Influence of traffic vehicles against ground fundamental frequency prediction using ambient vibration technique
Ambient vibration (AV) technique is widely used nowadays for ground fundamental frequency prediction. This technique is easy, quick, non-destructive, less operator required and reliable result. The input motions of ambient vibration are originally collected from surrounding natural and artificial...
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| Main Authors: | , , , , , , |
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| Format: | Conference or Workshop Item |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/7073/1/P9106_17e48f28074bb5e67f70df19e49e122b.pdf http://eprints.uthm.edu.my/7073/ https://doi.org/10.1088/1742-6596/995/1/012101 |
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| Summary: | Ambient vibration (AV) technique is widely used nowadays for ground fundamental
frequency prediction. This technique is easy, quick, non-destructive, less operator required and
reliable result. The input motions of ambient vibration are originally collected from
surrounding natural and artificial excitations. But, careful data acquisition controlled must be
implemented to reduce the intrusion of short period noise that could imply the quality of
frequency prediction of an investigated site. In this study, investigation on the primary noise
intrusion under peak (morning, afternoon and evening) and off peak (early morning) traffic
flows (only 8 meter from sensor to road shoulder) against the stability and quality of ground
fundamental frequency prediction were carried out. None of specific standard is available for
AV data acquisition and processing. Thus, some field and processing parameters recommended
by previous studies and guideline were considered. Two units of 1 Hz tri-axial seismometer
sensor were closely positioned in front of the main entrance Universiti Tun Hussein Onn
Malaysia. 15 minutes of recording length were taken during peak and off peak periods of
traffic flows. All passing vehicles were counted and grouped into four classes. Three
components of ambient vibration time series recorded in the North-South: NS, East-West: EW
and vertical: UD directions were automatically computed into Horizontal to Vertical Spectral
Ratio (HVSR), by using open source software of GEOPSY for fundamental ground frequency,
Fo determination. Single sharp peak pattern of HVSR curves have been obtained at peak
frequencies between 1.33 to 1.38 Hz which classified under soft to dense soil classification.
Even identical HVSR curves pattern with close frequencies prediction were obtained under
both periods of AV measurement, however the total numbers of stable and quality windows
selected for HVSR computation were significantly different but both have satisfied the
requirement given by SESAME (2004) guideline. Besides, the second peak frequencies from
the early morning HVSR curve was clearly indicated between 8.23 to 8.55 Hz at very low
amplitude (Ao < 2), but it should be neglected according to the similar guideline criteria. In
conclusion, the ground fundamental frequency using HVSR method was successfully
determined by 1 Hz seismometer instrument with recommended to specific parameters consideration on field as well as data processing, without disruption from the nearest traffic
excitations. |
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