钢管混凝土悬链线深拱单点加载试验研究

Concrete-filled steel tubular (CFST) catenary arches are widely used in bridge engineering, but there is rarely investigation on the in-plane stability performance. In this paper, in-plane stability tests of two CFST catenary deep arches with the span of 6 m, the rise-to-span ratio of 1/4.5 and the axis coefficient of 2, were conducted under the mid-span and quarter-point concentrated loadings, respectively. The test results show the test arch under mid-span loading lost stability in a symmetric mode while the arch under quarter-point loading fails asymmetrically. Local buckling is observed on the upper edge at the loading point when the catenary arches fail. The confining effect of outer steel tube on core concrete is obvious after 60% of the ultimate load is reached. In addition, the finite element (FE) model of CFST catenary arches was established with the beam-element method. And the effects of slenderness ratio, rise-to-span ratio, steel ratio and arch axis coefficient on the bearing capacity were analyzed. It is found that the bearing capacity of CFST catenary arches under the single-point loading is strengthened with the decrease of slenderness ratio and the increase of rise-to-span ratio and steel ratio, while the effect of arch axis coefficient is small and can be ignored.