A STUDY ON DYNAMIC CHARACTERISTICS OF TRADITIONAL WOODEN BUILDING BY MICRO TREMOR MEASUREMENT

为了了解传统木结构建筑的动力特性，对平条宫遗址和法隆寺建筑的重建建筑进行了微动测量。通过FFT分析，我们得到了以下几点认识.重建建筑：从4 Hz到10 Hz有4个谱峰，从低频开始依次为脊向平行振型、梁向平行振型和扭转振型。在低频范围内，分析得到的固有频率和振型与实测结果吻合较好.法隆寺塔：10 Hz以下的三个固有频率，分别为0.9Hz、2.5Hz和4.2Hz。振型在0.9Hz时为对角线方向的平行振型，在2.5Hz时为垂直二阶振型，在5层柱底高度处反相。第5层的轨迹有时表现为平行振动，有时表现为圆振动。刚度值随层数的增加而减小.近藤和 ...更多信息 中门：每栋建筑物在10 Hz以下有两个固有频率，近藤为1.80Hz和2.07Hz，中门为1.56Hz和1.80Hz。两栋建筑的主振型均为梁向平行振型，次振型均为山脊向平行振型。阻尼系数为1.7- 4.4%。由自振频率计算的近藤第一层的刚度值为2.79-3.69*10^4kg/cm，柱抗摇刚度所占的比例为75- 81%。大琴道：10 Hz以下的四个固有频率，分别为1.7Hz、2.1Hz、2.5Hz和4.1Hz。主振型为梁向平行振型，次振型为脊向平行振型。第三种模式为束流方向的扭转模式。阻尼系数为1.9- 2.5%。由固有频率计算的大江户的刚度值为1.9- 2.5%。根据固有频率计算的大江户的刚度值为1.62*10^4 - 2.50 * 10^4 kg/cm，由于柱摇摆阻力而导致的刚度百分比被认为是88- 95%。少

To understand dynamic characteristics of traditional wooden buildings, micro tremor measurements were performed on rebuilt buildings of Heijo palace site and Horyuji buildings. By the FFT analysis we obtained the knowledges as the following.1. Rebuilt buildings : Four spectrum peaks from 4Hz to 10Hz, and three vibration modes which were parallel mode in the ridge direction, parallel mode in the beam direction and torsional mode in order from lower frequency. Analytic natural frequencies and vibration modes agreed well with those of measurement in lower frequencies.2. Horyuji pagoda : Three natural frequencies under 10Hz, which were 0.9Hz, 2.5Hz, and 4.2Hz. Vibration mode at 0.9Hz was parallel mode in the diagonal direction and at 2.5Hz it was virtical second mode with phases reversed at the height of 5th story culumn botom. Locus of 5th story shows sometimes parallel vibration and sometimes circular vibration. Values of stiffness which decrease as the story number increase.3. Kondo and … More Chumon : Two natural frequencies for each building under 10Hz, which were 1.80Hz and 2.07Hz for kondo and 1.56Hz and 1.80Hz for Chumon. For both buildings, primary vibration mode was parallel mode in the beam direction and second mode was parallel mode in the ridge direction. Damping factors were 1.7-4.4%. Values of stiffness of Kondo first story calculated from natural frequencies were 2.79-3.69*10^4kg/cm and the percentage of stiffness due to column rocking resistance is considered to be 75-81%.4. Dai-kodo : Four natural frequencies under 10Hz, which were 1.7Hz, 2.1Hz, 2.5Hz and 4.1Hz. Primary vibration mode was parallel mode in the beam direction and second mode was parallel mode in the ridge direction. The Third mode was twist mode in the beam direction. Damping factors were 1.9-2.5%. Values of stiffness of Dai-kodo calculated from natural frequencies were 1.9-2.5%. Values of stiffness of Dai-kodo calculated from natural frequencies were 1.62*10^4 -2.50*10^4 kg/cm and the percentage of stiffness due to column rocking resistance is considered to be 88-95%. Less