Testing in-Phase Analysis for Adjacent Transmission Towers under Ambient Vibration

2011 ◽  
Vol 105-107 ◽  
pp. 112-116
Author(s):  
Xiang Mei Yan
Keyword(s):  
Dynamic Characteristics ◽  
Damping Ratio ◽  
Longitudinal Direction ◽  
Ambient Vibration ◽  
Induced Response ◽  
Line System ◽  
Vibration Data ◽  
Transmission Towers ◽  
Ambient Vibration Testing ◽  
Suspended Cables

Based on the random vibration and system identification theory, the ambient vibration testing of two adjacent transmission towers were carried out, dynamic characteristics of the towers were obtained from ambient vibration data. The result shown that the suspended cables not only have mass effects, but have coupled stiffness effects applied to tower on transverse direction and longitudinal direction. At the same, testing value shows that the two adjacent towers have basically the same dynamic characteristics and damping ratio of the two transmission towers less than 0.01. Owing to the influence of conductors, frequency of the insulators is different to the towers at the two directions. It is disadvantage for wind-induced response of transmission line system under ambient loads.

Dynamic Characteristics Analysis of Two Adjacent Transmission Towers

2012 ◽  
Vol 446-449 ◽  
pp. 833-836
Author(s):  
Xiang Mei Yan
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Characteristics ◽  
Transverse Direction ◽  
Longitudinal Direction ◽  
Transmission Towers ◽  
Straight Line ◽  
Characteristics Analysis ◽  
Suspended Cables ◽  
Analysis Models ◽  
Dynamic Characteristics Analysis

Dynamic analysis models of two adjacent transmission towers, two adjacent corner towers and the correspond single-tower are established, its dynamic characteristics are analyzed and compared. The results showed that: Dynamic characteristics of two adjacent transmission towers are close, but the towers connected with the corner tower changes much. Compared with the single-tower, its dynamic characteristics have changed regardless of corner tower or straight line transmission towers. It is also shown that suspended cables not only have mass effects, but have coupled stiffness effects applied to towers on transverse direction and longitudinal direction.

Structural System Identification of Elevated Steel Water Tank Using Ambient Vibration Test and Calibration of Numerical Model

2020 ◽  
Vol 20 (10) ◽  
pp. 2071010
Author(s):  
Mohammad Alembagheri ◽  
Maria Rashidi ◽  
Mohammad Seyedkazemi
Keyword(s):  
System Identification ◽  
Numerical Model ◽  
Dynamic Properties ◽  
Ambient Vibration ◽  
Water Tank ◽  
Ambient Vibration Test ◽  
Vibration Data ◽  
Steel Material ◽  
Ambient Vibration Testing ◽  
Structural System Identification

This research aims to investigate the feasibility of using ambient vibration testing for system identification of an elevated water tank. To identify the natural dynamic properties, the experimental study is carried out on an elevated steel water tank located in Tehran. The tank is instrumented with a sensitive velocimeter sensor (microtremor), and the ambient velocity of the tank is recorded for 30[Formula: see text]min in three orthogonal axes. Employing the peak-picking method in the frequency domain, the fundamental frequency of the tank is determined as about 1.9[Formula: see text]Hz. Then, the numerical model of the tank is generated and calibrated based on the obtained data. In the primary modeling, the values of natural frequencies of the tank are in good agreement with the results of the ambient vibration data. This finding is judged to be reasonable considering no clear sign of corrosion in the steel material.

scholarly journals Damping and Natural Period Evaluation of Tall RC Buildings Using Full-Scale Data in Korea

2020 ◽  
Vol 10 (5) ◽  
pp. 1568
Author(s):  
Taehyu Ha ◽  
Seung-Hoon Shin ◽  
Hongjin Kim
Keyword(s):  
Damping Ratio ◽  
Tall Buildings ◽  
Vibration Measurement ◽  
Ambient Vibration ◽  
Induced Response ◽  
Rc Buildings ◽  
Natural Period ◽  
Rc Structures ◽  
High Rise ◽  
Induced Motion

In recent years, the main usage of reinforced concrete (RC) structures in Korea has shifted from low-rise residential and commercial buildings to high-rise buildings. Because an increasing number of high-rise RC buildings are being built, especially in coastal cities, which are periodically hit by typhoons, wind-induced motion and the corresponding serviceability issues have attracted considerable attention. Natural period and damping ratio are the most important factors for estimating the design wind load and wind-induced response in the design of tall buildings. However, the Korean Building Code (KBC 2009) does not specify empirical formulae for estimating the natural period and damping ratio for wind design, unlike seismic design. In this study, the damping ratio and natural period of existing concrete buildings in Korea are measured and compared to those obtained using the formulae provided in various codes and research works. Furthermore, design formulae for estimating natural frequency and damping ratio for wind design are proposed based on the measured data. For this purpose, ambient vibration measurement is performed for 58 RC buildings with heights of 24.2–305 m.

