Research On Overall Seismic Performance Analysis Of Rigid Pile Composite Foundation- Foundation-Upper Structure

As a new type of foundation ground, rigid pile composite foundation has been widely used in 10 to 30-storey high-rise building to withstand the design basis.Because of its uneven load capacity, small differential settlement, construction speed, good economic characteristics.However, due to its own rigid composite foundation structure complexity, there is now relatively few studies of its seismic performance, in practical engineering design, plus a lack of considering the effect of horizontal seismic loads, some security risks and uncertainties are given to composite foundation when establishing high-rise buildings..In this paper, we studying on the seismic performance of rigid pile composite foundation and superstructure, a numerical analysis method is adopted, and considering the condition of the soil layer and the existence of the basement in Zhengzhou, research and analysis of the rigid pile composite foundation- Foundation- Superstructure dynamic mutual role in the overall system of seismic performance,and the cushion of the composite foundation layer slip damping mechanism and its effects on the seismic response of upper structure. On this basis, the sensitivity analysis of the factors affecting the seismic performance of composite foundation is carried out. The main research contents of this paper are as follows:(1) In this paper, based on the ABAQUS finite element software, the 8 * 8rigid pile composite foundation model and the common pile foundation model are established, according to the selection, when modeling unit connection, boundary condition and damping calculation of one are described, based on the comparison of vibration characteristics of rigid pile composite foundation and pile foundation, from its vibration analysis of the seismic performance of the advantage and disadvantage of the two;(2) Dynamic time history response of rigid pile composite foundation and ordinary pile foundation under the action of rare earthquake and rare earthquake are compared and analyzed, the results show that under frequently occurred earthquake,the composite foundation cushion damping effect compared with the ordinary pile is not obvious, but in rare earthquake, response of composite foundation pile,foundation, cushion response and superstructure response compared with common pile foundation have significantly reduced, showing the great earthquake of rigid pile composite foundation has better seismic behavior.(3) The rigid pile composite foundation with cushion layer, the thickness and modulus of pile pile diameter and pile length, the basement and the soil stratification of rigid pile composite foundation of the sensitivity analysis, the results show that the cushion thickness is more and more big, modulus are smaller, is between layers of rigid pile composite foundation superstructure displacement is smaller, and the bending moment of the pile body is the same. In addition, pile pile diameter is more big, pile length is smaller, earthquake resistance becomes more favorable, the composite foundation are basement and in-homogeneous soil and seismic response of large, is not conducive to seismic.