| Concrete filled steel tubular (CFST) truss rib arch usually used to design the large span arch bridge. It consisting of longitudinal CFST elements, hollow steel tubular diagonal lacing or steel plate web. Comparing the reinforced concrete, single tube and dumbbell-shaped cross section, it has a higher efficiency of cross-section. The lateral bracings are linked between the two ribs too ensure lateral stability of the truss rib arch. So researching the influence of lateral bracing to the CFST truss arch outside stable performance has important theoretical significance and value of the works.In this paper, we had introduced the overview of the CFST structure and its development, and listed the research results of some domestic and foreign researchers from the stability of CFST truss rib arch bridge. Then it briefly introduced the theories and methods of elastic stability and ultimate strength which are about the CFST truss rib arch. Among, the elastic stability analysis of the CFST has a larger proportion, the analysis of ultimate bearing capacity is smaller; there are more of the researches use software to analyze the stability of CFST arch, just a little to establish the actual model and research. This makes we should be further explored the design parameters of the CFST truss rib arch.In this paper, we used the self-designed CFST truss arch for the study, and using ANSYS finite element analysis software to establish the spatial finite element model of the arch. We had analyzed the arch of the instability modes, elastic stability coefficient and studied the research which is considering the material nonlinearity and geometric nonlinearity ultimate bearing capacity. We explored the lateral bracings of the arrangement, the style and the stiffness how to influence the CFST truss rib arch out-of-plane stable performance. The following conclusions:(1)Try to choose a suitable numbers and spacing of the lateral bracings in the arch design, because they can improve CFST truss arch outside stability.(2)The relative rubbing would be large at the point of quarter on the arch. Therefore, we should be set a strong lateral bracing on it. And to avoid the maximum spacing fall on it to make the arch elastic stability lower.(3)The dome should be set a lateral bracing to enhance the horizontal linkages of the arch and increase elastic stability. Moreover, it just choose the "一" shaped lateral bracing to enough to ensure elastic stability, reduce the weight and ease the construction process of the lateral bracings.(4)For the style of lateral bracing, the lateral bracing of "米" shaped and "X" shaped could get a higher coefficient of elastic stability. The end of the lateral bracing use the "K" shaped would be achieved deck clearance requirements easily, and the elastic stability does not decrease.(5)The influence of the lateral bracing’s stiffness to the arch is not obvious. When designing, selecting the appropriate pipe wall thickness can both to ensure local bucking not occur, but also can reduce the weight.(6)According to the results of using the ultimate strength analysis with the thousandth of the initial defect, the influence of lateral bracing to the CFST truss rib arch ultimate bearing capacity is the same of the influence of its elastic stability.(7)To the CFST truss rib arch, the ultimate bearing capacity factor is smaller than the elastic stability coefficient. All of the models’ coefficients have a difference of about 15%. It means in considering the problem of the CFST truss rib arch stability, necessary to carry out analysis of elastic stability, but also take into account the question of its ultimate capacity factor. Both are indispensable. |
PDF Full Text Request