Analytical Study on Wind-Induced Vibration and its Control of Transmission Towers in Mountainous Area

2011 ◽  
Vol 105-107 ◽  
pp. 635-639
Author(s):  
Zheng Yi Sheng ◽  
Chun Xia ◽  
Wei Ping Xu ◽  
Peng Yun Li
Keyword(s):  
Induced Response ◽  
Mountainous Area ◽  
Superposition Method ◽  
Transmission Tower ◽  
Control Effect ◽  
Line System ◽  
Viscoelastic Dampers ◽  
Transmission Towers ◽  
Out Of Plane ◽  
Wind Induced Vibration

A method for analyzing wind-induced vibration and its control of transmission tower-line system in mountainous area is described. The method is applied to a real transmission line containing two self-supporting steel angle towers, 3 spans of conductors and ground lines together with insulators. Analyses are conducted for the out-of-plane wind direction, and the fluctuating wind load on tower-line system is simulated by harmony superposition method and davenport spectrum. The numerical results indicate that the wind-induced response and its control effect are mainly related to the stiffness of the towers, rather than the mounting height or the spans of the power lines. At the same time, viscoelastic dampers fixed on the main members can suppress the wind-induced displacement of the towers effectively.

scholarly journals Dynamic Behavior of a Suspended Steel Space Frame-Glass Composite Floor

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Zhihao Wang ◽  
Xin Qi ◽  
Youkun Huang ◽  
Buqiao Fan ◽  
Xiaoke Li
Keyword(s):  
Dynamic Characteristics ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Vertical Vibration ◽  
Ambient Vibration ◽  
Fe Model ◽  
Glass Composite ◽  
Space Frame ◽  
Vertical Stiffness ◽  
Steel Space Frame

This study investigates the dynamic performance of a large-span suspended steel space frame-glass composite floor (SSSF-GCF). Both the ambient vibration and the human-induced vibration of the floor were experimentally measured to identify vertical dynamic characteristics and evaluate vibration serviceability of the floor. Although vertical dynamic characteristics of the floor based on the global simplified finite element (FE) model of the structure agree well with those identified via experimental modal analysis, the global simplified FE model significantly underestimates vertical vibration amplitudes of the floor due to the coupled effect between two layers. Accordingly, an equivalent local FE model of the floor system was proposed and updated via adjusting the vertical stiffness of the interstory hanging pillars. It is shown that the equivalent local FE model can well predict both the dynamic characteristics and human-induced vibration response of the floor. Finally, the effect of the damping ratio on the acceleration response of the floor was numerically demonstrated with the verified local FE model.

Before and after Retrofit Behavior and Performance of a 55-Story Tall Building Inferred from Distant Earthquake and Ambient Vibration Data

2017 ◽  
Vol 33 (4) ◽  
pp. 1599-1626 ◽  
Author(s):  
Mehmet Çelebi ◽  
Toshihide Kashima ◽  
S. Farid Ghahari ◽  
Shin Koyama ◽  
Ertuğrul Taciroğlu ◽  
...  
Keyword(s):  
Damping Ratio ◽  
Tohoku Earthquake ◽  
Tall Building ◽  
Ambient Vibration ◽  
Positive Finding ◽  
Vibration Data ◽  
Long Period ◽  
Before And After ◽  
And Performance ◽  
The Impact

A sparsely instrumented 55-story building in Osaka, Japan, had recorded unprecedented, severe, and long-duration, long-period resonating responses during the 11 March 2011 M9.0 Tohoku earthquake that occurred at 767 km distance. Thereafter, studies of the records resulted in the implementation of a significant retrofit design, comprising dampers and buckling restrained braces (BRBs). The responses of the retrofitted building were also recorded during the 24 April 2016 M7.3 Kumamoto earthquake that occurred at 478 km. The earthquake and on-demand acquired ambient response data are analyzed in this study to assess the impact of this rare, retrofitted and instrumented tall building subjected to long period strong shaking from events originating at far distances. As expected, the fundamental frequency and critical damping ratio of the building increased, albeit small, after the retrofit as compared to before the retrofit. Increase of damping percentage is a positive finding and indicates that even larger percentages may be attained under shaking stronger than the 2016 event. The records indicate that the building still experiences significant resonance, torsion, as well as a beating effect.

Dynamic characteristics of the Crowchild Trail Bridge

2000 ◽  
Vol 27 (5) ◽  
pp. 1046-1056 ◽  
Author(s):  
Carlos E Ventura ◽  
Tuna Onur ◽  
Pei-Chin Tsai
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Analytical Models ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Good Match ◽  
Structural Dynamic ◽  
Ambient Vibration Testing ◽  
Ambient Vibration Measurements

This paper presents the results of a study on the dynamic characteristics of the Crowchild Trail Bridge in Calgary, Alberta. This bridge is currently being monitored by members of the Intelligent Sensing for Innovative Structures Network (ISIS Canada). The effects of various modeling assumptions on the computed dynamic characteristics of the bridge are investigated and discussed in this paper. The dynamic characteristics of the bridge were determined by means of ambient vibration measurements and were used to calibrate a number of computer models developed by four different groups of engineers. The results of this study showed that in order to properly calibrate a model of the bridge for structural dynamic analysis, it is necessary to have not only a good match of experimental and analytical natural frequencies but also a good match of experimental and analytical mode shapes. Improper determination of dynamic characteristics of a bridge using analytical models could lead to erroneous conclusions on its expected behaviour under dynamic loading.Key words: ambient vibration testing, dynamic characteristics, bridge modeling, instrumentation, accelerometers, modal analysis.

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