2018 Volume 18 Issue 5 Pages 5_88-5_107
Vibration characteristics and relevance to damage on pile-heads of a tilted high-rise building with pile foundation and high aspect ratio are investigated with a translation-rotation model in this paper. The building has steel reinforced concrete (SRC) structure and a rectangular plane of a 1×5 span with 14 stories. The eaves height is 39.5m and the aspect ratio is 3.66 in the short side. Reinforced concrete multi-story shear walls are perpendicularly built in every span of the long side. Moreover, cast-in-place concrete pile foundation is adopted for the substructure and the length is 27.5m. 2011 Tohoku earthquake brought about the inclination by an angle of 1/105 to the short side direction. The cause has not been clarified yet. As the building with the substructure is a typical sort of high-rise condominium on soft soil in Japan, it would be important to know the vibration behavior and very useful to quantify bearing capacities of the damaged substructure for judging the continuous availabilities or the maintenances after the inclination. A micro-tremor observation in the site has been implemented and the records show that the building in the short side has noticeably vertical vibration characteristic in a low area of frequency, which is not usually seen on stably conditioned buildings. In this research, a simple translation-rotation model of the building, which is coupled by horizontal and vertical movement with rotation, has been proposed to understand the phenomenon. The analyses similarly demonstrate the characteristics and indicate the present bearing capacities of the damaged pile heads in terms of the stiffness respectively.
