Effect of placement schedule on the thermal and structural response of RCC dams, using finite element analysis

In Comparison with other massive concrete structures, thermal stresses of RCC dams have an important rule in the structural analysis, due to their construction method. Throughout this paper the Finite-Element based computer code, called STARD, along with other necessary relationships for determination of temperature and stresses are introduced. The code is then applied to the real field-scale problem of Roodbar RCC dam, to determine the impact of placement schedule on the thermal stresses of the dam. The finite element model of the dam is generated for every construction phase, by applying Birth & Death of Elements technique. The entire procedure is repeated until the whole dam is constructed. Throughout the analyses, in addition to placement schedule,, the impact of some other influencing factors, such as daily variations of temperature, hydration induced heat generation, initial temperature of rock foundation, placement temperature of each layer, various boundary conditions and module of elasticity, are also investigated. Based on the results of this study, it might be concluded that for a given RCC dam, placement operation, if started on the warm season, would lead to higher thermal stresses in long-term, because of which thermal cracks may form and propagate throughout the entire body, particularly near dam foundation.