Seismic Analyses Of The Two Pall-typed Frictional Brace Systems

Frictional energy dissipation technology is a very important research direction in structure vibration control because frictional damper can improve seismic performance of structure with easy fabrication,simple installation,and economical applicability.But the braces of Pall-typed friction damper are easily buckled in a severe earthquake,and its non-recoverable deformation is large.To overcome these shortcomings,this paper proposes two new brace systems,steel buckling-restrained brace and SMA brace, to replace the ordinary braces.and this paper analyzes the hysteretic behaviors of the two new Pall-typed frictional damper using the finite element software ANSYS12.0.In the last,the paper analyzes the seismic performances of the 10-floor steel frame with the two new type Pall dampers and compares their effects with the frame without dampers.The main contents of this paper are as follows:(1) Pall-BRB system,the Pall-typed frictional damper with steel buckling-restained braces(BRB),is proposed.The paper analyzes the hysteretic behaviord of the BRB brace,and studies the effects of the various parameters on the hysteretic behavior.Then the hysteretic behaviors of the single floor steel frame with the new Pall-typed frictional damper are analyzed in detail.The results show that,the brace can easily yielded under tension and comparession and have good capacity to dissipate energy.The results also reveal that the BRB brace system can overcome the default of the ordinary brace and make the force of the frame structure more reasonable.(2) Pall-SMA brace system,the Pall-typed frictional damper with SMA(Shape Memory Alloy) braces,is proposed based on the super-elastic and shape memory properties.The super-elastic and hystereic behaviors of the SMA brace are studied using ANSYS12.0,and the effect of the various material parameters are also analyzed.Then the paper studies the hysteretic behaviors of the single floor steel frame with the new Pall-typed frictional damper in detail,and also analyzes the effects of the length and the stiffness of the SMA brace on it's hysteretic behavior.The results indicate that the hysteretic loops of the Pall-SMA frictional damper is full and the capability to dissipate energy is better. (3) Taking a steel frame building with the two new Pall-typed frictional dampers as a example in this paper, the responses and the seismic performances of this building subjected to the different predominant period of seismic waves loads are analyzed.The results show that,the two new structures can improve the seismic performance of the frame effectively,and they can also overcome the defaults of the structure with the ordinary Pall-typed frictional dampers.