The paper analyzes structure of a underground garage,and it compares application of floor structure without beam system and main and sub floor structure system in practical project through calculation,and it also analyzes from stucture safety,reasonability,economic aspects and so on,so as to make sure the reasonable structure scheme.

Overall design of main girder structure is conducted and some special structures are added to it.

The Interaction between Primary and Secondary Structure and Initially Research on Fluid-Solid Effort;

By using modal truncation technique,the frequency-domain modal transfer function and displacement response of the primary and secondary structures are obtained respectively.

To a typical model of primary-secondary systems, the response spectra of absolute acceleration and relative displacement of the secondary structure are obtained, in which coupling effet between the prima.

To a typical model of primary-secondary systems,the response spectra of absolute acceleration and of relative displacement of the secondary structure is attained where coupling is conside.

Hybrid modal synthesis with connecting area considered separately is proposed, which is very efficient to analyze dynamic characteristics of multiply supported primary-secondary systems with different connecting element stiffness and damping.