Experimental study on failure of concrete filled steel tubular arch with catenary

In order to explore the mechanical properties of the catenary concrete-filled steel tube arch bridge, a 1:16 scale model test was carried out based on the single tube concrete arch bridge-washiwo bridge with a net span of 95 m. Two concrete-filled steel tubular catenary arch plane single point loading tests were conducted. The test arch span was 5.938 m, the rise span ratio was 1/3.5, and the arch axis coefficient was 1.5. The loading conditions were vault loading and quarter point loading respectively. The test results show that the failure mode of the arch is four hinge failure under the condition of vault and quarter load, Under the two loading conditions, the external deformation of the arch at the loading point is large, but there is no local buckling. After reaching 55% of the ultimate load, the steel pipe of the arch rib begins to restrain the core concrete, and the restraining effect of the steel pipe on the core concrete is earlier than that of the parabolic arch. The deformation and strain of arch under l/4 loading condition are greater than that under vault loading condition, indicating that l/4 loading condition is more unfavorable. In addition, the parameter expansion analysis of catenary concrete-filled steel tubular arch was carried out by using ANSYS beam element method, and the effects of different loading methods, arch axis coefficient, rise span ratio, and steel ratio on the ultimate bearing capacity of the arch were analyzed. The results show that different loading methods, rise span ratio and steel ratio have great influence on the bearing capacity of the arch, and the arch axis coefficient has little influence. With the increase of steel ratio and rise span ratio, the bearing capacity of arch increases correspondingly. The research results can supplement the bearing capacity test library of concrete-filled steel tube arch and provide reference for engineering design, and also pave the foundation for theoretical calculation of catenary concrete-filled steel tube arch. © 2023, Central South University Press. All rights reserved.