轴压套管构件的理论和试验分析及设计

针对轴压套管构件，分析了柔性套筒约束下内核的变形过程，提出了套管构件的设计公式、相关构造和内核的轴力-轴向位移非线性计算模型.理论与试验的对比研究表明：当内核与套筒的刚度比小于0.005时，内核可以由低阶屈曲模态变形到高阶屈曲模态；当内核与套筒的刚度比大于0.005时，内核将与套筒一起发生侧向失稳破坏.套筒较刚、内核长细比较小、内核-套筒净间隙较大，不利于显著提高内核的轴压承载力．内核外伸套筒部位是薄弱部位，为避免该部位的屈曲，需要减小该部位的长度，并对该薄弱部位予以加强.与传统圆钢管相比，套管构件中轴压内核的承载力有大幅度提高，同时内核的延性有较大改善.

Theoretical and Experimental Analysis of Axial Compression Sleeved Column and Its Design

This paper presented the theoretical solutions and the experimental tests of the deformation processes of the inner core constrained by flexible sleeve in a sleeved column, and proposed the design formulas, relevant details and the nonlinear computation model of inner core''s axial load-displacement. The results indicate: (1) when the stiffness ratio between the inner core and the sleeve is smaller than 0.005, the inner core will snap from low order mode to high order mode; when the stiffness ratio is larger than 0.005, the inner core and the sleeve will buckle together laterally; (2) the stiff sleeve, small slenderness ratio of the inner core and the large net clearance between the inner core and the sleeve exert adverse effects on the remarkable improvement of the inner core''s bearing capacity; the parts of the inner core outside the sleeve are most vulnerable, their length must be small and the parts must be strengthened to avoid the local buckling of the inner core; and (3) compared with the conventional circular steel tube, the compression capacity of the inner core has been improved substantially and its ductility has also been greatly improved.