A Study of Thermal Cracking in The Buttresses Blocks in Itaipu Dam: Thermochemical-Mechanical Numerical Analysis

Resumo

The Itaipu hydropower plant is a world leader in clean and renewable energy. One of the main structures
is the right bank dam, which is composed of buttress blocks. It was built in 1978 and in 1980 the first cracks were
already observed. The thermo-mechanical model, which predicts an increase in temperature inside the concrete
mass due to the hydration of the cement, explains the thermal stresses in these dam blocks. In order to validate this
model and verify if those cracks in Itaipu buttresses are thermal cracks, the block was modeled in DamThe software
in 3D simulating the D38 block. The 3D simulation achieved results that are close to those observed in the field
regarding the position of cracks in the blocks and the temperature developed inside the blocks, compared to the
temperatures observed in the thermometers. The model, already verified in previous works, was validated, as it
was able to predict the temperatures and the tendency to crack. This indicates that it is a reliable program for
designing structures and anticipating undesirable cracks in massive concrete structures. It was also noticed that
the cracks have a thermal origin and may have a mechanical contribution, but not exclusively.