Flood Repair and Resilience presentation

1. Queensland Road Infrastructure
Network – Flooding Resilience
and Repair
By Jack Leeson

2. Queensland’s Road Infrastructure Network
State Government Owned Road Infrastructure Assets
• 80% of Queensland’s total roads
• 33 352km of roads
• $61.48 billion
State Government Spending on Natural Disaster Recovery
• $817.4 million (annually)

3. Pavement
Flexible Pavements
• Most Common
• Lower Cost
• Lower Strength
• Poor Flood Resilience
• 66% of all roads in Australia are unsealed
• The majority of sealed roads are unbound granular pavements
with a sprayed seal surface
Rigid Pavements
• Least Common
• High Cost
• Higher Strength
• High Flood Resilience

4. Pavement
Failures
Causes
• Water infiltration
• Pavement Swelling
• Traffic loading on
weakened pavements
Failures
• Surface Cracking
• Pot Holes
• Rutting
Surface Cracking
Pot Hole
Rutting

5. Bridges Types used in
Queensland
• Timber
 Original bridges built in Queensland
 High maintenance
 Being replaced by modern concrete structures
(Bridge Renewal Program)
• Steel
 Originally used for long span crossings
 Prone to vibration and deflection issues
 High maintenance costs (repainting)
 Not commonly built today
• Concrete
 Most commonly used today
 Prestressed concrete spans and reinforce
concrete designs
 Lower maintenance and longer design life
Timber Bridge
Steel Bridge
Concrete Bridge

6. Common Bridge Damage and Failures
Common Bridge Damage
• Debris and silt build up
• Scouring of abutments,
piers and road
approaches
Common Bridge Failures
• Timber bridges
• Severe scouring and
settlement
Build up of Debris on Bridge
Abutment and Road Approach Scouring

7. Culverts
Culvert Types
• Box Culverts
Precast Concrete
Segments
Cast-In-Place Concrete
Structure
• Pipe Culverts
Precast Concrete
Segments
Corrugated Steel
Segments
Concrete Box Culvert
Corrugated Steel Pipe Culvert

8. Culvert Failures
Common Types of Culvert Failure
• Apron cracking and failure
• Scouring (Upstream and Downstream)
Culvert Apron Failure and Downstream Scouring

9. 2010-2012 Queensland Floods
Damage
• $7 billion worth of damage to state controlled roads
• 85% - Road Repairs
 Pavement Repairs
 Sealing Repairs
 Culvert Repairs and Replacements
• 5% - Bridge Repairs and Replacements
 2 Timber Bridge Failures
 1 Steel Girder Bridge Failure
Response
• Fire Brigades – Clearing debris from roads and bridges
• Australian Army – Engineering and Repair Works
• Australian Navy – Divers assessing scouring damage
• Private Engineering Consultants – Infrastructure Assessments

10. Pavement Rehabilitation
Repair
• Pavement Stabilisation
Low lying areas
Floodways
High Importance Roads
Improving Resilience
• Cementitious Material
• Culvert Crossings
• Flood Plain Bridges
Pavement Stabilisation

11. Bridge Rehabilitation
Immediate Repair
• Clearing Debris and Silt
• Dumping Rock Riprap for Scour Damage
Improving Resilience
• Replacing Timber Bridges with Concrete Structures
• Improved Scouring Protection
 Gabion Walls
 Gabion Mattresses
 Grout Filled Mattresses
 Articulated concrete block system
Gabion Wall

12. Culvert Rehabilitation
Repair
• Clearing Debris and Silt
• Dumping Rock Riprap for Scour Damage
Improving Resilience
• Improved Scouring Protection
 Gabion Mattresses
 Grout Filled Mattresses
 Articulated concrete block system
• Increasing Culvert sizes
• Replacing Culverts with Bridges

13. Conclusion
• Flooding will continue to be an issue for the Queensland
road infrastructure network
• Flood repairs and resilience will be at the forefront of
future engineering practices
• The recommendations established in this presentation
should be considered for future flood repair works and
flood resilience planning