Chapter 4 Bridge Inspection Reporting

Topic 4.1 Structure Inventory

4.1.1 Introduction

A good bridge inspection reporting system is essential to document bridge conditions and to protect the public’s safety and investment in bridge structures. It is, therefore, essential that bridge inspection data be clear, accurate, and complete, since it is an integral part of the lifelong record file of the bridge.

Because of the requirements that are fulfilled in accordance with the National Bridge Inspection Standards (NBIS), it is necessary to employ a uniform bridge inspection reporting system. A uniform reporting system is essential to evaluate the condition of a structure correctly and efficiently. It is a valuable aid in establishing maintenance priorities and replacement priorities, and in determining structure capacity and the cost of maintaining the nation’s bridges. Consequently, importance of the reporting system cannot be overemphasized. Success of any bridge inspection program is dependent upon its reporting system.

4.1.2 FHWA Structure Inventory, Appraisal and Condition Ratings

The FHWA Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation’s Bridges (FHWA Coding Guide) is used for defining the bridge inventory and the items to be used to collect information on the overall condition of the deck, superstructure, substructure, and channel. The data is reported to FHWA in accordance with the FHWA Coding Guide. It is not an inspection guide. Each state may use its own coding scheme, provided that the data is directly translatable into the format of the FHWA Coding Guide. In other words, the states are responsible for having the capability to obtain, store, and report certain information about bridges, for collection by FHWA as requested.

The Structure Inventory and Appraisal (SI&A) sheet is a tabulation of information that is submitted for each individual structure (see Figure 4.1.1).

For the small structures and culverts that are less than or equal to 20 feet, some states still collect the inventory information and generate a “local” database.

It is important to note that the SI&A sheet is not an inspection form. Rather, it is a summary sheet of bridge data required by the FHWA to effectively monitor and manage the National Bridge Inspection Program and the Highway Bridge Program.

Substitutes for the SI&A Sheet

There are suitable substitutes for the SI&A sheet. Some states simply reprint the federal form with the same items and item numbers. A few states have elaborate Bridge Management Systems (BMS) with different item numbers that collect all the data listed on the SI&A form plus additional items not reported to the FHWA (see Figures 4.1.1 through 4.1.5).

Data Entry Requirements

For routine, in-depth, fracture critical member, underwater, damage and special inspections, the NBIS requires entry of the SI&A data into the State or Federal agency inventory within 90 days of the date of inspection for State or Federal agency bridges and within 180 days of the date of inspection for all other bridges.

For existing bridge modifications that alter previously recorded data and for new bridges, the NBIS requires entry of the SI&A data into the State or Federal agency inventory within 90 days after the completion of the work for State or Federal agency bridges and within 180 days after the completion of the work for all other bridges.

For changes in load restriction or closure status, the NBIS requires entry of the SI&A data into the State or Federal agency inventory within 90 days after the change in status of the structure for State or Federal agency bridges and within 180 days after the change in status of the structure for all other bridges.

Example of a Structure Inventory and Appraisal Sheet with element level data

Figure 4.1.1 Example SI&A Sheet with Element Level Data

Example of a typical Structure Inventory and Appraisal sheet with NBI data only

Figure 4.1.2 Typical SI&A Sheet with NBI Data Only

First page of an Oregon Bridge Inspection Report with element level data

Figure 4.1.3 Oregon Bridge Inspection Report with Element Level Data

Second page of an Oregon Bridge Inspection Report with element level data

Figure 4.1.3 Oregon Bridge Inspection Report with Element Level Data (cont.)

Example of an Arizona Structure Inventory and Appraisal sheet

Figure 4.1.4 Arizona Structural Inventory and Appraisal Sheet

First page of a Florida Structure and Inventory Appraisal Sheet

Figure 4.1.5 Florida Structural Inventory and Appraisal Sheet

Second page of a Florida Structure and Inventory Appraisal Sheet

Figure 4.1.5 Florida Structural Inventory and Appraisal Sheet (Continued)

Third page of a Florida Structure and Inventory Appraisal Sheet

Figure 4.1.5 Florida Structural Inventory and Appraisal Sheet (Continued)

Fourth page of a Florida Structure and Inventory Appraisal Sheet

Figure 4.1.5 Florida Structural Inventory and Appraisal Sheet (Continued)

Some agencies furnish standardized sketch sheets and photo sheets to inspectors for report generation. Some agencies have developed their forms on software packages for use on portable computers (see Figures 4.1.6 and 4.1.7) or wearable computers (see Figures 4.1.8 and 4.1.9).

Photograph of a portable computer

Figure 4.1.6 Portable Computer

Photograph of an inspector using a portable computer

Figure 4.1.7 Inspector Using Portable Computer

Photograph of a wearable computer with its case

Figure 4.1.8 Wearable Computer with Case

Photograph of an inspector using a wearable computer

Figure 4.1.9 Inspector Using Wearable Computer

The data and information required of states by the FHWA is listed in the FHWA Coding Guide and AASHTO Manual for Bridge Evaluation. It is important to note that several items listed in the FHWA Coding Guide apply to both the field and office personnel responsible for bridge inspections. The bridge inspector is typically not required to obtain the data for all the items during every inspection of a bridge. Once a bridge has been inventoried, the majority of the geometric and other inventory items will remain unchanged. The inspector is responsible for spot checking to see if inventoried items are consistent with observations at the bridge site.

4.1.3 Inventory Items

Inventory items pertain to a bridge’s characteristics. For the most part, these items are permanent characteristics, which only change when the bridge is altered in some way, such as reconstruction or load restriction. Inventory items include the following SI&A items:

All inventory items are explained in the FHWA Coding Guide. Although inventory items are usually provided from previous reports, the inspector is responsible for verifying and updating the inventory data as needed. See Topic 4.2 for condition and appraisal rating items.

4.1.4 Condition and Appraisal Rating Items

Condition Rating Items

Condition ratings are used to describe the existing, in-place bridge as compared to the as-built condition. Condition ratings are typically coded by the inspector. Condition rating items include:

Appraisal Rating Items

Condition ratings are a judgment of a bridge component condition in comparison to current standards. Appraisal items are used to evaluate a bridge in relation to the level of service which it provides on the highway system of which it is a part. The structure will be compared to a new one which is built to current standards for that particular type of road. Appraisal rating items include:

4.1.5 The Role of Inventory Items in Bridge Management Systems

Inventory items are an important part of an owner’s Bridge Management System (BMS). Bridge owners use the inventory items to help plan inspection, maintenance, and reconstruction of their bridges, as well as classify their bridges. There have been times when there has been a problem on a particular bridge and the owners used the inventory items of that bridge to search for the same potential problems that might exist on other bridges.

Topic 4.2 Condition and Appraisal

4.2.1 Introduction

The reported condition of an element or component is an evaluation of its current physical state compared to what it was on the day it was built. Appraisal rating items are used to evaluate a bridge in relation to the level of service it provides on the highway system of which it is a part.

4.2.2 Condition Rating Items

Deck, Superstructure and Substructure

Accurate assignment of condition ratings is dependent upon the bridge inspector’s ability to identify the bridge components and their elements. Bridge components are the major parts comprising a bridge including the deck, superstructure, and substructure. Bridge elements are individual members comprised of basic shapes and materials connected together to form bridge components.

The overall condition rating of bridge components is directly related to the physical deficiencies of bridge elements.

Evaluating Elements

The inspector is responsible for evaluating each element of each component and assigning to it a descriptive condition rating of “good,” “fair,” or “poor,” based on the physical deficiencies found on the individual element. The following guidelines are used in establishing an element’s condition rating:

To ensure a comprehensive inspection and as a part of the requirements of record keeping and documentation, an inspector is responsible for recording the location, type, size, quantity, and severity of deterioration and deficiencies for each element of a given component.

Evaluating Components

The following major components of bridges receive an overall Structure Inventory and Appraisal (SI&A) component condition rating:

Component Condition Rating Guidelines

NBI component condition ratings for deck, superstructure, or substructure components, in general, should reflect the overall condition of the component rather than localized conditions. This has been true for many years and is emphasized in the FHWA Coding Guide with the following wording:

Condition codes are properly used when they provide an overall characterization of the general condition of the entire component being rated. Conversely, they are improperly used if they attempt to describe localized or nominally occurring instances of deterioration or disrepair. Correct assignment of a condition code must, therefore, consider both the severity of the deterioration or disrepair and the extent to which it is widespread throughout the component being rated.

Although the FHWA Coding Guide states that it is improper to use the condition codes to describe localized instances of deterioration or disrepair, it also states that the inspector must consider both the severity and extent of the deterioration. With this in mind, there are occasions when a severe, localized condition affects the structural capacity of a component member. It is important to recognize that the coding applies to all primary members of a component. Therefore, localized conditions that impact the structural capacity of just one member can impact the overall performance of the entire component. The affect on structural capacity is dependent upon several factors including the type and extent of the deterioration, as well as the location along the member. An inspector may need to discuss the observed condition with an engineer to make this determination. When these situations occur, it is appropriate to assign a lower component condition rating for that component from a safety perspective and is in keeping with the intent of the National Bridge Inspection Program.

When these localized conditions are determined to be such that prompt action is needed and/or the overall component condition rating is affected, the conditions should also be addressed through the "critical findings" process that is identified in the NBIS regulation. The NBI component condition rating should be reviewed and appropriately adjusted once the critical finding has been addressed. This adjustment will depend on how the critical finding was addressed and how that action relates to the original rating rationale.

