京沪高速南京长江大桥结点受力性能分析

在建中的京沪高速南京大胜关长江大桥是1座6线铁路三主桁的六跨连续钢桁拱桥,桥面系为道碴整体桥面的多横梁体系,主桁下弦结点的构造很复杂。在全桥整体分析的基础上,对结点考虑构造细节作了更精确的局部分析。论述了结点的截取原则和范围,力边界条件、位移边界条件的施加方法,结点受力状态可能最不利活载工况的选取原则和选取方法。对结点选取5种可能最不利活载工况与恒载和风荷载组合后进行了局部分析。结果表明:局部分析可以获得结点板等部位整体分析中无法得到详细的应力分布;整体分析中与结点相连的杆端应力集中现象在局部分析中得到很大的,表明结点处加高、加厚、加强等构造措施很有效。

Local mechanical analysis of the Joints of Nanjing Yangzi River bridge of Beijing-Shanghai high speed railway

The abuilding Nanjing Dashengguan Yangzi River Bridge(NJB) of Beijjing-Shanghai high speed railway is a continuous steel truss arch bridge with 6 spans,3 principle trusses,6 railway lines,and integral ballast deck.The floor system of the bridge is multiple cross girder system.The structure of the low chord joints of the main truss is rather complicated.On the basis of the analysis of whole NJB,more accurate local analysis was applied on the joint with consideration of the structural details.The author disserted the principle and range of intercepting the local model,the methods of applying force and displacement boundary condition,the principle and method of selecting likely most unfavorable live load condition for the joints mechanical states.For each joint,5 possible least favorable live load conditions were chosen.The local analysis was done with the combination of the chosen least favorable live load condition,dead load and wind load.The results show that more detailed stress distribution of joint board can be got from local analysis,which is unable got from the integral analysis,the stress concentration phenomenon on the end of the chord connected with the joints is improved in the local analysis compared with the integral analysis,which demonstrates the structural measures such as heightening,thickening and strengthening the joints are very effective.