Bridge trusses. My photo received 1st honorable mention at the SJCC
A bridge truss is a structure composed of straight members connected at joints to form a stable framework. Trusses are commonly used in bridge construction to support the bridge span and transfer the loads to the supports, typically abutments or piers.
Here are some key aspects of bridge trusses:
- Types of Trusses:
- King Post Truss: Simple truss design with a vertical member (king post) supported by inclined members.
- Queen Post Truss: Similar to the king post truss but with two vertical posts (queen posts) for added support.
- Howe Truss: Diagonal members slant toward the center, with vertical members between them.
- Pratt Truss: Diagonal members slant towards the center, with vertical members extending from the top chord to the bottom chord.
- Warren Truss: Diagonal members form equilateral triangles, and vertical members connect the midpoints of the diagonals.
- Truss Bridge: A bridge composed entirely of truss elements, often in a Pratt or Warren configuration.
- Steel Trusses: Commonly used for their strength and durability, especially in large and long-span bridges.
- Wooden Trusses: Historically used and still in use for shorter spans or in rehabilitation projects.
- Concrete Trusses: Used in some modern bridge designs, especially for supporting heavy loads.
- Chords: The top and bottom horizontal members of the truss.
- Web Members: The diagonal and vertical members that connect the chords.
- Joints or Nodes: Points where the members meet.
- Trusses are efficient in supporting heavy loads over long spans.
- They are relatively lightweight compared to solid girder structures.
- Trusses can be prefabricated, making on-site assembly faster.
- The open framework of trusses can be susceptible to wind forces.
- Maintenance can be challenging, especially if there is corrosion in steel trusses.
- Design Considerations:
- Engineers consider factors such as the span length, load-bearing capacity, material strength, and environmental conditions when designing a truss bridge.
- Famous truss bridges include the Golden Gate Bridge (a suspension bridge with elements of a truss) and the Forth Bridge in Scotland (a cantilever truss bridge).
Truss bridges come in various designs, and the choice of a specific type depends on the engineering requirements, aesthetic considerations, and the environmental conditions of the bridge location.
My other bridge photography work