The coding of NBI condition items should be viewed as important, but secondary, to the recognition of and follow-up on critical findings.

Currently, states employ two approaches to coding condition items when localized areas of severe deterioration are encountered. Some will account for the severity of a localized area of deterioration by lowering the condition rating of an entire component. The component condition rating is adjusted after the deteriorated area is improved (i.e., rating may rise if physical improvements are made, or may stay the same if the bridge is posted for load restrictions and/or supported with temporary shoring). FHWA recognizes this approach when the severity of the localized deterioration affects the structural capacity of the component.

Other states “rate to the average” regardless of the severity of a localized area of deterioration. This approach relies heavily on ensuring that critical findings are addressed in a timely manner regardless of the component condition rating value. If the localized area of severe deterioration is not improved following the critical finding follow-up process, the component condition rating may need to be lowered to account for the severity of the deterioration if structural capacity is affected.

Either approach to coding the condition items results in the same ultimate outcome, i.e. critical inspection findings are addressed to ensure continued safe use of the bridge and component condition ratings eventually reflect the overall condition of the component. If the approach is to consider both the severity and extent of a component’s deterioration in rating each component at the time of inspection (or up to 90 days after the inspection as required by the NBIS), there cannot be any assumptions about future improvements made to a localized area. Only if an improvement is made, the rating should then be raised as appropriate. If the improvement is made within 90 days of the inspection, there is no need to consider the localized deterioration in the rating.

The following general component condition rating guidelines (obtained from the 1995 edition of the FHWA Coding Guide) are to be used in the evaluation of the deck (Item 58), superstructure (Item 59), and substructure (Item 60):

Code Description

N

NOT APPLICABLE

9

EXCELLENT CONDITION

8

VERY GOOD CONDITION - no problems noted.

7

GOOD CONDITION - some minor problems.

6

SATISFACTORY CONDITION - structural elements show some minor deterioration.

5

FAIR CONDITION - all primary structural elements are sound but may have minor section loss, cracking, spalling, or scour.

4

POOR CONDITION - advanced section loss, deterioration, spalling, or scour.

3

SERIOUS CONDITION - loss of section, deterioration, spalling, or scour have seriously affected primary structural components. Local failures are possible. Fatigue cracks in steel or shear cracks in concrete may be present.

2

CRITICAL CONDITION - advanced deterioration of primary structural elements. Fatigue cracks in steel or shear cracks in concrete may be present or scour may have removed substructure support. Unless closely monitored it may be necessary to close the bridge until corrective action is taken.

1

“IMMINENT” FAILURE CONDITION - major deterioration or section loss present in critical structural components, or obvious vertical or horizontal movement affecting structure stability. Bridge is closed to traffic but corrective action may put bridge back in light service.

0

FAILED CONDITION - out of service; beyond corrective action.

The component condition rating guidelines presented above are general in nature and can be applied to all bridge components and material types.

Structural capacity is defined as the designed strength of the member. However, structural capacity is different than load-carrying capacity. Load-carrying capacity refers to the ability of the member to carry the legal loads of the highway system of which the bridge is a part. Therefore, a bridge could possibly have good structural capacity yet be load posted because it is unable to carry the legal loads.

A bridge’s load-carrying capacity is not to influence component condition ratings. The fact that a bridge was designed for less than current legal loads, and may even be posted, has no influence upon component condition ratings.

Component condition ratings are determined by applying condition descriptions, which are general in nature, covering a broad array of bridge components and material types. The inspector is responsible for being familiar with terminology concerning material types and associated deficiency to utilize condition descriptions for accurately assigning component condition ratings. The following illustrates several common deficiency terms found in condition descriptions and their associated material types:

Establishing a link between material type and deficiency allows for accurate component condition ratings determined by utilizing condition descriptions for ratings 9 through 1 found in the general component condition rating guidelines.

Supplemental component condition rating guidelines, which may be developed by individual states, are intended to be used in addition to the FHWA Coding Guide to make it easier for the inspector to assign the most appropriate condition rating to the component being considered and improve uniformity.

Using the material and component specific supplemental rating guidelines (found in the 1995 edition of the FHWA Coding Guide) helps to clarify how each type of deficiency affects the component condition rating. Care has to be taken not to “pigeonhole” the rating based on only one word or phrase. The following is one suggested method for determining proper component condition ratings:

This procedure generally works with all of the component condition rating guidelines.

4.2.3 Channel and Channel Protection Condition Ratings

General

For structures located over waterways, a Structure Inventory and Appraisal (SI&A) condition rating is provided for the channel and channel protection:

Overall Condition

This item describes the physical conditions associated with the flow of water through the bridge such as stream stability and the condition of the channel, riprap, slope protection, or stream control devices, including spur dikes. The inspector should be particularly concerned with visible signs of excessive water velocity which may cause undermining of slope protection, erosion of banks, and realignment of the stream. Accumulation of drift and debris on the superstructure and substructure should be noted on the inspection form but not included in the component condition rating of the superstructure and substructure.

Evaluate and code the condition in accordance with the previously described general component condition ratings, procedures to account for critical findings, and the following descriptive codes:

Code Description

N

Not applicable. Use when bridge is not over a waterway (channel).

9

There are no noticeable or noteworthy deficiencies which affect the condition of the channel.

8

Banks are protected or well vegetated. River control devices such as spur dikes and embankment protection are not required or are in a stable condition.

7

Bank protection is in need of minor repairs. River control devices and embankment protection have a little minor deficiency. Banks and/or channel have minor amounts of drift.

6

Bank is beginning to slump. River control devices and embankment protection have widespread minor deficiency. There is minor streambed movement evident. Debris is restricting the channel slightly.

5

Bank protection is being eroded. River control devices and/or embankment have major deficiency. Trees and brush restrict the channel.

4

Bank and embankment protection is severely undermined. River control devices have severe deficiency. Large deposits of debris are in the channel.

3

Bank protection has failed. River control devices have been destroyed. Streambed aggradation, degradation, or lateral movement has changed the channel to now threaten the bridge and/or approach roadway.

2

The channel has changed to the extent the bridge is near a state of collapse.

1

Bridge closed because of channel failure. Corrective action may put bridge back in light service.

0

Bridge closed because of channel failure. Replacement necessary.

4.2.4 Culvert Condition Ratings

General

When assigning a culvert condition rating, all areas of the culvert and the possible effects on the overall structure are investigated. The inspector considers whether the component is functioning properly, whether it could pose a threat to safety or cause property damage, and whether it could cause more extensive damage if not repaired.

Evaluating Elements

Chapter 14 addresses the individual elements of various culverts. The overall component condition rating considers all of the elements which make up a culvert and are useful in establishing maintenance, rehabilitation, and replacement programs and priorities.

Although some of the individual elements of culverts are not directly considered in the FHWA Coding Guide, these supplemental items are useful in determining the overall culvert condition ratings. They may also be included as part of an agency's bridge management system.

Evaluating Components

In addition to the major components of bridges (deck, superstructure, and substructure), culverts also receive a Structure Inventory and Appraisal (SI&A) overall component condition rating:

Component Condition Rating Guidelines

This item evaluates the alignment, settlement, joints, structural condition, scour, and other items associated with culverts. The component condition rating code is intended to be an overall condition evaluation of the culvert. Integral wingwalls to the first construction or expansion joint are included in the evaluation.

Item 58 - Deck, Item 59 - Superstructure, and Item 60 - Substructure should be coded N for all culverts.

Evaluate and code the culvert condition in accordance with the previously described general component condition ratings, procedures to account for critical findings and the following descriptive codes:

Code Description

N

Not applicable. Use if structure is not a culvert.

9

No deficiencies.

8

No noticeable or noteworthy deficiencies which affect the condition of the culvert. Insignificant scrape marks caused by drift.

7

Shrinkage cracks, light scaling, and insignificant spalling which does not expose reinforcing steel. Insignificant damage caused by drift with no misalignment and not requiring corrective action. Some minor scouring has occurred near curtain walls, wingwalls, or pipes. Metal culverts have a smooth symmetrical curvature with superficial corrosion and no pitting.

6

Deterioration or initial disintegration, minor chloride contamination, cracking with some leaching, or spalls on concrete or masonry walls and slabs. Local minor scouring at curtain walls, wingwalls, or pipes. Metal culverts have a smooth curvature, non-symmetrical shape, significant corrosion, or moderate pitting.

5

Moderate to major deterioration or disintegration, extensive cracking and leaching, or spalls on concrete or masonry walls and slabs. Minor settlement or misalignment. Noticeable scouring or erosion at curtain walls, wingwalls, or pipes. Metal culverts have significant distortion and deflection in one section, significant corrosion or deep pitting.

4

Large spalls, heavy scaling, wide cracks, considerable efflorescence, or opened construction joint permitting loss of backfill. Considerable settlement or misalignment. Considerable scouring or erosion at curtain walls, wingwalls, or pipes. Metal culverts have significant distortion and deflection throughout, extensive corrosion or deep pitting.

3

Any condition described in Code 4 but which is excessive in scope. Severe movement or differential settlement of the segments, or loss of fill. Holes may exist in walls or slabs. Integral wingwalls nearly severed from culvert. Severe scour or erosion at curtain walls, wingwalls, or pipes. Metal culverts have extreme distortion and deflection in one section, extensive corrosion, or deep pitting with scattered perforations.

