Study of Shear strength of Shear Keys by reinforcing with Shear Reinforcement and Steel Plates at the joints of Precast Concrete Box Girder Bridge Segments.

Abstract

Shear keys at the joints of precast box girder bridges are critical components because they are subjected to shear forces and are potential points of structural failure. The failure mode is typically sudden. Therefore, an effective shear key must be strong and durable against shear forces and have a long service life. This research aims to enhance the shear capacity of joints in box girder bridges by doing experiments of the simulated web section of precast concrete bridges with multiple shear keys. Three types of shear keys were examined: standard concrete shear keys, reinforced shear keys with additional shear reinforcement, and steel plate-reinforced shear keys with dowel bars. Each type consists of different geometric shapes: trapezoidal, triangular, and semi-circular. From test results, the steel plate-reinforced shear keys with dowel bars provided the highest shear capacity, followed by reinforced shear keys with additional shear reinforcement, and standard concrete shear keys, respectively. Additionally, the geometry of the shear keys also influenced the shear capacity, with the semi-circular shape providing the highest strength, followed by the triangular and trapezoidal shapes, respectively.