scholarly journals Three-Dimensional Nonlinear Seismic Response of Immersed Tunnel in Horizontally Layered Site under Obliquely Incident SV Waves

2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Xiaojie Zhou ◽  
Qinghua Liang ◽  
Yueyu Zhang ◽  
Zhongxian Liu ◽  
Ying He
Keyword(s):  
Seismic Response ◽  
Seismic Waves ◽  
Dynamic Stiffness ◽  
Soil Layer ◽  
Three Dimensional ◽  
Equivalent Linearization ◽  
Nonlinear Seismic Response ◽  
Obliquely Incident ◽  
Immersed Tunnel ◽  
Shear Keys

A three-dimensional (3D) detailed numerical model of an immersed tunnel in a horizontally layered site is established in this study. The 3D seismic response of the immersed tunnel in a horizontally layered site subjected to obliquely incident waves is analyzed based on the precise dynamic stiffness matrix of the soil layer and half-space via combined viscous-spring boundary and equivalent node stress methods. The nonlinear effects of external and internal site conditions on the whole model were determined by equivalent linearization algorithm and Mohr–Coulomb model, respectively. The proposed model was then applied to investigate the nonlinear seismic response of an immersed tunnel in the Haihe River subjected to seismic waves of oblique incidence. The dislocation (opening) of pipe joints in the immersed tunnel were analyzed to determine the response characteristics of the shear keys and overall displacement of the tunnel; the dynamic responses of the immersed tunnel subjected to obliquely incident seismic waves markedly differ from those of vertically incident seismic SV waves. The maximum stress value of shear keys and the maximum dislocation of the pipe joint appear as upon critical angle. The overall displacement of the tunnel increases as incident angle increases. Under severe earthquake conditions, both the pipe corners and midspan section of the roof and floor are likely to produce crack. These areas need careful consideration in the seismic design of immersed tunnel structures.

Nonlinear Seismic Response of Rock Tunnels Crossing Inactive Fault under Obliquely Incident Seismic P Waves

2021 ◽  
Vol 32 (5) ◽  
pp. 1174-1189
Author(s):  
Hongyun Jiao ◽  
Xiuli Du ◽  
Mi Zhao ◽  
Jingqi Huang ◽  
Xu Zhao ◽  
...  
Keyword(s):  
Seismic Response ◽  
P Waves ◽  
Nonlinear Seismic Response ◽  
Obliquely Incident ◽  
Rock Tunnels

scholarly journals Viscoelastic Boundary Conditions for Multiple Excitation Sources in the Time Domain

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Chen Xia ◽  
Chengzhi Qi ◽  
Xiaozhao Li
Keyword(s):  
Finite Element ◽  
Seismic Response ◽  
Time Domain ◽  
Seismic Waves ◽  
Three Dimensional ◽  
Seismic Loads ◽  
Element Analysis ◽  
Artificial Boundaries ◽  
The Time Domain ◽  
Transmitting Boundaries

Transmitting boundaries are important for modeling the wave propagation in the finite element analysis of dynamic foundation problems. In this study, viscoelastic boundaries for multiple seismic waves or excitations sources were derived for two-dimensional and three-dimensional conditions in the time domain, which were proved to be solid by finite element models. Then, the method for equivalent forces’ input of seismic waves was also described when the proposed artificial boundaries were applied. Comparisons between numerical calculations and analytical results validate this seismic excitation input method. The seismic response of subway station under different seismic loads input methods indicates that asymmetric input seismic loads would cause different deformations from the symmetric input seismic loads, and whether it would increase or decrease the seismic response depends on the parameters of the specific structure and surrounding soil.

