FIELD INSPECTION GUIDE

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FIELD INSPECTION GUIDE

Apr 2008

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Suggestions, comments, and requests for changes or revisions to the Field Guide or inquir- ies about training sources should be directed to:

Ministry of Transportation, Ontario Engineering Standard Branch Bridge Office

Bridge Evaluation and Inspection Group 301 St. Paul Street, 2nd Floor

St. Catharines, Ontario L2R 7R4

Tel: (905) 704-2406 Fax: (905) 704-2060

Apr 2008

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F O R M S

PREFACE

The “Field Inspection Guide” is a condensed version of the “Ontario Structure Inspection Manual (OSIM).

It summarizes the major parts of the main manual including inspection procedures, material defects, condition states, maintenance needs and perform- ance deficiencies.

References to the main manual are also made in this Field Guide so that the inspector can obtain more comprehensive information, if required.

4 TABLE OF CONTENTS

Page 1) STRUCTURAL INSPECTIONS

1. Inspection Objectives 5

2. Inspection Accuracy 5

3. Additional Investigations 6

4. Site Inspection 6

5. Post Inspection Procedures 8

2) HELPFUL HINTS 1. Condition 10

2. Excellent & Good 11

3. Recommended Work 13

4. Performance Deficiencies 15

5. Maintenance 16

APPENDIX A—MATERIAL DEFECTS 17

1. Concrete Defects 18

2. Steel/Aluminum Defects 24

3. Wood Defects 30

4. Masonry Defects 32

6. Asphalt Defects 34

7. Coatings 42

APPENDIX B -

ELEMENT

APPENDIX C -

CONDITION

DEFICIENCIES

APPENDIX E—OSIM

FORMS

ST RUCT HINTS DEF E CT S

DEFICIENCIES FORMS

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1. STRUCTURAL INSPECTIONS

1.1 INSPECTION OBJECTIVES (Part 1, Sect. 1.2)

The goal of the structural inspection is to ensure, within an economic framework, an acceptable standard for structures in terms of public safety, comfort and convenience. The main objectives are to:

• maintain structures in a safe condition

• prolong the life of structures

• identify maintenance & repair needs

• provide the basis for structure management

1.2 INSPECTION ACCURACY (Part 1, Sect. 1.3)

In order to achieve the inspection objectives and adequate accuracy, the inspector should spend at least 2 hours at a typical bridge site to adequately assess the condition of all elements.

The inspection should be a visual inspection per- formed “Close enough to determine the element condition”, and generally conducted “within arms length” of the element.

In some cases it may be possible to inspect a por- tion of the bridge close-up and then estimating the condition of the remaining inaccessible parts by visually comparing them to the partial close-up in- spection. If this is done, periodic Enhanced OSIM inspections must be done to closely inspect all components as described in Part 1, Section 1.3.2 of the OSIM.

Additional equipment should be used to facilitate inspection, when necessary (Bridgemaster, bucket truck, ladder, etc).

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Additional specialized testing (NDT, etc) should be recommended for critical structures (fatigue prone, fracture critical, hangers, etc)

1.3 ADDITIONAL INVESTIGATIONS (Part 1– Clause 1.3.4)

If during a detailed visual inspection, the inspector feels that more detailed information is needed, specialized inspections (within a certain timeframe*)can be requested. Some of these investigations are:

• Detailed Deck Condition Survey

• Non-destructive Delamination Survey of Asphalt Covered Decks

• Substructure Condition Survey

• Detailed Coating Condition Survey

• Underwater investigation

• Fatigue investigation

• Seismic investigation

• Structure evaluation

• Monitoring, etc.

* Normal timeframe is within 2 years

1.4 SITE INSPECTION (Part 2-Clause 1.5.2)

The inspector shall:

• Arrange for special equipment/traffic control and safety devices, as required for site.

• Complete an overview inspection of the site to:

⇒ Assess the overall integrity of the structure and identify areas where more detailed examination may be required

⇒ Observe the bridge under truck loading and identify any abnormal flexibility, deflections or noises (rattling or vibration

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⇒ of members)

⇒ Look for abnormal deflections, settlements or rotations by looking along the rail or barrier wall or other members

⇒ Identify obstacles that may either interfere with the inspection or indicate a need for additional special equipment.

• Determine the quantities in each condition state based on the severity of material defects in the appropriate units (m2, each, etc.), for each element. Details of condition states and material defects are included in Appendix “A” and “C”.

The element list is included in Appendix “B” and the OSIM form for recording information is included in Appendix “E”.

