Performance evaluation of vibration-sensitive equipment foundations under ground-transmitted excitation

2003 ◽  
Vol 40 (3) ◽  
pp. 598-615 ◽  
Author(s):  
M Hesham El Naggar
Keyword(s):  
Ground Surface ◽  
Time History ◽  
Ground Vibration ◽  
Frequency Domain Analysis ◽  
Vibration Monitoring ◽  
Normal Operation ◽  
Response Analysis ◽  
The Third ◽  
Final Design ◽  
Dynamic Investigation

The planning of foundations for equipment that is sensitive to vibrations requires a thorough dynamic investigation of the proposed location of the foundation with regard to the effect of already existing or additional vibration sources. This paper discusses the analyses performed for a number of foundations supporting vibration-sensitive equipment that has been subjected to ground-transmitted excitations. These analyses considered the dynamic response of the foundations resulting from the normal operation of the supported equipment or the ground-transmitted excitations. In one case, the foundation of the Canadian Light Source, a third generation synchrotron that will be capable of generating electromagnetic radiation used in the study of the atomic and subatomic structure of materials, is examined. Another case involves the vibration analysis of a magnetic resonance imaging unit affected by traffic excitation. In the third case, a power plant facility that is subjected to blast-induced vibration from an adjacent quarry is investigated. The last case involves the response analysis of a compressor foundation affected by the ground-transmitted vibration from another compressor situated on a different foundation within the same facility. To assess the level of seismic excitation at the site due to traffic on an adjacent roadway in the first two cases and to blasting activity in the third case, extensive "green field" ground vibration-monitoring programs were carried out. The ground accelerations due to traffic and blasting were measured and recorded for three directions simultaneously: a vertical and two orthogonal horizontal directions. The measurements with the most intense ground accelerations taken at the ground surface in the location of the future equipment foundation were selected as the final design acceleration time-history. A Fourier analysis approach was used to predict the response of the foundation to the ground-induced vibrations in the first three cases, and a frequency domain analysis was used in the last case.Key words: machine foundations, vibration, blasting, kinematic, soil-structure interaction.

Site response analysis of liquefiable soil employing continuous wavelet transform

2022 ◽  
Vol 12 (1) ◽  
pp. 1-33
Author(s):  
D. Chavan ◽  
T.G. Sitharam ◽  
P. Anbazhagan
Keyword(s):  
Wavelet Transform ◽  
Site Response ◽  
Amplitude Spectrum ◽  
Ground Surface ◽  
Time History ◽  
Response Analysis ◽  
Fourier Amplitude ◽  
Acceleration Time ◽  
Liquefiable Soil ◽  
Fourier Amplitude Spectrum

Propagation of the earthquake motion towards the ground surface alters both the acceleration and frequency content of the motion. Acceleration time record and Fourier amplitude spectrum of the motion reveal changes in the acceleration and frequency content. However, Fourier amplitude spectrum fails to give frequency-time variation. Wavelet transform overcomes this difficulty. In the present study, site response analysis of a liquefiable soil domain has been investigated employing wavelet transform. Three earthquake motions with distinct predominant frequencies are considered. It is revealed that the moment soil undergoes initial liquefaction, it causes a spike in the acceleration time history. Frequency of the spikes is found to be greater than the predominant frequency of the acceleration-time history recorded at the ground surface from the analysis. Interestingly, the spikes belong to the sharp tips of the shear stress-shear strain curve. Immediately after the spike, acceleration deamplification is observed. Post-liquefaction deamplification (filtering) of the frequency components is also observed.

SEISMIC TIME-HISTORY GROUND-MOTIONS FOR A SPECIFIC SITE IN JAKARTA

2015 ◽  
Vol 77 (11) ◽  
Author(s):  
I Wayan Sengara ◽  
Muhammad Addifa Yulman ◽  
Andri Mulia
Keyword(s):  
Seismic Hazard ◽  
Linear Time ◽  
Site Response ◽  
Ground Motions ◽  
Ground Surface ◽  
Time History ◽  
Response Analysis ◽  
Building Collapse ◽  
Surface Development ◽  
Time Histories

