Types of Steel Truss Bridges

Steel truss bridges use trusses as their primary load-bearing components. They can be categorized based on different criteria, including structural form, deck position, and purpose.

1. By Truss Configuration

• Warren Truss Bridge

  • Composed of alternating diagonal members forming equilateral triangles.

  • Features: Simple design, material efficiency, ideal for medium spans.

  • Variant: Warren truss with verticals (for added stability).

• Pratt Truss Bridge

  • Diagonal members slope downward toward the center, with verticals in compression.

  • Features: Efficient material usage, commonly used in railway bridges.

• Howe Truss Bridge

  • Diagonal members slope upward toward the center, with verticals in tension.

  • Features: Originally used in timber bridges, now in steel-wood hybrids.

• K-Truss Bridge

  • Diagonal members form "K" shapes, creating smaller triangular subdivisions.

  • Features: High resistance to lateral forces, suitable for long spans.

• Bailey Truss Bridge

  • Modular, prefabricated design for rapid assembly.

  • Features: Often used for military or temporary bridges.

2. By Deck Position

• Deck Truss Bridge: Deck runs atop the truss (good for low-clearance bridges).

• Through Truss Bridge: Deck is suspended within the truss (allows high clearance for navigation).

• Half-Through Truss Bridge: Deck is supported midway, combining features of both.

3. By Purpose

• Railway Truss Bridges: High stiffness (e.g., Pratt truss).

• Highway Truss Bridges: Balance of economy and aesthetics (e.g., Warren truss).

• Pedestrian Truss Bridges: Lightweight with architectural appeal.

• Temporary Truss Bridges: Demountable (e.g., Bailey bridges).

4. Notable Variations

• Continuous Truss Bridges: Multi-span designs for long distances (e.g., Quebec Bridge).

• Cantilever Truss Bridges: Built outward from piers (e.g., Forth Bridge).

• Arch-Truss Hybrids: Combine truss and arch systems (e.g., Sydney Harbour Bridge).

Advantages: Long spans, prefabrication-friendly.
Challenges: Corrosion maintenance, complex joint detailing.