• Determine the performance deficiencies, maintenance needs, recommended work and time frame for work for each element. Details of these are included in the Appendix “D” of this Guide

• Take photographs to adequately describe the structure and the defects found including all areas of POOR.

• Update element quantities/dimensions if required.

• Correct missing/erroneous inventory data

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1.5 POST INSPECTION PROCEDURES (Part 2 - Clause 1.5.3)

The inspector shall:

• Ensure that all inspection equipment and temporary traffic control devices are removed from the site and the site is left in workmanlike order

• Ensure the appropriate follow-up action is taken (notify bridge owner immediately) for any critical structural defects or deficiencies (i.e.

fatigue cracks in steel, imminent deck punch through, etc.) and all other unsafe conditions that are discovered in the field.

• Submit the Maintenance Needs list to the maintenance crew for action

• Ensure additional investigations are initiated in the timeframe recommended

• Write all necessary follow-up correspondence and reports

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2. HELPFUL HINTS (Part 2, Section 4)

1. CONDITION

• First look for areas of POOR

•

Concrete

⇒

Spalls, delaminations, severe scaling, wide cracks (4m=1 sq.m defect area)

•

Steel

⇒

More than 10% section loss, cracks and deformations

•

Actual inspection quantity (e.g. sq.m.) should be used for elements in Poor condition—not percent.

• Next, look for areas of FAIR

•

Concrete

⇒

Medium defects (medium scaling, medium cracks, etc.)

•

Steel

⇒

1% to 10% section loss

•

Each Area of Poor (except for very large areas) should generally have an equal area of associated Fair sur- rounding it.

•

Remainder of areas probably in Good or Excellent Condition.

•

Actual Good or Excellent depends on visual inspection; however, age of structure can be used as a guide, depending on environmental expo- sure of element (see section 2.2 of this guide).

•

Similar guidance based on age does not exist for the transition from Good to Fair Condition.

⇒

Fair is determined by visual iden- tification of defects.

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2. EXCELLENT AND GOOD

• All materials must begin in the Excellent condition state

• Once any defect is visible, it drops to the Good condition state

• The defects may not be visible from a distance, but are from close-up.

• Guidance is provided below for the age of compo- nent when transition* from Excellent to Good is expected:

• Concrete, ACR Steel, Coated Steel, Coating:

• Severe—5 years

• Moderate—15 years

• Benign—25 years

*

Transition can be spread over a few inspections.

•

Defects in Good condition state include (see Tables in Appendix C for complete list):

• ACR Steel

• First signs of patina flaking

• Coated Steel

• First signs of surface rust

• First signs of coating lifting from steel

• Re-coated steel that had rust previ- ously

• Coating

• First signs of adhesion or coating related defects

• Concrete

• Hairline and Narrow cracks

• Surface carbonization

• Light scaling

• Other light defects

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Examples of Environments

Severe Moderate Benign

Exposed

Concrete Deck

Concrete Deck with wa- terproofing

Exterior Soffit Interior Soffit Railings and

inside face of Barrier Walls

Outside face of barrier wall

Abutment in splash zone

Abutment at expansion joint

Abutment with no joint (integral abutment) Pier in

splash zone

Pier at expan- sion joint

Pier with no joint (where deck con- tinuous)

End Portion of Beams (at joints)

Remainder of Beams Joints

OSIM FORMS

(Part 2, Section 7)

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3.

Work on Element Recommended work

- Must be consistent with condition of element.

- Must be used for elements that cause a bridge to be placed on a capital construction program, typi- cally the 5 main elements listed below.

- Can be used for other elements as required.

- Must not be used for work that is carried out as maintenance.

- Must not be used for additional investigations or functional deficiencies.

Recommended work on an element can be either:

- “Rehabilitation”

- “Replacement”

The timeframe for the work is either:

- “1 to 5 years”, - ”6 to 10 years”

Typically, the 5 main elements require repair in 1 to 5 years when:

Deck Top 10% to 20% Poor Deck Soffit 5% to 15% Poor Barrier Wall 15% to 30% Poor Expansion Joint 15% to 25% Poor Girders 5% to 10% Poor

o Sometimes, a lower percentage of Poor may also trigger a rehab for critical ele- ments.

o If there are immediate safety concerns with some elements, a Structural Mainte- nance item should be recorded.

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Work on Structure

Work on structure is only required when there is enough to warrant placing the bridge on the capital construction program.

Recommended work on the structure can be either:

- “Minor Rehabilitation” that include work on ele- ments other than the deck (i.e. barriers, bear- ings, etc.)

