The Impact Of An Adjacent Structure On The Horizontal And Torsional Foundation Input Motion Of An Embedded Foundation

The shortage of urban area leads to the densification of the buildings. While the constructions are becoming taller and taller, the space between them tends to be narrower and narrower. In response to this phenomenon, the seismic design of buildings was required to be more rigorous. At present, the seismic code of our country stipulates that we should conduct the seismic analysis based on the rigid foundation assumption, which only calculates a single structure of the seismic response, not conforming to the reality. Usually, there will be adjacent buildings near the existing buildings. When the earthquake occurs, the dynamic response of the neighboring buildings will have an effect on the existing buildings through soil. To solve this problem, it is necessary for us to take the interaction of soil—adjacent structure into account in the construction of seismic fortification.Currently, there are many research achievements about the interaction of soil—adjacent structure. Researchers primarily focused on dynamic response of structure in previous studies, but paid little attention to the dynamic response of embedded foundation. The dynamic response of embedded foundation, being the most basic parameters to the research of the interaction of soil—adjacent structure, reflects the dynamic property of the constructions, hence it is necessary for us to carry on a research for it. Establishing the three-dimensional finite element model of soil—adjacent structure by ABAQUS, this thesis tries to analyze the effect of the soil-adjacent structure interaction on the input motion of an embedded foundation in horizontal and torsional directions under the seismic situation.The main contents of this thesis are as follows:(1)First of all, using the ABAQUS set up a three-dimensional finite element analysis model, namely, the free field soil, the embedded foundation-soil and the embedded foundation-soil-adjacent buildings. Then through a modal analysis based on the finite element models, this paper extracts the natural frequencies and calculates the Rayleigh damping coefficient of each model.(2) Altering the base spacing between embedded foundation and adjacent buildings, then, tries to analyze the seismic time history of the above model. Conducting Fourier transformation to time history data by software FORTRAN, it is changing curves in the frequency domain can be obtained. The result shows that the alteration of base spacing has certain effect on the horizontal and torsional foundation input motion of an embedded foundation.(3) Changing the height of adjacent buildings, then, tries to analyze the seismic time history of the above model adopting the same data processing methods as mentioned above. The consequence proves that changing the height of adjacent buildings influences the horizontal and torsional foundation input motion of an embedded foundation.(4) Replacing the embedded foundation as the constructions, changing the above two influence parameters, then, establishing three-dimensional finite element analysis models of the two buildings, this thesis tries to analyze the effect of the soil-adjacent structure interaction on the horizontal and torsional foundation input motion of adjacent buildings, the results are presented to verify the effectiveness of the above rules.