Vibration-controlling Structure like a Five-story Pagoda Temple
We made every effort to assure safety from swaying when the tower is subjected to an earthquake or strong wind. Finally, we arrived at the conclusion that a new vibration-controlling system should be used in which a cylindrical core of reinforced concrete at the center (center column*) is structurally isolated from the peripheral steel framing, with the upper part of the core column made to function as ga balancing weight.h
This control system is in principle a new application of the modern gAdded Mass Control Mechanism *h and can reduce the response shear force by 40% during an earthquake.
The traditional towers in Japan, gfive-story pagoda temples*,h have never fallen down due to any earthquake to date, which mysterious fact is ascribed to the templefs "Shimbashira iCenter Columnj" built at the center of the temple.
When it came to building a super-high tower of 634m with modern construction techniques, we happened to meet with the traditional tower construction technique. We call the present vibration-controlling system "Shimbashira-SeishiniCenter Column Vibration Controlj".
- Added Mass Control Mechanism
- This mechanism is to control the swaying motions of a structure as a whole during an earthquake by providing added mass (balancing weight) so as to move in slightly delayed timing from the swaying motion in a counterbalancing way to set off the movement of the structure by the movement of the weight. Usually, steel ingots or concrete mass is used as the added mass, and sometimes equipment for building service systems, or a heat accumulator, are used for the same purpose. The present case of the core column (the staircase) used as the added mass is a worldfs first attempt.
- Five-story Pagoda Temple
- It is a unique traditional tower of wood construction in Japan. Though there are records that five-story pagoda temples collapsed or were damaged due to typhoon or fire, no record is available of such a temple collapsing due to an earthquake. Hence, such temples are considered to have excellent earthquake resistance. Though such resistance is accounted for in various ways, it cannot be denied that the center column has played a major role.
- Center Column
- It primarily refers to the column built at the center of the pagoda or other temple tower. In the case of the Sky Tree tower, it refers to the cylindrical shell built at its center (made of reinforced concrete and used as a staircase).