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1
Content available remote Probabilistic finite element analysis of failures in concrete dams with large asperities in the rock-concrete interface
Ulfberg Adrian, Gonzalez-Libreros Jaime, Das Oisik, Bista Dipen, Westberg Wilde Marie, Johansson Fredrik, Sas Gabriel
Archives of Civil and Mechanical Engineering
|
2023
|
Vol. 23, no. 2
art. no. e109, 2023
EN
Common analytical assessment methods for concrete dams are unlikely to predict material fracture in the dam body because of the assumption of rigid body behavior and uniform- or linear stress distribution along a predetermined failure surface. Hence, probabilistic non-linear finite element analysis, calibrated from scale model tests, was implemented in this study to investigate the impact of concrete material parameters (modulus of elasticity, tensile strength, compressive strength, fracture energy) on the ultimate capacity of scaled model dams. The investigated dam section has two types of large asperities, located near the downstream and/or upstream end of the rock-concrete interface. These large-scale asperities significantly increased the interface roughness. Post-processing of the numerical simulations showed interlocking between the buttress and the downstream asperity leading to fracture of the buttress with the capacity being determined mainly by the tensile strength of the buttress material. The capacity of a model with an asperity near the upstream side, with lower inclination, was less dependent on the material parameters of the buttress as failure occurred by sliding along the interface, even with inferior material parameters. Results of this study show that material parameters of the concrete in a dam body can govern the load capacity of the dam granted that significant geometrical variations in the rock-concrete interface exists. The material parameters of the dam body and their impact on the capacity with respect to the failure mechanism that developed for some of the studied models are not commonly considered to be decisive for the load capacity. Also, no analytical assessment method for this type of failure exists. This implies that common assessment methods may misjudge the capacity and important parameters for certain failure types that may develop in dams.
2
Content available Deterministic seismic damage analysis for concrete gravity dams: a case study of oued fodda dam
Ouzandja Djamel, Berrabah Amina Tahar
Acta Mechanica et Automatica
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2023
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Vol. 17, no. 3
347--356
EN
One of the major dangers for seismic damage of concrete dams is the propagation of cracks in dam concrete. The present study undertakes a numerical investigation of the seismic damage for Oued Fodda concrete gravity dam, located in the northwest of Algeria, considering the impacts of properties of joints along the dam-foundation rock interface and cross-stream earthquake excitation. Three-dimensional transient analyses for coupled dam-foundation rock system are carried out using Ansys software. The hydrodynamic effect of reservoir fluid is modelled using the added mass approach. The smeared crack approach is utilised to present the seismic damage of dam concrete using the Willam and Warnke failure criterion. The dam-foundation rock interface joints are presented with two ways, adhesive joints and frictional joints. The Drucker–Prager model is considered for dam concrete in nonlinear analyses. Consideration of the study results indicates that the frictional joints model can reduce the seismic response and damage hazard of the dam body to a better extent compared with the adhesive joints model. Furthermore, the application of cross-stream earthquake excitation reveals the significant effect on cracking response of the dam in the two models of joints.
3
Content available Reliability assessment and sensitivity analysis of concrete gravity dams by considering uncertainty in reservoir water levels and dam body materials
Pouraminian Majid, Pourbakhshian Somayyeh, Noroozinejad Farsangi Ehsan
Civil and Environmental Engineering Reports
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2020
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Vol. 30, no. 1
1--17
EN
An elaborate safety assessment of the Pine Flat (PF) concrete gravity dam (CGD) has been conducted in this paper. Structural analysis was performed by taking into account the uncertainties in the physical and mechanical properties of the dam body materials and the reservoir water level. The coefficient of variation of 5 and 10 percent and the Gaussian distribution (GAUS) are assigned to random variables (RVs). Sensitivity analysis (SA) of the RVs is done, and important parameters introduced. SA is done to identify the most influential RVs on the structural response. Also, the modulus of elasticity of concrete is the most effective parameter in response to horizontal deformation of the dam crest. The concrete density and US hydrostatic pressure height are the most effective parameters, and the Poisson's ratio is the insignificant parameter on the dam response. To be confident in the safety of the dam body under usual loading, including the dam weight and the upstream (US) hydrostatic pressure, the reliability index (RI) has been obtained by Monte Carlo simulation. The RI for the coefficients of variation of 5 and 10 percent were obtained at 4.38 and 2.47, respectively. If the dispersion of RVs is high, then the dam will be at risk of failure.
4
Content available Telematics in the technical condition monitoring of concrete dams structures using wireless sensor networks
Keosysano S., Szpytko J.
Archives of Transport System Telematics
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2019
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Vol. 12, iss. 1
22--28
EN
The safety of concrete dams, such as gravity dams, buttress dams, and arch dams, is directly related to not only its social and economic benefits, but also the personal and property safety of residents around the reservoir area. Therefore, it is of great importance to monitor the health of concrete dams using the obtained real-time information. In this paper, reviewed using an automatic wireless sensor monitoring system for temperature and humidity monitoring within concrete structures and A Real-Time Temperature Data Transmission Approach for Intelligent Cooling Control of Mass Concrete by using temperature sensors in arch dam. Structural Health Monitoring (SHM) aims to develop automated systems for the continuous monitoring, inspection, and damage detection of structures with minimum labour involvement.
