TRAIL BRIDGE INSPECTION BRIDGE INSPECTION PROCEDURES

TRAIL BRIDGE INSPECTIONTRAIL BRIDGE INSPECTION

BRIDGE INSPECTION PROCEDURESBRIDGE INSPECTION PROCEDURES

Objectives:Objectives:

Learn the different inspection methodsLearn the different inspection methods

Learn a standard procedure to conduct Learn a standard procedure to conduct routine bridge inspectionroutine bridge inspection

Learn what to look for during an inspectionLearn what to look for during an inspection

Bridges Inspection MethodsBridges Inspection Methods

There are three basic methods used to There are three basic methods used to inspect a timber bridge.inspect a timber bridge.

They include:They include:

– VisualVisual

– PhysicalPhysical

– Advanced inspection techniquesAdvanced inspection techniques

Visual InspectionsVisual Inspections

For timber members, visual inspections For timber members, visual inspections reveal areas that need further investigation reveal areas that need further investigation such as checks, splits, shakes, fungus such as checks, splits, shakes, fungus decay, deflection, or loose fasteners.decay, deflection, or loose fasteners.

Types of Visual InspectionsTypes of Visual Inspections

Cursory InspectionCursory Inspection– Involves reviewing the previous inspection Involves reviewing the previous inspection

report and visually examining the membersreport and visually examining the members– Involves a visual assessment to identify Involves a visual assessment to identify

obvious defectsobvious defects

““Hands-on” Inspection. Hands-on” Inspection. – Requires the inspector to visually assess all Requires the inspector to visually assess all

defective timber surfaces at a distance no defective timber surfaces at a distance no further than an arm’s lengthfurther than an arm’s length

– Timber surfaces are given close visual Timber surfaces are given close visual attention to quantify and qualify any defects.attention to quantify and qualify any defects.

Physical ExaminationPhysical ExaminationOnce the defects are identified visuallyOnce the defects are identified visually

Physical procedures are then used to find Physical procedures are then used to find out the extent of the deterioration or decayout the extent of the deterioration or decay

The basic methods for physical The basic methods for physical examination are:examination are:– Pick TestPick Test– SoundingSounding

Pick TestPick Test

Probing with a pointed tool such as an awl will Probing with a pointed tool such as an awl will locate decay near the wood surface. locate decay near the wood surface.

Decay will be evidenced by excessive softness Decay will be evidenced by excessive softness or lack of resistance to the probe penetration or lack of resistance to the probe penetration and the breakage pattern of the splinters. and the breakage pattern of the splinters.

A brash break indicates decayed wood, whereas A brash break indicates decayed wood, whereas a crisp splintered break with the splinter hinging a crisp splintered break with the splinter hinging from one end indicates sound wood. from one end indicates sound wood.

Pick TestPick Test

Decayed wood breaks abruptly across grain without splintering.

Sound wood pries out as long splinters.

SoundingSoundingSounding the surface by striking it with a Sounding the surface by striking it with a hammer is one of the oldest and most commonly hammer is one of the oldest and most commonly used inspection methods.used inspection methods.

Although sounding is widely used, interpretation Although sounding is widely used, interpretation is VERY subjective.is VERY subjective.

Soundings are based on the tonal quality of the Soundings are based on the tonal quality of the ensuing sounds and the rebound of the hammerensuing sounds and the rebound of the hammer

Practical experience has shown that sounding is Practical experience has shown that sounding is only useful for members less than 4 inches thick.only useful for members less than 4 inches thick.

SoundingSoundingInterpreting Soundings:Interpreting Soundings:

Sound timber gives a crisp sound. Sound timber gives a crisp sound.

Defective timber gives a dull sound.Defective timber gives a dull sound.

Loose hardware will vibrate.Loose hardware will vibrate.

Note:Note: A 2 inch thick shell A 2 inch thick shell

of competent wood is of competent wood is

sufficient to masksufficient to mask

any interior rotany interior rot..

Advanced Inspection Advanced Inspection TechniquesTechniques

Other types of advanced inspection Other types of advanced inspection techniques are:techniques are:– Coring and DrillingCoring and Drilling– Resistograph DrillResistograph Drill– Stress Wave MeterStress Wave Meter– Moisture MeterMoisture Meter

These techniques are beyond the scope of These techniques are beyond the scope of this training course.this training course.

General Bridge Inspection General Bridge Inspection ProceduresProcedures

The bridge inspection procedure should be The bridge inspection procedure should be completed completed by the numbers.by the numbers.

Which means the bridge is inspected in a Which means the bridge is inspected in a methodical way from either top to bottom methodical way from either top to bottom or bottom to top.or bottom to top.

