This paper focuses on the development, verification and application of a three-dimensional finite element code for coupled thermal and structural analysis of roller compacted concrete arch dams. The Karun III Arch dam located on Karun River, Iran, which was originally designed as a conventional concrete arch dam, has been taken for the purpose of verification of the finite element code. In this study, RCC technology has been ascertained as an alternative method to reduce the cost of the project and make it competitive. A numerical procedure to simulate the construction process of RCC arch dams is presented. It takes into account the more relevant features of the behavior of concrete such as hydration, ageing and creep. A viscoelastic model, including ageing effects and thermal dependent properties is adopted for the concrete. The different isothermal temperature influence on creep and elastic modulus is taken into account by the maturity concept. Crack index is used to assess the occurrence of crack and evaluate the level of safety of the dam. This study demonstrates that, high tensile stress concentration has been observed at the lower part and the abutment boundaries of the dam. Keywords: RCC, arch, thermal stress, creep, mechanical behavior, crack safety factor, finite element method. Reference to this paper should be made as follows: Abdulrazeg, A. A.; Noorzaei, J.; Jaafar, M. S.; Khanehzaei, P.; Mohamed, T. A. 2014. Thermal and structural analysis of RCC double-curvature arch dam, Journal of Civil Engineering and Management 20(3): 434-445. http://dx.
A combined thermal and mechanical action in roller compacted concrete (RCC) dam analysis is carried out using a three-dimensional finite element method. In this work a numerical procedure for the simulation of construction process and service life of RCC dams is presented. It takes into account the more relevant features of the behavior of concrete such as hydration, ageing and creep. A viscoelastic model, including ageing effects and thermal dependent properties is adopted for the concrete. The different isothermal temperature influence on creep and elastic modulus is taken into account by the maturity concept, and the influence of the change of temperature on creep is considered by introducing a transient thermal creep term. Crack index is used to assess the risk of occurrence of crack either at short or long term. This study demonstrates that, the increase of the elastic modulus has been accelerated due to the high temperature of hydration at the initial stage, and consequently stresses are increased.
Temperature control plays an important role in the design and construction of rollercompacted concrete (RCC) dams. Hydration of cement and climatic changes on the convective boundaries are the two main heat sources of the temperature rise in RCC dams. Therefore, the effects of these two factors have to be determined accurately in order to reduce the risk of thermally induced cracking in these dams. Simplified approaches are usually adopted to approximate the temperature changes on the upstream dam side after the dam reservoir is filled. These simplified approaches are usually based on long-term observations of similar reservoirs. However, it is practically hard to generalise the conditions of these reservoirs with respect to the reservoir under consideration. In this work, the finite-element method has been used to simulate the heat exchange between the RCC dam body and the reservoir water taking into account the reservoir operation. A realistic isothermal profile has been obtained that has been used to determine the cracking probability of the RCC dam body.
Abstract. This study describes the implementation of a 2-D finite element model of an integral abutment bridge (IAB) system which explicitly incorporates the nonlinear soil response. The superstructure members have been represented by means of three-node isoparametric beam elements with three degrees of freedom per node. The soil mass is idealized by eight node isoperimetric quadrilateral element at near field and five node isoparametric infinite element to simulate the far field behavior of the soil media. The non-linearity of the soil mass has been represented by using the Duncan and Chang hyperbolic model. The applicability of this model was demonstrated by analyzing a single span IAB. This study has shown that the soil nonlinearity has significant effect on the response of the structure, where the displacement that have been obtained on basis of nonlinear analysis is 1.5-2.0 times higher than that obtained from linear analysis. The stress magnitudes in the nonlinear analysis are also higher where in some point the difference reached almost 3 times.
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