scholarly journals Investigation of Ground Vibration of Full-Stone Foundation under Dynamic Compaction

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Jiawen Wu ◽  
Linjian Ma ◽  
Jun Shi ◽  
Yangyang Sun ◽  
Jiewei Ke ◽  
...  
Keyword(s):  
Single Point ◽  
Time History ◽  
Ground Vibration ◽  
Average Frequency ◽  
Dynamic Compaction ◽  
Peak Ground Velocity ◽  
Vibration Velocity ◽  
Ground Acceleration ◽  
Frequency Spectra ◽  
Equivalent Factor

This study focuses on the ground vibration of a full-stone foundation treatment project. The single-point dynamic compaction test was performed using a tamping machine at an energy level of 3200 kN·m. Time-history curves of ground vibration velocity were recorded under 10 times tamping within 120 m distance. The effects of tamping times on the waveform of velocity and frequency spectra were assessed, as well as of peak ground velocity (PGV), peak ground acceleration (PGA), and average frequency. Furthermore, the attenuations of PGV, PGA, and average frequency were also analyzed in detail. It has been founded that increasing tamping times of dynamic compaction can effectively improve PGV and PGA. For the frequency spectra, the increasing tamping times contribute to a higher frequency range, more primary frequencies, and a larger frequency domain. However, the three parameters, namely, PGV, PGA, and average frequency, remain stable roughly when they reach a threshold of test tamping times. The attenuations of PGV and PGA with the proportional distance follow the power law with negative exponents. Furthermore, the fitted equivalent factor increases while the damped exponential decreases persistently with the increase of tamping times. The average frequency is negatively linearly correlated with the proportional tamping distances.

The Finite Element Model Determination in the Loess Regions under Subway Vibration Loads

2011 ◽  
Vol 368-373 ◽  
pp. 2586-2590
Author(s):  
Zhao Bo Meng ◽  
Shi Cai Cui ◽  
Teng Fei Zhao ◽  
Liu Qin Jin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Low Frequency ◽  
Time History ◽  
Ground Vibration ◽  
Element Model ◽  
Vibration Velocity

According to measured shear wave velocity of Xi’an Bell Tower area (Loess Area), the dynamic parameters of site soil are determined by using the relationship between shear wave velocity and compression wave velocity. Using Matlab program, the finite element size for low frequency subway vibration is obtained by analyzing soil dispersion phenomenon. On this basis, two-dimensional model with viscous - elastic boundaries is established by using the ANSYS program. The load-time history of the train is applied to the right tunnel, and the effects of the depth and breadth of the different models on the ground vibration velocity are discussed. Finally, the dimensions and element sizes of finite element model are obtained for the Xi'an No. 2 Metro Line with 15m depth in the loess regions.

scholarly journals Computation of Ground Vibrations Generated by Accelerating and Braking Road Vehicles

1996 ◽  
Vol 2 (3) ◽  
pp. 299-321 ◽  
Author(s):  
Victor V. Krylov
Keyword(s):  
Poisson Ratio ◽  
Vertical Component ◽  
Traction Force ◽  
Ground Vibration ◽  
Constant Speed ◽  
Vibration Velocity ◽  
Ground Vibrations ◽  
Road Vehicles ◽  
Frequency Spectra ◽  
Vehicle Movement

The problem of ground vibration generation by accelerating and braking road vehicles is considered theoretically for vehicles accelerating (decelerating) with a constant acceleration a from rest to a constant speed, or braking to a stop from a constant speed. According to the low-frequency approximation considered, an accelerating or braking vehicle of mass M is modelled as a point horizontal traction force Fx = aM applied to the ground and moving along with the vehicle. Frequency spectra of the vertical component of the ground vibration velocity are investigated as functions of acceleration, final (initial) speed of the vehicle, ground attenuation, Poisson ratio, and radiation angle Θ relative to the direction of the vehicle movement. It is shown that, in contrast to vehicles travelling on uneven roads, the ground vibrations generated by accelerating and braking vehicles are characterised by directivity patterns V(Θ), which show, in particular, that there is no radiation in the directions perpendicular to the direction of vehicle movement.

