In-plane bearing capacity analysis of concrete catenary arch with rigid skeleton: test and simulation

Abstract Although the rigid skeleton concrete arch has been widely used in engineering, the research on the failure mode and bearing capacity of this kind of arch is very few, and the previous research on the bearing capacity of arch is mostly concrete arch or concrete filled steel tube arch. To better understand the mechanical properties of rigid skeleton catenary arches, three arch models with a span of 12 m were constructed. The study focuses on the in-plane failure mode and mechanical characteristics of the arches. It analyzes the variation law of the load–displacement curve, the section strain characteristics, the strain behavior of the steel tube and concrete encasement, and the influence of different loading methods and longitudinal reinforcement ratio on the mechanical properties of arch. On this basis, based on the verified ANSYS simulation model, the influence of key parameters such as arch axis coefficient and rise span ratio on the bearing capacity of arch ribs under multi-point loading is analyzed. The load–displacement curve of rigid skeleton concrete arch has experienced three typical stages: elasticity, crack propagation, and yield of reinforcement and steel tube. And the plastic deformation of arch rib is increased in crack stage and steel tube yield stage. Regardless of the load at L/2 or at the quarter point, when the arch rib is damaged, the concrete crack at the loading point develops fully, the concrete is crushed, and the steel tube and reinforcement yield. Compared with the concrete arch without rigid skeleton, the bearing capacity of the arch under L/2 and quarter point loading conditions increases by 45.6% and 43.7%, respectively. The rigid skeleton and concrete can resist external loads together. The contribution of rigid skeleton to the bearing capacity of arch can not be ignored. Under different levels of load, the strain distribution of encased concrete and steel tubes along the section height is coincident. The encased concrete and steel tube of the rigid skeleton arch can work together without sliding. When the arch rib is subjected to multi-point symmetrical loads, the slenderness ratio has the greatest influence on the bearing capacity, followed by the arch axis coefficient. Among them, the slenderness ratio changes from 48 to 90, resulting in a 52.2% reduction in the bearing capacity. When the slenderness ratio changes from 90 to 130, the bearing capacity decreases by 46.4%.