Abstract
In this paper we are concerned. with the concrete floating floor construction, which is one of the most promising ways to control floor impact sound. We try to calculate the effectiveness of this construction as precisely as possible by using the vibration transmissibility of the whole system. The calculation itself is as follows. We divide the whole system into the two parts -the upper part, which is made up of the mass of floating screed and spring of resilient material- and the lower part, which consists of the mass and the spring of concrete floor slab. We presuppose that either part is independent and complete of itself. That is, we are allowed to regard each part as a single degree-of-freedom vibration system. Then, we are in a position to calculate the vibration transmissibility of each part. Next, we convolute both transmissibilities in order to have total transmissibility of the whole system. In the process of calculation we combine the whole frequency range of the upper part, but only the first order of resonance frequency band of the lower part so that the calculation may realistic as well as reasonable. We justify our way of thinking by demonstrating that the calculated total transmibility appoximately equals to the one measured in a field experiment in the whole frequency range.