scholarly journals Generation of Low-Frequency Rayleigh Waves by Heavy Lorries

1995 ◽  
Vol 14 (4) ◽  
pp. 165-172 ◽  
Author(s):  
V.V. Krylov
Keyword(s):  
Vertical Component ◽  
Low Frequency ◽  
Traction Force ◽  
Ground Vibration ◽  
Vibration Velocity ◽  
Ground Vibrations ◽  
Frequency Spectra ◽  
Road Surfaces ◽  
Road Surface Roughness ◽  
Vehicle Movement

Generation of low-frequency ground vibrations by heavy lorries is considered theoretically for both vehicles accelerating (decelerating) with a constant acceleration and vehicles travelling at constant speed on damaged or bumpy surfaces. In the case of damaged or bumpy surfaces, excitation of axle-hop resonances is taken into account, whereas an accelerating or braking vehicle is modelled as a point horizontal traction force applied to the ground and moving along with the vehicle. Frequency spectra of the vertical component of the ground vibration velocity are investigated for different functions of road surface roughness, acceleration, final (initial) speed of the vehicle, ground attenuation, Poisson's ratio, and radiation angle relative to the direction of the vehicle movement. It is shown that damaged or bumpy road surfaces normally generate vibrations of higher amplitudes, in comparison with accelerating and braking lorries. In contrast to vehicles travelling along bumpy or uneven roads and generating vibrations propagating at all directions, the ground vibrations generated by accelerating and braking vehicles are characterised by the directivity function showing that there is no radiation in the direction perpendicular to the vehicle movement.

scholarly journals Monitoring the Dynamic Response of a Buried Polyethylene Pipe to a Blast Wave: An Experimental Study

2019 ◽  
Vol 9 (8) ◽  
pp. 1663 ◽  
Author(s):  
Zhong ◽  
Gong ◽  
Han ◽  
Li
Keyword(s):  
Dynamic Response ◽  
Ground Vibration ◽  
Average Frequency ◽  
Blast Waves ◽  
Dynamic Strain ◽  
Vibration Velocity ◽  
Hoop Strain ◽  
Scaled Distance ◽  
Charge Mass ◽  
Explosive Source

Although the use of polyethylene (PE) pipelines has become increasingly widespread in recent years, few studies have addressed their seismic design and ability to withstand blast waves. In order to establish their seismic capacity, the dynamic response of buried pipelines subjected to blast waves must be explored in depth. Here, we studied the dynamic response of PE pipes situated near an explosive source. Time histories of dynamic strains were measured by conventional strain gauges after simple waterproof treatment, and pipe and ground vibration velocity curves were obtained. Based on the experimental data, the attenuation law of the peak strains under the conditions of different charge masses and blast center distances was analyzed, and the spectrum characteristics of strain, velocity of the pipe, and ground velocity were studied. The results revealed that a large hoop strain on the PE pipes was produced due to the local impact near the explosive source. We found that peak hoop strain (PHS) or peak axial strain (PAS) had a power attenuation relationship with the scaled distance, and this relationship could also be derived by dimensional analysis. The average frequency of strains had the same attenuation form as the charge mass, which was between 10 Hz and 50 Hz. Additionally, the vibration of the pipe showed a low frequency. We also determined that the attenuation of the average frequency of pipe and ground vibration velocity was closely related to the charge mass and the scaled distance. Pipe peak vibration velocity (PPVV), ground peak particle velocity (GPPV), and the peak dynamic strain of pipe were highly positively correlated, which verifies the feasibility of using GPPV to characterize pipeline vibration and strain level. Thus, a blasting criterion of 10% minimum request strength (MRS) for PE pipe was proposed, which means that the additional PHS or PAS of the dangerous point must be less than 10% MRS, and we also propose limiting the safety distance–charge mass for blasts near buried PE pipelines by the criterion. Some results in this paper can serve as the basis for future in-depth theoretical research.

Energy Variation Characteristics of Exploding Ground Motion within Typical Loess Field of China

2012 ◽  
Vol 594-597 ◽  
pp. 8-17
Author(s):  
Jun Jie Sun ◽  
Lan Min Wang ◽  
Wen Tong Tian
Keyword(s):  
Ground Motion ◽  
Frequency Spectrum ◽  
Spectral Response ◽  
Strong Shock ◽  
Time History ◽  
Ground Vibration ◽  
Ground Acceleration ◽  
Short Delay ◽  
Variation Characteristics ◽  
Unsaturated Loess

