EVALUATION OF HEAVY-WEIGHT FLOOR IMPACT SOUND INSULATION PERFORMANCE OF COLD-FORMED STEEL FRAMED HOUSE WITH LATTICE-ARRAYED FLOOR JOISTS

The number of cold-formed steel framed houses is increasing and they tend to be built as apartment houses rather than detached houses. Along with this trend, heavy-floor impact sound insulation performance of the houses is expected to be improved. In order to meet this expectation, experimental test and numerical analysis are carried out, using the really-constructed houses as specimens. The results indicate, 1) in order to improve the heavy-floor impact sound insulation performance of cold-formed steel framed houses, sound pressure in a frequency band of 63 Hz has to be reduced, 2) floors of cold-formed steel houses tend to vibrate in a perpendicular direction to floor joists axis in the low-ranged frequency band, which is caused by the anisotropy of floor bending stiffness, 3) considering the vibrating mode shape, to improve sound insulation performance, it seems one of the solutions to increase the floor bending stiffness of weak axis, and 4) the possibility of the suggested solution is confirmed through the on-site test.