# AN ANALYTICAL-NUMERICAL STUDY OF THERMAL STRESS IN STRUCTURES OF MASS CONCRETE

## Palavras-chave:

Thermomechanical stress, Temperature, Mass Concrete, Finite Element Method, Problems coupled## Resumo

The construction of gravity dams was a milestone for the development of studies and technological

control of the concrete of mass, because the internal temperature increases began to appear and this generated

cracks. During the process of hydration of the cement particles, there is release of heat, in a process called heat of

hydration, raising internally the temperature of the concrete. This phenomenon causes the internal temperature of

the concrete to differ from the surface temperature, resulting in a thermal gradient, in addition to a slow cooling in

the core of the structures. These temperature changes give rise to thermal stresses, which if not foreseen and

prevented can cause damage to the constructions, when they exceed the capacity of resistance of the concrete.

Thermal stresses take into account the phenomenon of the intrinsic creep in the concrete: there is variation of the

modulus of elasticity over time with the change of temperature. There are a few techniques to try to minimize this

problem, such as building in layers, launching concrete at lower temperatures, use of cements with low heat of

hydration, and more. An effective way of preventing thermal problems in mass concrete is the numerical

simulation, being possible with the mechanism, predict the most critical regions and analyze the probability of

structural damage. In view of the context, this work shows numerical thermal simulations using the Finite Element

Method - FEM, through the ANSYS program for mass concrete structures built in layers. With the numerical

results, the analitical tensions arising from the temperature changes of the bodies are analyzed. It seeks to expose

some of the most favorable conditions in the construction process, identifying possible cracking sites, through

numerical and analytical analysis, contributing to the dissemination of these studies and showing to the community

in interest, constructive methods and methods of analysis that can induce safer construction.