Experimental and theoretical investigation on the mechanical properties of corroded stud shear connectors

Abstract

To accurately assess the durability of steel-concrete composite members, the mechanical properties of corroded stud shear connectors were investigated experimentally and theoretically. First, 48 stud specimens were exposed to artificially accelerated corrosion in two corrosion conditions (artificial climate and constant current conditions) and monotonically tested under tensile loads. Results indicated that stud corrosion significantly reduced its strength, while having a negligible effect on its elastic modulus. For the specimen with a 16.1% corrosion ratio in the artificial climate conditions, the yield strength and tensile strength decreased by 35.9% and 33.4%, respectively. The tensile property degradation models in two accelerated corrosion conditions were established. Afterward, the shear properties of corroded studs were investigated through 7 push-out tests. It was found that corrosion also had a significant effect on the stud shear strength and deformation behavior. When the average corrosion ratio of the studs reached 7.6%, its shear strength decreased by 7.8%. Another novelty of the present work lies in the analytical development of a theoretical load-slip relationship of stud based on the Winkle foundation model and a simplified elastic-plastic constitutive relationship of concrete. Furthermore, a significant contribution of this work is the introduction of a series of degradation factors that enabled the derivation of the formulas featured by shear stiffness, shear strength, and load-slip relationship of corroded studs. All these theoretical formulas were well validated against the experiments regardless of whether the stud was corroded.