- “Major Rehabilitation” that include work to the deck (i.e. patch-waterproof-pave, overlay, etc.) plus possibly other elements.

- “Replacement” of entire structure.

The timeframe for the work is either:

- “1 to 5 years”, - ”6 to 10 years”

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Maintenance NeedDescription 8 Repair of Bridge ConcreteThe repair of all concrete components of the structure, such as curbs, pedestrian walks, concrete handrail posts, parapet walls, abutments and piers, except when the repair is more directly associated with one of the other defined bridge maintenance operationsor the quantity of repair is excessive for a maintenance operation. 9 Repair of Bridge TimberThe repair of all bridge timber, including the repair of timber decks on steel bridges. 10 Bailey Bridges – Installation, Maintenance and Removal The installation, removal, repair and maintenance work that is unique to Bailey Bridges, but not including work defined by other structural maintenance operations. 11 Animal/Pest Control The installation and maintenance of animal/pest control devices under bridge structures such as pigeon-proofing. 12 Bridge Surface RepairThe repair of bridge surfaces such as pothole patching. 13 Erosion Control at BridgesOperations performed to prevent or repair damage due to erosion, such as scour at abutments and around piers, and washouts on slopes. Includes removal of obstructions to water flow, clearing of vegetation growth, extension of deck drains, etc. 14 Concrete SealingThe sealing or treatment of bridge concrete surfaces with approved materials, as well as the preparation of surfaces prior to treatment. 15 Rout and Seal – Concrete and Asphalt Pavement on Bridge Decks The routing of joints and/or cracks in concrete and asphalt pavement and the filling of same with joint fillers or rubberized asphaltic sealing compounds. 16 Bridge Deck DrainageThe repair, maintenance, and replacement of bridge deck drains. Includes steaming and calcium application to unthaw. 17 Scaling (Loose Concrete or ACR Steel)The removal of loose delaminated concrete or delaminated patina of ACR steel girders that pose a risk as a falling hazard. 18 Other Maintenance A maintenance activity that does not fit into any other category.

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Maintenance NeedDescription 1 Lift and Swing Bridge MaintenanceThe operation, maintenance and repair activities that are unique to lift and swing bridge structures, including all mechanical equipment and electrical devices such as signals, flashers, lighting, navigation lights, etc., but not including work defined by other structural maintenance operations. 2 Bridge Cleaning The cleaning of bridge components including: 1)Washing of bearings, bearing seats, truss members, etc. 2)Sweeping of bridge decks, curbs and gutters. 3)Removal of debris from expansion joints. 4)Debris pick-up or minor removal of aggregate. 5)Cleaning of catch-basins, man-holes and deck drains. 3 Bridge Railing System MaintenanceThe painting, repair and/or replacement of metal handrails, railing systems and posts, as well as touch-up painting activities. 4 Painting Steel Bridge StructuresThe preparation (sandblasting, etc.) and painting of structural steel. Includes handrails when performed as part of an overall bridge painting operation. 5 Bridge Deck Joint RepairThe repair and/or replacement of expansion and/or fixed deck joints and end dams. 6 Bridge Bearing MaintenanceThe adjustment, repair and/or replacement of bridge bearings. Includes all work directly associated with bridge bearings. 7 Repair to Structural Steel The repair of all structural steel, including repair or replacement of steel components, bolts and fasteners.

Table 6.1: Maintenance Needs (Part 2, Section 6)

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4. PERFORMANCE DEFICIENCIES (Part 2, Section 6)

A Performance Deficiency should be recorded if an element’s ability to perform its intended function is in question.

• “Suspected” Performance Deficiencies are re- corded for each element

• Potential Deficiencies categorized as

“Suspected” since often difficult to ascertain the significance of defect at the time of the inspec- tion

• “Suspected” Performance Deficiencies usually indicate some follow-up action is required (strength evaluation, specialized inspection, monitoring, etc.)

• Standard List of possible deficiencies are shown on the inspection form (see Appendix D and Appendix E).

• Follow-up action can be addressed under

“Additional Investigations” or “Special Notes”

for the bridge.

Example:

A severely corroded girder at the midspan

• Can the girder safely carry traffic loading?

• Inspector cannot determine this in the field

• Inspector can only indicate “Suspected” Per- formance Deficiency for a follow-up strength evaluation

• Only then can decision be made whether bridge needs strengthening or posting

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5. MAINTENANCE (Part 2, Section 6)

There are two types of maintenance work that are performed:

Structural Maintenance Work

- Is work to improve the structural capacity of a specific element and not part of a larger con- struction contract

- Is generally only done to one element - Include emergency repairs and holding strat-

egy repairs

- Is work that requires engineering drawings to complete the work.

