Earthquake engineering for large dams. Second edition

Priscu, R.; Popovici, A.; Stematiu, Dan; Stere, Constantin A.

doi:10.1016/0148-9062(86)90650-9

Cited by 5 publications

(2 citation statements)

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“…This is the essence of Pseudo-Dynamic Method, where static loadings replace the dynamic effects produced by seismic excitation. One should note that this type of analysis, as its name indicates, does not correspond to a true dynamic analysis, since the time varying nature of the response is neglected (Priscu, 1985).…”

Section: Pseudo-dynamic Methodsmentioning

confidence: 99%

“…In current Brazilian practice this term varies between 0.05-0.10g, where g represents the acceleration of gravity. According Priscu (1985), the main disadvantages of this procedure arise from: (i) neglecting structural elasticity, (ii) assuming uniform foundation acceleration over time, (iii) neglecting structural damping and (iv) structural dynamic response. Chopra and Chakrabarti (1971) investigated the accident at Koyna Dam (India, 1967, during an earthquake of magnitude 6.5), where the dam was designed with a seismic coefficient of 0.05g.…”

Section: Pseudo-static or Seismic Coefficient Proceduresmentioning

confidence: 99%

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Dynamic Response of Dam-Reservoir Systems: Review and a Semi-Analytical Proposal

Ribeiro

Pedroso

2017

Lat. Am. j. solids struct.

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This paper presents a review of current techniques employed for dynamic analysis of concrete gravity dams under seismic action. Traditional procedures applied in design bureaus, such as the Pseudo-Static method, often neglect structural dynamic properties, as well as ground amplification effects. A practical alternative arises with the Pseudo-Dynamic method, which considers a simplified spectrum response in the fundamental mode. The authors propose a self-contained development and detailed examples of this latter method, including a comparison with finite element models using transient response of fluid-structure systems. It is verified that application of the traditional procedure should be done carefully and limited to extremely rigid dams. On the other hand, the proposed development is straightforward and in agreement with finite element results for general cases where dam flexibility plays an important role. The last few years in Brazil have indicated a growing interest in national engineering for earthquake-resistant design. The first design code dedicated exclusively to this type of analysis was approved in 2006 (NBR15421, 2006. However, computation of earthquake effects in design of special structures, such as concrete dams, aqueducts and nuclear power plants, has being done for decades, although in a simplified form. Noteworthy is the Pseudo-Static Method (or Seismic Coefficient Method), where the structural mass is treated as an accelerated rigid body. In this case, the seismic coefficient matches exactly the structural acceleration, which is usually taken as a fraction of gravitational acceleration. Due to its simplistic nature, the Pseudo-Static procedure is still widely used in the seismic analysis of structures, although condemned by international codes (FERC, 2002). This type of analysis is usually defined as traditional procedure for seismic design. In general, the Pseudo-Static Method will produce the same results for any given structure with equal mass. That is, both structures will be subjected to the same seismic loading and no consideration will be made in relation to the dynamic properties of both (such as vibration period, for example). As a consequence, dynamic amplification effects are neglected and the response is valid only for infinitely rigid structures.The traditional procedure is increasingly destined to oblivion. The main reason is the absence of dynamic properties of the structure. In the specific case of concrete dams two major hypotheses govern the problem: (i) fluid is treated as incompressible and (ii) the dam moves with uniform acceleration along its height. The method basis comes from the classic work of Westergaard (1933), published almost 80 years ago. The last decades were marked by new calculation procedures and additional contributions to the legacy of Westergaard. These new procedures, such as the PseudoDynamic Method, require additional complexity in computation of earthquake forces. On the other hand, provide a more coherent representation of dynamic effects...

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Section: Pseudo-dynamic Methodsmentioning

confidence: 99%

Section: Pseudo-static or Seismic Coefficient Proceduresmentioning

confidence: 99%