Thermal stress

Thermal stress in reinforcement of concrete structures (concrete plicae and other slab having air voids) generate the so-called acoustic resonance. In the daytime these designs are heated and deformed due to thermal expansion. In the reinforcing frame, a voltage is applied, the metal rods slightly compressed or bent. And when the night comes, the house cools down the temperature of concrete structures decreases. In this moment may sharply be the relaxation of rebar that will sound to the people below as the impact of a heavy ball on a hard surface. Then follows an oscillatory returning metal to its original position. This causes a sound similar to a rolling ball, and the like.

Similar properties has devasena, especially at this time of the year when the difference between day and night temperature is especially great.

Translated by «Yandex.Translator»