Routine Maintenance Work

- Is for preventative maintenance and minor re- pair work that can be performed without engi- neering direction.

- Is usually carried out by bridge crews or road maintenance contractors

For all Maintenance work a standard list of mainte- nance needs are shown on the inspection form (see Appendix D, or Appendix E). The mainte- nance needs list should be forwarded to mainte- nance crews for action, with urgent items flagged for immediate attention.

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15 Unstable EmbankmentsEmbankments•Settlement of embankment, slope protections or approach roadway; •Sliding failure of the toe or slopes of the embankment; •Surface or deep seated slips; •Loss of embankment material from under foundations.

Geotechnical investigation 16Other

14 Undermining of FoundationStreams & Waterways or Foundation

•Loss of material supporting foundations due to scour or erosion. Underwater Investigation

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Suspected PerformanceElement Name (Examples) Description of DeficiencyPossible Follow-up Action 13 Flooding/Channel Blockage Streams & Waterways•The inspector should look for the following evidence of high water levels, inadequate opening at the structure and adverse affects on other components of the structure: •Bending or buckling of the lower chord of steel trusses in the downstream direction by ice or heavy debris; •Ice scars and damage to substructures; •Coarse debris, such as branches and small trees, caught or wedged under the superstructure; •Fine debris, such as grass and twigs, on fences, trees, embankments, structures, etc.; •Wash lines on bare soil slopes; •Mud or silt deposited on embankments; •Marks and stains on structures.

•Determine historical frequency of flooding and recorded water levels and compare to current high water elevation •Monitor water elevations throughout year •Perform hydrology study

Table 5.1: Suspected Performance Deficiencies (Part 2, Section 5)

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APPENDIX A

MATERIAL DEFECTS

This appendix contains a simplified table for material defects and condition states by combining the information from OSIM Part 1, Section 2 and Part 2, Section 4

TABLES 1. Concrete

2. Steel/Aluminum 3. Wood

4. Masonry

5. Asphalt Wearing Surface 6. Asphalt Covered Deck 7. Coating

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1. CONCRETE (Part 1, Sect. 2.2 and Part 2, Table 4.5) DEFECTCONDITION STATE GOOD(LIGHT) FAIR(MEDIUM) POOR (SEVERE / VERY SEVERE) Scaling Local flaking/loss of surface portion of concrete or mortar due to freeze-thaw Up to 5 mm depth 6 - 10 mm depth > 10 mm depth Disintegra- tion Physical deterioration or breaking down of the concrete into small fragments All Erosion Deterioration of concrete brought about by water-borne sand and gravel particles scrubbing against surfaces All Corrosion of Reinforce- ment

Deterioration of reinforcement by electrolysis Due to drains/chairs Rust stains from reinforcement Exposed reinforce- ment with rust Delamina- tion Discontinuity of the surface concrete which is substantially, but not completely detached from concrete below or above it. All

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10 Surface PondingSidewalk, Wearing surface•Water ponding on sidewalks/wearing surface, as it presents a safety hazard, especially if allowed to freeze; •Fill in depression with asphalt (Maintenance Operation) 11 Deck Drainage Drainage System•Deck drains not provided where necessary, or have inadequate size of opening; •Deck drains and drainage systems improperly constructed with inadequate slopes or sharp directional changes; •Drainage system plugged or partially plugged and not allowing for free and unobstructed flow of water; •Drainage outlets discharging directly onto structure components or roadways below the deck; •Drainage outlets discharging directly onto embankment without proper provision for collecting, channelling and controlling of discharge with splashpads, spillways or gutters; •Inadequate provision for drainage at the structure approaches.

•Review deck drainage requirements 12 Slippery Surfaces Deck Top•Loss in riding comfort and potential loss of vehicle control due to defects in the component material; •Loss of protection to underlying surfaces due to defects in the wearing surface materials;

•Resurface problem area (Maintenance Operation)

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Suspected Performance Element Name (Examples)Description of DeficiencyPossible Follow-up Action 9 Rough Riding SurfaceWearing Surface, Approach slabs •Rough approaches, settlement or consolidation of approach embankments, or deterioration of the approach slabs or ramps, resulting in vehicles "bouncing" onto the bridge. In addition to applying excessive dynamic loading to the bridge, this may also result in difficulty in maintaining vehicle control •Depressions and cracks in the roadway pavement above culverts and soil-steel structures;