It is important to document the inspection.It is important to document the inspection.

General Bridge Inspection General Bridge Inspection ProceduresProcedures

Documentation should include:Documentation should include:– An inspection report and notesAn inspection report and notes– And lots of photographsAnd lots of photographs

Photographs should be a minimum of 10 Photographs should be a minimum of 10 pictures with additional pictures of pictures with additional pictures of problem areas. problem areas.

General Bridge Inspection General Bridge Inspection ProceduresProcedures

Minimum required photographs:Minimum required photographs:1)1) Near approach looking at the bridgeNear approach looking at the bridge2)2) Far approach looking at the bridgeFar approach looking at the bridge3)3) Bridge deck and railingBridge deck and railing4)4) Underside of the deck and beamsUnderside of the deck and beams5)5) Upstream looking downstream at the bridgeUpstream looking downstream at the bridge6)6) Downstream looking upstream at the bridgeDownstream looking upstream at the bridge7)7) Looking upstream from the bridgeLooking upstream from the bridge8)8) Looking downstream from the bridgeLooking downstream from the bridge9)9) Near side substructureNear side substructure10)10) Far side substructureFar side substructure

Near and far approaches looking at the Near and far approaches looking at the bridgebridge

Bridge Deck and RailingBridge Deck and Railing

Underside of Deck and BeamsUnderside of Deck and Beams

Looking upstream and Looking upstream and downstream from the bridge downstream from the bridge

deckdeck

Looking upstream and Looking upstream and downstream at the bridgedownstream at the bridge

Looking at right and left Looking at right and left abutmentsabutments

Additional PhotosAdditional Photos

Anything that needs to be noted or watched.Anything that needs to be noted or watched.

Starting an InspectionStarting an Inspection

First conduct a cursory visual inspection of First conduct a cursory visual inspection of the entire bridge looking for indications of the entire bridge looking for indications of

problems.problems.

Cursory Visual InspectionCursory Visual InspectionLook for:Look for:

– Sagging or twisted beamsSagging or twisted beams– Hanging or broken beamsHanging or broken beams– Pounding waterPounding water– SettlementSettlement

Next, conduct a hands-on visual inspection Next, conduct a hands-on visual inspection of the bridge parts taking into account of the bridge parts taking into account any indications of problem found during any indications of problem found during the cursory inspection. the cursory inspection.

During the hands-on visual inspection, the During the hands-on visual inspection, the inspector should look for signs of inspector should look for signs of deterioration or decay that will require a deterioration or decay that will require a physical examination.physical examination.

Where to look for decay?Where to look for decay?

Where to look for decay?Where to look for decay?

– Around Checks– Around Splits– Around Shakes– Around Cracks– Around Fasteners– Areas in contact with soil– Areas where debris and water collect

Conduct the inspectionConduct the inspection

BY THE NUMBERSBY THE NUMBERS

Start at the top of the bridge and work your Start at the top of the bridge and work your way down the load paths. This will help way down the load paths. This will help you from missing any parts of the you from missing any parts of the structure.structure.

One Inspection order could be:One Inspection order could be:1.1. Railings/curbsRailings/curbs2.2. Decking (Planks)Decking (Planks)3.3. Superstructure (Beams, Stringers)Superstructure (Beams, Stringers)4.4. Substructure (Abutments, Sills)Substructure (Abutments, Sills)5.5. ChannelChannel6.6. ApproachesApproaches7.7. SignageSignage

General Bridge Inspection General Bridge Inspection ProceduresProcedures

1) Inspection of railings/curbing1) Inspection of railings/curbingThings to looking for?Things to looking for?

Missing rails, posts, curbs or hardwareMissing rails, posts, curbs or hardware

Broken rails, posts or curbsBroken rails, posts or curbs

Deteriorated (rotten) rails, posts or curbsDeteriorated (rotten) rails, posts or curbs

1) Inspection of railings/curbing1) Inspection of railings/curbing

Missing rails, posts, curbs or hardwareMissing rails, posts, curbs or hardware

1) Inspection of railings/curbing1) Inspection of railings/curbing

Broken rails, Broken rails, posts or curbsposts or curbs

1) Inspection of railings/curbing1) Inspection of railings/curbing

Deteriorated (rotten) rails, posts or curbsDeteriorated (rotten) rails, posts or curbs

General Bridge Inspection General Bridge Inspection ProceduresProcedures

2) Inspection of decking2) Inspection of deckingThings to looking for?Things to looking for?

