Diagnosis of concrete dams by flat-jack tests and inverse analyses based on proper orthogonal decomposition

Garbowski, Tomasz; Maier, G.; Novati, G.

doi:10.2140/jomms.2011.6.181

Cited by 29 publications

(19 citation statements)

References 21 publications

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“…1 However, it was also pointed out that the magnitude of error function J changes noticeably when the Poisson's ratios change. This is in contrast to the results of Oliveira et al, 3 & Garbowski et al 4 In the following, the obtained results of this study have been outlined in Tables 1-3. For the sake of brevity, all the results are not presented here.…”

Section: Long-term Deterioration: Heterogeneously and Orthotropicallycontrasting

confidence: 91%

“…hydrostatic and gravity loads can provide a dominant state of stresses in the concrete, each of them makes the evolution of the long-term deterioration of the dam to take anisotropic features. After extensive examination of the literatures, the authors 3,4 concluded that probably the only two diagnostic studies conducted on concrete dams considered the degradation of concrete as an anisotropic process. Oliveira & his collaborators 3 performed a modal analysis on the Cabril arch dam located in Portugal using an inverse analysis method for dam material parameter identification.…”

Section: Part I: Transversely Isotropic Elastic Degraded Dammentioning

confidence: 99%

“…the elastic modulus and Poisson's ratio of the plane of isotropy are known values and only three remained unknown material parameters were identified in their research. On the other hand, Garbowski et al, 4 performed an inverse analysis on a roller compacted concrete dam using the so called DIC technique (Digital Image Correlation) for analyzing the obtained images from a portion of the surface of the dam which experienced some displacements under the pressure imposed on it with a flat-jack through a T-shaped slots. They have identified the elastic and shear modulus of the concrete in the presence of orthotropy.…”

Section: Part I: Transversely Isotropic Elastic Degraded Dammentioning

confidence: 99%

“…Apart from these two mentioned deficiencies, they have considered the dam as a homogeneous medium and taken the Poisson's ratio components of transversely isotropic elastic tensors as known parameters. 5 So, they have only identified three remained other parameters like the work of Oliveira et al 4 This issue motivated the authors of this article to investigate in more detail the long-term aggression of concrete of the Dez dam in the presence of anisotropy using the innovative thermal inverse analysis. 1 Considering Figure 1, the constitutive law for the long-term deterioration of Dez concrete can be stated as a relation (1):…”

Section: Part I: Transversely Isotropic Elastic Degraded Dammentioning

confidence: 99%

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Ageing Effects on the Dam-Reservoir-Foundation Interaction Response of the Dez Concrete Arch Dam

Labibzadeh¹,

Khayat²

2017

FMRIJ

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In the first part of this document, the degradation of the mechanical properties of the mass concrete of the Dez concrete arch dam under the long-term effects of its environment as well as its loading history has been investigated using an innovate inverse analysis method. For performing that inverse analysis, an objective function was defined and then it was attempted to minimize that. That function was defined as the sum of the squared differences between the displacements obtained from a developed enhanced FE model in the ABAQUS standard software by the authors in the current study for each assumed set of the degraded mechanical properties of the dam as input variables and those obtained from the inverse pendulum's records of the dam. For the sake of the generality of the problem, in performing such FE analyses, it was assumed that the behavior of the concrete material of the Dez dam has transformed gradually from initial homogeneous and isotropic undamaged behavior to the heterogeneous and orthotropic deteriorated behavior under the long-term effects of the environment as well as load agencies. Hence, the vertical sections of the dam were divided into nine and six subsections along the thickness and height directions of the dam respectively. In each subsection, a transversely isotropic degraded elastic constitutive law was considered for characterizing the concrete long-term deterioration phenomenon. Obtained results revealed that the long-term deterioration of the mass concrete of the Dez dam is in fact a heterogeneous and anisotropic process because that the magnitude of the above mentioned defined objective function was obtained smaller than the corresponding value in the previous study of the authors which was performed based on the homogeneous and isotropic damage evolution assumptions. Core test results from the mass concrete of the dam reported by a consulting engineer company confirmed the concrete degradation predicted by the proposed model. After that, the behavior of this dam against an earthquake excitation was investigated considering the above mentioned degradation of its mechanical properties and the obtained results were compared with its corresponding behavior considering its initial undamaged mechanical properties for the mass concrete. Comparisons revealed considerable growth in the enveloped tensile stresses which can change the initial assumed safety margin design factors of the dam and necessitates the re-evaluating of the dam stability.

