Sismic Analysis Of The New Steel X-braces Structure

In order to improve the lateral stiffness of structure effectively, the braces were installed in the frame structure. To the traditional system, the braces undertook part of vertical forces under the vertical loads, so stiffness and bearing capacity of braces cannot be used to resist horizontal load completely. In order to solve this problem, we usually installed the braces after completing installation of the main structure and most of the vertical load had been to the column. But this method is not ideal, which will extend the time of the project, at the same time the columns had already been made compression deformation, the actual size of the braces had been changed compared with the design size. So we proposed a new type of steel braced structure which braces did not bear the vertical loads.The new X-braced steel frames which the braces and beams connected through the bracket completed the independent vertical deformation between the braces and beams and coordinate horizontal displacement by changing the connection of braces and beam. The paper analyzed the performance of the new X-braced steel frames under different load by the finite element software ANSYS and compared the old and the new system of seismic performances.The new X-braced steel frames could realize the idea that the brace do not bear any force under the vertical loads and play the lateral stiffness of the braces. The decreasing of web thickness of the bracket will lead reducing of the lateral stiffness of a new system but the ductility will enhanced. In the elastic state, the lateral stiffness of new system and traditional system are the same, but the compressive brace of traditional system buckling was earlier than The new system.Then lateral resistance of the new system is superior to the traditional system and the horizontal carrying capacity of the new system is greater than the traditional system, the lateral performance of the two systems were gradually tended to be the same after tensile braces yield.In cyclic loading, the hysteretic behavior of the new system was superior to the traditional system and stiffness degradation of the new system was later than the traditional system.Under the action of seismic waves, When the structure was into the plastic state, the lateral resistance of the new system was grater than the traditional system,it played a better performance than the traditional system.