钢结构斜隅支撑体系弹塑性计算方法研究

An analysis method for elastoplastic calculation of knee bracing frame

钢结构斜隅支撑体系是一种新型结构体系。与一般的纯框架和中心支撑框架体系不同,该体系综合了延性好、抗侧移刚度大的特点。在遭遇罕遇地震荷载作用下,结构通过隅撑的弯曲屈服耗能,保证其他主要构件不受损伤,使得震后修复较为容易且费用较低。但此类结构复杂的非线性分析在一定程度上阻碍了其推广与应用。本文经过力学分析推导,结合有限元方法和塑性铰理论提出了一种简化计算分析模型。采用该模型,整个求解过程仅涉及少量的线性计算,不涉及迭代,可以有效地简化斜隅支撑结构在侧向荷载作用下的弹塑性受力分析。算例表明,该计算方法建模合理,运算速度快。同时,计算结果稳定、可靠,与有限元分析程序得出的结果具有较好的一致性。

<Abstrcat> An analysis method is presented for the determination of the elastoplastic behaviour of a new structural system, named knee bracing frame. Different from the moment-resisting and concentrically braced frames, the knee bracing frame combines excellent ductility and lateral stiffness by setting the diagonal brace to a knee element instead of beam-column joint. Through the flexural yielding of the knee element under a severe earthquake, the structure could dissipate most of the input energy. No damage would occur to the main structural members and the rehabilitation could be very easy and not costly. However, despite its favorable features, this new system had not been widely used since its presentation. One difficulty that stops it from wide application is the complex nonlinear analysis. To make a simplification, a mathematical analysis model is formulated by combining use of the finite element method (FEM) and the plastic hinge theories. With this model, no iteration is involved in the solving procedure and only a few simple calculations are needed. In the end, examples are presented, which show that by using the analysis model, an easier and faster calculation could be expected, and the results are stable and reliable and consistent with the results of FEM.