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Section: Long-term Deterioration: Heterogeneously and Orthotropicallycontrasting

confidence: 91%

Section: Part I: Transversely Isotropic Elastic Degraded Dammentioning

confidence: 99%

Section: Part I: Transversely Isotropic Elastic Degraded Dammentioning

confidence: 99%

Section: Part I: Transversely Isotropic Elastic Degraded Dammentioning

confidence: 99%

See 2 more Smart Citations

Ageing Effects on the Dam-Reservoir-Foundation Interaction Response of the Dez Concrete Arch Dam

Labibzadeh¹,

Khayat²

2017

FMRIJ

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“…Some approaches are based on e.g. optimization of loads (Mróz and Garstecki, 2005), information on natural frequencies (Dems and Mróz, 2001), heat transfer (Ziopaja et al, 2011) or inverse analysis (Garbowski et al, 2011; Knitter-Piątkowska and Garbowski, 2013). Variety of methods are based on comparison of the response of damaged and undamaged structures.…”

Section: Introductionmentioning

confidence: 99%

Selected problems of damage detection in internally supported plates using one-dimensional Discrete Wavelet Transform

Guminiak

Knitter-Piątkowska

2018

jtam

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The paper is concerned with damage detection in plates while using the Discrete Wavelet Transform (DWT). Rectangular plate structures resting on a Winkler or elastic half-space type foundation, with free boundaries are examined. Plate bending is described and solved by the Boundary Element Method in a direct approach. Defects are introduced by additional edges forming slots in relation to the basic plate domain. Numerical investigation is conducted basing on signal analysis of the structural static response and by taking advantage of multi-resolution analysis (MRA) of the signal function which can be represented in a multi-scale manner. The obtained signal is decomposed with the use of Daubechies or Coiflet wavelet families. The white noise generator is used to model measurement inaccuracy which is an inevitable element of a real experiment. The efficiency of DWT of the contaminated signal in damage detection is studied.

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Saw‐cut method verification for determining the most important factors influencing its applicability

Kralovanec,

Moravcik,

Zahuranec

et al. 2024

Structural Concrete

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The current situation with prestressed structures raises questions about the ways how to determine residual prestressing which is the crucial factor for the evaluation of the prestressed structure. Therefore, this study aims to enhance existing knowledge of the so‐called Saw‐cut method which is considered a non‐destructive indirect technique. The presented study focuses on the determination of various factors which could influence the applicability and accuracy of this method such as both compressive and tensile normal stress release, the type of measuring instrument (linear foil strain gauge or newly developed FBG sensor), and the length of the normal stress release recording (up to almost 9 h). The obtained results suggest that tensile normal stress release could be more problematic for the evaluation than compressive normal stress release. Moreover, the application of FBG sensors seems to be more precise but also more complicated regarding the installation, recording and costs. Finally, the time span of the measurement can influence the residual normal stress release. For practical reasons, 60 min after the performance of the final sawing should be sufficient. Finally, when used at locations with adequate compressive normal stress, the Saw‐cut method seems to be a promising tool for prestressing evaluation.

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Diagnosis of concrete dams by flat-jack tests and inverse analyses based on proper orthogonal decomposition

Cited by 29 publications

References 21 publications

Ageing Effects on the Dam-Reservoir-Foundation Interaction Response of the Dez Concrete Arch Dam

Ageing Effects on the Dam-Reservoir-Foundation Interaction Response of the Dez Concrete Arch Dam

Selected problems of damage detection in internally supported plates using one-dimensional Discrete Wavelet Transform

Saw‐cut method verification for determining the most important factors influencing its applicability

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