scholarly journals Field Test for a Base Isolation Structure on Condition of Horizontal and Initial Displacement

2021 ◽  
Vol 12 (1) ◽  
pp. 232
Author(s):  
Ying-Xiong Wu ◽  
Xin-Jun Dong ◽  
You-Qin Lin ◽  
Hao-De Cheng
Keyword(s):  
Dynamic Response ◽  
Dynamic Characteristics ◽  
Natural Vibration ◽  
Base Isolation ◽  
Seismic Structure ◽  
Control Effect ◽  
Initial Displacement ◽  
Pump System ◽  
Vibration Period ◽  
Isolation Layer

There are a few isolated structures that have been subjected to seismic testing. An isolated structure is incapable of tracking, adjusting, and controlling its dynamic characteristics. As a result, field evaluations of solitary structures’ dynamic characteristics are important. The horizontal initial displacement of a base isolation kindergarten made of 46 isolation bearings is 75 mm. The method for creating the horizontal initial displacement condition is illustrated, as are the primary test findings. Horizontal initial displacement is accomplished with the assistance of a reaction wall, rods, and hydraulic pump system. To begin, we removed the building using hydraulic jacks to produce horizontal displacement of the isolation layer and then attached rods to support the building. The rods were then shot and unloaded, causing the building to shake freely, and its dynamic response and other parameters were tested. The results indicate that the natural vibration period of an isolated structure is much greater than the natural vibration period of a seismic structure. The isolation layer’s hysteretic curve as completely filled; upon unloading, the isolation layer as promptly reset; the dynamic response control effect of each was visible, but the top floor’s acceleration was magnified by approximately 1.27 times.

Brief Introduction of Traditional Seismic Technology and Emerging Isolation Technology

2014 ◽  
Vol 1010-1012 ◽  
pp. 250-253
Author(s):  
Ji Yang Li ◽  
Wen Fang Zhang
Keyword(s):  
Control System ◽  
Seismic Response ◽  
Seismic Isolation ◽  
Passive Control ◽  
Base Isolation ◽  
Seismic Structure ◽  
Natural Period ◽  
Isolation Layer ◽  
Passive Seismic

Seismic can be divided into passive seismic and active seismic. Seismic isolation technology belong to the second type. Base isolation structure is defined by setting the isolation layer between the superstructure and foundation building, to extend the natural period architecture, increasing the damping to reduce structural seismic response. It is a passive control system. Compared with the traditional seismic structure, it mainly through the isolation layer to absorb and dissipate energy, reducing the response to the earthquake.

The Dynamic Characteristics Analysis of Liaocheng Guangyue Tower

2015 ◽  
Vol 744-746 ◽  
pp. 920-923
Author(s):  
Zhao Bo Meng ◽  
Yu Cao ◽  
Jie Jin
Keyword(s):  
Numerical Analysis ◽  
Dynamic Characteristics ◽  
Natural Vibration ◽  
Damping Ratio ◽  
Analysis Method ◽  
Vibration Period ◽  
Incentive Effect ◽  
First Order ◽  
Characteristics Analysis ◽  
Dynamic Characteristics Analysis

Taking Liaocheng Guangyue tower as an example, based on the on-site measurements, to determine its dynamic characteristics and provide a basis by numerical analysis method for determining traffic incentive effect on the ancient timber buildings. From the research, we can conclude that the first-order self-vibration frequency of Guangyue tower can be taken as 1.638Hz, the corresponding natural vibration period is 0.61s,the damping ratio is 1.098.

