral analysis. Recordings of layout 1 showed that the motion of the dam body, limited to the narrow range 0.3-0.5 Hz and dominating frequencies 0.37 and 0.42 Hz, is equivalent, in terms of amplitude in time and in frequency content, along the three directions, i.e. deformation is along a direction not orthogonal to the dam. The analysis of layout 2 pointed out that the motion, limited to the narrow range 0.3-0.75 Hz and dominating frequency 0.62 Hz, is equivalent, in terms of amplitude in time and in frequency content, along the three directions; for the frequency 0.62 Hz a change in direction, from orthogonal to longitudinal to the dam, is observed from the dam body to the right abutment. © 2015, International Society for Structural Health Monitoring of Intelligent Infrastructure, ISHMII. All rights reserved.
|Titolo:||Ambient noise measurements on the earth dam at Bomba, Italy|
|Data di pubblicazione:||2015|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|