Based on in-situ observational data, we analyzed energy features of strong ground motion induced by short delay blasting in unsaturated loess field through three aspects of time history, frequency spectrum and attenuation. For time histories, the data show exploding ground motion has two essential characteristics, i.e. larger peak ground acceleration (PGA) and shorter duration. Analysis results reveal the effective duration (ground acceleration exceeding a certain magnitude) is the pivotal factor influencing design effects of the blasting. The spectral response, meanwhile, attenuates with the increase of observational distances (apart from the centre of exploding field), especially for those higher frequency components. Values of H/V figured relative features of horizontal component to vertical one of frequency spectrum of exploding ground vibration become greater while distances widen. As exploding energy accumulated, moreover, lower frequency energy distinctly increases and the feature of frequency spectrum of the strong shock gradually approaches an actual seismic oscillation.

scholarly journals Attenuation relationships of peak ground motions in the Jazan Region

2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Ali K. Abdelfattah ◽  
Abdullah Al-amri ◽  
Kamal Abdelrahman ◽  
Muhamed Fnais ◽  
Saleh Qaysi
Keyword(s):  
Saudi Arabia ◽  
Ground Motions ◽  
Prediction Equation ◽  
Peak Ground Velocity ◽  
Local Magnitude ◽  
Ground Acceleration ◽  
Data Set ◽  
Hypocentral Distance ◽  
Distance Range ◽  
Attenuation Relationships

AbstractIn this study, attenuation relationships are proposed to more accurately predict ground motions in the southernmost part of the Arabian Shield in the Jazan Region of Saudi Arabia. A data set composed of 72 earthquakes, with normal to strike-slip focal mechanisms over a local magnitude range of 2.0–5.1 and a distance range of 5–200 km, was used to investigate the predictive attenuation relationship of the peak ground motion as a function of the hypocentral distance and local magnitude. To obtain the space parameters of the empirical relationships, non-linear regression was performed over a hypocentral distance range of 4–200 km. The means of 638 peak ground acceleration (PGA) and peak ground velocity (PGV) values calculated from the records of the horizontal components were used to derive the predictive relationships of the earthquake ground motions. The relationships accounted for the site-correlation coefficient but not for the earthquake source implications. The derived predictive attenuation relationships for PGV and PGA are$$ {\log}_{10}(PGV)=-1.05+0.65\cdotp {M}_L-0.66\cdotp {\log}_{10}(r)-0.04\cdotp r, $$ log 10 PGV = − 1.05 + 0.65 · M L − 0.66 · log 10 r − 0.04 · r , $$ {\log}_{10}(PGA)=-1.36+0.85\cdotp {M}_L-0.85\cdotp {\log}_{10}(r)-0.005\cdotp r, $$ log 10 PGA = − 1.36 + 0.85 · M L − 0.85 · log 10 r − 0.005 · r , respectively. These new relationships were compared to the grand-motion prediction equation published for western Saudi Arabia and indicate good agreement with the only data set of observed ground motions available for an ML 4.9 earthquake that occurred in 2014 in southwestern Saudi Arabia, implying that the developed relationship can be used to generate earthquake shaking maps within a few minutes of the event based on prior information on magnitudes and hypocentral distances taking into considerations the local site characteristics.

Low Frequency Noise from a Big Building Due to Oscillatory Forces of a Machine

1982 ◽  
Vol 1 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Niichi Nishiwaki ◽  
Noboru Fujio ◽  
Takuji Mori
Keyword(s):  
Low Frequency ◽  
Ground Vibration ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Ground Acceleration ◽  
Building Frames ◽  
Acceleration Level ◽  
Residential District ◽  
Factory Building ◽  
Grinding Mill

People living in houses near a big factory complained about chattering of glass windows. At one of these houses, the SPL of low frequency noise was about 66 dB at 5.5 Hz and ground acceleration level was about 40 dB at 9 Hz in the horizontal direction. (0 dB acceleration = 10−5 m/s2). We found that the noise and ground vibration were caused by a big grinding mill in the factory, because both SPL and acceleration level at the residential district were considerably decreased when the mill was not in operation. We also confirmed that low frequency noise was not transmitted from the grinding mill directly, but was due to the resonant vibration of walls of the factory building. Two ideas are studied here to suppress the noise, one of which is to isolate the vibration of the grinding mill at its foundation, and the other is to improve the stiffness of the building frames to stop the wall vibration. As a result of the study, the latter method to increase the stiffness of the building was adopted. The SPL of low frequency noise near the wall was decreased.

