The Experimental And Theoretical Study On The Over-all Seismic Behavior Of D-Type Eccentrically Braced Frames

Eccentrically braced frame is a new lateral-loads-resisting system which combines the advantages of both moment-resisting frames and concentrically braced frames. It can meet the requirements of strength, stiffness and energy dissipation capacity of the structure. The domestic and foreign study on the Eccentrically Braced Frames mainly focused on a single link, but seldom regarded the over-all behavior of the frame. The over-all seismic behavior of D-type Eccentrically Braced Frames is studied by the method of the experiment and the finite element analysis in the paper.First, some factor that effects the seismic behavior of D-type Eccentrically Braced Frames is discussed in details. One third scale model of the traditional D-type Eccentrically Braced Frames is built according to this. The models are contrastively analyzed by experiment and finite element analysis. The deficiencies of the traditional D-type Eccentrically Braced Frames are indicated and the validity of the theoretical analysis is verified.A new connection between link and column is proposed in this paper according to the deficiencies mentioned above. The beam web and flange in the beam-column connections are all reinforced effectively. The new protocol is analyzed comparing to the traditional D-type Eccentrically Braced Frames by ANSYS. The results indicate that the new protocol can draw the shear link away from the column face, preclude yielding in the link in the region adjacent to the column and draw the plastic hinges away from the welds. The new protocols can also relax the extreme local deformation in the link flanges in order to allow the rotation of the links and develop plastic deformation sufficiently sufficiency. The new protocols perform good seismic behavior. The concentration of stress and strain in the top flange owing to a great deal of welds was reduced to avoid the brittle failure.Finally, the influence on the structure behavior in consideration of the change in size of the side-plate is discussed in the paper. The stress distribution of the key part of the connection is also discussed. Results are drawn which can be referred as theoretical foundation for further research on the application of the new protocols.