Indonesia has developed new seismic building code based on risk-targeted ground-motions adopting 1 % probability of building collapse in 50 years. The new seismic design criterion, which is presented in the code, have combined both seismic hazard and building fragility. For performance-based analysis of high-rise buildings, a complex non-linear time-history analysis is needed. This paper presents results of study on development of the time-history with emphasing on procedure of developing pairs of time-history at ground surface for spesific site in Jakarta with reference to 2012 International Building Codes and ASCE-SEI-7-10. The study involves generation of time-history from reference base-rock through site-response analysis to ground surface. Development of time-history at ground surface with a procedure involving Square Root of the Sum of the Square method (SRSS) in order to reasonably scaled time-histories through spectral matching technique is presented herein. The matched time-histories are developed from various strong-motion records representing different earthquake sources dominant to control the site evaluated from de-aggregation within seismic hazard analysis. This work also adopts baseline corrections in which velocity and displacement components of matched time-histories can be drifted to zero at the end of recorded seismic time.

scholarly journals Measurement and Numerical Simulation of Ground and Subgrade Vibrations of Beijing Urban Rail Line 13

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Futong Wang ◽  
Leilei Yan ◽  
Qi Jiang ◽  
Xiaxin Tao
Keyword(s):  
Numerical Simulation ◽  
Traffic Congestion ◽  
Ground Surface ◽  
Time History ◽  
Ground Vibration ◽  
Urban Rail Transit ◽  
Attenuation Relationship ◽  
Vibration Intensity ◽  
Urban Rail ◽  
Rail Line

Urban rail transit is an effective way to deal with the problem of traffic congestion in major cities. Trains travel through dense residential and commercial areas, providing convenient transportation while also result in vibration problems in the surrounding environment. Long-lasting vibrations result in disturbance to people’s sleep, malfunction of sensitive equipment, and even damage to heritage buildings. Compared with elevated and tunnel sections, ground surface urban railway generates vibrations and propagates to the surroundings via a more direct path in the form of surface waves, which makes the environmental problem more prominent. Due to the complexity of the train-track-ground system, the characteristics of the vibration propagation and attenuation are yet to be revealed. In this paper, we investigate the vibration of the ground and the subgrade next to the Beijing Urban Rail Line 13 by a field measurement combined with a mathematical model. The duration of ground vibration is divided into two parts: the train passing time and the Doppler effect-related tailing part. Through a regression analysis of the duration, the train passing time is identified and the train traveling speed is estimated. The attenuation relationship of ground vibration intensity is expressed by a piecewise function. In the subgrade, the vibration intensity of particle decays with increasing depth and the stress decay rate is faster than that of the acceleration. The dynamic wheel/rail interaction behaves stationary and periodic, and the magnitude fluctuates up and down with the quasi-static axle weight. The intensity attenuation relationship fitted in this paper provides a basis for designing new lines and renewing old lines and can be used as a reference for the development of vibration-reduction technology. The simulated time history of the wheel-rail force provides an excitation sample for further model experiments and numerical simulation. The proposed train speed identification method may be useful for parameter identification of moving sources such as ships, automobiles, and airplanes.

Research on transformer vibration monitoring and diagnosis based on Internet of things

2021 ◽  
Vol 30 (1) ◽  
pp. 677-688
Author(s):  
Zhenzhuo Wang ◽  
Amit Sharma
Keyword(s):  
Internet Of Things ◽  
Power Distribution ◽  
Vibration Analysis ◽  
Vibration Monitoring ◽  
Power Transformers ◽  
Normal Operation ◽  
Analysis Method ◽  
Power Distribution Network ◽  
Monitoring And Diagnosis ◽  
Distribution Transformers

Abstract A recent advent has been seen in the usage of Internet of things (IoT) for autonomous devices for exchange of data. A large number of transformers are required to distribute the power over a wide area. To ensure the normal operation of transformer, live detection and fault diagnosis methods of power transformers are studied. This article presents an IoT-based approach for condition monitoring and controlling a large number of distribution transformers utilized in a power distribution network. In this article, the vibration analysis method is used to carry out the research. The results show that the accuracy of the improved diagnosis algorithm is 99.01, 100, and 100% for normal, aging, and fault transformers. The system designed in this article can effectively monitor the healthy operation of power transformers in remote and real-time. The safety, stability, and reliability of transformer operation are improved.

