THE STATIC BEHAVIORS AND NUMERICAL PREDICTION ON DISPLACEMENT OF AN EXISTING ARCH DAM

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Nishiuchi Tatsuo
Keyword(s):  
Numerical Analysis ◽  
Load Capacity ◽  
Numerical Prediction ◽  
Arch Dam ◽  
Mechanical Resistance ◽  
Analysis Model ◽  
Element Analysis ◽  
Seismic Safety ◽  
Arch Dams ◽  
Contraction Joints

In order to estimate the seismic safety of existing arch dams, it is essential to assess the static behavior and the mechanical resistance of arch dam. Numerical analysis model for transverse joints (contraction joints) of the arch dam is developed considering the separation, sliding and re-contact behaviors of contraction joints. The static behaviors of an arch dam under annual change of temperature and water level were calculated by using non-linear three-dimensional finite element analysis method that incorporated the developed numerical analysis model of contraction joints. The displacement of the dam body was compared both in analysis and in measured data. At a result, the calculated results can give a good estimation for dam deformation of an existing arch dam caused by those loads. In addition, the effective arch zone was formed under consecutive contraction joints. Thus, the nature of load capacity mechanism was identified. Using these calculated results, the numerical prediction on the displacement of an existing arch dam was proposed for daily management.

A Comparative Study of Cantilever- and Integral-Type Dead Loads on the Seismic Responses of High Arch Dams

2019 ◽  
Vol 19 (03) ◽  
pp. 1950021 ◽  
Author(s):  
Shengshan Guo ◽  
Hui Liang ◽  
Deyu Li ◽  
Houqun Chen ◽  
Jianxin Liao
Keyword(s):  
Finite Element ◽  
Arch Dam ◽  
Dynamic Responses ◽  
Analysis Model ◽  
Integral Type ◽  
Dead Load ◽  
High Arch Dam ◽  
Arch Dams ◽  
Fine Mesh ◽  
Contraction Joints

The actual dead load of an arch dam should be applied gradually through staged construction and sequenced grouting. However, the cantilever- and integral-type dead loads commonly used in the analysis of arch dams represent simplified versions of the actual loading. In this paper, these two types of dead loads, i.e. cantilever and integral types, are presented based on the Lagrange multiplier method considering the nonlinear behaviors of contraction joints. Based on the finite element method and an appropriate contact model together with artificial viscoelastic boundary conditions, a dynamic analysis model of a dam–foundation–reservoir system is established in consideration of the interactions between the arch dam and foundation, the opening and closing of contraction joints, and the radiation damping effect of the far-field boundary. Taking a 300 m high arch dam in the strong earthquake area of West China as an example, a fine mesh finite element model with a total of approximately 3.5 million degrees of freedom is established. The separate effects of the cantilever and integral dead loads on the static and dynamic responses of the dam are studied. The results demonstrate that the distribution and magnitude of the contraction joint opening width and maximum tensile stress are different under the two different dead load simplifications.

Study on Deformation-Based Seismic Performance Index of Arch Dams

2012 ◽  
Vol 226-228 ◽  
pp. 1401-1405
Author(s):  
Xiao Wen Yao ◽  
Jian Qun Jiang
Keyword(s):  
Seismic Performance ◽  
Performance Index ◽  
Regional Scale ◽  
Arch Dam ◽  
Seismic Excitations ◽  
Dam Foundation ◽  
Seismic Safety ◽  
Arch Dams ◽  
Contraction Joints ◽  
Concrete Damage

Concrete arch dams are critical structures, the failure of which would lead to catastrophic effects on a regional scale. Considering the uncertainty characteristics of earthquake and the self-adjustment of inner force of arch dams, it’s necessary to investigate the seismic performance index of arch dam for holistically evaluating the seismic safety of arch dam-foundation system subjected to high intensity seismic excitations. By considering the contraction joints movement and concrete material nonlinearity, a series of dynamic response-history analyses of arch dam were carried out under increasing levels of earthquakes. Based on these analyses, the performance index of crest deformation is recommended for the seismic safety assessment of arch dam. And several performance stages of seismic response including the opening of contraction joints and the distribution of concrete damage are also investigated.

scholarly journals The Effect of Shear Sliding of Vertical Contraction Joints on Seismic Response of High Arch Dams with Fine Finite Element Model

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Shengshan Guo ◽  
Jianxin Liao ◽  
Hailong Huang ◽  
Hui Liang ◽  
Deyu Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Response ◽  
Element Model ◽  
Arch Dam ◽  
Slip Condition ◽  
Dead Load ◽  
High Arch Dam ◽  
Arch Dams ◽  
Contraction Joints

