Hisatoshi Kashiwa

STUDY ON RESPONSE OF BASE-ISOLATION BUILDING IN OBLIQUE COLLISION WITH RETAINING WALL

When large earthquake beyond the input level in the aseismic design occurs, a base-isolated building may collide with surrounding retaining wall. Then superstructure and base isolator are severely damaged and the building doesnt keep its performance. To address this subject, we study response of a base-isolation building in collision including oblique impact to retaining wall. This paper discusses experiments of base-isolated building model taking oblique collision into account. Based on the results of experiments, we analyze oblique collision in detail by 3D-FEM. Furthermore response of a real-scale base-isolation building is studied when building collides with retaining wall. As a result of these studies, we show the influence of oblique collision on response of base-isolation building, retaining wall and surrounding soil during extra-large earthquake.

EARTHQUAKE RESPONSE OF BUILDING SUPPORTED ON PILES CONSIDERED WITH NONLINEARITY OF PILE-SOIL SYSTEM

To investigate effects of nonlinear soil-structure interaction, we study the influence of the nonlinearity of pile damage on building response. In this paper, it is presented that the results of the centrifuge tests considering elasto-plastic behavior of pile and its simulation analysis. The following conclusions were obtained: (1) The response of the building, which is calculated considering the nonlinear characteristics of pile damage during the main shock, is smaller than that of the building which is calculated without the nonlinearity of pile. (2) In frequency transfer function between the ground and the building, the reduction of predominant frequency is mainly caused by the nonlinearity of the soil around piles. (3) The nonlinearity of pile damage has a very small effect in the building response in aftershock.