•Smooth out asphalt at approach (Maintenance operation) •Strength evaluation

8 Pedestrian/ vehicular hazardArmouring/ retaining devices, Sidewalk

•Vertical or horizontal misalignment across the joint; •Severe material defects (e.g. Spalling) •Horizontal, vertical or rotational displacements in curbs and sidewalks as they are hazardous to pedestrian and vehicular safety, and present obstructions to snow plows. •Inadequate curb height, or loss of curb height for sidewalks due to the placement of an additional layer of wearing surface or deck overlay

•Remove obstruction (Maintenance operation) •Review Code requirements for curb height

Table 5.1: Suspected Performance Deficiencies (Part 2, Section 5) 1. CONCRETE DEFECTCONDITION STATE GOOD (LIGHT) FAIR(MEDIUM) POOR (SEVERE / VERY SEVERE) Spalling Fragments which have been detached from a larger concrete mass All CrackingLinear fracture which extends partly or completely through the member. < 0.3 mm 0.3 - 1.0 mm wide> 1.0 mm wide Alkali- Aggregate Reaction

Aggregates react adversely with the alkalies in cement to produce a highly expansive alkali- silica gel Hairline pattern cracks < 0.1 mm Narrow pattern cracks 0.1 - 0.3 mm wideMedium-wide pattern cracks > 0.3 mm wide

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1. CONCRETE DEFECTCONDITION STATE GOOD (LIGHT) FAIR(MEDIUM) POOR (SEVERE and VERY SEVERE) Honeycombing Produced due to the improper or incomplete vibration of the concrete which results in voids being left in the concrete where the mortar failed to completely fill the spaces between the coarse aggregate particles Holes up to 25 mm dia. Holes 25 - 50 mm dia. Holes more than 50 mm dia. Pop-Outs Shallow conical depressions resulting from the breaking away of small portions of the concrete surface, due to the expansion of some aggregates due to frost action. Holes up to 25 mm dia. Holes 25 - 50 mm dia. Holes more than 50 mm dia.

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Suspected Performance Deficiency

Element Name (Examples)Description of DeficiencyPossible Follow-up Action 5 Seized Bearings Bearings •Binding or jamming of expansion or rotational components due to corrosion, lack of lubrication or damage to sliding surfaces;

•Strength evaluation to account for change in articulation •Lubricate Bearings (Maintenance Operation) 6 Bearing not uniformly loaded/ unstable

Elastomeric Bearing, Rocker Bearing, etc •Non-uniform contact of bearing surfaces with each other or with bearing seat •Excessive inclinations of bearings

•Regular monitoring of bearing movements 7 Jammed expansion Joint Armouring/ retaining devices•Inadequate joint gap to accommodate anticipated further movement; •Surfacing materials have jammed in the joints during resurfacing of deck; •Design or construction problems not allowing proper movement of multi-seal joints.

•Regular monitoring of deck movements •Clean out gap (Maintenance operation)

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Suspected Performance Deficiency Element Name (Examples) Description of DeficiencyPossible Follow-up Action 4 Continuing MovementsAbutment Wall, Pier, Deck Top, Bearings, etc

•Out of plumb of abutment walls, piles, piers or other components supported on them; •Tilting or bulging of Retained Soil System (RSS) walls •Unusual or unexpected substructure movements occurring during the passage of heavy vehicles over the bridge; •Tapering or misalignment of cracks and joints in foundations, abutments, piers or other components supported on them; •Sudden drops or kinks in the structure profile over piers or abutment walls when sighting along railings or beam lines; •Abnormally large or small openings or misalignment of deck expansion joints at abutments and piers; •Abnormal displacements or inclinations of bearings; •Abnormally large or small clearance between ballast wall and superstructure; •Cracks in abutment wall and ballast wall •Shift in alignment from original position;

•Regular monitoring and measurement of movements, inclinations, crack widths, etc. •Underwater investigation •Geotechnical investigation

Table 5.1: Suspected Performance Deficiencies (Part 2, Section 5) 1. CONCRETE DEFECTCONDITION STATE GOOD (LIGHT) FAIR(MEDIUM) POOR (SEVERE and VERY SEVERE) Stratification Separation of concrete into layers prior to hardening due to over-vibration. ALL Segregation Concrete not uniform due to falling concrete (poor placement) ALL Cold Joints Caused by hardened concrete prior to the next adjacent pour ALL Deposits Water seeped through concrete, leaching chemicals and depositing them on the surface - efflorescence ALL Abrasion ALL

Wearing caused by vehicles or snow-plough blades

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