2

Integral wingwalls collapsed, severe settlement of roadway due to loss of fill. Section of culvert may have failed and can no longer support embankment. Complete undermining at curtain walls and pipes. Corrective action required to maintain traffic. Metal culverts have extreme distortion and deflection throughout with extensive perforations due to corrosion.

1

Bridge closed. Corrective action may put bridge back in light service.

0

Bridge closed. Replacement necessary.

4.2.5 Appraisal Rating Items

Appraisal Rating Guidelines

The following SI&A items are known as appraisal rating items:

Appraisal rating items are used to evaluate a bridge in relation to the level of service it provides on the highway system of which it is a part. The level of service for a bridge describes the function the bridge provides for the highway system carried by the bridge. The structure is compared to a new one that is built to current standards for that particular class of road. The exception is Item 72, Approach Roadway Alignment. Rather than comparing the alignment to current standards, it is compared to the general existing alignment of the roadway approaches to the bridge compared to the general highway.

The level of service goals used to appraise bridge adequacy vary depending on the highway functional classification, traffic volume, and other factors. The goals are set with the recognition that widely varying traffic needs exist throughout highway systems. Many bridges on local roads can adequately serve traffic needs with lower load capacity and geometric standards than would be necessary for bridges on heavily traveled main highways.

If national uniformity and consistency are to be achieved, similar structure, roadway, and vehicle characteristics are evaluated using identical standards. Therefore, tables and charts have been developed which are used to evaluate the appraisal rating items for all bridges submitted to the National Bridge Inventory, regardless of individual state criteria used to evaluate bridges.

The following general appraisal rating guidelines (obtained from the 1995 edition of the FHWA Coding Guide) are used to evaluate structural evaluation (Item 67), deck geometry (Item 68), underclearances (Item 69), waterway adequacy (Item 71) and approach roadway alignment (Item 72).

Code Description

N

Not applicable

9

Superior to present desirable criteria

8

Equal to present desirable criteria

7

Better than present minimum criteria

6

Equal to present minimum criteria

5

Somewhat better than minimum adequacy to tolerate being left in place as is

4

Meets minimum tolerable limits to be left in place as is

3

Basically intolerable, requiring high priority of corrective action

2

Basically intolerable, requiring high priority of replacement

1

This value of rating code not used

0

Bridge closed

The specific tables for Item 67 - Structural Evaluation, Item 68 - Deck Geometry, Item 69 - Underclearances, Vertical and Horizontal, Item 71 - Waterway Adequacy and Item 72 - Approach Roadway Alignment appear in the FHWA Coding Guide and are detailed enough that several states now program their computerized bridge management system to automatically calculate several of the appraisal rating items. Thus, some inspectors may not be responsible for coding these items. Inspectors may be asked to field verify the computed appraisal ratings.

Item 67 - Structural Evaluation - The item description and procedures used to determine the Structural Evaluation Appraisal Rating are located in Item 67 of the FHWA Coding Guide. This item is coded by the FHWA Edit/Update program, not the inspector. The correct way to evaluate this item for bridges is to consider the following factors:

Item 68 - Deck Geometry - The deck geometry appraisal evaluates the curb to curb bridge roadway width and the minimum vertical clearance over the bridge roadway. This item is coded by determining two appraisal ratings, one for bridge roadway width and one for the minimum vertical clearance. The lower of these two is the appraisal rating. This item is coded by the FHWA Edit/Update program, not the inspector. The FHWA Coding Guide includes the following scenarios to choose from for the bridge roadway width appraisal:

Item 69 - Underclearances, Vertical and Horizontal - This item refers to the vertical and horizontal underclearances from the through roadway under the structure to the superstructure or substructure units. The item description and coding guidelines, which are located in Item 69 of the FHWA Coding Guide, are used to determine the Underclearance Appraisal Rating. This item is similar to Item 68 in that two different ratings are developed: one for vertical underclearance and one for horizontal underclearance. The lower of these two is the appraisal rating. This item is coded by the FHWA Edit/Update program, not the inspector.

Item 71 - Waterway Adequacy - Waterway adequacy is appraised with respect to passage of flow through the bridge. The rating is tied to flood frequencies and traffic delays. Appraisal ratings are assigned by the table contained in Item 71 of the FHWA Coding Guide and are based on the functional classification of the road carried by the structure, hydraulic and traffic data for the structure, and site conditions. This item is not coded by the FHWA Edit/Update program.

Item 72 - Approach Roadway Alignment - This appraisal is based on comparing the alignment of the bridge approaches to the general highway alignment of the section of roadway on which the structure is located. The rating guidelines are correctly applied by determining if the vertical or horizontal curvature of the bridge approaches differs from the section of highway the bridge is on, resulting in a reduction of vehicle operating speed to cross the bridge. This item is not coded by the FHWA Edit/Update program. The guidelines for FHWA Item 72, Appraisal or Approach Roadway Alignment, are as follows:

The following guidelines indicate a means of determining the difference between a minor reduction and substantial reduction of operating speed:

The remaining codes between these general values are applied at the inspector’s discretion.

A narrow bridge does not affect the Approach Roadway Alignment Appraisal. The narrow bridge would be accounted for in Item 68, Deck Geometry.

Items affecting sight distance at the bridge, unrelated to vertical and horizontal curvature of the roadway, such as vegetation growth and substructure units of overpass structures do not affect the Approach Roadway Alignment Appraisal.

Item 36 - Traffic Safety Features - For structures on the National Highway System (NHS), this appraisal is based on comparing the traffic safety features in place at the bridge site to current national standards set by regulation, so that an evaluation of their adequacy can be made. For structures not on the National Highway System (NHS), the procedure is the same, however, it shall be the responsibility of the highway agency (state, county, local, or federal) to set standards. The item description and procedures used to determine the Traffic Safety Feature Appraisal Rating are located in Item 36 of the FHWA Coding Guide. The following are the traffic safety features to be coded:

Item 113 - Scour Critical Bridges - This item is used to identify the current status of the bridge regarding its vulnerability to scour. A scour critical bridge is one with abutment or pier foundations that are rated as unstable due to observed scour at the bridge site, or a scour potential as determined from a scour evaluation study including a scour analysis made by hydraulic, geotechnical, or structural engineers. The item description, procedures, and code descriptions are located in Item 113 of the FHWA Coding Guide.

4.2.6 Functionally Obsolete and Structurally Deficient

Definitions

A bridge is considered to be functionally obsolete if it has deck geometry, load carrying capacity, clearance or approach roadway alignment that no longer meets the criteria for the system of which the bridge is a part. Examples include bridges with inadequate lane widths or shoulder widths, insufficient vertical clearances to serve the traffic demand, or bridges that may be occasionally flooded.

Bridges are considered structurally deficient where significant load carrying elements are found to be in poor or worse condition due to deterioration and/or damage, or the adequacy of the waterway opening provided by the bridge is determined to be extremely insufficient to the point of causing intolerable traffic interruptions.

Any bridge classified as structurally deficient is excluded from the functionally obsolete category. Bridges that are structurally deficient and functionally obsolete are reported together as deficient bridges.

General Qualifications

In order to be considered for either the structurally deficient or functionally obsolete classification, a highway bridge must meet the following:

Structurally Deficient (SD) -

  1. A condition rating of 4 or less for
  2. Item 58 - Deck; or
    • Item 59 - Superstructures; or
    • Item 60 - Substructures; or
    • Item 62 - Culvert and Retaining Walls.(1) or
  3. An appraisal rating of 2 or less for
    • Item 67 - Structural Evaluation; or
    • Item 71 - Waterway Adequacy.(2)

Functionally Obsolete (FO) -

  1. An appraisal rating of 3 or less for
    • Item 68 - Deck Geometry; or
    • Item 69 - Underclearances;(3) or
    • Item 72 - Approach Roadway Alignment. or
  1. An appraisal rating of 3 for
    • Item 67 - Structural Evaluation; or
    • Item 71 - Waterway Adequacy.(2)

Footnotes for structurally deficient and functionally obsolete:

(1) Item 62 applies only if the last digit of Item 43 (Structure Type) is coded 19.

(2) Item 71 applies only if the last digit of Item 42 (Type of Service) is coded 0, 5, 6, 7, 8 or 9.

(3) Item 69 applies only if the last digit of Item 42 is coded 0, 1, 2, 4, 6, 7 or 8.

4.2.7 Sufficiency Rating

Definition

Sufficiency rating (S.R.) is a calculated numeric value used to indicate the sufficiency of a bridge to remain in service. The rating is calculated using the sufficiency rating formula. Sufficiency rating is discussed in detail in Appendix B of the FHWA Coding Guide.

Sufficiency Rating Formula

S.R. = S1 + S2 + S3 - S4

(entirely deficient)≤ S.R. ≤ 100 (entirely sufficient)

where: S1=55% max.; based on structural adequacy and safety (i.e., superstructure, substructure or culvert condition and load capacity).

S2=30% max.; deals with serviceability and functional obsolescence (items such as deck condition, structural evaluation, deck geometry, underclearances, waterway adequacy, approach road alignment).

S3=15% max.; concerns essentiality for public use (items such as detour length, average daily traffic, and STRAHNET (Strategic Highway Corridor Network).

S4=13% max.; deals with special reductions based on detour length, traffic safety features, and structure type.

Twenty NBI items are used to calculate these four factors which therefore determine the sufficiency rating. Sufficiency rating is not normally calculated manually. Usually, it is included in the agency’s inventory computer program and is calculated automatically by the computer based upon the inventory data collected by the bridge inspector. The sufficiency rating is calculated by the FHWA Edit/Update program.

