Abstract
Walking is an essential part of life or work and causes floor vibrations. Recently, the need for large-scale wooden buildings has been increasing. However, there is no guide to design for floor vibrations caused by walking of large-span wooden floors. Therefore we considered the relationship between vertical vibration and properties of wooden school and office floors and human sensory evaluation. We found that the percentage of persons indicating perception of vibration, expecting those who answered unnoticed, was larger than the perception probability indicated in Guideline for the evaluation of habitability to building vibration published by Architectural Institute of Japan (AIJ). When the floor response acceleration was over 4 cm/s2, the percentage of persons who perceived the vibration was 100%. At the next step, we considered the relationship between the weighted acceleration level according to frequencies and the ratio of deflections including creep to spans, calculated by the experimental stiffness. Finally we suggest a tentative design target for large-span wooden floor as follows. In order to get the weighted acceleration level to be 65 dB, we must set the ratio of beam deflections including creep to span at less than 1/500 according to Building Standards Law and at less than 1/600 according to Standard for Structural Design of Timber Structures by AIJ. We also must set the floor natural frequency to be over 12 Hz. These values are available under the condition that the natural frequency of wooden floors is from 9.5 Hz to 12.5 Hz.