Experimental Investigation on Mid-Story Isolated Structures

2010 ◽  
Vol 163-167 ◽  
pp. 4014-4021
Author(s):  
Xiang Yun Huang ◽  
Fu Lin Zhou ◽  
She Liang Wang ◽  
Liu Han Wen Heisha ◽  
Xue Hai Luo
Keyword(s):  
Dynamic Characteristics ◽  
Shaking Table Test ◽  
Base Isolation ◽  
Shaking Table ◽  
Dynamic Responses ◽  
Seismic Responses ◽  
Isolation Technique ◽  
Vertical Stiffness ◽  
Isolation Layer ◽  
Rubber Bearings

Isolation technique has been acceded as a part of the China Seismic Code for Design of Buildings. In this code, the limitations for using isolation design are very strict, superstructure must be regular and the isolation layer must be located on the top of base (base isolated structure). Because of the needs of architecture and function or the feasibility of technique, some limitations have been broken in recent projects. Sometimes isolated layer can be set on the intermediate story, so-called the mid-story isolated structure. According to the characteristic of structure, isolation layer of mid-story isolated structure is set on a place where the structure’s vertical stiffness is suddenly changed, as like the top of the first story, middle story, conversion story of the structure. Laminated rubber bearings (LRB) are adopted as an isolation layer. Because the isolation layer is set on intermediate story, the whole structure is divided into superstructure and substructure; the structure’s dynamic characteristics are changed. The mechanism of mid-story isolated structure appears different characteristic compared with base isolation. The aim of mid-story isolation is not only to reduce seismic responses of superstructure, but also to reduce seismic responses of the substructure. Theoretical analysis and the shaking table test of the mid-story isolated structure were carried. And the response of mid-story isolated structure is discussed by comparing with the response of base-isolated structure and base fixed structure. The key problems of mid-story isolated structure are the force condition and the interaction of the structure up and below the isolation layer. Many factors, such as the number of story, mass, stiffness of superstructure and substructure, parameter of the isolation layer, have influence on the seismic behavior of the mid-story isolated structure. The optimum combination relationship of these factors is presented and dynamic characteristics and dynamic responses are investigated.

Research on Shaking Table Test of Base and Story Isolation Structures

2014 ◽  
Vol 580-583 ◽  
pp. 1776-1781
Author(s):  
Guo Chen Zheng ◽  
Hang Li Xu
Keyword(s):  
Natural Vibration ◽  
Shaking Table Test ◽  
Steel Frame ◽  
Shaking Table ◽  
Seismic Structure ◽  
Shaking Table Tests ◽  
Frame Model ◽  
Isolation Layer ◽  
Damping Effect ◽  
Scale Down

The shaking table tests are conducted on a 5-floor steel frame model with a scale down of 1:6. The traditional anti-seismic structure and isolation structures with isolation layer in different position are adopted. The results indicate that the natural vibration periods of isolation structure are longer than anti-seismic structure, and when the isolation layer is located in a lower position, the period becomes longer and the damping effect is better.

Influence of Floor Opening Location on the Dynamic Characteristics of the Building

2014 ◽  
Vol 933 ◽  
pp. 310-312
Author(s):  
Peng Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Natural Vibration ◽  
Frame Structure ◽  
Vibration Period

Based on the frame structure of a floor partial discontinuity, the paper using SATWE software, analyzed dynamic characteristics of the structure and focused on the effect of floor opening position on natural vibration period, and provided reference for the design of building floor partial discontinuity.

Analysis on Influencing Factors of the Moment that Slider Begins to Slide for Sliding Base-Isolated System

2012 ◽  
Vol 166-169 ◽  
pp. 2713-2717
Author(s):  
Min Sun ◽  
Yu Guo Zhang ◽  
Yong Niu
Keyword(s):  
Friction Coefficient ◽  
Natural Vibration ◽  
Damping Ratio ◽  
Harmonic Excitation ◽  
Design Parameters ◽  
External Excitation ◽  
Vibration Period ◽  
Isolation Layer ◽  
The Moment ◽  
System Characteristics

The moment that isolation layer slider begins to slide has great effects on the whole system characteristics for sliding base-isolated system,and the moment plays a crucial role for the analysis of system energy and the confirmation of energy spectrum.Change rules of the moment that isolation layer slider begins to slide under the influence of the acting parameters and system’s design parameters,Taking two particle of plain sliding base-isolated system of building structure under harmonic excitation as the research object,are studied by using the numerical analysis method.The results show that the moment will be delayed if the friction coefficient of isolation layer or the natural vibration period of superstructure will be increased,and the moment will be advanced under the condition that the damping ratio of superstructure or external excitation which is exerted on structure being increased,while the mass ratio of isolation layer slider and superstructure has a very complex effect on the moment that isolation layer slider begins to slide,and the influence law relates to friction coefficient.