Uses

Sufficiency Rating (SR) is used by the federal and state agencies to determine the relative sufficiencies of all of the nation’s bridges. In the recent past, eligibility for federal funding with Highway Bridge Program funds has been determined by the following criteria:

S.R. ≤ 80E ligible for rehabilitation

S.R. < 50 Eligible for replacement

Some states use the sufficiency rating as the basis for establishing priority for repair or replacement of bridges; the lower the rating, the higher the priority. Several states have developed specific bridge management procedures with priority guidelines for repair or replacement of bridges. By using these types of procedures, priority ratings can be established by considering the significance or impact of such level-of-service parameters as traffic volume and class of highway.

Topic 4.3 Introduction to Element Level Evaluation

4.3.1 Introduction

Managers of large inventories of infrastructure assets need a tool to effectively manage these assets. For bridge data, element level inspection has been successfully used as a basis for data collection, performance measurement, resource allocation, and management decision support. Although component condition rating and reporting, as described in the FHWA Coding Guide, provides a consistent method for evaluation and reporting, the data is not comprehensive enough to support bridge preservation performance-based decision support.

The Pontis CoRe (Commonly Recognized) Element Report (June 1993), which is the basis of the AASHTO CoRe Element Guide, was prepared by technical working group representatives from California, Colorado, Minnesota, Oregon, Virginia, Washington, and the Federal Highway Administration. The Pontis CoRE Report explains the reasoning behind the selection of bridge items that require inspection for a successful Bridge Management System. Pontis is ‘bridge’ in Latin.

In 2010, the AASHTO Guide Manual for Bridge Element Inspection was developed to address improvements to the existing CoRe Element Guide. This reference manual was prepared by representatives from California, Idaho, Michigan, Montana, New York and FHWA to further enhance bridge management. The Guide Manual was revised in 2013 and is titled Manual for Bridge Element Inspection.

Significant changes from the CoRe Element Guide to the Manual for Bridge Element Inspection include:

4.3.2 Element Level Inspection Development

In developing a system for standardized data collection, the FHWA needed to look at the shortcomings of NBI (National Bridge Inventory) data. The problems with NBI data included:

A system was developed which included a standardized description of bridge elements at a greater level of detail. The FHWA created a task force to revise the standards and created a manual called "Commonly Recognized (CoRe) Structural Elements". The AASHTO Guide for CoRe Element Manual defined each element, the unit of measurement, definitions of a set of 3-5 standardized condition states, and feasible actions for each condition state. The CoRe Element Manual was accepted as an official AASHTO manual in May 1995. Some states developed their own CoRe Element Manual based on the AASHTO Core Element Manual. Approximately 40 states perform element level inspection.

In 2010, the limitations of the CoRe Element Manual were again addressed. These problems included:

The National Bridge Element and Bridge Management Element system provides multiple distress paths for each defined condition state. This allows for deficiencies to be identified within each overall element assessment. The AASHTO Guide Manual for Bridge Element Inspection defines each element, description, unit of measurement or quantity calculation, set of four standardized condition states, feasibility actions, element commentary, and element definitions. The AASHTO Guide Manual for Bridge Element Inspection, First Edition, 2011, was first published as an official manual in February 2011. The 2011 version was replaced in 2013 with the AASHTO Manual for Bridge Element Inspection, First Edition 2013. In 2015, Interims for the Manual were released.

4.3.3 Element Level Rating Terminology

The AASHTO Manual for Bridge Element Inspection, First Edition, 2013 (see Figure 4.3.1) provides a description of structural elements that are commonly used in highway bridge construction and encountered on bridge safety inspections.

The following terms are used to describe bridge element-level inspection:

AASHTO Manual for Bridge Element Inspection 2015 Interim

Figure 4.3.1 AASHTO Manual for Bridge Element Inspection

4.3.4 Basic Requirements of National Bridge Elements

In the development of National Bridge Elements, it was important that the specification must be generic. Different agencies have varying maintenance practices, funding mechanisms, policy concerns and terminology. However, the physical components of bridges and deterioration processes are not unique. Agencies must be able to customize the generic standard to satisfy their own purposes without sacrificing the benefits of a common standard. Any changes to elements could introduce incompatibility between agencies. For this reason, agencies cannot change the number of condition states and the intent of the condition state language.

To avoid this from happening, the AASHTO Manual for Bridge Element Inspection provides the ability of an agency to add custom agency developed elements or modify recommended Bridge Management Elements. It is possible for future National Bridge Elements or Bridge Management Elements to be added. These elements must be permanent, have clear distinction and be defined as concisely as possible. The guidelines for developing National Bridge Elements include:

One primary use of definitions is to establish a useful inventory. In the field, each element must be clearly identified, measured and counted economically. It is also important to describe element attributes, such as size, material, condition and serviceability, quantitatively. The commonality aspect of National Bridge Elements depends on having definitions that are widely understood and are stable over time. One major factor contributing to definitions being widely understood is NHI’s bridge inspection related training courses.

4.3.5 Bridge Element Identification

National Bridge Elements

AASHTO National Bridge Elements describe primary load carrying members, including:

See Figures 4.3.2 - 4.3.7 for a list of AASHTO National Bridge Elements for decks/slabs, railings, superstructure, substructure, bearings, and culverts.

Decks/Slabs National Bridge Element names and numbers that are in the AASHTO Manual for Bridge Element Inspection, all with the unit of square feet. Reinforced Concrete Deck is number 12 and Reinforced Concrete Slab is number 38. Prestressed Concrete Deck is number 13. Prestressed Concrete Top Flange is number 15. Reinforced Concrete Top Flange is number 16. Open Grid Steel Deck is number 28. Concrete Filled Grid Steel Deck is number 29. Corrugate/Orthotropic/Etc. is number 30. Timber Deck is number 31 and Timber Slab is number 54. Other Material Deck is number 60 and Other Material Slab is number 65.

Figure 4.3.2 Decks/Slabs National Bridge Elements in the AASHTO Manual for Bridge Element Inspection

Railings National Bridge Elements in the AASHTO Manual for Bridge Element Inspection show the description and number of the each element, all with the same unit of measure in length, feet. Metal Bridge Railing is number 330. Reinforced Concrete Bridge Railing is number 331. Timber Bridge Railing is number 332. Other Bridge Railing is number 333. Masonry Bridge Railing is number 334.

Figure 4.3.3 Railings National Bridge Elements in the AASHTO Manual for Bridge Element Inspection

Superstructure National Bridge Elements in the AASHTO Manual for Bridge Element Inspection show the description and number of the each element.The following elements have the same unit of measure in length, feet: Girder/Beams (Steel is number 107, Prestressed Concrete is number 110, Reinforced Concrete is number 110, Timber is number 111, and Other is number 112), Closed Web/Box Girder (Steel is number 102, Prestressed Concrete is number 104, Reinforced Concrete is number 105, and Other is number 106), Stringer (Steel is number 113, Prestressed Concrete is number 115, Reinforced Concrete is number 116, Timber is 117, and Other is number 118), Truss (Steel is number 120, Timber is number 135, and Other is number 136), Arch (Steel is number 141, Prestressed Concrete is number 143, Reinforced Concrete is number 144, Timber is number 146, Masonry is number 145, and Other is number 142), Floorbeam (Steel is number 152, Prestressed Concrete is number 154, Reinforced Concrete is number 154, Timber is number 156, and Other is number 157), and Primary Cables (Steel is number 147). The following elements is measured in each: Secondary Cables (Steel is number 148 and Other is number 149), Gusset Plates (Steel is number 162), and Pin, Pin and Hanger Assembly, or Both (Steel is number 161).

Figure 4.3.4 Superstructure National Bridge Elements in the AASHTO Manual for Bridge Element Inspection

Bearing National Bridge Elements in the AASHTO Manual for Bridge Element Inspection show the description and number of the each element, all measured in the same unit of measure in each: Elastomeric Bearing is number 310, Movable Bearing is number 311, Enclosed/Concealed Bearing is number 312, Fixed Bearing is number 313, Pot Bearing is number 314, Disk Bearing is number 315, and Other Bearing is number 316.

Figure 4.3.5 Bearings National Bridge Elements in the AASHTO Manual for Bridge Element Inspection

Substructure National Bridge Elements in the AASHTO Manual for Bridge Element Inspection show the description and number of the each element.The following elements have the same unit of measure in length, feet: Column Tower (Trestle) (Steel is number 202 and Timber is number 208), Pier Wall (Reinforced Concrete is number 210, Timber is number 212, Masonry is number 213, and Other is number 211), Abutment (Steel is number 219, Reinforced Concrete is number 215, Timber is 216, Masonry is number 217, and Other is number 218), Pier Cap (Steel is number 231, Prestressed Concrete is number 233, Reinforced Concrete is number 234, Timber is number 235, and Other is number 236), Pile Cap/Footing (Reinforced Concrete is number 220). The following elements is measured in each: Columns (Steel is number 202, Prestressed Concrete is number 204, Reinforced Concrete is number 205, Timber is number 206, and Other is number 203), and Pile (Steel is number 225, Prestressed Concrete is number 226, Reinforced Concrete is number 227, Timber is number 228, and Other is number 229).

Figure 4.3.6 Substructure National Bridge Elements in the AASHTO Manual for Bridge Element Inspection

Culvert National Bridge Elements in the AASHTO Manual for Bridge Element Inspection show the description and number of the each element which are all measured in length, feet. Steel is number 240, Prestressed Concrete is number 245, Reinforced Concrete is number 241, Timber is number 242, Masonry is number 244, and Other is number 243.

