Plate Girder Flange Splice Loads

In a plate girder, the flanges are designed primarily to resist the bending moment. The bending moment induces axial stresses (tension on one side and compression on the other) within the flanges.

Flange Splice Function

A flange splice is used to join sections of the flange, often when the required length of the flange exceeds standard available sections. The main purpose of this splice is to transfer the axial forces experienced by the flange across the joint.

Force Analysis

• Bending Moment: While the overall bending moment creates axial forces in the flange, the splice itself directly transmits the resulting axial force, not the bending moment itself as a discrete force.
• Shear Force: The web of the plate girder is primarily responsible for resisting the shear forces. Flanges and their splices experience minimal shear force compared to the axial load.
• Axial Force: The splice must be designed to handle the continuous axial tension or compression that exists in the flange due to the bending action of the girder. This is the dominant force that the splice needs to transfer.

Therefore, the flange splice in a plate girder is subjected primarily to axial force.