井塔结构的动力特性和弹塑性分析

根据井塔结构的特点，将其划为等价平面问题。考虑了杆件的轴向变形、剪切变形、杆端刚域影响和由竖向荷载引起柱的Ｐ－△效应。引入了虚拟剪切梁的概念。建立了杆系－层模型。动力特性分析时，将水平自由度视为主动力自由度，把结构质量集中到楼层上。弹塑性分析时，选用弯矩－曲率双线性恢复力模型，并给出了判别条件。在算例中，为了了解结构进入弹塑性状态的过程，采用逐级施加倒三角形分布荷载的加载制度。

DYNAMIC CHARACTERISTICS AND ELASTO-PLASTIC ANALYSIS OF SHAFT-TOWER STRUCTURES

in this paper structure is regarded as equivalent plane problem based on mechanical properties of shaft-tower structures. Taking into consideration of the axial and shear deformation, effect of stiff region of a member ends, as well as axial force-lateral displacement effect,the concept of fictitious shear beams is introduced. The member-floor mechanical model is established. In the dynamic analysis the horizontal freedom degree is considered as the main freedom.The mass of structure is concentrated on the floors. In elasto-plastic analysis, double-line bending moment vs curvature relationship is used, and discriminant condition is given. In some computational examples in order to understand how structure enters into the elasto-plastic state a step loading system in inverted triangular distribution is introduced.