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以空心薄壁高大墩为研究对象,从重庆石门大桥主桥墩Auto-CAD模型出发,选取模型下部桥墩的中面,导入有限元软件Sap 2000,分别选取粱单元和板单元建立了矩形截面和圆端形截面的压杆模型和压板模型,对比分析了两种模型在不同的长细比下的稳定性,并考察出稳定系数随长细比变化的规律性及两种理论各自的适用范围。结果表明,随长细比的增大,模型的稳定系数减小。在长细比较大的时候,稳定系数变化快,在长细比比较小的时候,稳定系数变化缓慢。在不考虑流水冲击时,采用矩形截面比圆端形截面更安全,且施工方便。在长细比大于1∶3.27的范围内,压板理论比压杆理论保守,在此范围内,建议采用压板理论;在长细比为1∶3.27~1∶6.07的范围内,两种理论差异小,均可采用。当长细比小于1∶6.07时,稳定系数很小,结构非常容易发生屈曲。
Taking the hollow thin-walled tall piers as the research object, from the Auto-CAD model of the main bridge piers of Shimen Bridge in Chongqing, the midsection of the piers in the lower part of the model is selected and the finite element software Sap 2000 is introduced. The rectangular cross-section and circular The stability of the two models at different slenderness ratios is compared and analyzed. The regularity of the variation of the stability coefficient with the slenderness ratio and the applicable range of the two theories are also studied. The results show that as the slenderness ratio increases, the stability coefficient of the model decreases. When the slenderness is relatively large, the stability coefficient changes rapidly, and when the slenderness ratio is small, the stability coefficient changes slowly. Without considering the impact of running water, the use of rectangular cross-section than the round section safer, and convenient construction. In the slenderness ratio of more than 1: 3.27, the theory of pressure plate is more conservative than the theory of pressure rod, in this range, it is recommended to use the pressure plate theory; in the slenderness ratio of 1: 3.27 ~ 1: 6.07, the two theoretical differences Small, can be used. When slenderness ratio is less than 1: 6.07, the stability coefficient is very small, the structure is very prone to buckling.