Earthquake analysis of concrete gravity dams including reservoir bottom absorption and dam-water-foundation rock interaction

Possible base sliding induced by an earthquake on concrete gravity dams is obtained by a simplified procedure. The model is a nonlinear single-degree-of-freedom system which takes into account dam-water-foundation interaction based on the model developed by Fenves and Chopra (1987). The nonlinearity is in the foundation rock, since a threshold value for the sliding foundation resistance, modeled with the Mohr-Coulomb yielding criterion including a frictional and a cohesive component, is imposed. Nonlinear step by dams is obtained by a simplified procedure. The model is a nonlinear single-degree-of-freedom system which takes into account dam-water-foundation interaction based on the model developed by Fenves and Chopra (1987). The nonlinearity is in the foundation rock, since a threshold value for the sliding foundation resistance, modeled with the Mohr-Coulomb yielding criterion including a frictional and a cohesive component, is imposed. Nonlinear step by step dynamic analyses are carried out on four case studies representing typical examples of Italian concrete gravity dams by utilizing several natural earthquakes. On the basis of the obtained results, a simplified methodology to estimate residual displacement without performing nonlinear dynamic analysis is presented. An example of application using as seismic input the elastic response spectra furnished by the Italian Code is also presented.

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Investigating the Effect of Depth and Impedance of Foundation Rock in Seismic Analysis of Gravity Dams

International Journal of Geotechnical Earthquake Engineering ◽

10.4018/ijgee.2014070101 ◽

2014 ◽

Vol 5 (2) ◽

pp. 1-18

Author(s):

Sharad Joshi ◽

Ishwer Datt Gupta ◽

Lalitha R. Pattanur ◽

Pranesh B. Murnal

Keyword(s):

Half Space ◽

Seismic Analysis ◽

Free Field ◽

Time History ◽

Gravity Dams ◽

Ground Acceleration ◽

Rock Interaction ◽

Foundation Block ◽

Substructure Approach ◽

Foundation Rock

The inhomogenieties of the foundation can be modeled explicitly in standard FEM procedure, however, the results vary significantly with the extent of foundation block modeled and mechanism of applying the input earthquake excitation. The substructure approach provides mathematically exact solution but assumes average properties for the entire foundation as viscoelastic half space. This paper has carried out detailed investigations with varying impedance contrasts and different size of foundation block to show that the results, with suitably deconvoluted free-field ground acceleration time-history applied at the base of foundation block in the FEM approach, are in good agreement with the substructure approach. However, the other variants of the FEM approach may lead to erroneous and overestimated stresses in the dam body. As the foundation of gravity dams can generally be approximated as an equivalent homogeneous half-space, the more accurate and efficient substructure approach can be used to model the dam-foundation rock interaction (SSI) effects in most practical situations.

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Thermal Behavior of Roller-Compacted-Concrete Gravity Dams

International Review of Civil Engineering (IRECE) ◽

10.15866/irece.v7i3.9639 ◽

2016 ◽

Vol 7 (3) ◽

pp. 63

Author(s):

Ayoub Benchara ◽

Ali Taleb

Keyword(s):

Thermal Behavior ◽

Gravity Dams ◽

Roller Compacted Concrete ◽

Concrete Gravity Dams

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Application of Digital Simulation Software ANSYS in Rolling Concrete Dams Construction Technology

Materials Science Forum ◽

10.4028/www.scientific.net/msf.704-705.352 ◽

2011 ◽

Vol 704-705 ◽

pp. 352-357

Author(s):

Gui Xiang Zeng

Keyword(s):

Digital Simulation ◽

Simulation Software ◽

Construction Technology ◽

Dynamic Features ◽

Concrete Gravity Dam ◽

Gravity Dams ◽

Concrete Dam ◽

Concrete Gravity Dams ◽

Xinjiang Autonomous Region ◽

Important Significance

Taking a large hydropower station in Xinjiang Autonomous Region as an example, and based on the limited unit method, the structure and seism forces features and response rules of rolling concrete gravity dam under different construction conditions were studied. The purpose for the paper is to understand dam working status under the different design conditions, and to evaluate anti-earthquake safety capability. It is proved that the present findings should play an important significance in the development of rolling concrete dam construction technology. Key words: Rolling Concrete Gravity Dams, Limited Unit Methods, Static Force Analysis, Dynamic Features.

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