scholarly journals Seismic Hazard Assessment for the Tianshui Urban Area, Gansu Province, China

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Zhenming Wang ◽  
David T. Butler ◽  
Edward W. Woolery ◽  
Lanmin Wang
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Design ◽  
Hazard Analysis ◽  
Seismic Hazard Assessment ◽  
Gansu Province ◽  
Mitigation Measures ◽  
Peak Ground Velocity ◽  
Ground Acceleration ◽  
Acceleration Time Histories

A scenario seismic hazard analysis was performed for the city of Tianshui. The scenario hazard analysis utilized the best available geologic and seismological information as well as composite source model (i.e., ground motion simulation) to derive ground motion hazards in terms of acceleration time histories, peak values (e.g., peak ground acceleration and peak ground velocity), and response spectra. This study confirms that Tianshui is facing significant seismic hazard, and certain mitigation measures, such as better seismic design for buildings and other structures, should be developed and implemented. This study shows that PGA of 0.3 g (equivalent to Chinese intensity VIII) should be considered for seismic design of general building and PGA of 0.4 g (equivalent to Chinese intensity IX) for seismic design of critical facility in Tianshui.

Nonlinear Site Effects from the 30 November 2018 Anchorage, Alaska, Earthquake

2021 ◽  
Author(s):  
John D. Thornley ◽  
Utpal Dutta ◽  
John Douglas ◽  
Zhaohui (Joey) Yang
Keyword(s):  
Site Response ◽  
Strong Motion ◽  
North American Plate ◽  
Peak Ground Velocity ◽  
Reference Station ◽  
Earthquake Hazards ◽  
Ground Acceleration ◽  
Nonlinear Site Response ◽  
Generalized Inversion Technique ◽  
Versus Peak

ABSTRACT Anchorage, Alaska, is a natural laboratory for recording strong ground motions from a variety of earthquake sources. The city is situated in a tectonic region that includes the interface and intraslab earthquakes related to the subducting Pacific plate and crustal earthquakes from the upper North American plate. The generalized inversion technique was used with a local rock reference station to develop site response at >20 strong-motion stations in Anchorage. A database of 94 events recorded at these sites from 2005 to 2019 was also compiled and processed to compare their site response with those in the 2018 Mw 7.1 event (main event). The database is divided into three datasets, including 75 events prior to the main event, the main event, and 19 aftershocks. The stations were subdivided into the site classes defined in the National Earthquake Hazards Reduction Program based on estimated average shear-wave velocity in of the upper 30 m (VS30), and site-response results from the datasets were compared. Nonlinear site response was observed at class D and DE sites (VS30 of 215–300 and 150–215  m/s, respectively) but not at class CD and C sites (VS30 of 300–440 and 440–640  m/s, respectively). The relationship of peak ground acceleration versus peak ground velocity divided by VS30 (shear-strain proxy) was shown to further support the observation that sites with lower VS30 experienced nonlinear site response.

scholarly journals Performance of an Existing Reinforced Concrete Building Designed in Accordance to Older Indonesian Seismic Code: A Case Study for a Hotel in Kupang, Indonesia

2018 ◽  
Vol 20 (1) ◽  
pp. 35
Author(s):  
Pamuda Pudjisuryadi ◽  
Benjamin Lumantarna ◽  
Ryan Setiawan ◽  
Christian Handoko
Keyword(s):  
Plastic Hinge ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Ground Acceleration ◽  
Seismic Code ◽  
Damage Level ◽  
History Analysis ◽  
Nonlinear Time History ◽  
Seismic Hazard Map

The recent seismic code SNI 1726-2012 is significantly different compared to the older code SNI 1726-2002. The seismic hazard map was significantly changed and the level of maximum considered earthquake was significantly increased. Therefore, buildings designed according to outdated code may not resist the higher demand required by newer code. In this study, seismic performance of Hotel X in Kupang, Indonesia which was designed based on SNI-1726-2002 is investigated. The structure was analyzed using Nonlinear Time History Analysis. The seismic load used was a spectrum consistent ground acceleration generated from El-Centro 18 May 1940 North-South component in accordance to SNI 1726-2012. The results show that Hotel X can resist maximum considered earthquake required by SNI 1726-2012. The maximum drift ratio is 0.81% which is lower than the limit set by FEMA 356-2000 (2%). Plastic hinge damage level is also lower than the allowance in ACMC 2001.

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