1 A SIMPLIFIED METHOD FOR DYMANIC RESPONSE ANALYSIS OF SOIL-PILE-BUILDING INTERACTION SYSTEM IN LARGE STRAIN LEVELS OF SOILS

A series of shaking-table tests of a scaled soil-pile-building model were performed in order to study the effects of the plastic deformation of soil on dynamic characteristics of the soil-pile-building interaction system. The elasto-plastic material for model ground was made by Plasticine, whose strain dependency of the stiffness and the damping are similar to those of clayey soils. The input motion is 1968 Hachinohe EW and its maximum accelerations were set to be 100, 300 600 cm/s2 at the shaking table. Results show the average value of maximum soil strain became from 0.0018 to 0.018 and the natural frequency and the amplification factor decrease by 28 % and 39%, respectively. Dynamic response analyses, which combined the mass-spring model (SR model) having swaying and rocking spring and dashpots located at the foundation of the building and an equivalent linearization method, were carried out. The difference in the natural frequency obtained by the test and analyses were within 5 % and those of maximum acceleration at the building are within 10%