Microtremor Soil-Structure Resonance Study in the Bovec Basin (NW Slovenia) Related to 1998 and 2004 Damaging Earthquakes

Gosar, Andrej

doi:10.1007/978-1-4020-9196-4_18

Cited by 4 publications

(4 citation statements)

References 18 publications

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“…9(e) has been indicated to existence of deep contrast soil layer profile underlying the ground surface to the bedrock. Some investigation on similar HVSR trend are also described in [11], [13], [24], [25]. Strong ground amplification could considerably contaminate the structure response and causes misinterpretation of the first mode frequency on building using ambient vibration technique, if without special attention and filtering protocols were taken.…”

Section: Results and Discussion 31 Natural Frequenciesmentioning

confidence: 95%

“…In fact, it has also been expanded in estimating vulnerabilities of all types of structures and ground. Ambient vibration test has also been used to identify the dynamic characteristics of ground and different types of building [9,10,11], that very useful in resonance effect studies [12], [13]. According to [14], through the study on building diagnosis, it shows that in structural damage detection, the natural frequency is not the only one to be considered as the main parameter but also important to their mode shape evaluation.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Steel Stairwell Dynamic Characteristics, Under Few Mass Configurations Using Ambient Vibration Method

Kamarudin¹,

Mokhatar²,

Noh³

et al. 2019

IJIE

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Application of external mass on existing emergency steel stairwell in this study has altered the natural frequency when the resonance threshold has been reached and allows disruption to the human comfort feeling. Ambient vibration testing and modal analysis were carried out on 6 meter height of emergency steel stairway portal frame by using 1 Hz of tri-axial seismometer sensor and open source software of GEOPSY as the processing tool. The stairwell platforms were subjected by cumulative ascending static mass configurations of 300 kg, 600 kg and 900 kg. Identification of the predominant first mode frequency, f1, and mode shapes were made with specified empirical filtering protocols were applied. Fourier Amplitude Spectra (FAS) was used to transform the ambient vibration time series, when the first predominant frequency under bare frame (BF) condition shows at 8.32 Hz. f1 decreased linearly to 7.35 Hz (BF+300kg), 6.77 Hz (BF+600kg) and 6.23 Hz (BF+900 kg), when the masses were increased. In addition, at these frequencies' ranges, bad human subjective experiences could be triggered as recommended by previous researchers between 8 to 5 Hz. Besides, the deflection shapes from the first mode frequency was also illustrated at higher deflection amplitude to one of the portal frame's column which resisting two stairwell platforms. These amplitudes are higher when f1 is decreasing. It can be concluded that, ambient vibration approach has efficiently evaluated the dynamic characteristics and its influence against the structureperson interaction on existing steel stairwell portal frame in this study. Further strengthening work on the steel frame could decrease the reductions percentages of the predominant frequencies, deflection amplitudes and even increase the human comfort level when using the stairwell, especially during building evacuation procedure.

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Section: Results and Discussion 31 Natural Frequenciesmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Evaluation of Steel Stairwell Dynamic Characteristics, Under Few Mass Configurations Using Ambient Vibration Method

Kamarudin¹,

Mokhatar²,

Noh³

et al. 2019

IJIE

View full text Add to dashboard Cite

show abstract

“…In order to get a good quality signal and sufficient windows during analysis stage, all noise disturbances especially transient and bad weather conditions were strictly avoided as recommended in the SESAME [11] guideline. Other parameters such as sampling rate of 100 Hz at the optimum gain and 15-minutes of recording length were used, discounting all frequencies below 1 Hz [12]. All ambient vibration signals were recorded in the vertical direction (V) as well as North-South (NS) and East-West (EW) in the horizontal directions.…”

Section: Kku International Engineeringmentioning

confidence: 99%

Vulnerability Assessment of Existing Low-Rise Reinforced Concrete School Buildings in Low Seismic Region Using Ambient Noise Method

Kamarudin

Ibrahim

et al. 2014

AMR

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Ground movements triggered by the Bukit Tinggi earthquakes in 2007 to 2009 are believed to be the possible cause of several structural damages on a secondary school building of SMK Bukit Tinggi, in the state of Pahang, Malaysia. This paper describes the ambient noise study conducted on the damaged building (a 4-storey reinforced concrete frame laboratory building) and the adjacent buildings using tri-axial 1 Hz seismometer sensors. Fourier amplitude spectra (FAS) analysis was applied to determine the buildings natural frequencies for vulnerability assessment of the damaged structure in both longitudinal and transverse axes. Significant multiple peaks of FAS curves used for natural frequencies determination of the buildings show values between 4.18 to 4.34 Hz, 5.04 to 5.23 Hz, 6.07 to 6.54 Hz and 8.17 to 8.81 Hz, indicating the existence of translational and torsional vibration modes acting on the buildings. Differences in dynamic behaviour between the laboratory and the adjacent buildings may be responsible for the structural damages due to the independent structural response and excessive torsional effect during the Bukit Tinggi earthquake tremors.

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“…A sampling rate of 50 Hz is sufficient, as the maximum frequency of engineering interest is not higher than 25 Hz, although higher sampling rates do not influence HVSR results [1]. c. According to [10], the gain was adjusted to minimize signal saturation from the three components of ambient vibration time histories. It should also be kept in mind that, whatever the type of sensor used, it is not recommended to use too high of a gain, which would result in excessive signal saturation and severely compromise the result [7].…”

Section: Fieldwork and Data Logger Parametersmentioning

confidence: 99%

Influence of Traffic Vehicles Against Ground Fundamental Frequency Prediction using Ambient Vibration Technique

Kamarudin

Noh

Mokhatar

et al. 2018

J. Phys.: Conf. Ser.

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Abstract. 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.

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Microtremor Soil-Structure Resonance Study in the Bovec Basin (NW Slovenia) Related to 1998 and 2004 Damaging Earthquakes

Cited by 4 publications

References 18 publications

Evaluation of Steel Stairwell Dynamic Characteristics, Under Few Mass Configurations Using Ambient Vibration Method

Evaluation of Steel Stairwell Dynamic Characteristics, Under Few Mass Configurations Using Ambient Vibration Method

Vulnerability Assessment of Existing Low-Rise Reinforced Concrete School Buildings in Low Seismic Region Using Ambient Noise Method

Influence of Traffic Vehicles Against Ground Fundamental Frequency Prediction using Ambient Vibration Technique

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