Analysis And Applied Research On Pushover Of RC Frame Structure Based On Single Foundation

Soil-structure interaction is an important factor affecting the seismic response of structures, but most of the current seismic design methods use rigid foundation assumption method instead of considering its impact. The method of performance-based seismic design has been considered as the development direction of seismic design since it came into being. FEMA study reported that the method of performance-based seismic design should be based on reliability theory. As the core method of performance-based seismic design, random Pushover analysis method has been some development, but these studies are mainly confined to rigid assumptions, without considering soil-structure interaction, and the method is not mature enough yet. Thus, it’s necessary to study the reliability and applicability of the certain Pushover analysis method under the condition of considering soil-structure interaction.Firstly, the theory of soil-structure interaction is introduced, including the factors of soil-structure interaction, modeling and the calculation of its parameters; the basic principles of Pushover analysis method is discussed from lateral load patterns, solution of the structural seismic performance point as well as structural seismic performance evaluation; The constitutive relation and concentrated plastic hinge model of the finite element software SAP2000 are described in detail. And the result of an example shows that it is necessary to consider soil-structure interaction in Pushover analysis method.Then, a 6-story plane frame structure on single foundation is analysed, under the condition of the rigid foundation assumption and considering soil-structure interaction, to compare natural period of vibration and modal participating mass ratio. Through the structural model in both cases subject to different lateral force loading mode, compare the structural capacity curves, the structural seismic performance point in rare earthquake and the seismic response at the point in different lateral force loading mode. A comparison among different categories of the site through Pushover analysis has been carried out, to compare the difference of vibration characteristics, capacity curve, the structural seismic performance point in rare earthquake, the seismic response at the point and structure yielding mechanism.Next, the influence on seismic responses of the structure from foundation beam on the single foundation is explored. Foundation beams with different sizes of interface on single foundation are modeled. Through comparing the difference of the seismic responses between the models, some suggestions are put forward for the design of foundation beam.Thereafter, the Whittier Narrows wave, TAFT wave and an artificial wave are chosen to carry out nonlinear dynamic time-history analysis for these seven models, comparing the seismic response of structures under different seismic waves including base shear, lateral vertices and interstory drift. By comparing the time history analysis results and the Pushover analysis results, verify the Pushover analysis method considering the influences of single foundation on seismic performance of structure of the research is effective and feasible.Finally, Pushover analysis for the 6-story of plane frames based on single foundation, from 6 degrees to 9 degrees in various site conditions designed by PKPM, are carried out. And obtain capacity curve and the structural seismic performance point of these structures under the condition of the rigid foundation assumption and considering soil-structure interaction. Randomly select 500 actual earthquake records for different site conditions and seismic grouping from the Pacific Earthquake Engineering Research Center. The actual demand spectrum Pushover analysis is carried out using these actual earthquake records. By comparing the top displacement obtained from the certain Pushover analysis and the actual demand spectrum Pushover analysis discuss the reliability and applicability of the certain Pushover analysis method in various conditions under the condition of considering soil-structure interaction.