5
Content available Analysis of Changes in the Trends Recorded in Piezometers of the Solina Dam in the Study Period 2010-2015
Lach S. K.
Journal of Ecological Engineering
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2018
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Vol. 19, nr 1
150--155
EN
This paper aims to analyze the changes in the trends of water levels in closed piezometers installed in the largest dam in Poland, i.e. Solina Dam located in the Podkarpackie province. The scope of the research includes the analysis of water levels in piezometers in the study period between 2010 and 2015. Statistical tests for identifying and rejecting outliers were performed before carrying out the analysis of the data acquired from the Automatic Technical Dam Monitoring System including: two variants of the Q-Dixon’s test (denoted as N9 and N13), as well as Grubbs’ test and Hampel’s test. A hypothesis was formulated that a change in the trend occurred after the flood in 2010. Using the least squares method , for each piezometer, two trend lines were matched to their water levels – the first one for the year 2010 and the second one for the period of 2011-2015. In this way, two slope coefficients of the linear function were obtained, together with the estimation of their errors. These slopes were compared using a statistical parallelism test.
6
Content available remote Simplified reliability analysis of multi hazard risk in gravity dams via machine learning techniques
Hariri-Ardebili M. A., Pourkamali-Anaraki F.
Archives of Civil and Mechanical Engineering
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2018
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Vol. 18, no. 2
592--610
EN
Deterministic analysis does not provide a comprehensive model for concrete dam response under multi-hazard risk. Thus, the use of probabilistic approach is usually recommended which is problematic due to high computational demand. This paper presents a simplified reliability analysis framework for gravity dams subjected to flooding, earthquakes, and aging. A group of time-variant degradation models are proposed for different random variables. Response of the dam is presented by explicit limit state functions. The probability of failure is directly computed by either classical Monte Carlo simulation or the refined importance sampling technique. Next, three machine learning techniques (i.e., K-nearest neighbor, support vector machine, and naive Bayes classifier) are adopted for binary classification of the structural results. These methods are then demonstrated in terms of accuracy, applicability and computational time for prediction of the failure probability. Results are then generalized for different dam classes (based on the height-to-width ratio), various water levels, earthquake intensity, degradation rate, and cross-correlation between the random variables. Finally, a sigmoid-type function is proposed for analytical calculation of the failure probability for different classes of gravity dams. This function is then specialized for the hydrological hazard and the failure surface is presented as a direct function of the dam's height and width.
7
Content available remote Comparison of temperature and displacements of a gravity section and a buttress section illustrated with the example of concrete dam in Rożnów
Kasprzak A., Popielski P.
Technical Transactions
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2017
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Vol. 2(114)
91--103
EN
This paper presents the results and the process of numerical analysis of a selected section of the concrete dam in Rożnów. The calculations were carried out for two different variants: the gravity section and the buttress section. The effects of the geometry on the temperature distribution inside the section, and the effect of the temperature on displacements, were examined.
PL
W artykule przedstawiono wyniki i proces analizy numerycznej dla wybranej sekcji zapory betonowej w Rożnowie. Obliczenia przeprowadzono dla dwóch różnych wariantów, dla sekcji ciężkiej i półciężkiej, sprawdzając wpływ geometrii na warunki temperaturowe, rozkład temperatury wewnątrz sekcji oraz ich wpływ na przemieszczenia.
8
Content available Terrestrial Laser Scanning in Monitoring Hydrotechnical Objects
Zaczek-Peplinska J., Kowalska M. E.
Journal of Ecological Engineering
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2016
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Vol. 17, nr 4
120--128
EN
Developing Terrestrial Laser Scanning technology is provided by modern measuring instruments, i.e. total stations and laser scanners. Owing to these instruments, periodic control measurements of concrete dams carried out as a part of geodetic surveying provide point models characterised by quasi-continuity. Basing on the results of these surveys, it is possible to conduct a number of geometric analyses, as well as to obtain information for detailed analytic and calculative deliberations. A scanner, similarly to a total station, determines spatial coordinates (X, Y, Z) of the surveyed points by identifying distances and angles. Registration of intensity of the reflected laser beam (Intensity) sent out by the scanner provides additional information on the surveyed object. Thanks to high working speed and a large amount of collected data, scanners have become an essential tool for a geodesist.This paper evaluates the possibility of applying Terrestrial Laser Scanning to test deformations and shifts of flagged points of concrete dam construction based on experimental measurements, including object inventory and evaluation of the dam’s concrete structure condition.
9
Content available Study of the influence of temperature and water level of the reservoir about the displacement of a concrete dam
Oro S. R., Mafioleti T. R., Chaves Neto A., Garcia S. R. P., Neumann C.
