【作者】 朱晶晶；

【导师】 李亚明； 唐柏鉴；

【作者基本信息】 江苏科技大学 ， 结构工程， 2010， 硕士

【摘要】 预应力钢压杆是通过对普通钢压杆增加弹性侧向支承来提高其稳定承载力的一种构件,是预应力钢结构中的基本构件之一。在预应力钢压杆中,拉索的初始预应力是决定其稳定承载力的重要因素,虽然预应力钢结构近年来得到了迅速发展,但是对预应力钢压杆的初始预应力取值研究较少。本文着重研究了初始预应力的取值方法,给出了简便可行的计算公式,分析了相关参数,并采用有限元软件SAP2000对预应力钢压杆进行了屈曲分析、屈曲后分析和初始几何变形敏感性分析。具体如下:1.分析了预应力钢压杆的正对称屈曲和反对称屈曲,根据预应力钢压杆屈曲时拉索中力的大小,将初始预应力划分为三个范围,并推导了每个范围的初始预应力公式,给出了采用不同数量的正弦曲线叠加来模拟中心杆变形时,最佳初始预应力和最大屈曲临界荷载的理论结果;并对最佳初始预应力取值产生较大影响的三个参数(节间数、拉索直径、撑杆长度)进行了分析。2.对施加不同初始预应力的钢压杆进行了屈曲后分析和初始几何变形敏感性分析,讨论了最佳初始预应力的取值方法。3.因为不对称屈曲的最大临界荷载在某些情况下是三种屈曲模态中最小的,所以本文进一步推导了适用于所有屈曲模态的初始预应力公式,并给出了相应的设计建议。研究结果表明:理论计算时可以选取与预应力钢压杆节间数N相同数量的正弦曲线叠加来模拟中心杆变形,并且理论结果与SAP2000的分析结果吻合较好。施加最佳初始预应力时,预应力钢压杆屈曲后性能非常不稳定,并且对初始几何变形也非常敏感;而当施加的力略大于最佳初始预应力时,屈曲后性能较稳定,并且对初始几何变形敏感性较小,更重要的是可以保持有较高的屈曲临界荷载;但是初始预应力如果加太大,则会减小屈曲临界荷载;所以实际工程中只须施加比最佳初始预应力略大的力即可。更多还原

【Abstract】 A prestressed steel stayed column is a structural component that is reinforced by stays and rods such that its strength is increased in axial compression, it is one of the basic components of prestressed steel structure. The prestress in the stays determine the stable loading capacity of the prestressed steel stayed column, although the prestressed steel structure has developed rapidly in the past few years, the prestress has been the least studied. This dissertation studies of the value of the prestress, not only gives the formula,but also analysis the parameters. Then, buckling and post-buckling and initial geometric imperfection sensitivity are analyzed by using SAP2000. The main works are:1. Symmetric and anti-symmetric buckling are analyzed. The prestress in the stays is divided into three zones according to its value. Different formulas are given in these three zones. Theoretical results of the optimum prestress and the maximum critical buckling load which are calculated by the formulas using different composition sinusoidal are contrasted. Parameters which influence the optimum prestress are also analyzed.2. Post-buckling and initial geometric imperfection sensitivity are analyzed for prestressed steel stayed columns which have different prestress.3. Because the maximum critical buckling load of the asymmetric buckling is the lowest of the three buckling modes in some cases,the dissertation derive the formula of prestress which is adequate for all buckling modes and give the design recommendations finally.The research results have shown that:The number of the sinusoidal can be selected as the same as the internode number N and the theoretical results agree well with the results of SAP2000.The post-buckling response of the column is unstable when the optimum prestress is taken and it shows great sensibility to the initial geometric imperfection, but when a larger prestress is taken; the column has a stable post-buckling response and is insensitive to the initial geometric imperfection. Considering greater prestress will diminish the magnitude of the critical buckling load, so prestress which is slightly larger than the optimum prestress would be the best in practical engineering.更多还原