Figure 4.3.7 Culverts National Bridge Elements in the AASHTO Manual for Bridge Element Inspection

Bridge Management Elements

AASHTO Bridge Management Elements represent a recommended condition assessment language that can be modified to suit the agency's needs. The following types of elements are defined as Bridge Management Elements:

See Figures 4.3.8 - 4.3.10 for a list of AASHTO Bridge Management Elements for joints, approach slabs, wearing surfaces, and protection systems.

Joint Bridge Management Elements in the AASHTO Manual for Bridge Element Inspection show the description and number of the each element, which all have the same unit of measure in length, feet.They include: Strip Seal Expansion Joint is number 300, Pourable Joint Seal is number 301, Compression Joint Seal is number 302, Assembly/Joint Seal (Modular) is number 303, Open Expansion Joint is number 304, Assembly Joint without Seal is number 305, and Other Joint is number 306.

Figure 4.3.8 Joints Bridge Management Elements in the AASHTO Manual for Bridge Element Inspection

Joint Bridge Management Elements in the AASHTO Manual for Bridge Element Inspection show the description and number of the each element, which all have the same unit of measure in area, square feet.They include: Prestressed Approach Slab is number 320 and Reinforced Concrete Slab is number 321.

Figure 4.3.9 Approach Slabs Bridge Management Elements in the AASHTO Manual for Bridge Element Inspection

Wearing Surfaces and Protective System Bridge Management Elements in the AASHTO Manual for Bridge Element Inspection show the description and number of the each element, which all have the same unit of measure in area, square feet. They include: Wearing Surface is number 51, Steel Protective Coating is number 515, Concrete Reinforcing Steel Protective System is number 520, and Concrete Protective Coating is number 521.

Figure 4.3.10 Wearing Surfaces and Protective Systems in the AASHTO Manual for Bridge Element Inspection

Defect Flags

Defect Flags (Smart Flags) were used prior to 2013 to provide additional information about the condition of AASHTO bridge elements. The defect descriptions have been incorporated into many of the National Bridge Elements and Bridge Management Elements.

Agency Developed Elements

Agencies may develop sub-elements that use the same condition state definitions as their associated NBE or BME elements. This allows for more detailed element descriptions. They are a subset of the NBE or BME and allow a more detailed classification. They are often created to distinguish a different size, location or exposure.

The element identification members 800 and above are not used in the 2013 AASHTO Manual for Bridge Inspection and are reserved for Agency purposes.

Agency developed elements fall into three main categories: subsets of NBEs, BMEs, or elements that are independent of defined elements. Agency Developed Element guidelines are listed below:

Agency Defined Subsets of NBEs

For agency defined sub-sets of National Bridge Elements, the agency must be able to combine the sub-elements back together to form the original NBE element for NBI submission with the original condition state and element definition language.

Agency Defined Subsets of BMEs

For agency defined sub-sets of Bridge Management Elements, the agency must be able to combine the sub-elements back together to form the original BME element with the original condition state and element definition language. FHWA requires agencies to submit BME data for concrete and steel protective systems and wearing surfaces. However, custom elements of this type must retain the original number of condition states using a good, fair, poor, severe description.

Independent Agency Developed Elements

For Agency Defined Elements that are not sub-sets of National Bridge Elements or Bridge Management Elements, the only requirement is the standardized number of condition states (four). These elements may include inventory items or specific aspects of the structure. Independent Agency Defined Elements may or may not include feasible actions, deficiency, or official condition state language.

Examples of potential independent agency developed elements include approach guardrail, approach guardrail ends, seismic retrofit components, tunnels, condition of drainage components or lighting fixtures, or ancillary items such as overhead signing structures.

4.3.6 Condition States

The scale of good-fair-poor-severe on its own is insufficient to allow objective assessment of observed conditions in the field. It was decided to measure bridge condition on a single scale that reflects common processes for deterioration and the effect on serviceability. The general pattern for a Bridge Element having four condition status is as follows:

  1. Good - No deterioration to minor deterioration
  2. Fair - Minor to Moderate deterioration
  3. Poor - Moderate to Severe deterioration
  4. Severe - Beyond the limits established in Condition State 3 and/or warrants a structural review to determine strength or serviceability of the element or bridge

Each of these levels of deterioration is called a condition state. The condition state methodology provides two types of information about a bridge element’s deterioration:

The severity is important for selection of a feasible and cost effective preservation treatment, and extent is important for cost estimation.

Assignment of quantities to condition states is determined from element definitions and element commentary for National Bridge Elements. Condition state definitions are guidelines to the bridge inspector for categorization of the severity of the deficiency. Element commentary represents additional considerations for the inspector during the collection of data. From this information, the inspector can complete the element level evaluation.

4.3.7 Feasible Actions

Feasible actions are those that an agency may take to address a defect. They represent a set of responses that may be taken for an element based upon quantities within a given condition state. They also represent general guidance on agency preservation strategies and can be customized by each agency for each element and condition state.

A summary of feasible actions and associated condition states is given below. Depending on the element, some feasible actions/conditions states may not be available. Other feasible actions, such as "Do Nothing", are available for all elements and condition states. “Do Nothing” can be used for all the elements in condition states since the possibility of nothing that needs to be done due to the condition of the element being good or to be used if the condition of the bridge is so severe, the bridge is closed and or there is a feasible action already taking place.

Feasible Action Condition State

 

1

2

3

4

Do Nothing

Protect

Preserve (for other culverts and other railings )

 

 

Repair

 

Rehab

 

 

Reset (for bearings only)

 

 

Replace

 

 

4.3.8 Environments

An element can exist in one of four environments, which describe different weather or operating conditions. The environments are important for deterioration models and prediction of future conditions. The four environments are defined in general terms as follows:

  1. Benign - No environmental or operational conditions affecting deterioration
  2. Low - Environmental or operational conditions create no adverse impacts, or are mitigated by past non-maintenance actions or highly effective protective systems
  3. Moderate - Typical level of environmental or operational conditions influence on deterioration
  4. Severe - Environmental or operational conditions factors contribute to more rapid deterioration. Protective systems are not in place or are ineffective

Environment policies are used for element level inspection and set by individual state agencies.

4.3.9 The Role of Element Level Data in Bridge Management Systems

An immediate application of Bridge Elements is the collection and analysis of performance data. It is essential that original data collection be as objective and repeatable as possible. This raw, objective data must be stored so that the analysis may be updated or improved at a later time. Bridge Elements must be usable to support management decision making. The large volume of raw data collected must be transformed into useful information. For this reason, the development of Bridge Elements is heavily influenced by the parallel development of previous CoRe elements and previous software programs such as Pontis.

Condition state data provides quantitative data about the physical condition and performance of bridge elements. This data is also, the effects of treatment actions can be tracked over time. Element level data is an essential part of the following BMS functions. Element level inspections can track the effectiveness of action over time by showing the various condition states and how they may change over time after the bridge element is either repaired, replaced, or nothing would be done. Potential applications for agencies includes:

Topic 4.4 Record Keeping and Documentation

4.4.1 Introduction

Bridge owners maintain a complete, accurate, and current record of each bridge under their jurisdiction. Such information relating directly to the inspection, design, performance and maintenance of the bridge is vital to the effective management of a population of bridges. Additionally, this information provides a record that may be important for repair, rehabilitation, or replacement of their assets.

The first section in this topic covers the critical components of the bridge record, while the remaining sections provide the inspector with guidance on how to thoroughly organize inspection data and produce an accurate and effective inspection report.

4.4.2 Bridge Records

Bridge records, or files, are used to maintain detailed, cumulative and up-to-date information on each structure. A thorough study of the available historical information can be extremely valuable in identifying possible critical areas of structural or hydraulic components and features.

The contents of any particular bridge file may vary depending upon the size and age of the structure, the functional classification of the road carried by the structure, and the informational needs of the agencies responsible for inspection and maintenance. The bridge file is not only a resource to the bridge owner, but also a resource to the inspector. The inspector will gain valuable insight into the bridge by being familiarized with it prior to the inspection. It is recommended that the following types of information be assembled when possible.

According to the AASHTO Manual for Bridge Evaluation, the bridge record includes the following information:

Construction, “as-built,” or shop and working plans are included in a bridge record. If plans are not available, determine the following types of construction information: date built; type of structure, including size, shape, and material; design capacity; and design service life. Hydraulic data is also assembled where available, including structure profile gradeline, elevation of inverts or footings, stream channel and water surface during normal and high flows, design storm frequency, drainage area, design discharge, date of design policy, flow conditions, limits of flood plain, type of energy dissipaters (if present), cut-off wall depth, channel alignment, and channel protection.

Specifications

The bridge record includes a complete copy of the technical specifications used to design and build the bridge. When a general specification was used, only the special provisions are included in the file. The edition and date of the general specifications are noted in the bridge record.

Correspondence

The bridge record includes any applicable letters, memorandums, and notices of project completion, construction diaries, telephone logs, and any other information directly concerning the bridge in chronological order.

Photographs

Photographs are used to supplement the inspection notes and sketches. A minimum of two photographs are included in the bridge record: a topside view of the bridge roadway and at least one elevation view of the bridge. Photographs showing major deficiencies or other features, such as utility attachments or channel alignment, also are included. Photographs that show load posting signs are also provided, if applicable.