International Journal of Applied Mechanics and Engineering
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2016
|
Vol. 21, no. 1
107--120
EN
Multivariate techniques are used in this study to analyze the monitoring data displacements of a concrete dam, measured by means of pendulums, extensometer bases and multiple rod extensometers, taking into account the action of environmental conditions, bounded by the surface temperature of the concrete at ambient temperature and the tank water level. The canonical correlation analysis is used to evaluate the influence of environmental variables in the displacement of structures and dam foundations. The factor analysis is used to identify data sources of variability and order the sensors according to the action of factors. The dates of the measurements are grouped according to similarities in the present observations, by applying the cluster analysis. Then the discriminant analysis is used to assess the groups as to their homogeneity. The results demonstrate that the techniques used for distinguishing the dam responses and identify the effects of changes in environmental conditions on the displacements of the structures and dam foundations.
10
Content available remote Problemy wykonawcze związane z budową zapory betonowej w Niedowie
Kmita A., Kostecki S., Logoń D., Musiał M., Pawlak W., Rędowicz W.
Materiały Budowlane
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2015
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nr 9
71--73
PL
W artykule przedstawiono problemy wykonawcze związane z odbudową zapory na rzece Witka w Niedowie. Skoncentrowano się na opisie realizowanych badań mieszanki betonowej oraz betonu na budowie i w laboratorium. Dodatkowo zaprezentowano główne problemy dotyczące doradztwa naukowego.
EN
In the paper the executive problems connected with the reconstruction of the dam on Witka river in Niedów. Due to the scientific supervision provided by authors the investigations on concrete mixture and concrete in the site and laboratory were described. Additionally, the main problems concerning scientific advisory were presented.
11
Content available remote O sprężaniu betonowych zapór wodnych
Mucha J., Żyła M., Sadowski T., Szydłowski R.
Materiały Budowlane
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2015
|
nr 9
94--95
PL
Wznoszenie masywnych zapór wodnych zapoczątkowano w starożytnej Mezopotamii i na Bliskim Wschodzie. Pierwszym zaporom stabilność zapewniała ich ogromna masa. Obecnie zapory są kotwione do podłoża kotwami dużej mocy. Rozwiązanie takie zapewnia stabilność zapór przy zmniejszonej ich masywności. W artykule, na przykładzie wzmocnienia zapory Eder w Niemczech, przedstawiono system sprężania zapór wodnych oraz wynikające z tego korzyści.
EN
Erection of dams was initiated in the ancient Mesopotamia and in the Middle East. The stability of the first dams was achieved by the large mass of masonry and concrete material. The development of ground anchoring system enabled post-tensioning of the dams. The dam stability is ensured with reduced material mass. This paper present the example of Eder Dam (Germany) strengthening with prestressing tendons and derived advantages from prestressing.
12
Content available Measuring system for monitoring of concrete dam deformations
Bryś H., Mirek G.
Reports on Geodesy
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2007
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z. 1/82
39-45
13
Content available Investigation of possibilities to use fern modelling in the process of modernisation of control networks for concrete dams
Zaczek-Peplinska J., Popielski P.
Reports on Geodesy
|
2007
|
z. 1/82
417-423
EN
The paper presents analysis of possibilities to utilise results of modelling the work of concrete dam construction elements, obtained by means of the finite elements method (FEM), for the needs of modernisation of a control network. Such analysis should answer the question, whether - basing on the results of modelling with the use of currently controlled points of the object, as the network nodes, and pointing to zones (locations) of threats - it will be possible to formulate recommendations concerning the improvement of a set of controlled points and to perform related modifications of the existing control network.
14
Content available remote Zastosowanie tomografii tłumienia w badaniach niejednorodności korpusu zapór betonowych
Dec J.
Technika Poszukiwań Geologicznych
|
1998
|
R. 37, nr 3
59-63
PL
W poniższym artykule przedstawiono zastosowanie metody tomografii sejsmicznej do badania niejednorodności oraz monitorowania zmian, jakie zachodzą w wyniku wzmacniania stwierdzonych w badanej przestrzeni stref anomalnych (osłabionych). Prezentowane wyniki uzyskane zostały z prześwietlań korpusu zapory betonowej w Wapiennicy, które realizowano w wybranym bloku korpusu przed i po pracach remontowych. Omówiono zastosowanie tomografii prędkościowej i tomografii tłumienia w monitorowaniu efektywności prac remontowych oraz porównano rezultaty uzyskiwane dla obu odmian metody.
EN
Possibility of use of seismic velocity and attenuation tomography measurements to diagnosis of anomaly zones of concrete dams has been discussed in this paper. Some examples of the correlation and differences between velocity and attenuation tomography are presented. Results of tomography measurements, obtained for the concrete dam in Wapiennica, are shown in form of distribution maps of the P-wave velocity and attenuation coefficients. Repetition of tomographic measurements in the same geometry can supply useful information on changes of the integrity of concrete dams.
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