地震直後における建物健全性評価のための限られた階の加速度記録に基づく建物全層応答推定手法

 Recently it has been demanded to evaluate structural safety and function recovery of buildings shortly after subjected to an earthquake. Seismic response of each floor of a building can be easily measured if sensors are installed on every floor. High performance sensors are generally expensive, so it is difficult to install sensors on every floor of a building, especially of a high rise building. Several methods have been proposed to estimate seismic response of each floor of a building by utilizing sensors installed on a limited number of stories. Most of these methods are techniques based on the modal analysis, and have already attained to a practical application level. The main aim of those methods is to estimate structural health determination and damage-identification at each floor level by using a limited number of high-precision conventional servo-type accelerometers. However, applicability of those methods has not been examined in detail as for nonlinear deformation of the building and as for effects of location and numbers of sensors on simulation response analyses.<br> In this paper, we will examine the applicability and effects of our estimation method according to the modal shape calculated on the basic of the design model of building by using experimental data of the large shaking table test of the 1/3 scaled 18-story steel high-rise building executed in December 2013 at E-Defense. Artificial generated earthquake motions were used as input for the large shaking table test, and the amplitude levels of the input motions were repeatedly increased until the model specimen was collapsed. We installed 25 servo-type accelerometers in the model specimen on each floor. Response states of the whole building were evaluated by using a few points of sensors. From the viewpoint of structural health monitoring, we focus on the maximum story drift angle of buildings. We analyzed the results estimated from limited point accelerometers by comparing with observed data form all sensors in addition to other data such as displacement meters.<br> In this paper, we can draw our conclusions as follows.<br> 1) Up to 0.03 radian in the maximum story drift angle, results estimated from 5 points of sensors (1, 4, 10, 15 and RFL) correspond approximately to the observed results in the 18 story steel high-rise building model.<br> 2) It is important that sensors should be properly installed on the building by considering the mode shape of design model in order to evaluate better seismic response.<br> 3) It is true that more sensors give better accuracy of evaluating building response. Especially, more sensors are needed if the building shows strong nonlinearities over 0.01 radian.