Based on some assumptions,the free vibration frequency of the structures with an outrigger is analyzed,and the relation between the location of the outrigger and the free vibration frequency is inferred through a computer program.

And according to the different values of the stiffness ratio of core-column,the stiffness ratio of core-outrigger,and the stiffness ratio of tube and columns,the relation between the location of the outrigger and the free vibration frequency were inferred through a computer program.

Seismic response analysis of strengthened story structure and seismic energy dissipation structure;

Seismic effect of frame-tube structure with strengthened story and three different seismic energy-dissipation stories is analyzed.

Thus, the frame - core structure with strengthened story is formed.

This paper presents the structural design of this building,including foundation design,the method to resist the buoyancy,the steel concrete column frame joint and the structure of the story with outriggers,etc.

At present, in order to improve the effect caused by vertical rigidity revulsion of strengthened storey, structure engineers always take the measure of increasing the thickness of slab of the strengthened storey or near the strengthened storey.

Adding the strengthened storey in the super high rise steel concrete composite structure can increase the structural rigidity and decrease lateral displacement.

This paper presents some problems to which attention should be paid when using frame-core wall structures with strengthened storeys in seismic regions- They include irregularities of structural rigidity and inner forces, weak storeys pnduced by strengthened ones, structural arrangements and selection of rigidities of outriggers for strengthened storeys and concepts of aseismic design.