In recent years, it has been actively researched to improve the seismic performance of houses by using shear walls with energy absorption even in houses.
In this paper, we focused on U-shaped steel devices that are also used in seismic isolation devices. It is well known that U-shapes have very high ductility due to the use of energy absorption through bending deformation. Therefore, it can be used as a connection method incorporated as a damping member of an H-shaped beam-column joint, or as a damping member between an interpolation panel of a lightweight wall and vertical frame members. In previous studies, a U-shaped damper with a relatively large ratio of radius-to-thickness was used in order to take advantage of excellent energy absorption performance. On the other hand, in this paper, we propose a shear wall aiming to utilize the energy absorption capacity of U-shaped damper by amplifying device deformation. In this case, the number of devices installed on the shear wall is reduced, and the shape of the proposed U-shaped damper has a smaller ratio of radius to thickness and a larger ratio of width to thickness compared to previous studies. Therefore, the effect of these form factors on U-shaped devices needs to be clarified.
First, elemental tests were conducted on U-shaped devices to clarify the basic performance and the effects of shape factor on elasto-plastic behavior. The U-shaped device exhibited stable spindle-type hysteresis and excellent performance as a damper.
In addition, we tried to derive evaluation formulae for elastic stiffness and plastic strength required for the design of U-shaped devices. The elastic stiffness was calculated from elastic strain energy, and the collapse load was calculated based on limit analysis. As a result of comparing the calculated values with the experimental values, design formulae that can evaluate the experimental values could be derived.
Finally, a shear test was carried out on the shear wall with the U-shaped device installed to confirm its performance as a shear wall. Regardless of the position where the U-shaped device was installed, energy could be absorbed by being deformed evenly, and it exhibited excellent deformation performance as a shear wall. In addition, the device evaluation formulae (elastic stiffness and plastic strength) are extended to shear wall evaluation. The results show that the elastic stiffness and the plastic strength of the shear wall including the frame can be evaluated using the proposed design formulae.
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