Nightingale T.

This paper outlines and evaluates a non-destructive experimental technique to obtain in-situ measures of the real part of the bending wavenumber in the two principal directions of a wood joist floor. In-situ measured wavenumbers are compared to those obtained from beam samples cut from the floor sheathing to identify the frequency range when the joists significantly affect vibration response in the floor sheathing. Wavenumber measurements confirm the highly orthotropic nature. Measurements indicate that wavenumbers in the direction parallel to the joists are a function of location between the joists. Lower wavenumbers in this direction can be expected closer to the joists. Measured wavenumbers are compared when the joist floor has various toppings to assess how toppings modify the vibration response of a floor. For flanking transmission vibration attenuation from impact sources is of particular interest because it determines the structure borne power incident on a flanking junction. Using the intensity relation, measured wavenumbers, and vibration mapping data, estimates of an effective loss factor are obtained. These results are compared to estimates obtained using the power injection method and decay rate method to assess the suitability of the approach.