Research On The Ultimate Load-Carrying Capacity Of The Three-center Arch

The arch is applied in bridge engineering, hydraulic engineering and building engineering widely. As one kind of arches, the three-center arch appears in hydraulic engineering and industrial structure usually, but it appears in building structure hardly. Present-day, there are lack of authoritative definitions and unitive parameters of three-center arches. On studies of the stability of three-center arches, one hand, stability theories of hinged cycloidal arch present are consulted; on the other hand, regarding three-center arches as random axis arches, frames are adopted to analyze approximately. The gymnasium of a university which has a creationary architectural design and a original structural design is a hinged three-center arch with variable sections. The out-of-plane stability of arcuated construction is assured by longitudinal connective components and constitution measure so it is important to research its in-plane stability. The definition and parameter of three-center arches are provided in this paper. Also the in-plane stability of the three-center arch is analyzed by the finite element program of ANSYS.The major contents are summarized as follow:(1)Stabilities of the cycloidal arch with hinged ends and the three-center arch with hinged ends under radial and vertical uniform pressure are compared. First, the stability theory of the cycloidal arch with hinged ends is summarized. Second, using ANSYS soft and considering geometrical nonlinear behavior, the stability of the filled spandrel cycloidal arch with hinged ends under radial and vertical uniform pressure are compared. And the error and applicability range of using the stability theory of cycloidal arch under radial uniform pressure to analyze the stability of which under vertical uniform pressure are obtained. Finally, the applicability of above conclusion for the hinged three-center arch with flat long middle part and large curvity side part is discussed in this paper. (2) Stabilities of the three-center arch with hinged ends and the tilted column portal frame are evaluated. The stability theory of straight column portal frames with prismatic members is mature, but there is lack of research on tilted column portal frames. The regularity of the critical force of in-plane buckling between the hinged three-center arch and the tilted column portal frame are compared in this paper by taking account of variation of parameter. And the applicability and the accuracy of substituting frames for arches to analyzing the stability approximately are gained.(3)The influence of initial imperfect on the three-center arch is analyzed in the paper. For steel structure, the influence of initial imperfect should not be ignored. There are many examples on elastoplastic and large deformation structural analyses by ANSYS soft, but there are lack of studies on the analysis of the ultimate strength capacity of structures with considering residual stress. In this paper, considering geometric initial imperfect and residual stress the in-plane stability of the gymnasium is analyzed by ANSYS soft and the security of the structure is evaluated.