Behavior of damaged reinforced concrete arches retrofitted with corrugated stainless steel arches: Experiment, numerical analysis, and calculation method

To address damage in arch components, which are the primary bearing parts of arch bridges, a retrofitting method using corrugated stainless steel (CSS) arches is proposed. This method features convenient construction and low maintenance costs. To evaluate the effectiveness of this retrofitting method, tests were conducted on one reinforced concrete arch (original structure) and one reinforced concrete arch retrofitted with a CSS arch (retrofitted structure), investigating their failure modes, peak bearing capacity, initial stiffness, ductility, and other indices. The test results showed that the original structure exhibits diagonal-tensile failure at the arch ends, whereas the retrofitted structure shows typical shear-compression failure. Compared with the original structure, the retrofitted structure exhibited a 71.6 % increase in peak bearing capacity and a 119.7 % increase in stiffness, while maintaining comparable ductility. A detailed nonlinear finite element model incorporating the damage conditions of the original structure was developed. A parametric study was conducted on key factors including grout material thickness, grout material strength, CSS arch thickness, CSS arch strength, loading history, span, and rise span ratio. The results demonstrate that increasing the grout material thickness from 50 mm to 150 mm and the CSS arch thickness from 3 mm to 9 mm resulted in bearing capacity enhancements of 36.2 %–37.4 % and 24.5 %–26.1 %, respectively. The increase in both parameters was shown to significantly improve the bearing capacity of the retrofitted structure. Finally, a calculation method for the buckling bearing capacity of the retrofitted structure was proposed.