Steel plate girder bridge is a bridge composed of steel plates welded, bolted or riveted to form a solid belly steel beam as the main bearing structure, and the cross section is mostly I-shaped.

• By driving mode: Upper bearing plate beam and bottom bearing plate beam
• By connection: Riveted plate beam, fully welded plate beam and bolted welded plate beam

The economic span of simply supported steel plate girder bridge is generally below 40m, and the economic span of continuous steel plate girder bridge can reach 60m.

Composition of upper bearing plate and beam:

• Load-bearing structure (main beam)
• Bridge floor
• Connecting system
• Support

The bridge deck is located on the upper flange of the main beam. The small span can use equal section beam while large span can use variable section beam.

Key differences from upper bearing design:

• Bridge deck is located at the lower flange of the main beam
• Standard design center distance between two main beams is 5.4m
• Lower building height (from rail bottom to beam bottom)
• Requires more materials and labor for manufacturing
• Cannot be transported as complete units due to width

• Railway Bridges: Accommodates heavy train loads with necessary clearance
• Highway Bridges: Used for overpasses, interchanges, and flyovers
• Transportation Corridors: Suitable for high-traffic areas and major routes

• Components suitable for industrial manufacturing
• Easy transportation and fast on-site installation
• Simple repair and replacement
• Requires weather protection (prone to rust)
• Higher noise levels in railway applications