Photo Log

Keep a photo log during the inspection. The photo log includes the date, photo number, and description of each photograph. It is best to be very specific when describing the photos (see Figure 4.4.1). Descriptions include both the location of the member and a brief description of any deficiencies.

Sample of a photo log

Figure 4.4.1 Sample Photo Log

Materials and Tests

Certificates for the type, grade, and quality of materials used in construction of the bridge are included in the bridge record. Examples include steel mill certificates, concrete delivery slips, and any other manufacturers' certificates. The certificates are retained in accordance with bridge owner policy and statute of limitations.

Reports for any non-destructive or laboratory testing either during or after construction are included. If any field load testing is performed, provide the reports in the bridge record.

Maintenance and Repair History

Information about repairs and rehabilitation activities are included in the bridge record. This chronological record includes details such as the date, project description, contractor, cost, contract number and any other related data. The types and amount of repairs performed at a bridge or culvert site can be extremely useful. For example, frequent roadway patching due to recurring settlement over a culvert or approach roadway for a bridge may indicate serious problems that are not readily apparent through a visual inspection of the structure.

Coating History

This information in the bridge record documents the surface protective coatings used, including surface preparation, application method, dry film paint thickness, types of paint, concrete and timber sealants, and other protective membranes.

Accident Records

Include details of accidents or damage to the bridge in the bridge record (see Figure 4.4.2). This information includes the date of the occurrence, description of the accident, member damage and repairs, and any investigative reports.

Photograph of a accident involving constructin equipment and a bridge

Figure 4.4.2 Accident Involving Construction Equipment and a Bridge

Posting

Each bridge record includes load capacity calculations and any required posting arising from the load ratings. The summary of posting actions includes the date of posting and a description of the signing used (see Figure 4.4.3).

Photograph of a truck crossing over a posted bridge

Figure 4.4.3 Posted Bridge

Permit Loads

A record of the most significant single-trip permit loads using the bridge are included in the bridge record. This information is to include any applicable documentation and calculations.

Flood and Scour Data

A chronological history of major flooding events are included for bridges over water (see Figure 4.4.4). This history includes the high water marks at the bridge site, scour evaluation, scour history, and any plan of action.

Photograph of a bridge after a flood event

Figure 4.4.4 Flood Event

Traffic Data

When available, the bridge record contains a history of the variations in Average Daily Traffic (ADT) and Average Daily Truck Traffic (ADTT) including the frequency and types of vehicles using the bridge. ADT and ADTT are important factors in determining fatigue life and are monitored for each bridge and each traffic lane on the bridge. If available, weights of the vehicles using the bridge are also included in the bridge record.

Inspection History

Reports from previous inspections can be particularly useful in identifying specific locations that require special attention during an inspection. Information from earlier inspections can be compared against current conditions to estimate rates of deterioration and to help judge the seriousness of the problems detected and the anticipated remaining life of the structure.

This chronological record of inspections performed on the bridge includes the date and type of inspection. The initial inspection report is included in the bridge record. Earthquake data, fracture critical member information, deck evaluations, and corrosion studies are also included when available.

Inspection Requirements

Inspections are planned and prepared for by taking into account needed access, inspection equipment, structural details, inspection methods, and the required qualifications of inspection personnel. In addition, the National Bridge Inspection Standards require that written inspection procedures for specific types of more complex inspections (fracture critical, underwater, and complex bridges) be developed to address those items that need to be communicated to an inspection team leader to ensure a successful bridge inspection. Section 4 of the AASHTO MBE has general considerations regarding inspection plans. An owner may have general overall inspection procedures in their bridge inspection manual that address common aspects of these more complex inspections, however, each bridge will have written inspection procedures specific to each bridge which address items unique to each bridge. The following items are to be addressed for each of these types of bridge inspections, either in the bridge specific inspection procedures, or by referring to general inspection procedures (typically in an agency's bridge inspection manual):

Other items that may be addressed depending on each unique situation might include:

Any special requirements to ensure inspector and public safety, including a traffic management plan, are also included.

Structure Inventory and Appraisal Sheets

A chronological record of SI&A forms used by the bridge owner is included in the bridge record. Refer to Topic 4.1 for a complete description of SI&A sample form.

Inventories and Inspections

Inspection reports are included as part of the bridge record. This information includes the results of all inventories and bridge inspections and can include construction or repair activities.

Bridge Inspection Forms

Many bridge owners have standard inspection forms. These forms are used for each bridge in their system and give the inspector a checklist of items that are to be reviewed. Another benefit of standardized forms is that it organizes bridge reports into a consistent format (see Figures 4.4.5 and 4.4.24 that are located at the end of this topic).

Example of an element level inspection form

Figure 4.4.5 Element Level Example Inspection Form

Rating Records

A complete record of the determination of the bridge’s load-carrying capacity is included in the bridge record (see Figure 4.4.6). This information will include the design load to indicate the live load the bridge was designed for, the analysis methods used to determine the inventory and operating ratings, and the inventory and operating ratings for the bridge. The capacity calculations will be signed and dated by the individual who determined them, together with any assumptions used.

Example of a load rating summary sheet

Figure 4.4.6 Example Load Rating Summary Sheet

Post or restrict the bridge in accordance with the AASHTO Manual for Bridge Evaluation or in accordance with State law, when the maximum unrestricted legal loads or State routine permit loads exceed that allowed under the operating rating or equivalent rating factor.

4.4.3 Methods of Inspection Documentation

Traditional

Note all signs of distress and deterioration with sufficient precision so that future inspectors can readily make a comparison of conditions. The most commonly used method for record keeping is pencil and paper. The inspector writes findings on forms, sketches, and notebooks (see Figure 4.4.7). This method is extremely flexible in that the inspector can draw whatever configurations are necessary to best describe and document deficiencies.

Photograph of an inspector taking notes

Figure 4.4.7 Inspector Taking Notes

Electronic Data Collection

Another method of record keeping is electronic data collection (see Figure 4.4.8). This technology provides a significant advantage in a number of areas. With all the bridge data available at the site, the inspector can retrieve and edit previous records and save them as current inspection data. This not only saves time but eliminates the need for reentering data. Also, it eliminates errors that can occur when transferring the inspector’s field notes to the computer back at the office. Electronic data collection provides a logical and systematic sequence of inspection, ensuring that no bridge elements are overlooked. It also allows the inspector to compare the current deficiencies with previous reports and note if any deterioration has gotten worse.

Photograph of an inspector using a electronic data collection device

Figure 4.4.8 Electronic Data Collection

4.4.4 Inspection Report Documentation

While the inspection of small bridges usually only requires the use of the standard inspection form, the inspection of large or complex bridges requires the use of an inspection file, in addition to any standard inspection forms. The inspection file contains:

When the above, detailed file format is selected for recording bridge inspection results, the information is to be recorded systematically. However, many bridge owners differ significantly in their required format. Most of the above information, if not provided on the inspection report, is available in the bridge record.

Element Identification

Identify the elements by the type of material, construction method, and the function that each element or member performs.

Some examples of elements or members and their abbreviations:

Verify that element descriptions or abbreviations are consistent with bridge owner nomenclature.

Structure Site Orientation

Structure site orientation is normally established according to highway direction of inventory, mile markers, segments, or stationing. It is important that the orientation of each bridge be clearly established. The following are some examples:

Bridge Member Orientation

When describing bridge members, it is important to clearly identify the specific element or member that has the deficiency. The following are some examples to orient bridge members:

If the orientation used during the inspection differs in any way with that used in existing documents, clearly state these differences in the inspection notes.

Example of a span numbering scheme

Figure 4.4.9 Sample Span Numbering Scheme

Example of a typical section numbering scheme

Figure 4.4.10 Sample Typical Section Numbering Scheme

Example of a structure orientation sketch

Figure 4.4.11 Sample Structure Orientation Sketch

Example of a truss numbering scheme

Figure 4.4.12 Sample Truss Numbering Scheme

Element Dimensions

Document sufficient dimensions to establish the size or cross section and other pertinent dimensions of elements. These include:

Sketch with steel superstructure dimensions

Figure 4.4.13 Steel Superstructure Dimensions

Sketch with truss and field splice dimensions

Figure 4.4.14 Truss Member and Field Splice Dimensions

Exact member dimensions are required to determine section properties used to calculate a load-rating analysis.

Inspection Notes and Sketches

In most cases, it will be possible to insert reproductions of portions of the plans in the inspection notes. However, in some instances, sketches will have to be drawn. The inspector may be able to pre-draw the sketches in the office and fill them out in the field (see Figures 4.4.15 through 4.4.17).

Sketch of a framing plan

Figure 4.4.15 Framing Plan

Sketch of a girder elevation

Figure 4.4.16 Girder Elevation

Typical prepared sketches of a culvert

Figure 4.4.17 Typical Prepared Culvert Sketches

The first sketch in the field inspection notes normally portrays the general layout of the bridge and site information, illustrating the structure plan and elevation data (see Figures 4.4.18 and 4.4.19). The immediate area, the stream or terrain obstacle layout, major utilities, and any other pertinent details are also included.

Sample sketch of a general plan

Figure 4.4.18 Sample General Plan Sketch

Sample sketch of a general elevation

Figure 4.4.19 Sample General Elevation Sketch

Deficiency Identification

Identify material deficiencies. as presented in Topic 6.1 - Timber, Topic 6.2 - Concrete, Topic 6.3 - Steel, Topic 6.5 - Masonry.

The exact location, severity and extent of deficiencies are used to determine the capacity of the bridge in its current condition.