Missing planks or hardwareMissing planks or hardware

Broken planks or hardwareBroken planks or hardware

Deteriorated (rotten) planksDeteriorated (rotten) planks

Wear of the deckWear of the deck

Debris on deckDebris on deck

2) Inspection of decking2) Inspection of decking

Missing planks or hardwareMissing planks or hardware

2) Inspection of decking2) Inspection of decking

Broken planks or Broken planks or hardwarehardware

2) Inspection of decking2) Inspection of deckingDeteriorated (rotten) planksDeteriorated (rotten) planks

2) Inspection of decking2) Inspection of deckingWear of the deckWear of the deck

2) Inspection of decking2) Inspection of deckingDebris on deckDebris on deck

General Bridge Inspection General Bridge Inspection ProceduresProcedures

3) Inspection of superstructure3) Inspection of superstructureThings to looking for?Things to looking for?

Sagging beamsSagging beams

Broken or cracked beamsBroken or cracked beams

Missing hardwareMissing hardware

Deteriorated (rotten) beamsDeteriorated (rotten) beams

Impact damage of beams from floating Impact damage of beams from floating debris or icedebris or ice

3) Inspection of superstructure3) Inspection of superstructure

Sagging beamsSagging beams

3) Inspection of superstructure3) Inspection of superstructure

Broken or cracked beamsBroken or cracked beams

3) Inspection of superstructure3) Inspection of superstructure

Deteriorated (rotten) beamsDeteriorated (rotten) beams

3) Inspection of superstructure3) Inspection of superstructure

Impact damage of beams from floating Impact damage of beams from floating debris or icedebris or ice

General Bridge Inspection General Bridge Inspection ProceduresProcedures

4) Inspection of substructure4) Inspection of substructureThings to looking for?Things to looking for?

Settlement of the substructureSettlement of the substructure

Missing substructure or hardwareMissing substructure or hardware

Deteriorated (rotten) substructureDeteriorated (rotten) substructure

Damage of substructure from floating debris Damage of substructure from floating debris or iceor ice

Scour damageScour damage

4) Inspection of substructure4) Inspection of substructure

Settlement of the substructureSettlement of the substructure

4) Inspection of substructure4) Inspection of substructure

Deteriorated (rotten) substructureDeteriorated (rotten) substructure

4) Inspection of substructure4) Inspection of substructure

Scour damageScour damage

4) Inspection of substructure4) Inspection of substructure

Other things to look for:Other things to look for:Missing substructure or hardwareMissing substructure or hardware

Damage of substructure from floating debris Damage of substructure from floating debris or iceor ice

General Bridge Inspection General Bridge Inspection ProceduresProcedures

5) Inspection of the Channel5) Inspection of the ChannelThings to looking for?Things to looking for?

Degrading of the stream (down cutting)Degrading of the stream (down cutting)

Aggrading of the stream (deposits)Aggrading of the stream (deposits)

Scour of the banksScour of the banks

Loss of bank protectionLoss of bank protection

Floating debris or Ice damageFloating debris or Ice damage

General Bridge Inspection General Bridge Inspection ProceduresProcedures

6) Inspection of approaches6) Inspection of approachesThings to looking for?Things to looking for?

Approach material washed awayApproach material washed away

Slumping of the approaches at the backwallSlumping of the approaches at the backwall

Unraveling at the edges of trailUnraveling at the edges of trail

PotholesPotholes

General Bridge Inspection General Bridge Inspection ProceduresProcedures

7) Inspection of signs7) Inspection of signsThings to looking for?Things to looking for?

Broken or damaged signs and postsBroken or damaged signs and posts

Don’t forget to count the bullet holesDon’t forget to count the bullet holes

Missing fastnersMissing fastners

Missing signs/object markers for ATV and Missing signs/object markers for ATV and Snowmobile bridgesSnowmobile bridges

ReferencesReferencesFHWA FHWA Bridge Inspection Reference ManualBridge Inspection Reference ManualFHWA FHWA Field Manual for Timber Bridge Inspection, DraftField Manual for Timber Bridge Inspection, DraftFPL FPL Controlling Decay in Water Front StructuresControlling Decay in Water Front StructuresFPL FPL Timber Bridges Design, Construction, Inspection Timber Bridges Design, Construction, Inspection and Maintenanceand MaintenanceFPL FPL Wood HandbookWood HandbookFPS FPS Wood and Timber Condition Assessment ManualWood and Timber Condition Assessment ManualR6 Trail Bridge InspectionR6 Trail Bridge InspectionR10 Training PowerPoint’sR10 Training PowerPoint’s

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Bridge Inspection ProceduresBridge Inspection Procedures