Cyclic Behavior of Steel-Concrete Composite Dowel by Clothoid-Shaped Shear Connectors under Fully Reversed Cyclic Stress

Abstract

Recently, novel types of shear connectors have been investigated enthusiastically in Europe. Among the new connector geometries, clothoid-shaped shear connectors are used practically for bridge engineering. Although various schemes for evaluating mechanical performance can be used, they were established based on the pushout test database. During their time of use, the concrete slab is expected to be subjected to fully reversed cyclic stress during an earthquake. The stress history thereby differs from those of standard pushout tests, resulting in the discrepancy from the evaluation equations. To address this concern through this study, cyclic loading tests were conducted, imposing compressive and tensile stresses cyclically. A comprehensive experiment using 14 specimens with various influential parameters revealed the cyclic behavior and stress transfer mechanism. The results confirmed that the mechanical capacity of a composite dowel with a clothoid-shaped shear connector is dependent on the stress orientation. Furthermore, the applicability of earlier evaluation formulae was clarified based on established knowledge of experimentally obtained data. Because the necessity for reflecting the stress history was demonstrated, this research newly presents a formula for evaluation of the ultimate shear strength and load-displacement relation.