Efeitos térmicos em estruturas maciças de concreto

Abstract

This work studies thermal effects on mass concrete structures, considering the incremental construction of the structure. Particular attention is given to problem of thermal stress which are find in gravity concrete dams, caused, mainly, by high increases of temperature and following gradual cooling, during the inicial phasis of hardening of concrete, dued the quantity of heat generated by the reactions of cement hidration. The temperature distribution is evaluated by transient linear analysis of heat transfer using the finite elements method on a bidimensional field. In order to calculated the thermal stress, concrete is supposed to be a linear elastic material, and conventional linear analysis with the finite element method is applied. The formulation of the aging material viscoelastic linear analysis is presented. This method reflects more sharply the concrete behavior and the problem is solved elasticaly through the method of equivalent temperature field. Finally, simple examples, are presented as well as a actual application in the thermal analysis of a gravity dams.