Study on the Selecting Principle of Test Soil Samples in Nonlinear Seismic Response Analysis of Stratified Site

2012 ◽  
Vol 170-173 ◽  
pp. 984-993
Author(s):  
Xue Liang Chen ◽  
Meng Tan Gao ◽  
Tie Fei Li ◽  
Zhao Lun Yan
Keyword(s):  
Soil Sample ◽  
Seismic Response ◽  
Soil Layer ◽  
Soil Samples ◽  
Response Analysis ◽  
Soil Test ◽  
Calculation Error ◽  
Iron And Steel ◽  
Nonlinear Seismic Response ◽  
Test Soil

Soil dynamic nonlinear experimental results have significant impacts on the seismic response of engineering site, but how reasonable and effective to select soil samples for soil test, there is no good solution. Using detailed drilling velocity, density data, and rich soil test data of Shanxi Linfen Iron and Steel Hospital engineering site, four models are established and are analyzed for this problem. The results showed that: less than 3 meters of soil layer, each layer select one soil sample, for the thick soil layer, the rules of selecting one soil sample about every 3m thickness for the soil test, are recommended. If selecting one soil sample about every 5m~6m thickness for the thick soil layer, the calculation error is about ±10%.

Three-dimensional finite element nonlinear dynamic analysis of pile groups for lateral transient and seismic excitations

2004 ◽  
Vol 41 (1) ◽  
pp. 118-133 ◽  
Author(s):  
Bal Krishna Maheshwari ◽  
Kevin Z Truman ◽  
M Hesham El Naggar ◽  
Phillip L Gould
Keyword(s):  
Finite Element ◽  
Seismic Response ◽  
Radiation Effects ◽  
Seismic Analysis ◽  
Dynamic Stiffness ◽  
Three Dimensional ◽  
Nonlinear Dynamic Analysis ◽  
Element Formulation ◽  
Pile Groups ◽  
Pile Cap

The effects of material nonlinearity of soil and separation at the soil–pile interface on the dynamic behaviour of a single pile and pile groups are investigated. An advanced plasticity-based soil model, hierarchical single surface (HiSS), is incorporated in the finite element formulation. To simulate radiation effects, proper boundary conditions are used. The model and algorithm are verified with analytical results that are available for elastic and elastoplastic soil models. Analyses are performed for seismic excitation and for the load applied on the pile cap. For seismic analysis, both harmonic and transient excitations are considered. For loading on the pile cap, dynamic stiffness of the soil–pile system is derived and the effect of nonlinearity is investigated. The effects of spacing between piles are investigated, and it was found that the effect of soil nonlinearity on the seismic response is very much dependent on the frequency of excitation. For the loading on a pile cap, the nonlinearity increases the response for most of the frequencies of excitation while decreasing the dynamic stiffness of the soil–pile system.Key words: pile groups, plasticity, separation, dynamic stiffness, seismic response.

scholarly journals Nonlinear Seismic Response Analysis of Curved and Skewed Bridge System with Spherical Bearings

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Junwon Seo ◽  
Daniel G. Linzell ◽  
Jong Wan Hu
Keyword(s):  
Seismic Response ◽  
Three Dimensional ◽  
The United States ◽  
Performance Criteria ◽  
Radius Of Curvature ◽  
Response Analysis ◽  
Nonlinear Seismic Response ◽  
Equivalent Frame ◽  
Skewed Bridge ◽  
Bridge System

A three-dimensional (3D) modeling approach to investigate nonlinear seismic response of a curved and skewed bridge system is proposed. The approach is applied to a three-span curved and skewed steel girder bridge in the United States. The superstructure is modeled using 3D frame elements for the girders, truss elements for the cross-frames, and equivalent frame elements to represent the deck. Spherical bearings are modeled with zero-length elements coupled with hysteretic material models. Nonlinear seismic responses of the bearings subjected to actual ground motions are examined in various directions. Findings indicate that the bearings experience moderate damage for most loading scenarios based on FEMA seismic performance criteria. Further, the bearing responses are different for the loading scenarios because of seismic effects caused by interactions between excitation direction and radius of curvature.