Shaking Table Test Study on Mid-Story Isolation Structures

2012 ◽  
Vol 446-449 ◽  
pp. 378-381
Author(s):  
Jian Min Jin ◽  
Ping Tan ◽  
Fu Lin Zhou ◽  
Yu Hong Ma ◽  
Chao Yong Shen
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Shaking Table Test ◽  
Base Isolation ◽  
Shaking Table ◽  
Natural Period ◽  
Isolation System ◽  
Isolation Layer ◽  
Lead Rubber Bearing ◽  
Complex Structural

Mid-story isolation structure is developing from base isolation structures. As a complex structural system, the work mechanism of base isolation structure is not entirely appropriate for mid-story isolation structure, and the prolonging of structural natural period may not be able to decrease the seismic response of substructure and superstructure simultaneously. In this paper, for a four-story steel frame model, whose prototype first natural period is about 1s without seismic isolation design, the seismic responses and isolation effectiveness of mid-story isolation system with lead rubber bearing are studied experimentally by changing the location of isolation layer. Respectively, the locations of isolation layer are set at bottom of the first story, top of the first story, top of the second story and top of the third story. The results show that mid-story isolation can reduce seismic response in general, and substructure acceleration may be amplified.

scholarly journals Analysis of the natural oscillation frequency of the long-span trusses with flanged connections

2021 ◽  
pp. 76-85
Author(s):  
Татьяна Георгиевна Рытова ◽  
Людмила Анатольевна Максимова ◽  
Анастасия Георгиевна Николаева ◽  
Татьяна Михайловна Макарова ◽  
Надежда Георгиевна Пфаненштиль
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Frequency ◽  
Natural Vibration ◽  
Natural Oscillation ◽  
Natural Vibration Frequency ◽  
Building Structures ◽  
Long Span ◽  
Local Areas ◽  
Calculation Results ◽  
Natural Oscillation Frequency

Приводится анализ частоты собственных колебаний большепролетной фермы с фланцевыми соединениями. Выполнен расчет фланцевого соединения с различными случаями исключения болтов из работы соединения. Анализ результата расчета показал, что возникновение повреждений и дефектов конструкций здания в локальных зонах, величина которых несущественно снижает общую жесткость каркаса, практически не влияет на динамические характеристики каркаса. The analysis of the natural vibration frequency of a large-span truss with flanged connections is given. The calculation of the flange connection with various cases of exclusion of bolts from the connection operation is performed. Analysis of the calculation results showed that the occurrence of damage and defects in the building structures in local areas, the value of which significantly reduces the overall rigidity of the frame, practically does not affect the dynamic characteristics of the frame.

Modal Analysis of Wind Turbine Blades Based on ANSYS Modeling

2013 ◽  
Vol 790 ◽  
pp. 655-658
Author(s):  
Chi Chen ◽  
Min Wang ◽  
Long Zou
Keyword(s):  
Wind Turbine ◽  
Modal Analysis ◽  
Detailed Analysis ◽  
Dynamic Characteristics ◽  
Natural Vibration ◽  
Turbine Blades ◽  
Mode Shapes ◽  
Wind Turbine Blades ◽  
Horizontal Axis Wind Turbine ◽  
Basic Parameters

The modal analysis is an approximate method to study the dynamic characteristics of the structure, the modal is the natural vibration characteristics of the structure, each modal has a specific natural frequency, damping ratios and mode shapes. This thesis will take 1.2MW horizontal axis wind turbine blade for example, and use parametric language APDL of ANSYS for directly modeling, then set the basic parameters of the material, mesh and discuss modal analysis, lastly conduct a detailed analysis of the results.

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