Seismic Response Observation of Super High-Rise Buildings Throughout their Construction Stage and Development of Long-Stroke Shaking Table for Tracing Long-Period Floor Response

本课题基于超高层建筑施工阶段的大量观测数据，对超高层建筑的基本动力特性进行了研究。为了了解结构相似但楼层数不同的建筑物在结构反应上的差异，可以在单个建筑物的施工期间进行观测，因为在不同楼层数完工的施工期间，地震可能会发生。在本研究中，我们观察了三座超高层建筑。我们澄清了自然周期与建筑高度近似成正比，而阻尼比则成反比。对于小阻尼的长周期建筑物，当自然周期接近土体的主周期时，长时程地震动极大地放大了建筑物的地震响应。这一现象可以从两个方面加以解释：一是观察……二是对一个单自由度系统的简单分析。自然周期和阻尼比的变化是从一座47层建筑在建时的微震记录中得到的。第一模态和第二模态的自然周期几乎随建筑高度线性增加，而阻尼比分散在0.5%左右。这个阻尼值对应于钢材本身的材料阻尼。为了促进超高层建筑应对预测的大地震引起的长周期地面运动的对策，有必要告知结构设计师和建筑业主，由于共振，建筑物可能会遭受意想不到的大响应。为了确保结构设计师和建筑业主意识到这种风险，他们有必要体验楼层的响应量。然后，他们将了解室内区域安全措施的必要性以及添加阻尼器以减少响应的重要性。由于用于驱动振动台的动态执行器的位移限制，传统的振动台无法再现这种运动。我们开发了一种新的振动台，名为“Triple-L振动筛”，代表“长冲程长周期线性振动筛”，以重现超高层建筑的反应。这个想法的创新之处在于使用了两个伺服电机，从两侧拉动连接到轨道上振动台的绳子，如图13和图2所示。与普通振动台相比，该系统不需要很大的空间，也不需要特殊的电源。该表再现了位移幅度达3米，速度为5米/秒，加速度为2G。通过这个表格，人们可以很容易地体验到各种建筑在不同土壤条件下的任意响应。少

In this research project, the fundamental dynamic properties of super high-rise buildings are investigated based on a large quantity of data observed during their construction stage. To understand the differences in structural response between structurally similar buildings with different numbers of floors, observations can be carried out in a single building during its construction, as earthquakes are likely to occur throughout the construction period when different numbers of floors have been completed. In this research, three super high-rise buildings have been observed. We clarify that the natural period is approximately proportional to the building height, while the damping ratio is inversely proportional. In the case of long-period buildings with small damping, when the natural period is close to the predominant period of soil, the seismic response of the building is enormously amplified for long-duration seismic ground motion. This phenomenon is explained from both observations … More and a simple analysis of a system with one degree of freedom. The changes in natural periods and damping ratios were obtained from microtremor records for a 47-story building while under construction. The natural period increases almost linearly with building height, both for the first and second modes, while the damping ratio is scattered around 0.5%. This damping value corresponds to the material damping of the steel itself.To promote countermeasures for super-high-rise buildings against long-period ground motions arising from predicted massive earthquakes, it is necessary to inform structural designers and building owners that buildings might suffer from an unexpectedly large response due to resonance. To ensure that structural designers and building owners are aware of this risk, it is necessary for them to experience the amount of floor response. They will then understand the necessity of safety measures for indoor areas and the importance of the addition of dampers to reduce the response.Conventional shaking tables are unable to reproduce this movement because of the displacement limit of the dynamic actuator used to drive the table. We developed a new shaking table named the 'Triple-L shaker,' which stands for he 'Long-stroke Long-period Linear shaker,' to reproduce the response of super-high-rise buildings. The innovation in this idea is the use of two servo-motors that pull the rope connected to the shaking table on the rail from both sides, as shown in Figure 13 and Photo 2. Compared with ordinary shaking tables, this system doesn't require a large space or special power supplies. The table reproduces amplitudes of displacement of up to 3 m, velocities of 5m/s, and acceleration of 2G. Using this table, people can easily experience the arbitrary response of various buildings upon different soil conditions. Less