scholarly journals Shaking Table Tests for Seismic Response of Orthogonal Overlapped Tunnel under Horizontal Seismic Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Honggang Wu ◽  
Hao Lei ◽  
Tianwen Lai
Keyword(s):  
Dynamic Response ◽  
Seismic Response ◽  
Seismic Wave ◽  
Shaking Table Test ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Acceleration Response ◽  
Test Device ◽  
Deformation Stages ◽  
Superposition Effect

This paper presents the seismic dynamic response and spectrum characteristics of an orthogonal overlapped tunnel by shaking table tests. First, a prototype of the engineering and shaking table test device, which was used to design details of the experiment, was developed. Then, the sensors used in the test were selected, and the measurement points were arranged. Subsequently, the Wenchuan seismic wave with horizontal direction in different peak ground accelerations was inputted into the model, followed by a short analysis of the seismic response of the overlapped tunnel in the shaking table test as well as the distribution of the peak acceleration. Throughout the studies, the model exhibited obvious deformation stages during the seismic wave loading process, which can be divided into elastic, plastic, plastic enhancement, and failure stage. In particular, the time- and frequency-domain characteristics of the key parts of the tunnel were discussed in detail by using the continuous wavelet transform (CWT) based on the Morlet wavelet as the basis function. We found that the acceleration response was more intense within 25–60 s after the seismic wave was inputted. Furthermore, owing to “the superposition effect,” the seismic response at the crown of the under-crossing tunnel was stronger than that at the invert of the upper-span tunnel. The low and medium frequencies in the transformation of small scales (5–20) significantly affected the overlapped tunnel. These results elucidate the seismic dynamic response of the overlapped tunnel and provide guidance for the design of stabilizing structures for reinforcing tunnels against earthquakes.

Seismic Response of Cable Net Facade

2010 ◽  
Vol 163-167 ◽  
pp. 165-168
Author(s):  
Ruo Qiang Feng ◽  
Ji Hong Ye ◽  
Yue Wu ◽  
Shi Zhao Shen
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Dynamic Response ◽  
Simulation Model ◽  
Seismic Response ◽  
Vibration Mode ◽  
Shaking Table Test ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Glass Panels

Shaking table tests and theoretical analysis were conducted to study of the seismic response of cable net facade. Firstly dynamic response of cable net façade under earthquake was investigated with shaking table test. Then a numerical simulation model of cable net façade was built for the dynamic analysis .And then with this model the seismic response was analyzed theoretically. The study indicates that: the seismic response of the cable net with glass panels and the cable net on most occasions are mainly decided by the symmetric modes, and the first vibration mode is dominant. The damping of cable net facade is mainly decided by glass panels.

Experimental Study on the Seismic Response of Subway Station in Soft Ground

2017 ◽  
Vol 11 (05) ◽  
pp. 1750020 ◽  
Author(s):  
Ma Xianfeng ◽  
Wang Guobo ◽  
Wu Jun ◽  
Ji Qianqian
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Shaking Table Test ◽  
Design Method ◽  
Underground Structure ◽  
Response Characteristic ◽  
Shaking Table ◽  
Subway Station ◽  
Soft Ground ◽  
Shaking Table Tests

Shaking table tests were conducted on typical models of subway structures subjected to several seismic shaking time histories to study seismic response of subway structures in soft ground as well as to provide data for validation of seismic design methods for underground structure. Three types of tests were presented herein, namely green field test, subway station test, and test for joint structure between subway station and tunnel. The similitude and modeling aspects of the 1g shaking table test are discussed. The seismic response of Shanghai clay in different depths was examined under different input waves to understand the acceleration amplification feature in both green field and in the presence of underground structure. Damage situation was checked on internal sections of both subway station and tunnels by halving the model structure. Structure deformation was investigated in terms of element strain under different earthquake loadings. The findings from this study provides useful pointers for future shaking table tests on underground structures/facilities, and the seismic response characteristic of underground structure derived from the shaking table test could be helpful for validating seismic design method for subway station.

Shaking Table Test of Underground Pipeline under Three Dimension Seismic Excitation – Numerical Simulation

2014 ◽  
Vol 919-921 ◽  
pp. 960-964 ◽  
Author(s):  
Xiao Fu ◽  
Jun Wei Bi ◽  
Zhi Jia Wang ◽  
Chang Wei Yang
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Seismic Response ◽  
Shaking Table Test ◽  
Time History ◽  
Shaking Table ◽  
Seismic Excitation ◽  
Underground Pipeline ◽  
Three Dimension ◽  
Seismic Structure

Based on the design of the large-scale shaking table test of an underground pipeline under three dimension seismic excitation, the dynamic response of the soil-structure is analyzed by using ANSYS. In the numerical simulation, Drucker-Prager constitutive model is adopted to simulate the soil, the interface between soil and pipeline are simulated with zero thickness contact elements, size effects of test box are diminished by defining viscoelastic boundary around soil, the acceleration time history curve of the original earthquake wave is compressed and processed according to using the model scale similarity and energy duration which is presented by Trifunac-Brady [1] , and then the characteristic of seismic response of the pipeline can be found. The results show that the top of pipeline is the seismic response intense regional, deformation displacements of the central areas at the bottom and top of pipeline are always larger than others, the entrance and exit are the weak positions of anti-seismic structure; moreover, the dynamic response and interactions of soil-pipeline in the model experiment can be more accurately simulated by the methods presented in the paper. Thus, it can be served as reference for the design and construction of subsurface structures.

scholarly journals Study on Synthesis Method of Multipoint Seismic Waves for Buried Oil and Gas Pipeline in Shaking Table Tests

