建物内を伝播するせん断波速度による実在建物の構造特性の評価

抄録

In this study, we have placed special emphasis on the velocity of propagation of shear waves through the building segment to evaluate individually the characteristics of the buildings. The study consists of the following 3 steps : first, to investigate the way of impact delivery and the properties of propagated waves with regard to a structurally simple building; secondly, to measure the shear wave velocity in several buildings of different structure and examine the resulting data; finally, to assess, in theoretical analysis, the applicability of this method by comparing the theoretical with the measured values. In the experiment constituting the first and second steps of the study, a horizontal impact force, exerted by about 15 persons, was imposed on the top of the building. Propagation of this wave motion was observed on each floor by vibration sensors. Shear wave velocities (sVs) measured for representative buildings of 3 different structural types are as follows : Steel frame : sVs=200〜300m/sec. Concrete encased column as part of steel frame : sVs=370m/sec. Concrete encased steel frame : sVs=450〜700m/sec. Buildings of the same structural type differ as to the above values principally depending on whether or not they are constructed with earthquake resisting walls or braces. In the case of a structurally simple building, theoretical examination ensured that the above measured values agree well with the theoretical values.