Deficiency Qualification

Describe the seriousness of a deficiency. For example:

Deficiency Quantification

Describe the quantity of a deficiency. For example:

Deficiency Location

The exact position of the deficiency on the element or member is required if load capacity analysis is to be performed. For example:

The accuracy of the load capacity analysis depends on precise location information for deficiencies:

Locating a deficiency may include tying it to an established permanent reference. Avoid using references that can change over time.

Some examples of proper referencing include:

Reference points to avoid, since these locations vary between inspections:

When documenting the deficiency locations on the deck, include the condition of deck and haunch, expansion joints, construction joints, curbs, sidewalks, parapets, and railings with the deck sketches (see Figure 4.4.20).

Sample of deck inspection notes

Figure 4.4.20 Sample Deck Inspection Notes

When documenting the deficiency location of the superstructure, sketch the superstructure units in plan view and elevation, or cross section if necessary. Items to be inspected include bearings, main-supporting longitudinal members, floorbeams, stringers, bracing, and diaphragms (see Figure 4.4.21).

Sample of superstructure inspection notes

Figure 4.4.21 Sample Superstructure Inspection Notes

Include sketches or drawings to describe the condition of each substructure unit (see Figure 4.4.22). In many cases, it is sufficient to draw typical units that identify the principal elements and deficiencies of the substructure. Identify each element of the substructure unit so that they can be cross referenced to the notes or sketches. Items to be identified include piling, footings, vertical supports, lateral bracing of members, and caps.

Sample of substructure inspection notes

Figure 4.4.22 Sample Substructure Inspection Notes

Include sketches or drawings to describe the condition of the channel (see Figure 4.4.23). Streambed materials, alignment, condition of the banks, and the condition of the bottom of the waterway (including scour holes) are included in the sketch.

Sample channel inspection notes

Figure 4.4.23 Sample Channel Inspection Notes

Summary of Findings

Report all deficiencies, no matter how minor they may seem. Be as descriptive as necessary to report not only the severity of the deficiency but the location as well. This will be described in further detail later in this topic. When reporting deficiencies, be objective and do not use terms such as “dangerous” or “hazardous”.

Example inspection form from a PennDOT Form D-450: Form A - Site Data

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450

Example inspection form from a PennDOT Form D-450: Form A - Site Data

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form B - Deck and Superstructure Data

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form B - Deck and Superstructure Data

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form C - Abutment Data

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form D - Pier Data

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form E - Element Data

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form F - Fracture Critical

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form G - Underwater Inspection

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form G - Underwater Inspection

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form H - Culvert Data

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form J - Channel and Waterway Data

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form K - Paint, Structure Appraisal and Load Ratings

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form M - Maintenance Needs Data

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Example inspection form from a PennDOT Form D-450: Form P - Inspection Adminstration

Figure 4.4.24 Example Inspection Form - PennDOT Form D-450 (continued)

Topic 4.5 Critical Findings

4.5.1 Definition

A critical finding are a structural or safety related deficiency that requires immediate follow-up inspection or action.

A structure related deficiencies can interrupt the load path, not allowing loads to be transferred as designed. This can cause surrounding elements to become overstressed or unstable, potentially leading to partial or total collapse of the structure. Critical findings may also be non-structural deficiencies which jeopardize the safety of motorists or pedestrians.

4.5.2 Procedures

As stated in the NBIS regulations, each state or federal agency is required to "establish a statewide procedure to assure that critical findings are addressed in a timely manner." Although specific procedures vary among agencies, general steps must be taken to assure that critical findings are identified and resolved as quickly and efficiently as possible. The viable options available are permanently repair, temporarily repair or restrict loads on the bridge.

Currently, states employ two approaches to coding condition items when localized areas of severe deterioration are encountered. Some will account for the severity of a localized area of deterioration by lowering the condition rating of an entire component. The component condition rating is adjusted after the deteriorated area is improved (i.e., rating may rise if physical improvements are made, or may stay the same if the bridge is posted for load restrictions and/or supported with temporary shoring). FHWA recognizes this approach when the severity of the localized deterioration affects the load-carrying capacity of the component.

Other states rate to the general condition regardless of the severity of a localized area of deterioration. This approach relies heavily on ensuring that critical findings are addressed in a timely manner regardless of the component condition rating value. If the localized area of severe deterioration is not improved following the critical finding follow-up process, the component rating may need to be lowered to account for the severity of the deterioration if structural capacity is affected.

Either approach to coding the condition items results in the same ultimate outcome, i.e. critical inspection findings are addressed to allow continued safe use of the bridge. Component ratings eventually reflect the overall condition of the component. If the approach is to consider both the severity and extent of a component’s deterioration in rating each component at the time of inspection (or up to 90 days after the inspection as required by the NBIS), there cannot be any assumptions about future improvements made to a localized area. Only if an improvement is made, the rating should then be raised as appropriate. If the improvement is made within 90 days of the inspection, there is no need to consider the localized deterioration in the rating.

Critical findings / critical follow-up report categorical contents with the documented status:

  1. Bridges that have critical findings in the process of being addressed.
  2. Bridges with work scheduled but not started yet.
  3. Bridges that have no plan in the works.
  4. Critical Finding is scour related.

Procedures for Inspectors

Upon identifying a potential critical finding, immediately report the deficiency to the appropriate agency official, bridge owner, or governing authority. For most agencies, a verbal notification is required soon after identifying the potential critical deficiency.

In addition to a verbal notification, agencies require immediate written notification of the potential critical finding. This notification is often presented in a standardized hardcopy or electronic format (see Figures 4.5.1 and 4.5.2), and is submitted soon after the verbal notification for most agencies. The written notification serves to document the critical finding by describing the extent of the deficiency complete with notes, photographs, sketches and drawings, measurements, possible causes, and recommendations for repair. Temporary actions may also be taken at this time to safeguard the public until proper repairs can be completed. These actions may include:

After submittal of the written report, the finding will be assessed and the severity determined along with a proposed repair strategy or plan of action. In accordance with NBIS regulations, the agency is also required to notify the FHWA of the critical finding. Public works officials or law enforcement may also be contacted as needed.

Example of a Missouri Department of Transportation Critical Inspection Finding Form

Figure 4.5.1 Missouri DOT Critical Inspection Finding Form

Example of a Washington State Department of Transportation "Critical Damage - Bridge Repair Report"

Figure 4.5.2 Washington State DOT "Critical Damage - Bridge Repair Report"

Office Priority Maintenance Procedures

Agencies establish priority maintenance procedures and prioritization criteria to help facilitate maintenance work plan strategies. Most agency systems utilize between three and five different prioritization levels ranging from general housekeeping and routine repairs to critical findings requiring immediate action. Examples of agency priority maintenance procedures are listed below in the order of most critical to least critical, with a description of each level.

Oregon Department of Transportation (ODOT)

North Carolina Department of Transportation (NCDOT)

Pennsylvania Department of Transportation (PennDOT)

Bridge Closing Procedure

In some situations, the bridge may need to be closed until the critical finding can be repaired. The decision to close the bridge may result from the nature of the critical finding upon initial discovery, an unacceptable timeframe in which the repairs are scheduled to be completed, or agency policy on critical findings.

For situations recommending closure of the bridge by the bridge inspector and/or bridge maintenance supervisor, follow established State or Federal Agency procedures. Examples of acceptable procedures include:

4.5.3 Examples of Critical Findings

FHWA guidance for a follow-up may include a procedure where the State promptly submits to the Division office a copy of inspection reports or recommendations for all on-system and off-system bridges that meet the following criteria:

  1. Bridges with recommendations for immediate work on fracture critical members;
  2. Bridges with recommendations for immediate correction of scour or hydraulic problems;
  3. Bridges with condition ratings of 3 or less for the superstructure or substructure or appraisal ratings of 3 or less for waterway adequacy; and
  4. Bridges with recommendations for immediate work to prevent substantial reduction in the safe load capacity.

Source: http://www.fhwa.dot.gov/bridge/0650csup.cfm

Many state agencies publish examples of critical findings for bridge inspectors. It should be noted that these lists are not all-inclusive or comprehensive and should only be used as guidance in determining whether or not a deficiency is a critical finding.

The critical findings listed below are organized by material type and application. These deficiencies represent excerpts obtained from several agencies' critical finding documentation

Timber

The following deficiencies represent examples of critical findings for timber:

Concrete

The following deficiencies represent examples of critical findings for concrete:

Steel

The following deficiencies represent examples of critical findings for steel:

Roadside Hardware or Safety Features

The following deficiencies represent examples of critical findings for traffic safety features:

Signs and Lighting

The following deficiencies represent examples of critical findings for signs and lighting:

Other

The following deficiencies represent other examples of critical findings:

4.5.4 Example Plans of Action

As previously mentioned, a statewide or Federal agency wide procedure must be established to assure that critical findings are addressed in a timely manner. The appropriate actions to be used for repair or mitigation of the critical finding must be quickly identified and efficiently carried out. The FHWA must be periodically notified of the actions that have been taken to resolve or monitor critical findings. It is the responsibility of Bridge Owners to implement procedures for addressing critical deficiencies including:

Some agencies have very strict timeframes (3 to 7 calendar days) for developing and accepting plans of action. For circumstances involving immediate attention or a more detailed solution, it may be necessary to begin addressing the critical finding (through permanent or temporary work) prior to the 100% development and acceptance of the plan of action. Example plans of action are given below for Pennsylvania DOT (Figure 4.5.3) and Washington State DOT (Figure 4.5.4).

