| 摘要 |
PROBLEM TO BE SOLVED: To provide a new and economically excellent floor structure based on a new method other than floor slab thickness changing means, in which a heavy floor impact sound cutoff performance in a frequency band of 63 Hz or a floor impact sound cutoff performance in all frequency bands is not deteriorated without changing the plane size of a floor slab when a lower order natural frequency of the floor slab is within the frequency band of 63 Hz or a slightly lower frequency band.SOLUTION: In a floor structure where a lower order natural frequency in which the impedance of a floor slab is reduced appears in a frequency band of 63 Hz, a tie-in part of a beam and the floor slab has a semi-rigid junction structure in which the slab thickness is partially reduced at four peripheral sides of the floor slab adjacent to lateral faces of beams. Thereby, the lower order natural frequency of the floor slab is shifted to a lower frequency than the frequency band of 63 Hz and a heavy floor impact sound cutoff performance of the floor slab is improved without changing rigidity of the whole floor slab. |
