Research On Spacial Stability Of High-rise Staggered-truss System In Steel Structure

The following works have been fulfilled within this thesis: First of all, based on the three-dimensional Virtual Work increment equation of Finite Deformation Theory, applied Updated Lagrange Method, and deduced geometric stiffness matrix of elements considering factors, such as the influence of shear force, second-order effects, warp distribution and section opening and close, and geometric initial stress stiffness. Meanwhile, establishing nonlinear finite element mechanical model of Staggered-truss System, offering theoretical evidence for the compilation of calculation software of the System.Secondly, Staggered-truss System be divided into strong-bracing and weak-bracing staggered truss by threshold stiffness of bracing, the objective is to use traditional coefficient for effective length to consider structure stability. It was clear from the height-width ratio of architecture and the span-depth ratio of truss impact greatly on second-order effects by analysis of examples; therefore, Second-Order Analysis Method should be introduced in analysis to consider structure stability.Finally, according to test on Judgment criteria of overall stability of the structure, presenting Judgment criteria of overall stability of Staggered-truss System in high-rise buildings, that is based on the load-displacement curve and slope of tangent line-controlled and element stiffness matrix (positive definite)-controlled. Moreover, using the Direct P-Δanalytic method, putting forward to considering simplified design method of the whole Second-order effects, thus greatly improving computational efficiency. In addition, also to the design of Overall Stability has made some suggestions.