Study on Damage and Strengthening Effects of Building Structures based on Vibration Tests using Impactor Machine

在地震工程中，研究建筑结构在地震作用下的破坏和抗震加固对结构动力性能的影响是十分重要的。基于振动试验的土-结构相互作用体系自然周期和振动模态的变化，为识别各结构部件的损伤和加固效果提供了可能。本课题首先对某既有建筑进行了加固前后的强制振动试验，研究了加固前后的损伤和加固效果。其次，开发了基于子结构法的土-结构相互作用体系振动台试验技术，并对模型结构进行了体系辨识；截至2001财政年度，在东北大学实际的9层钢筋混凝土建筑中，使用冲击机和不平衡质量式激振器进行了振动试验。在加固前和加固后分别进行了振动试验。在试验前的基础上，通过与能很好地解释建筑物建成后的结构模型的振动特性对比，探讨了损伤检测技术。对结构单元各部分的刚度折减系数进行了检测。然后，利用加固后的试验结果对其抗震加固效果进行了讨论。采用与试验前损伤检测相同的技术来识别结构单元各部分的刚度增加。2002财年，采用可控电磁振动台，开发了基于子结构法的振动台试验技术。该测试方法使得在任意土体条件下进行结构振动测试成为可能。首先对试验进行了数值模拟，通过利用加速度观测记录对废旧土弹簧进行系统识别，验证了试验技术的有效性。然后，利用该试验装置对不同土-结构体系进行了模型试验，并通过相互作用体系的系统辨识验证了试验技术的有效性。基于所建立的试验方法，可以对试验模型的损伤/加固效应进行评价。少

In earthquake engineering, it is important to investigate the change of dynamic property of building structure resulting from damage during earthquake and strengthening by seismic reinforcement work. The change of natural period and vibration modes of soil-structure interaction system based on vibration tests make it possible to identify the damage and strengthening effects of each structural parts. In this project, first, damage and strengthening effects were investigated based on the forced vibration tests at an existing building before and after reinforcement work. Second, the shaking table testing technique of soil-structure interaction system based on the substructure method was developed and system identification of the model structure was performed.Up to the fiscal year 2001, the vibration tests using impactor machine and unbalanced-mass type excitor are performed at the actual 9 story RC building of Tohoku University. The vibration tests were performed before the reinforcement … More work and after the work. Based on the before-test, the damage detection technique was first discussed by comparing the vibration characteristics using the structural model which explain well those after the building's completion. The stiffness reduction factors were detected for each portion of the structural elements. Then, the seismic strengthening effect was discussed using the test results after the reinforcement. The same technique as the damage detection for the before-test was used to identify the stiffness increase for each portion of the structural elementsIn fiscal year 2002, the shaking table testing technique based on the substructure method was developed using a controlable electro-magnetic type shaking table. The testing method makes it possible to perform the vibration test of structure on assumed arbitrary soil conditions. First, the numerical simulation of the test was performed and verified the validity of the testing technique through the system identification of the used soil spring using the acceleration observation record. Then, the model tests of the different soil-structure system are performed using the testing device and the efficiency of the testing technique was confirmed through the system identification of the interaction system. The damage/reinforcement effects of the testing model can be evaluated based on the developed testing method. Less