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.

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.

Dynamic Responses of Arch Dams Considering Different Reservoir Models

2011 ◽  
Vol 250-253 ◽  
pp. 3923-3926
Author(s):  
Shao Qing Hu ◽  
Bai Tao Sun
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Water Level ◽  
Element Model ◽  
Arch Dam ◽  
Dynamic Responses ◽  
Additional Mass ◽  
Mass Model ◽  
Arch Dams ◽  
Reservoir Models

In this paper, the dynamic responses of an arch dam in the case of normal water level and operating low water level were simulated by using additional mass model and incompressible finite element model for reservoir respectively. The results showed that the reservoir models have a great impact on dynamic response of arch dams. The maximum principle tensile stress using incompressible finite element model of fluid is less than that using additional mass model. With the depth of the reservoir water increasing, the hydrodynamic pressure acting ton the dam surface caused by earthquake force increased and the dynamic responses of dam also increased.

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.

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.

Seismic Stability Sensitivity and Uncertainty Analysis of a High Arch Dam-Foundation System

2019 ◽  
Vol 19 (07) ◽  
pp. 1950066 ◽  
Author(s):  
Hui Liang ◽  
Shengshan Guo ◽  
Jin Tu ◽  
Deyu Li
Keyword(s):  
Parameter Uncertainty ◽  
Area Ratio ◽  
Arch Dam ◽  
Seismic Stability ◽  
High Arch Dam ◽  
Friction Coefficients ◽  
Dam Foundation ◽  
Arch Dams ◽  
Stability Performance ◽  
Contraction Joints

Parameter uncertainty associated with concrete arch dams always arises from modeling assumptions and the lack of knowledge or information of the engineering geological situations, especially in the seismic stability analysis of arch dams. In this research, a high arch dam is selected as a case study for probabilistic analysis of the seismic stability performance. The arch dam abutment and the dam are coupled as a system. A comprehensive approach considering contraction joints, boundaries of the probable sliding rock mass and the dam-foundation interface is presented. The contact nonlinearity is solved by using the dynamic contact model with Lagrange multiplier method. The main parameters of the probable sliding block are considered as random variables containing the friction coefficients and cohesions. Both the slippage and sliding area ratio are chosen as the engineering demand parameters (EDP). The sensitivity analysis is performed to reveal the relative influence of each parameter separately by the approximate incremental dynamic analysis (IDA) method. The friction coefficients are shown to be more crucial than the cohesions on the dam’s resistance to seismic instability. The sliding area ratio can be better used for unveiling the sliding process of the arch dam of concern, while the slippage is useful for one to judging the stability of the arch dam under seismic hazards. The Latin hypercube sampling (LHS) with approximate moment estimation is used to investigate the parameter uncertainty to the seismic stability performance of the high arch dam. The results provide a useful reference for using the median/mean-parameter model to accurately estimate the median/mean response of the dam.

scholarly journals Seismic Assessment of Arch Dams Using Fragility Curves

2015 ◽  
Vol 1 (2) ◽  
pp. 14-20 ◽  
Author(s):  
Vandad Kadkhodayan ◽  
S. Meisam Aghajanzadeh ◽  
Hasan Mirzabozorg
Keyword(s):  
Fragility Curves ◽  
Routine Data ◽  
Seismic Assessment ◽  
Arch Dam ◽  
The Other ◽  
Intensity Measure ◽  
Limit States ◽  
High Arch Dam ◽  
Arch Dams ◽  
Engineering Demand Parameter

In the present paper, the IDA approach is applied to analyzing a thin high arch dam. The parameters of Sa, PGA and PGV are used as intensity measure (IM) and the overstressed area (OSA) is utilized as engineering demand parameter (EDP) and then, three limit states are assigned to the considered structure using the IDA curves. Subsequently, fragility curves are calculated and it is showed that the PGA is a better parameter to be taken as IM. In addition, it is found that the utilizing the proposed methodology, quantifying the qualitative limit states is probable. At last, having the fragility curves and considering their slope in addition to the other routine data which can be extracted from these curves, one may be able to conclude that in what performance level the considered dam body seems to be weak and needs retrofitting works.

scholarly journals Nonlinear Response of High Arch Dams to Nonuniform Seismic Excitation Considering Joint Effects

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Masoomeh Akbari ◽  
Mohammad Amin Hariri-Ardebili ◽  
Hasan Mirzabozorg
Keyword(s):  
Structural Response ◽  
Incompressible Material ◽  
Arch Dam ◽  
High Arch Dam ◽  
Arch Dams ◽  
Base Level ◽  
Nonlinear Responses ◽  
Wave Passage ◽  
Spatially Varying Ground Motions ◽  
Spatially Varying

Nonuniform excitation due to spatially varying ground motions on nonlinear responses of concrete arch dams is investigated. A high arch dam was selected as numerical example, reservoir was modelled as incompressible material, foundation was assumed as mass-less medium, and all contraction and peripheral joints were modelled considering the ability of opening/closing. This study used Monte-Carlo simulation approach for generating spatially nonuniform ground motion. In this approach, random seismic characteristics due to incoherence and wave passage effects were investigated and finally their effects on structural response were compared with uniform excitation at design base level earthquake. Based on the results, nonuniform input leads to some differences than uniform input. Moreover using nonuniform excitation increase, stresses on dam body.

Research Progress of Protected Plunge Pool of High Arch Dam

2014 ◽  
Vol 919-921 ◽  
pp. 1244-1247 ◽  
Author(s):  
Ying Kui Wang ◽  
Ren Qiang Liao
Keyword(s):  
Energy Dissipation ◽  
Southwest China ◽  
Arch Dam ◽  
Research Progress ◽  
Project Design ◽  
High Arch Dam ◽  
Arch Dams ◽  
Plunge Pool ◽  
Large Investment ◽  
High Arch Dams

The security researches of energy dissipation were always the focus in the High arch dams. Statistically, the trajectory type energy dissipation is the most widely used in the built high arch dams, and the protected plunge poor were always set downstream the dam body. However, the widely used protected plunge poor need large investment with the disadvantage of complicated operation and maintenance. Along with the construction of concrete high arch dam in the Southwest China, the “Reventment-Protected and Non-Bottom-Protected Plunge Pool” has been studied and proposed, which has the advantage of more simplified project design and more economy investment.

Study on Dynamics Characteristics of Concrete Floating Slab Track in Urban Track

2006 ◽  
Vol 302-303 ◽  
pp. 700-705 ◽  
Author(s):  
Gao Liang ◽  
Ke Ming Yin ◽  
Ge Yan Zhang
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Dynamic Responses ◽  
Finite Element Analyses ◽  
Analysis Model ◽  
Slab Track ◽  
Stiffness And Damping

In this paper, in order to do research on the characteristics of reducing vibration and declining noise of concrete floating slab track, the vertical dynamic analysis model of vehiclefloating slab track is established with the use of finite element analyses method. By using this model, dynamic responses of floating slab track are studied under different conditions of train’s speed, stiffness and damping of infrastructure, structure size, etc. On the basis of this research, some suggestions for design of floating slab track are put forward.

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.

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