Studies On Shear Distribution Of Concrete Filled Square Steel Tube Frame- Reinforced Concrete Core Wall Hybrid Structures

Concrete filled steel tube(CFST) frame- reinforced concrete(RC) core wall hybrid structures have been applied to tall buildings and super-tall buildings widely because of its better seismic performance and economic benefit. The study on hybrid structures have been behind of the project practice. How to guarantee that the frame can be the the second line of defense after the core wall cracking or failure is one of the most sophisticated problems needed to be solved urgently.This paper investigates the shearing force assignment rule and its affected factors of the concrete filled square steel tube frame- reinforced concrete core wall hybrid structures under the earthquake. The main study contents of this paper are:1. Modal analysis of 23 models of concrete filled square steel tube column-steel beam composite frame are conducted by using the program PKPM/SATWE and MIDAS/BUILDING. Among the affected factors, steel ratio of CFST columns, section size of CFST columns, beam height of steel beam, thickness of slab, concrete grade,steel grade are considered. According to the results, section size of CFST columns and beam height of steel beam are the greater factors of influence to the structural performance.2. Response spectrum analysis of 4 models of the concrete filled square steel tube frame- reinforced concrete core wall hybrid structures different in height are conducted by using the program PKPM/SATWE. Principle of keeping the stiffness ratio on frameand core wall is put forward. The shearing force assignment rule of hybrid structures in different heights has been clear.3. Nonlinear Static Analysis of 103 models of the concrete filled square steel tube frame- reinforced concrete core wall hybrid structures are conducted by using the program MIDAS/BUILDING.First, view from the compositive angle, the influence to the shearing force assignment rule of seismic action, building height,connection mode was studied in detail. Then, view frome the branch systems angle, the influence to the shearing force assignment rule of steel ratio of CFST columns, section size of CFST columns, thickness of shear wall, position and beam height of steel beam, thickness of slab was studied in combination with the connection mode of the branch systems.