| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of inspecting rapture of a building steel beam for quickly identifying a damaged region of a building without removing a fire resistive covering.SOLUTION: A vibration wave with a low frequency smaller than a vertical primary natural frequency of a floor supported by a building steel beam is given to one point (excitation point) installed in a part of the floor, and is received at two receiver points, and a response received at the receiver point is evaluated. In the excitation and the vibration reception, the frequency of the vibration wave having the low frequency is changed, and the excitation and the vibration reception are repeated. A first receiver point installed in the width-direction center part of the lower flange of the steel beam and a second receiver point installed in one width-direction outer end among the lower ends are set as two receiver points. When assuming that the Fourier spectrum in the first receiver point is F1 and the Fourier spectrum in the second receiver point is F2, the steel beam satisfying the following formula 1 is evaluated as an unsound steel beam.SELECTED DRAWING: Figure 1 |
