【作者】 张国军；

【导师】 张爱林；

【作者基本信息】 北京工业大学 ， 结构工程， 2006， 博士

【摘要】 预应力钢结构是钢结构领域的一个新体系,可以创造新颖的钢结构形式和独特的建筑风格。将预应力引入钢结构,可以充分发挥材料强度潜力,减少用钢量,同时还可以改善结构构件受力状态,降低应力峰值,增大结构刚度和稳定性,改善结构静、动力特性。多次预应力钢结构通过预应力→加载→预应力→……分多级施加预应力,不仅可以反复利用材料弹性界限内的抗压与抗拉强度,进一步提高结构承载能力,节约材料,产生更大的预应力效益,而且能够利用多次预应力,实现更大跨度的空间结构形式。本文通过理论分析、数值模拟和模型试验等研究手段,对多次预应力钢结构的稳定、优化、静动力特性及抗震性能进行了研究,论文的主要研究工作和相应研究成果如下:1.基于非线性有限元原理对预应力空间钢结构进行了稳定性能分析。以预应力拱桁架为对象进行了特征值屈曲分析、采用弧长法和牛顿-拉斐逊法进行了荷载-位移全过程屈曲分析,采用一致缺陷模态法进行了考虑初始缺陷下的结构非线性屈曲分析。得出了预应力拱桁架结构的平面外失稳特点,得到了预应力对结构稳定的影响规律,并指出了Ansys进行预应力钢结构屈曲分析的一些缺陷,对今后此类工程的设计具有一定的指导作用。2.提出了预应力和截面优化的数学模型及求解方法。在综合对比预应力钢结构分析中引入预应力的各种方法的基础上,首次提出了以拉索初始应力为设计变量、以结构杆件应力平方和最小为目标函数进行预应力优化的方法,并在此基础上建立了结构重量最轻为目标函数、预应力和截面两级优化的预应力空间钢结构优化设计模型,该模型考虑了结构应力约束、位移约束条件、长细比约束和变量上下限约束,并且同时考虑了杆单元和梁单元两类单元的稳定约束。编制了相应程序,算例表明所提出方法不仅可以满足工程优化设计需要而且可以较快地收敛得到满意的优化结果。3.针对多次预应力钢结构施工特点发明了一种在支座张拉端具有十字交错开槽环状夹片的多次张拉锚具的可滑移弹性减震支座。该支座利用铅芯橡胶垫作为弹性减震体。对该支座进行了力学性能研究及铅芯橡胶垫性能试验,建立了支座的力学模型,得到了铅芯橡胶垫的分析模型及各种相关性能。该支座在施工过程中可相对于支撑柱产生一定的滑移和转动,大大减小施工过程中支撑柱顶的水平反力,在施工完成后可使支座与支撑柱具有可靠的连接,传递轴向力与一定的剪力,并能在水平方向产生一定弹性变位和转动,适用于预应力网壳、预应力更多还原

【Abstract】 Multi-prestressed steel structure is a new system in the steel structures field. . Introducing prestress into steel structures can make full use of material strength, reduce the consumption of steel, improve the mechanics behavior of structutal members, debase the stress peak value, and enhance structural stiffness and stability. Through stepped tensioning and loading such as tensioning→loading→tensioning→…,multi-prestressed steel structures can multiply utilize material strength in elastic range, increase bearing capacity and economizing material further, produc more prestress efficiency. Further more, longer span spatial structure style can be carried out through multi-prestress.In this paper, the stability, optimization, static and dynamic performance and earthquake-resistance capability about multi-prestressed steel structures are studied through those research methods such as theoretical analysis, numerical simulation and model test, et al. The main research work and outcome of this paper are presented as following:1. Stability analysis is carried out with prestressed spatial steel structures according nonlinear finite element theory. Eigenvalue buckling analysis and load-displacement full process buckling analysis on the bases of arc-length method and Newton-Raphson method and nonlinear buckling analysis considering initial flaw based on uniform modal flaw method are carried out with prestressed arch truss. The buckling performance outside plane of prestressed arch truss and the influence of the prestress on structural stability are obtained through buckling analysis. The flaw of the buckling analysis of prestressed steel structures through Ansys is pointed out, which is helpful to the design of these kinds of engineering.2. The optimization model of prestress and cross-section and the resolve method are presented in this paper. Various methods of introducing prestress into the numerical analysis of the prestressed steel structures are summarized and comparied. A new method of optimization of prestress is presented, which takes initial stress as design variable, and takes minimum sum of squares of the structural member stress as objective function. On this base, two-level optimization model of prestress and cross-section for prestressed spatial steel structures is created, which involves the restriction of stress, local stability and displacement. The corresponding programma is更多还原