Test Research And Time-history Analysis On The Upper Structure Stiffness With Reinforced Asphalt Isolation Effect

With the rapid development of cities and towns, the height of the building structure is higher and higher, gradually from the low-rise buildings to the development of high-rise buildings. Cheap and effective isolation devices and the simple and practical structure design method are urgently needed, especially in many areas with the poor seismic consciousness. After several years of efforts, we have developed a kind of low cost and convenient reinforced asphalt base isolation device, which has good isolation performance.Reinforced asphalt isolation technology is mainly used in low-rise masonry structures, the upper part of which can be simplified as rigid body, and relevant research results show that this technology has very good isolation effect. With height of the high-rise building structure increased, its lateral stiffness become smaller, and the upper structure can't simply consider as a rigid body. The purpose of this article is to promote the application of reinforced asphalt isolation technique in the high-rise structure and provide advice for the structure design.The results, from the theoretical analysis and the vibration table test of the steel frame- reinforced asphalt isolation structure, found that the upper structure and isolation layer's horizontal stiffness ratio has obvious effect on vibration isolation effect. The time history analysis is applied to experiment model with the help of ANSYS software, and the analysis results fit well with the experiment's.The finite element model reasonably reflects the isolation mechanism and the dynamic response of the isolation structure, its results verify that the vibration isolation effect is remarkable when the stiffness ratio greater than 2.5. On this basis, a multi-layer full scale finite element model is established for validation, which shows the fundamental frequency of isolation structure decreased greatly,and the acceleration amplitude followed the law of diminishing with the increase of stiffness ratio.In this paper, the concept of stiffness ratio proposed, which considers the vibration isolation effect in combination with the stiffness ratio of upper structure and the isolation layer. So, we can reasonably determine the applicable scope of the isolation structure, and it should be a major innovation in the field of vibration isolation design. With the increase of height of the upper structure, the upper load will be increased. According to the second chapter, the amount of reinforcement needed will be more, then horizontal stiffness of isolation layer increases, namely, the lateral stiffness ratio decreased. At this time, the reasonable arrangement of the upper structure component is necessary, to ensure lateral stiffness ratio as large as possible, so that, the high-rise reinforced asphalt isolation structure will have ideal isolation effect.