Advanced Numerical Model for Irradiated Concrete
Abstract
In this report, we establish a numerical model for concrete exposed to irradiation to address these three critical points. The model accounts for creep in the cement paste and its coupling with damage, temperature and relative humidity. The shift in failure mode with the loading rate is also properly represented. The numerical model for creep has been validated and calibrated against different experiments in the literature [Wittmann, 1970, Le Roy, 1995]. Results from a simplified model are shown to showcase the ability of numerical homogenization to simulate irradiation effects in concrete. In future works, the complete model will be applied to the analysis of the irradiation experiments of Elleuch et al. [1972] and Kelly et al. [1969]. This requires a careful examination of the experimental environmental conditions as in both cases certain critical information are missing, including the relative humidity history. A sensitivity analysis will be conducted to provide lower and upper bounds of the concrete expansion under irradiation, and check if the scatter in the simulated results matches the one found in experiments. The numerical and experimental results will be compared in terms of expansion and loss of mechanical stiffness and strength. Both effects should be captured accordingly bymore »
 Authors:
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
 Publication Date:
 Research Org.:
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
 Sponsoring Org.:
 USDOE
 OSTI Identifier:
 1185949
 Report Number(s):
 ORNL/TM2015/97
RC0304000; NERC006
 DOE Contract Number:
 DEAC0500OR22725
 Resource Type:
 Technical Report
 Country of Publication:
 United States
 Language:
 English
 Subject:
 Concrete; Irradiation; Modeling
Citation Formats
Giorla, Alain B. Advanced Numerical Model for Irradiated Concrete. United States: N. p., 2015.
Web. doi:10.2172/1185949.
Giorla, Alain B. Advanced Numerical Model for Irradiated Concrete. United States. doi:10.2172/1185949.
Giorla, Alain B. 2015.
"Advanced Numerical Model for Irradiated Concrete". United States.
doi:10.2172/1185949. https://www.osti.gov/servlets/purl/1185949.
@article{osti_1185949,
title = {Advanced Numerical Model for Irradiated Concrete},
author = {Giorla, Alain B.},
abstractNote = {In this report, we establish a numerical model for concrete exposed to irradiation to address these three critical points. The model accounts for creep in the cement paste and its coupling with damage, temperature and relative humidity. The shift in failure mode with the loading rate is also properly represented. The numerical model for creep has been validated and calibrated against different experiments in the literature [Wittmann, 1970, Le Roy, 1995]. Results from a simplified model are shown to showcase the ability of numerical homogenization to simulate irradiation effects in concrete. In future works, the complete model will be applied to the analysis of the irradiation experiments of Elleuch et al. [1972] and Kelly et al. [1969]. This requires a careful examination of the experimental environmental conditions as in both cases certain critical information are missing, including the relative humidity history. A sensitivity analysis will be conducted to provide lower and upper bounds of the concrete expansion under irradiation, and check if the scatter in the simulated results matches the one found in experiments. The numerical and experimental results will be compared in terms of expansion and loss of mechanical stiffness and strength. Both effects should be captured accordingly by the model to validate it. Once the model has been validated on these two experiments, it can be applied to simulate concrete from nuclear power plants. To do so, the materials used in these concrete must be as well characterized as possible. The main parameters required are the mechanical properties of each constituent in the concrete (aggregates, cement paste), namely the elastic modulus, the creep properties, the tensile and compressive strength, the thermal expansion coefficient, and the drying shrinkage. These can be either measured experimentally, estimated from the initial composition in the case of cement paste, or backcalculated from mechanical tests on concrete. If some are unknown, a sensitivity analysis must be carried out to provide lower and upper bounds of the material behaviour. Finally, the model can be used as a basis to formulate a macroscopic material model for concrete subject to irradiation, which later can be used in structural analyses to estimate the structural impact of irradiation on nuclear power plants.},
doi = {10.2172/1185949},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2015,
month = 3
}

Knowledge of the magnitude and distribution of uplift pressures in cracks in concrete gravity dams is needed when assessing their stability and safety and in the design of rehabilitation schemes. In the conventional limit equilibrium approach for dam stability, the head distribution in all cracks is assumed to be uniform irrespective of the existence of drains and their operative conditions. This approach is conservative when the drains are in proper operating condition and are releasing some of the uplift pressure. Analytical studies on the effect of drains in reducing uplift in cracks have been reported in the literature. However, analyticalmore »

CRFLOOD: A numerical model to estimate uplift pressure distribution in cracks in concrete gravity dams. Volume 4, Final report
Knowledge of the magnitude and distribution of uplift pressures in cracks in concrete gravity dams is needed when assessing their stability and safety and in the design of rehabilitation schemes. In the conventional limit equilibrium approach for dam stability, the head distribution in all cracks is assumed to be uniform irrespective of the existence of drains and their operative conditions. This approach is conservative when the drains are in proper operating condition and are releasing some of the uplift pressure. Analytical studies on the effect of drains in reducing uplift in cracks have been reported in the literature. However, analyticalmore » 
Axisymmetric analysis of a 1:6scale reinforced concrete containment building using a distributed cracking model for the concrete
Results of axisymmetric structural analyses of a 1:6 scale model of a reinforced concrete nuclear containment building are presented. Both a finite element shell analysis and a simplified membrane analysis were made to predict the structural response and ultimate pressure capacity of the model. Analytical results indicate that the model will fail at an internal pressure of 187 psig when the stress level in the hoop reinforcement at the midsection of the cylinder exceeds the ultimate strength of the bar splices. 5 refs., 34 figs., 6 tabs.