Investigation of in-plane stability in bending-active arches

Abstract

Bending-active arches derive their curved shape from the elastic bending of an initially straight strut, a process that necessitates slender and flexible members. Recent interest in this structural form has been propelled by the adoption of fiber-reinforced polymer profiles, while stability remains a critical concern for bending-active arches. In this study, the in-plane instability of bending-active arches is investigated under both hinged and fixed support conditions, with mid-span concentrated loads and uniformly distributed loads considered. Analytical formulations capturing symmetric and antisymmetric instability modes are derived and validated against numerical simulations performed in Abaqus. A parametric study is then conducted to identify the roles of span ratio and loading configurations. Results indicate that symmetric instability generally exhibits a higher peak load than antisymmetric instability under the same span ratio, although antisymmetric instability often develops earlier—an exception arises at certain span ratios for arches with fixed supports. Under uniformly distributed loads, arches with larger span ratios may initially experience a negative (upward) mid-span deflection. Furthermore, half-span uniform loading consistently achieves higher peak loads than full-span uniform loading. In hinged arches subjected to mid-span concentrated loads, looping load–deflection behavior emerges, with smaller span ratios yielding higher peak loads.