The contraction joints of arch dams with and without shear keys are simplified to be with no-slip condition and with relative sliding condition, respectively. Based on the Lagrange multiplier method, a contact model considering the manner of independent cantilever dead load type with no-slip condition and relative sliding condition is proposed to model the nonlinearities of vertical contraction joins, which is special to the nonlinear analysis of arch dams considering the manner of dead load type. Different from the conventional Gauss iterative method, the strategy of the alternating iterative solution of normal force and tangential force is employed. The parallelization based on overlapping domain decomposition method (ODDM) and explicit message passing using distributed memory parallel computers is employed to improve the computational efficiency. An existing high arch dam with fine finite element model is analyzed to investigate the effect of shear sliding of vertical joints on seismic response of the arch dam. The result shows that the values of maximum principal tensile stress under relative sliding condition are significantly greater than those under no-slip condition.

Thermal Stress Analysis of Concrete Arch Dams Due to Environmental Action

2004 ◽  
Author(s):  
Farrokh Sheibany ◽  
Mohsen Ghaemian
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Solar Radiation ◽  
Dimensional Analysis ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Arch Dam ◽  
Downstream Face ◽  
Element Analysis ◽  
Arch Dams

A three-dimensional finite element analysis was carried out to determine the annual variation of temperature and thermal stresses of a concrete arch dam. Appropriate heat transfer boundary conditions in the dam body were used for air and reservoir temperature as well as solar radiation variations. Karaj arch dam in Iran was used as a case study. The rate of convergence of the numerical solution is examined. Results of the finite element analysis show that probable cracks occur in a very narrow region of the downstream face. Thermal loads have the most significant effects for causing downstream cracks in comparison with self-weigh and hydrostatic loads. The cracked areas of downstream face conform to the regions that have the highest temperature in downstream face. It can be associated to the solar radiation, which shows two-dimensional analysis of an arch dam cannot yields accurate results and three-dimensional analysis is necessary.

Seismic Safety Evaluation of High Arch Dams Using Concrete Damage Theory

2010 ◽  
Vol 29-32 ◽  
pp. 1476-1480
Author(s):  
Zhi Guo Niu ◽  
Jun Lu ◽  
Ri You
Keyword(s):  
Safety Evaluation ◽  
Nonlinear Behavior ◽  
Maximum Principal Stress ◽  
Arch Dam ◽  
Seismic Safety ◽  
Arch Dams ◽  
Earthquake Load ◽  
Concrete Damage ◽  
Damage Theory ◽  
High Arch Dams

To reasonably evaluate the seismic behavior of high arch dams, a damage plasticity model is adopted to simulate the dynamic nonlinear behavior of dam concrete for a hydropower station. Combining with the viscous-spring boundary and compressibility reservoir model, the maximum principal stress on upstream and downstream surfaces is obtained. The results show that the effects of material nonlinearity damage on the dynamic response of the arch dam are significant under earthquake load.

Numerical Analysis of the Dynamic Interaction Between Pantograph and Overhead Contact Line Using FEM

2011 ◽  
Author(s):  
Sung Pil Jung ◽  
Tae Won Park ◽  
Jin Hee Lee
Keyword(s):  
Numerical Analysis ◽  
Contact Line ◽  
Dynamic Interaction ◽  
Fe Analysis ◽  
Contact Forces ◽  
Analysis Program ◽  
Analysis Model ◽  
Element Analysis ◽  
Simulation Results ◽  
Analysis Models

This study aims to create a numerical analysis model which can investigate the interaction between pantograph and overhead contact line used for railway vehicles, and validate the simulation results according to EN 50318 standards. Finite element analysis models of pantograph and overhead contact line are created using SAMCEF, a commercial FE analysis program, and mean, standard deviation, maximum and minimum values of contact forces are obtained. The simulation results are validated according to EN 50318, and the reliability of SAMCEF as an analysis solver of railway vehicle’s catenary system is discussed.

