| Masonry building with bottom frames is widely applied as commercial building along the street due to its large bottom space, but the poor seismic performance has also been fully confirmed in Wenchuan earthquake. Story isolation is a new seismic isolation technology appeared in the development process of base-isolation, which provides new design ideas to improve the seismic performance of masonry buildings with bottom frames. A story isolated lower frame masonry structure system based on the previous research achievements of isolation technology is presented in this paper, and the theoretical analysis and numerical simulation is researched. This paper has completed the following major aspects.(1) Theoretical analysis of story isolated masonry buildings with bottom frames. The working mechanism of TMD system is briefly introduced from a theoretical view point. After the double mass model and multi-mass model are presented, the vibration equations of the two models are set up. Transfer function and variance analytical expression of structural displacement response under harmonic excitation of the double mass model are deduced. And the main index of isolating effect, "R" is presented.(2) Seismic response analysis of story isolated masonry buildings with bottom frames. Firstly, a building of upper five-story masonry structure with one story frame structure at bottom is chosen as an example, the seismic response (absolute accelerative speed, interlaminar shear force and story drift) under different earthquake waves are studied. Secondly, the seismic response of the same building adopting story isolation, base isolation and non-isolation are studied and compared.(3) Design method of the bottom frame structure. After adopting story isolation, the design and calculation of bottom frame are more complex, the seismic design and calculation method of bottom frame under seldom earthquake is presented based on the seismic analysis theory and numerical simulation analysis results.
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