| China is an earthquake-prone country, the seismic research of the building relates to the people's life and property safely. The main method of the traditional anti-earthquake is to regard "anti" as principle mainly. This kind of method depends on the own ductility of the structure to consume the earthquake energy, reduce the earthquake response, make the construction fracture but not collapse. It withstands the impact of earthquakes by the non-elastic appearance of the structure, so allow it to appear a certain degree of structural damage in the earthquakes. With the advancement of our society, the traditional seismic methods can not completely meet the needs of modern people, which make the isolated structures increasingly become the focus of research.This paper introduces the emergence of the early isolation and its history and development. The emphasis is on the base isolation technology, introduces its research and application, its advantages, principles and methods.This paper's research is based on the ELC seismic test data on horizontal vibration table of the durable metal sliding-isolated bearing by my mentor Professor Qinglai Chen, which is a National Research Institutes Technology Research and Development Funds to Special Projects. This sliding-isolated bearing is a new method of the base-isolated structures. First, this paper introduces the structural form of this kind of sliding-isolated bearing and the process of the vibration table test. Secondly, contrast the isolated strain data with the non-isolated data, which is measured by the strain gauge on the top of the upper steel frame column. According to observation and analysis of the test strain, it can reflect the feasibility and effectiveness of the sliding-isolated bearing from a new aspect. Strain is a direct reflection of the stress response, so it can exactly reflect the effect of the sliding-isolated bearing. The concrete steps and the results of this paper as follows:1. According to acceleration sensor data of the center point "0" of the upper steel frame, draw time history of the acceleration, and observe the isolated effects of the sliding-isolated bearing. By comparing the acceleration of the upper steel frame with the base 0 floor, 3 floors and the top 6 floors, the bearing's isolated effects are very distinct, the isolated acceleration of the top 6 floors is only about 70% of the base floor, rather than the non-isolated, its acceleration of the top 6 floors is nearly 2 times of the base floor. Through the accelerations of three kinds of damping value, we can see the third damping effect of the isolation is optimal. In addition to the inherent damping value of the sliding-isolated bearing itself, this proves that additional damping value may be not better if it is too large or too small, or it may be have to do with some characteristics, such as floors of the structure and Natural Vibration Periods. This needs to do more in-depth study.(Three kinds of damping value: first, the inherent damping value of the sliding-isolated bearing+100% additional damping value; second, the inherent damping value of the sliding-isolated bearing only; third, the inherent damping value of the sliding-isolated bearing+12% additional damping value)2. According to the strain absolute extremum of different seismic intensity and different test mode, draw the envelope diagram of strain extremum. By comparing the isolated structure with the non-isolated, analyze the isolated effects. Through the envelope diagram of strain extremum, we can see that with seismic intensity in the increased levels, the strain extremum of the isolated structure or non-isolated has all increased. However, the dispersion of the both becomes greater, that is, the strain amplitude of the isolated structure is lager than the non-isolated structure. This reflects intuitionisticly that the higher of seismic intensity, the better of the effect of the sliding-isolated bearing. Moreover, the strain extremum of the third damping is relatively smaller than the others, so the isolated effect with the third damping is more obvious than the others. This results and acceleration is in the same way.3. According to comparing the rest strain value with the corresponding moment of extremum contingency in different test mode, and the average strain value in certain period; both of which can reflect that the higher of seismic intensity, the better of the effect of the sliding-isolated bearing. This also can reflect the isolated effect with the third damping is more obvious than the others.The innovation of this paper is to prove the obvious isolated effect with the sliding-isolated bearing by the real variety of test strain in the structure. Based on scientific analysis of the experimental data, get some objective conclusions. From an important aspect, the conclusions of this paper reflect the effectiveness and feasibility of the durable metal sliding-isolated bearing. |
