Nonlinear Analysis in Limit States Design

为了修复现有的钢结构建筑，必须 根据承载能力评估结构的强度 能力的 还需要进一步分析风的影响， 确定结构在其原始条件下的适用性 以及如果需要，在加强之后。 目前的分析方法是 不足以确定结构系统的全部容量 因为他们忽略了 主要梁柱尺寸。 该项目将 研究几何非线性效应的意义， 材料性能与分析的两个和 三维框架系统。 研究的设计方法有 塑性分析法和极限状态法。 该项目将 制定详细的程序，以估计影响的几何 对塑性设计框架的刚度和强度的影响。 此外，简化规则，以确定何时进行二阶分析 将需要发展。

To rehabilitiate an existing steel-framed building, it is necessary to evaluate the strength of the structure in terms of its load-carrying capabilities. A further analysis for wind effects is also required to determine the suitability of the structure in its original condition and after strengthening, if required. Current methods of analysis are inadequate to determine the full capacity of the structural system because they neglect the effect of the geometrical changes in dimensions of the main beams and columns. This project will investigate the significance of nonliner effects of geometry and material properties in relation to the analysis of two-and three-dimensional frame systems. The design methods to be studies are the plastic analysis and the limit state methods. The project will develop detailed procedures to estimate the influence of geometric effects on the stiffness and strength of plastically designed frames. In addition, simplified rules to determine when a second order analysis is needed will be developed.