Numerical Analysis Of Seismic Performance Of Self-Centering Steel Frame Joints With Shape Memory Alloy Tenders

As for the performance-based seismic design, the largest deformation of buildings is an important parameter to discribe the extent of damage and the seismic performance of the structure. However, the rehabilitation and the reconstruction caused by the residual deformation will result in huge economic losses. As the weak and pivotal element in steel structure, beam-column joints have significant influence on seismic performance of structure. Shape memory alloy(SMA) is a kind of smart material with unique properties and have a wide application prospectin the field of structural vibration control. In this thesis, a kind of self-centering steel frame joint based on superelastic SMA was proposed to mitigate seismic response and to reduce residual deformation effectively. The main contents are included as follows:(1) Based on the FEM software ABAQUS, a subroutine program describing the one-dimensional piecewise linear constitutive model of the superelastic shape memory alloy was developed. With the open subroutine connector, the developed program was inserted in the material library of ABAQUS. With the numerical analysis of a real structure, the effectiveness of the program was vertified.(2) Based on the FEM software ABAQUS, a numerical model of the recentering steel frame joint was built. And the seismic performances of the recentering steel frame joint under the persudo-static cyclic loading were carried out. The cyclic properties, such as hysteretic behavior, skeleton curves, stiffness degradation, resudial deformation and energy dissipation, were analyzed and compared to the common steel frame joint. The analysis results show that bearing capacity of the SMA steel frame joint significantly increased, while the residual deformation dramatically dereased under the unloading, exhibiting satisfactory recentering capacity.(3) The main parameters of self-centering joint were analyzed, respectively choosing prestres of SMA, self-centering tendons position,self-centering tendons diameter, self-centering tendons number, angle iron thickness as the parameters.The results indicated that the above parameters have obvious influence on its recenteringcapacity.(4) Contrapose the deficiency of current seismic design code, the seismic performance objectives of self-centering frame was proposed. Finally the performance-based design method of self-centering steel frame joint were proposed.Therefore the application of SMA in self-centering steel frame joint has important scientific value for the research on seismic performance of self-centering steel frame joint, and provides some reference value for application of SMA in the practical engineering.