Deep Learning-Based Ground Vibration Monitoring: Reinforcement Learning and RNN-CNN Approach

2021 ◽  
pp. 1-5
Author(s):  
Sangseok Yun ◽  
Jae-Mo Kang ◽  
Jeongseok Ha ◽  
Sangho Lee ◽  
Dong-Woo Ryu ◽  
...  
Keyword(s):  
Deep Learning ◽  
Reinforcement Learning ◽  
Ground Vibration ◽  
Vibration Monitoring

Dynamic Response Analysis of Butt Joint of HTS-A Steel Considering Welding Residual Stresses

2013 ◽  
Vol 423-426 ◽  
pp. 944-950
Author(s):  
Wei Shen ◽  
Ren Jun Yan ◽  
Lin Xu ◽  
Kai Qin ◽  
Xin Yu Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Dynamic Response ◽  
Hot Spot ◽  
Time History ◽  
High Strength ◽  
Simulation Method ◽  
Butt Joint ◽  
Welding Residual Stress ◽  
Response Analysis ◽  
Hull Structure

This paper uses both numerical simulation method and experimental research method to study on welding residual stress of high-strength steel of the cone-cylinder hull. Welding is often accompanied by a larger welding residual stress, which directly affects the safety and service life of the hull structure. In order to obtain the distribution of the welding residual stress, the welding procedure was developed by its parameter language by using FE analysis software in this paper. Then the welding residual stress of hot spot region was measured through X-ray nondestructive testing method, and compared it with simulation results. Finally, considering the residual stress as the initial stress, this paper analyzed dynamic response process of the welding structure under combined actions of the welding residual stress and multiaxial loads, which could more accurately determine the stress of welding structure and the location of fatigue risk point. According to the amplitude of damage parameters and strain time-history curve, we can estimate the fatigue life of structure by selecting the corresponding damage models.

A Development of the Visco-Elastic Damper for Timber Structure and a Suggestion of the Technological Design Assistance System

2013 ◽  
Vol 778 ◽  
pp. 714-721
Author(s):  
Katsuhiko Kohara ◽  
Takeshi Nomura ◽  
Kazuyoshi Koumoto
Keyword(s):  
Seismic Response ◽  
Elastic Body ◽  
Structural Model ◽  
Time History ◽  
Timber Structure ◽  
Response Analysis ◽  
Frame Design ◽  
Timber Frame ◽  
Loading Tests ◽  
Controlled Structure

Our research team developed a brace type and an angle brace type of the visco-elastic damper on seismic-response controlled structure for timber structure. We performed various dependence evaluations by the materials examination of the styrene olefin-based visco-elastic body which we developed newly. We made a structural model using the performance that loading tests in timber frame. We inspected the validity of the structural model. In addition, we built a technical support system for damper setting by the time history response analysis so that a general design architect was easy to use the damper. We could express dynamics properties of visco-elastic body properties by Voigt model, and the structural model almost accorded with an examination property value. We made a structural model of the whole frame system by Kb of installation rigidity obtained from loading tests in timber frame. Because a design level almost accorded with experimental value, the validity of the frame design on seismic-response controlled structure in consideration of the dependence (distortion, frequency, temperature) of the visco-elastic body was confirmed. This visco-elastic damper on seismic-response controlled structure acquired minister authorization of Ministry of Land, Infrastructure and Transport. In addition, this damper acquired the certification of the Japan Building Disaster Prevention Association.

Preliminary microzonation of the Memphis, Tennessee, area

1982 ◽  
Vol 72 (3) ◽  
pp. 1011-1024
Author(s):  
Sunil Sharma ◽  
William D. Kovacs
Keyword(s):  
United States ◽  
Soil Properties ◽  
Damping Ratio ◽  
Ground Surface ◽  
Strong Motion ◽  
Response Analysis ◽  
Borehole Data ◽  
Central United States ◽  
Hazardous Zone ◽  
High Level

abstract The city of Memphis, which is situated very close to the inferred epicenter of one of the three major 1811 to 1812 earthquakes, is in a potentially hazardous zone which will be susceptible to the usual seismic hazards. By recognizing the high level of seismicity in the New Madrid area, this study attempts to microzone the potential hazards by considering the following subjects: (i) the seismicity of the central United States; (ii) design earthquakes; and (iii) response analysis which allows construction of the necessary microzonation maps. The seismicity of the region is evaluated from state-of-the-art literature as there is no recorded strong-motion data available for the central United States. Synthetically generated accelerograms, simulating the design earthquakes, were used to represent the ground motions which were applied at a depth of 45 m, below ground surface, at numerous sites in Memphis. The soil stratigraphy was conceptualized from borehole data, made available by local sources, and dynamic soil properties estimated from available empirical correlations. The results of the response analysis were transformed into microzonation maps depicting: (i) zones showing qualitative estimates of ground response; (ii) zones showing the natural frequency of the soils; (iii) zones showing the peak spectral acceleration for 2 per cent damping ratio; and (iv) zones of liquefaction potential. These maps are useful for preliminary design and are not intended to be used on a quantitative basis. Further investigation is necessary in determining the stratigraphy and soil properties for a site-specific design and analysis.

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