The Finite Element Analysis of Pile-Raft Foundation after Optimization of the Raft Thickness

2013 ◽  
Vol 712-715 ◽  
pp. 1037-1040
Author(s):  
Wei Yu Wang ◽  
Tuo Zhao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Analysis ◽  
Analysis Model ◽  
Element Analysis ◽  
Raft Foundation ◽  
The Finite Element Analysis ◽  
Pile Length

The numerical analysis model about pile-raft foundation was bulited by using finite element analysis software.The raft settlement, pile-top counterforce and soil counter force were analyzed by changing the thickness of raft .The thickness were 0.15m,0.20m,0.25m and 0.30m. It was said that it could effectively reduce the raft uneven settlement and realize the redistribution of the pile and soil counterforce by increasing raft thickness.After changing the pile length and the raft thickness The rule of raft settlement were analyzed. After the pile length and thickness of optimization,it was good to control settlement of the pile raft foundation.

scholarly journals Numerical Analysis of Ratcheting Under Bending- Membrane Loading Conditions

2020 ◽  
Vol 01 (01) ◽  
pp. 11-15
Author(s):  
Sajib Kumar Nath ◽  
Md Makfidunnabi ◽  
Md Abdullah Al Bari
Keyword(s):  
Numerical Analysis ◽  
Loading Conditions ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
Primary Stress ◽  
Fea Model ◽  
Nonlinear Elastic ◽  
Secondary Membrane ◽  
Incremental Collapse

Ratcheting is a vital failure mode when dynamic loading is present in the scenario and it can lead to fatigue or incremental collapse if not restricted. The purpose of this study is to propose a ratchet diagram for primary bending and secondary membrane loading conditions. For this, a finite element analysis model of a rectangular beam is prepared and solved by the numerical analysis software ‘ABAQUS’. The FEA model is validated by carried out a dynamic nonlinear elastic-plastic analysis with the analytical solution of Yamashita et al. for similar loading conditions. The ratchet occurrence conditions plotted in a non-dimensional stress parameter plot similar to the Bree diagram. The findings suggest that secondary stress rises for the occurrence of ratchet conditions as primary stress decreases. It also found a strong frequency dependency feature. The nature of the input frequency of cyclic loading in the proposed ratchet diagram has been discussed in terms of dynamic displacement over static displacement in the change of non-dimensional frequency of the loading.

scholarly journals Performance validation and dynamic response analysis of a deepwater cable bending restrictor

2020 ◽  
Vol 37 (3) ◽  
pp. 95-101
Author(s):  
Kang Yongtian ◽  
Xiao Wensheng ◽  
Zhang Dagang ◽  
Zhang Liang ◽  
Zhou Chouyao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Analysis ◽  
Dynamic Response ◽  
Bending Stiffness ◽  
Offshore Wind ◽  
Response Analysis ◽  
Analysis Model ◽  
Element Analysis ◽  
Cable Structure ◽  
Pipe Model

The deepwater cable bending restrictor is an important protective device for risers, umbilicals and cables in offshore engineering, protecting cable structure by controlling minimum bending radius. Its mechanical properties are analysed based on the numerical analysis model and finite element analysis (FEM) of ø175. The sensitivity analysis of using quantity of bending restrictors is also performed to show the effect of the quantity on bending stiffness. A testing scheme of bending stiffness of the bending restrictor is then formulated based on its structure. From numerical analysis results through test simulation, the tolerance is less than 3 %, which verifies the reliability of the numerical analysis model. Performance of the bending restrictor and dynamic response are analysed according to environmental parameters that occur once per 100 years from offshore wind power farms and pipein-pipe models, respectively. The results show the bending restrictor can effectively protect cable structure, and the pipein-pipe model is suitable for calculating mechanical properties of interaction between the bending restrictor and cable.

scholarly journals Effects of Contraction Joints on Vibrational Characteristics of Arch Dams: Experimental Study

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
S. S. Wang ◽  
Y. F. Zhang ◽  
M. S. Cao ◽  
W. Xu
Keyword(s):  
Arch Dam ◽  
Dynamic Responses ◽  
Scale Model ◽  
Scanning Laser ◽  
Laser Vibrometer ◽  
Full Field ◽  
Arch Dams ◽  
Contraction Joints ◽  
Vibrational Characteristics ◽  
Scanning Laser Vibrometer

This study experimentally investigates the effects of contraction joints on the vibrational characteristics of high arch dams. Three scale models of the world’s second highest dam, the Xiaowan Arch Dam, are used as experimental specimens identified by zero, one, and two contraction joints. When a scale model vibrates harmonically at a specific frequency, its operating deflection shape is acquired by using a scanning laser vibrometer to scan the side surface of the model. The effects of contraction joints on the vibrational characteristics of arch dams are studied by examining the changes in operating deflection shapes. Experimental results demonstrate that (i) contraction joints can significantly affect the vibrational characteristics of arch dams, (ii) the operating deflection shape intuitively illustrates the vibrational characteristics of arch dams, and (iii) a scanning laser vibrometer has marked advantages over traditional equipment in accurately and efficiently acquiring full-field dynamic responses of a structure.

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