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.

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.

Measurement of focused ultrasonic fields using a scanning laser vibrometer

2007 ◽  
Vol 121 (5) ◽  
pp. 2621-2627 ◽  
Author(s):  
Yuebing Wang ◽  
John Tyrer ◽  
Ping Zhihong ◽  
Wang Shiquan
Keyword(s):  
Scanning Laser ◽  
Laser Vibrometer ◽  
Ultrasonic Fields ◽  
Scanning Laser Vibrometer
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