Bridge

A bridge is a structure built to span a gorge, valley, road, railroad track, river, body of water, or any other physical obstacle.

Council owned bridges typically exist to allow vehicles and/or pedestrians to access to areas that would be otherwise inaccessable or only accessable via a longer alternate route.

Photos

Glossary of Austroads Terms

The Glossary of Austroads Terms defines a bridge as a structure designed to carry a road or path over an obstacle by spanning it.

Victorian Code of Practice for Operational Responsibility for Public Roads

The Victorian Code of Practice for Operational Responsibility for Public Roads defines a bridge as any sturcture including culverts, on, over or under a road that have a single span or diameter of 1.8 metres or greater, or have a waterway area of 3 sq.m. or greater and includes all structural components (eg. abutments, retaining walls, traffic safety barriers), and associated pathways, within the limits of the structure, but excludes approach embankments.

Types of Bridges

Wikipedia lists six main types of bridges: beam bridges, cantilever bridges, arch bridges, suspension bridges, cable-stayed bridges and truss bridges.

Bridge Materials

The majority of new local government controlled bridges are probably constructed from pre-cast concrete segments. Timber was a common bridge construction material in the past, and is still used in the construction of footbridges, but it is not common for new road bridges to be constructed from timber.

Bridge Components

Bridges are sometimes broken up into several components in an asset register, including;

• Superstructure
• Substructure
• Deck / Surface
• Guardrails / Parapet

Bridge Maintenance

The maintenance of timber bridges is an issue for many rural Councils. Fortunately the Queensland Main Roads Timber Bridge Maintenance Manual, which can be downloaded free of charge from the Main Roads website covers the maintenance of timber bridges in great detail.

As with other timber structures, timber bridges should be checked and treated for termites on a regular basis.

Condition Assessment Techniques

There are a number of Condition Assessment Techniques that can be applied to bridges, including;

• Visual Condition Inspection
• Test Drilling
• Resistograph / Drill Resistance
• Ground Penetrating Radar
• Stress Wave Non Destructive Testing
• Ultrasonic
• Radiography
• Vibrational Analysis
• Diagnostic Static Load Test

Related Pages

• Asset & Component Types
• Boardwalk
• Bridge Inspection
• Bridge Load Limit
• Footbridge
• Level 1 Bridge Inspection
• Major Culvert
• Road
• Bridge Asset Management System

External Links & References

1. Wikipedia Article
2. Bridge Management & Evaluation (ARRB)
3. Humes
4. Timber Bridge Management (NSW RTA)
5. Google Wave Timber Bridges Discussion
6. Trial of Ground Penetrating Radar to Locate Defects in Timber Bridge Girders
7. Nondestructive Evaluation Techniques for Timber Bridges
8. Queensland Main Roads Timber Bridge Maintenance Manual
9. Victoria's Arterial Bridge Strategy (VicRoads)
10. Short Span Steel Bridges - Myths and Realities