Nonlinear Seismic Responses of Container Cranes Including the Contact Problem Between Wheels and Rails

2004 ◽  
Vol 126 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Nobuyuki Kobayashi ◽  
Hiroshi Kuribara ◽  
Tomokazu Honda ◽  
Masahiro Watanabe
Keyword(s):  
Contact Problem ◽  
Seismic Response ◽  
Large Scale ◽  
Three Dimensional ◽  
Modeling Method ◽  
Contact Forces ◽  
Scale Model ◽  
Container Cranes ◽  
Nonlinear Seismic Response ◽  
Container Crane

This paper presents a modeling method based on multibody dynamics formulation for simulating the three-dimensional nonlinear seismic response of a large, movable container crane, including the contact problem regarding the wheels attached to the bottom of its legs and the rails on which they ride. As a container crane is large and flexible structure, its wheels should be lifted up and derailed due to the seismic excitation. The contact configuration and the contact forces between the wheels and the rail or the ground that significantly affect the seismic response of the structure are classified and calculated in reference to geometric relationships between contact-judging markers on the wheels and the rails. It is found that the numerical simulations with the presented modeling method quite accurately simulates the nonlinear seismic response of a container crane including the uplifting and derailment behavior of the wheels that is found in large-scale model shaking tests.

scholarly journals Study on the Seismic Effect of the Interbedded Soil Layer in the Yinchuan Alluvial Plain

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Shun Yang ◽  
Xin Han ◽  
Qiyun Lei ◽  
Sihan Yu ◽  
Chao Liu
Keyword(s):  
Seismic Response ◽  
Soil Layer ◽  
Peak Ground Velocity ◽  
Equivalent Linearization ◽  
Silty Clay ◽  
Spectral Acceleration ◽  
Ground Acceleration ◽  
Soil Layers ◽  
Amplification Effect ◽  
Soil Model

This paper presents a numerical analysis of two types of representative site profiles in the Yinchuan Plain under earthquake loading. The analyzed soil profiles, based on borehole investigations performed over the years, are used to explore the seismic response of the sites in this area. In total, eleven stratified soil models are used in this study, which can be grouped into two categories: a single interbedded soil model and multiple interbedded soil model. A one-dimensional equivalent linearization method is applied to evaluate the seismic response of different soil models under four exceeding probabilities in terms of peak ground acceleration (PGA), peak ground velocity (PGV), peak ground displacement (PGD), and spectral acceleration (Sa). The results show that the significant amplification effect of PGA occurs in rare and extremely rare earthquakes, with an amplification ratio of 1.4∼1.7 when the single silty clay layer is located at the model ground. In this scenario, the spectral acceleration is amplified at a period of approximately 1.0 s. For the multilayered soil cases, the amplification effect tends to decrease, whereas the characteristic periods increase with increasing numbers of soil layers and the ground acceleration is deamplified under a high motion intensity when the number of soil layers is ≥ 5. This study, to a certain degree, has reference value for seismic microzonation in this area.

Dynamic Time History Analysis on Groundwater Hydraulic Tunnel under Three Dimensional Viscoelastic Boundary Conditions

2013 ◽  
Vol 302 ◽  
pp. 622-627
Author(s):  
Ji Yao ◽  
Liang Cao ◽  
Hui Min Wang ◽  
Li Jie Zhang ◽  
Liang Wu ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Seismic Response ◽  
Seismic Waves ◽  
Three Dimensional ◽  
Time History ◽  
Element Model ◽  
Rigid Boundary ◽  
Dimensional Finite Element ◽  
Dynamic Time ◽  
Three Dimensional Finite Element

The three dimensional finite element model of a groundwater hydraulic tunnel was eatablished in this paper by FEM software ANSYS, two seismic waves of bedrock wave and EI-centro wave in similar sites were entered, and dynamic time history method was applied to compare the seismic response of the two hydraulic tunnels which were under rigid boundary conditions and viscoelastic boundary conditions respectively. The results showed that, the dynamic response of the model under rigid boundary conditions was larger than the response under viscoelastic boundary, and the viscoelastic boundary was closer to the actual situation. Under viscoelastic boundary conditions, the smaller depth of the hydraulic tunnel, the more intensive of the seismic response.

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