Toshiaki Nagao

SEISMIC BEHAVIOR OF PILE-SUPPORTED BUILDING WITH SEMI-RIGID PILE HEAD CONNECTIONS IN LIQUEFIABLE SOIL

Research Engineer, Technology Center, Taisei Corp., M. Eng. ** �������������������������� Prof., Dept. of Architecture and Building Engineering, Tokyo Institute of Technology, Dr. Eng. *** ������������������������ Chief Research Engineer, Technology Center, Taisei Corp., Dr. Eng. ������������������������������ ���������������������������� SEISMIC BEHAVIOR OF PILE-SUPPORTED BUILDING WITH SEMI-RIGID PILE HEAD CONNECTIONS IN LIQUEFIABLE SOIL DYNAMIC CENTRIFUGE MODEL TESTS OF BUILDING WITH EMBEDDED FOOTING IN NON-LIQUEFIABLE SURFACE LAYER

Dynamic centrifuge model test of pile-supported building with semi-rigid pile head connections in liquefiable soil

Abstract Dynamic centrifuge model tests were conducted to investigate the seismic behavior of buildings with semi-rigid pile head connections in liquefiable soil. The test results and analysis show that: (1) The semi-rigid pile head connections effectively reduce the bending moment of piles both before and during liquefaction; (2) The natural period of the soil-pile-structure system with semi-rigid pile head connections becomes longer than that with rigid pile head connections during liquefaction; (3) The hysteresis damping in the relation between inertia force of the structure and displacement of the foundation, with semi-rigid pile head connections, increases with larger displacement; and (4) The maximum acceleration of the superstructure with semi-rigid pile head connections is considerably smaller than that with rigid pile head connections in liquefied soil.

An Analytical Model for Embedded Foundations of Building Structures Subjected to Horizontal Loads

Abstract This paper describes an analytical model for predicting the load−displacement relationship of structures with embedded foundations subjected to horizontal loads. The proposed analytical model uses discrete springs to represent soil resistance (passive resistance, side friction, and base friction) and considers non–linear behavior using a hyperbolic function based on tests conducted by the authors. A method of estimating the initial tangent modulus of the hyperbola is also presented. Numerical analyses are carried out using the proposed model for two horizontal loading tests on actual caissons assumed to represent the basement of a building. The analytical results are in reasonably good agreement with the measured results.