江戸時代に建築された農家の水平加力試験の結果

抄録

Since little field test on the full-scale farmer's house, constructed with old conventional wood-frame contruction, has been carried out, authors made the full-scale tests on the house built in the late eighteenth century to find out the stiffness of a whole house in the lateral direction under lateral loading and to measure the natural frequency of vibration by dynamic response to horizontal reciprocating motion of the small mass. In lateral direction, frame 4 is the only frame in which shear walls (mud wall backed by bamboo-lath) were arranged. The lateral load was horizontally applied by pulling two points on a beam in frame C through wires as shown in Figs. 3 and 4. The following can be concluded from the test results. (1) Lateral load was increased up to 7.1 tonf, corresponding 21. 5 % of the weight of the tested house to be used for calculation of design load for earthquake, after repetitive loading as shown in Fig. 7. The slope of columns at 7.1 tonf were much larger than 1/120 rad. which is regarded as the basic deformation in the evaluation of the allowable racking strength of shear walls being used in the present houses, but all the joints did not reach the dangerous stage. (2) Horizontal plane at tie beam level rotated apparently about point 0 as seen in Fig. 14. This phenomenon indicates that the displacement parallel to loading direction is linearly proportional to the rotation angle with respect to the center of rigidity. (3) The natural frequency was about 2.0 Hz for both lateral and longitudinal directions, but was a little bit decreased after repetitive loading.