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Jian-Bo Dai ◽  
Gui-Di Zhang ◽  
Cheng-Tao Hu ◽  
Kai-Kai Cheng
Keyword(s):  
Seismic Wave ◽  
Seismic Waves ◽  
Oil And Gas ◽  
Shaking Table Test ◽  
Synthesis Method ◽  
Linear Structure ◽  
Gas Pipeline ◽  
Shaking Table ◽  
Infinite Length ◽  
Shaking Table Tests

The buried oil and gas pipeline is a linear structure with infinite length. In the shaking table test of its seismic response, it is necessary to input the spatially related multipoint seismic wave considering the propagation characteristics of ground motion. The multipoint seismic excitation shaking table tests and loading scheme of buried oil and gas pipelines are designed and formulated. The synthesis method of spatial correlation multipoint seismic wave for the buried oil and gas pipeline test is proposed in this study. The values of relevant parameters are analyzed, and corresponding program is compiled by MATLAB. The results show that the developed multipoint excitation shaking table seismic wave input scheme is reasonable. At the same time, the synthesized multipoint seismic wave based on the actual seismic record and artificial random simulation seismic wave can meet the test requirements, which suggests the testing effect is good.

Shaking table test of acceleration response of surrounding rock of the 3D cross tunnel under earthquake

2021 ◽  
pp. 107754632110399
Author(s):  
Lifang Pai ◽  
Honggang Wu ◽  
Hao Lei
Keyword(s):  
Wave Propagation ◽  
Seismic Wave ◽  
Seismic Design ◽  
Shaking Table Test ◽  
Seismic Wave Propagation ◽  
Surrounding Rock ◽  
Shaking Table ◽  
Peak Ground Velocity ◽  
Acceleration Response ◽  
Ground Acceleration

Taking the 3D cross-engineering of Caomeigou No.1 Tunnel and Pandaoling Tunnel as an example, a shaking table test was carried out to study the effect of tunnel spatial position on seismic wave propagation characteristics and acceleration response of surrounding rock under earthquake seismic excitation. Based on the influence of the spatial position of the tunnel, the characteristic form of the surrounding rock between the cross section and non-cross section is divided, and the accelerometer layout scheme is designed. Based on statistical probability, the ratio of peak ground velocity to peak ground acceleration (PGA) was introduced to quantitatively characterize the characteristics of seismic wave propagation spectrum. Furthermore, the SPECTR calculation was used to obtain the regional difference in the seismic wave propagation potential damage potential displacement parameter ( P d). Under the influence of the spatial location of the 3D cross tunnel, the peak acceleration and motion duration of the seismic wave are mainly reflected in the variation of the section along the elevation direction. Low-frequency (≤20 Hz) seismic waves have a greater impact on the tunnel structure, and peak ground velocity/peak ground acceleration ratio has a positive correlation with the peak input energy of ground motion. The ultra-small net-spacing cross tunnel has a spatially distributed coupling deformation effect. The crown of the upper-span tunnel is highly sensitive to earthquakes and becomes a weak link in seismic design. These results help us provide a theoretical basis for the seismic design of the cross-tunnel.

Seismic Response of Pile Groups Improved with Deep Cement mixing Columns in Liquefiable Sand: Shaking Table Tests

2021 ◽  
Author(s):  
Dingwen Zhang ◽  
Anhui Wang ◽  
Xuanming Ding
Keyword(s):  
Seismic Behavior ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Pile Group ◽  
Shaking Table ◽  
Excess Pore Pressure ◽  
Shaking Table Tests ◽  
Pile Groups ◽  
Acceleration Response ◽  
Table Model

A series of shaking table model tests were performed to examine the effects of deep cement mixing (DCM) columns with different reinforcement depths on the seismic behavior of a pile group in liquefiable sand. Due to the DCM column reinforcement, the fundamental natural frequency of the model ground increases noticeably. The excess pore pressure of soils reduces with the increase of reinforcement depths of the DCM columns. Before liquefaction, the acceleration response of soils in the improved cases is obviously lower than that in the unimproved case, but the acceleration attenuation is greater after liquefaction in the unimproved case. Moreover, the lateral displacement of the superstructure, the settlement of the raft, and the bending moment of the piles in the improved cases are significantly reduced compared to those in the unimproved case, and the reduction ratios rise with the increase of reinforcement depth of the DCM columns. However, reinforcement by the DCM columns may result in the variation of the location of the maximum moment that occurs in the pile.

Computer Simulation of the Shaking Table Tests on Harder Soil-Structure Interaction System

2011 ◽  
Vol 261-263 ◽  
pp. 1619-1624
Author(s):  
Pei Zhen Li ◽  
Jing Meng ◽  
Peng Zhao ◽  
Xi Lin Lu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Soil Structure ◽  
Shaking Table Test ◽  
Shaking Table ◽  
Soil Structure Interaction ◽  
Shaking Table Tests ◽  
Site Condition ◽  
Element Analysis ◽  
Structure Interaction

Shaking table test on soil-structure interaction system in harder site condition is presented briefly in this paper. Three-dimensional finite element analysis on shaking table test is carried out using ANSYS program. The surface-to-surface contact element is taken into consideration for the nonlinearity of the state of the interface of the soil-pile and an equivalent linear model is used for soil behavior. By comparing the results of the finite element analysis with the data from shaking table tests, the computational model is validated. Based on the calculation results, the paper gives the seismic responses under the consideration of soil-structure interaction in harder site condition, including acceleration response, contact analysis on soil pile interface and so on.

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.

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