Queensland Road Infrastructure Network Flooding Resilience and Repair

Queensland Road Infrastructure Network Flooding Resilience and RepairBy Jack Leeson

Queenslands Road Infrastructure NetworkState Government Owned Road Infrastructure Assets80% of Queenslands total roads33 352km of roads$61.48 billion

State Government Spending on Natural Disaster Recovery$817.4 million (annually)

PavementFlexible PavementsMost CommonLower CostLower StrengthPoor Flood Resilience66% of all roads in Australia are unsealedThe majority of sealed roads are unbound granular pavements with a sprayed seal surface Rigid PavementsLeast CommonHigh CostHigher StrengthHigh Flood Resilience

Pavement FailuresCausesWater infiltrationPavement SwellingTraffic loading on weakened pavements

FailuresSurface CrackingPot HolesRutting

Surface CrackingPot HoleRutting

Bridges Types used in QueenslandTimberOriginal bridges built in QueenslandHigh maintenanceBeing replaced by modern concrete structures (Bridge Renewal Program)

SteelOriginally used for long span crossingsProne to vibration and deflection issuesHigh maintenance costs (repainting)Not commonly built today

ConcreteMost commonly used todayPrestressed concrete spans and reinforce concrete designsLower maintenance and longer design life

Timber BridgeSteel BridgeConcrete Bridge

Common Bridge Damage and FailuresCommon Bridge DamageDebris and silt build upScouring of abutments, piers and road approaches

Common Bridge FailuresTimber bridgesSevere scouring and settlementBuild up of Debris on BridgeAbutment and Road Approach Scouring

CulvertsCulvert TypesBox CulvertsPrecast Concrete SegmentsCast-In-Place Concrete Structure

Pipe CulvertsPrecast Concrete SegmentsCorrugated Steel Segments

Concrete Box CulvertCorrugated Steel Pipe Culvert

Culvert FailuresCommon Types of Culvert FailureApron cracking and failureScouring (Upstream and Downstream)

Culvert Apron Failure and Downstream Scouring

2010-2012 Queensland FloodsDamage$7 billion worth of damage to state controlled roads85% - Road RepairsPavement RepairsSealing RepairsCulvert Repairs and Replacements5% - Bridge Repairs and Replacements2 Timber Bridge Failures1 Steel Girder Bridge Failure

ResponseFire Brigades Clearing debris from roads and bridgesAustralian Army Engineering and Repair WorksAustralian Navy Divers assessing scouring damagePrivate Engineering Consultants Infrastructure Assessments

Pavement RehabilitationRepairPavement StabilisationLow lying areasFloodwaysHigh Importance RoadsImproving ResilienceCementitious MaterialCulvert CrossingsFlood Plain Bridges

Pavement Stabilisation

Bridge RehabilitationImmediate RepairClearing Debris and SiltDumping Rock Riprap for Scour Damage

Improving ResilienceReplacing Timber Bridges with Concrete StructuresImproved Scouring ProtectionGabion WallsGabion MattressesGrout Filled MattressesArticulated concrete block system

Gabion Wall

Culvert RehabilitationRepairClearing Debris and SiltDumping Rock Riprap for Scour Damage

Improving ResilienceImproved Scouring ProtectionGabion MattressesGrout Filled MattressesArticulated concrete block systemIncreasing Culvert sizesReplacing Culverts with Bridges

ConclusionFlooding 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