Example of a Pennsylvania Department of Transportation Critical and High Priority Maintenance Items Flowchart for a Plan of Action

Figure 4.5.3 Pennsylvania DOT Critical and High Priority Maintenance Items - Flowchart for Plan of Action

Example of a Washington State Department of Transportation flowchart for field inspection procedures

Figure 4.5.4 Washington State DOT Flowchart for Field Inspection Procedure

After the plan of action has been accepted, recommended repair work will then be performed and completed within a few days up to several weeks, depending on the individual agency's regulations. A post-repair report will be generated documenting all necessary work done to address the critical finding and the date of completion. A follow-up inspection will also be conducted to assess the condition of the repairs. The FHWA will be notified of the repair and post-repair progress.

Topic 4.6 The Inspection Report

4.6.1 Introduction

The purpose of the bridge inspection reporting system is to have trained and experienced personnel record objective observations of all elements of a bridge and to make logical deductions and conclusions from their observations.

The bridge inspection report represents a systematic inventory of the current or existing condition of all bridge members and their possible future weaknesses. Moreover, bridge reports form the basis of quantifying the manpower, equipment, materials, and funds that are necessary to maintain the integrity of the structure.

A bridge inspection is not complete until an inspection report is finalized. The bridge inspection report documents all signs of distress and deterioration with sufficient precision so that future inspectors can readily make a comparison of condition. Bridge owners normally set the format to be used when preparing a bridge inspection report. A complete inspection report contains several parts, as outlined in this topic. A sample bridge inspection report is presented in Appendix A. Inspection reports are prepared for special inspections, which are conducted for checking a specific item where a problem or change may be anticipated. Even if no changes are evident, reports are still generated for each type of bridge inspection. Some bridge owners also request a special bridge inspection and report when planning a major rehabilitation.

4.6.2 Basic Components of a Comprehensive In-Depth Bridge Inspection Report

Table of Contents

The table of contents presents the general headings and topics of the inspection report in an orderly manner so that individual sections of the report can be found with ease. It generally follows the title page, and individual sections are listed with their corresponding starting page number.

Location Map

A map is normally included with a scale large enough to positively locate the structure. The bridge is clearly marked and labeled, and the map has a north arrow to aid with orientation. Some agencies may choose to use GPS coordinates or latitude/ longitude descriptions.

Bridge Description and History

The bridge description and history section of the report contains all pertinent data concerning the design, construction, and service of the bridge. The type of superstructure will generally be given first, followed by the type of abutments and piers or bents, along with their foundations. If data is available, indicate the type of foundation soil, maximum bearing pressures, and deep foundation capacities. The type of deck is also indicated.

The history of the bridge is from a structural standpoint and is developed from information obtained from design, construction and rehabilitation plans, previous inspection reports, maintenance records, discussions with maintenance crews and local residents, and any other available source that offers pertinent information. Typical items included in the history narrative are:

Design Data

The design information includes a description of the following:

Construction Data

The construction history of the bridge includes the date it was originally built, as well as the dates and descriptions of any repairs or reconstruction projects. State what plans are available, where they are filed, and whether they are “design”, “as-built”, or “rehabilitation” drawings.

Service Data

The average daily traffic (ADT) count and the average daily truck traffic (ADTT) count are included, along with the date of record. This information is updated approximately every five years. Other service data to consider includes the year of ADT and ADTT, facility carried, functional classification, and bypass detour length and map. In addition, environmental conditions that may have an effect on the bridge, such as salt spray, industrial gases, bird droppings, and ship and railroad traffic, are noted in the report.

Executive Summary

The executive summary is a narrative presentation summarizing the inspection and analysis findings in regard to the qualitative condition and the load capacity of the bridge, along with an overview of recommendations. A typical executive summary identifies the bridge (e.g., name, number, and location) and the date of inspection. The executive summary presents any high priority repair items.

Inspection Procedures

The procedures used to inspect the bridge are documented in the inspection report. In most instances, it is advantageous to inspect structures in the same sequence as the load path (i.e., the deck first, then the superstructure, and finally the substructure). This manual is organized and presented for that sequence.

Many inspections cannot follow this sequence due to traffic and lane-closure restrictions. It is useful to document whatever sequence was used during the inspection. This information will be useful in planning future inspections and will also serve as a checklist to make sure that all elements and components were inspected. The following information is typically included:

When structure plans are not in the bridge records and a load rating has not been calculated, it may be necessary to obtain field measurements to assist in the calculation of the load capacity of the structure.

Inspection Results

Provide narrative descriptions of the conditions both quantitative and qualitative, indicating the locations and the extent of the affected areas. Use agency-approved forms consistent with similar inspections. Note all signs of distress, failure, or defects with sufficient precision so that a deterioration rate can be determined. This is very important for determining estimated remaining life and an optimal preservation strategy. Take photographs in the field to show deficiencies and cross reference in the report or on forms where deficiencies are noted. Supplement written notes with sketches and photos to show location and physical characteristics of deficiencies, including a known object in the photograph for scale reference.

Note any load, speed, or traffic restrictions on the bridge. Indicate if the signs are missing or damaged. Take approach roadway photograph to confirm placement of load posting signs that includes the approach roadway, bridge and sign. Check for advanced warning signs. Include information about high water marks and unusual loadings. Note the weather conditions such as temperature, rain, or snow. Note all work or repairs to the bridge since last inspection. Verify or obtain new dimensions when improvement work has altered the structure. New streambed profiles and cross sections are taken to detect scour, channel migration, or channel aggradation and degradation. Note any channel restrictions (e.g. debris) that could impact stream flow and increase scour potential. State the seriousness and amount of all deficiencies at the bridge site.

Load Rating Summary

A summary of any load capacity rating analysis that has been performed is included in the report. The summary is presented in a table or chart. Governing load ratings are shown for both inventory and operating levels for all types of loadings used in the analysis. Identify the governing member for each rating. The governing member is the one that has the lowest capacity for a given type of loading.

For example, in a girder-floorbeam-stringer structure, Stringer three in Bay five may have the lowest capacity for carrying HS20 trucks, compared to all other stringers, floorbeams, or girders. The HS20 inventory and operating ratings for this stringer is reported, and it would be identified as the governing member.

Conclusions and Recommendations

A good inspection report explains in detail the type, severity and extent of any deficiency found on the bridge and points out any deviations or modifications that are contrary to the “as-built” construction plans. The depth of the report is consistent with the importance of the deficiencies. Not all deficiencies are of equal importance. For example, a crack in a prestressed concrete box beam which allows water to enter the beam is much more serious than a vertical crack in an abutment backwall or a spall in a corner of a slopewall.

The inspector’s experience and judgment are called upon when interpreting inspection results and arriving at reasonable and practical conclusions. Improper and misinformed conclusions will lead to improper recommendations. The inspector may need to play the role of a detective to conclude why, how, or when certain deficiencies occurred. Seek advice from more experienced personnel when you cannot confidently interpret the inspection findings.

The recommendations made by the inspector constitute the “focal point” of the operation of inspecting, recording, and reporting. The inspector reviews previous inspection recommendations and identifies any recommendations that have not been addressed, particularly if urgent. A thorough, well-documented inspection is essential for making informed and practical recommendations to correct or preclude bridge deficiencies.

All recommendations for preservation work, load rating, postings, and further inspection are included in this portion of the inspection report. Carefully consider the benefits to be derived from completing recommended work and the consequences if the work is not completed. List, in order of greatest urgency, any work that is necessary to maintain structural integrity and public safety. Recommendations concerning work are typically classified between three to five distinct prioritization levels, which range from the most severe or significant (critical) to a maintenance item that is considered routine or may only require monitoring (non-critical). The specific prioritization levels are set forth by each bridge-owning agency. Examples of agency priority maintenance procedures are listed in Topic 4.5.2.

The inspector decides whether a deficiency is a critical finding and needs immediate action using agency procedures. Usually this is easily determined, but occasionally the experience and judgment of a professional engineer may be required to reach a proper decision. A large hole through the deck of a bridge obviously needs attention, and a recommendation for immediate action is in order. Communicate the critical finding immediately and document actions taken in the report. By contrast, a slightly deteriorated bridge bearing may not be critical. A condition such as this would appropriately call for a recommendation for a preservation action.

Typically, most work recommendations submitted by the bridge inspector will be in the category of non-critical work. The recommended work is carefully described in the report along with a cost estimate.

If not already described in the executive summary, the conclusions and recommendations section of the report summarizes the following:

Some state and local agencies designate separate personnel, not the inspector in the field, to prepare recommendations and cost estimates.

Report Appendices

To achieve maximum effectiveness of the inspection report, the report appendices contain any back-up information used to substantiate the inspector’s findings, conclusions and recommendations. Typically, the appendices include photographs, drawings and sketches, and inspection forms (see Topic 4.4 for record keeping and documentation). Appendices may also include copies of any field notes used and specialist reports (e.g., underwater, nondestructive evaluation (NDE), and survey), or these documents may be referenced in the report. A load capacity rating analysis of the structure may also be incorporated into the report appendices. It is important to have the inspection report and all supplemental information, including report appendices, accurate with clear and concise descriptions or explanations.

Photographs

Photographs are a great asset to anyone reviewing reports on bridge structures. It is recommended that pictures be taken of any problem areas. Take pictures even if you think you can explain it completely in writing. It is better to take several photographs that may be considered unessential than to omit a photograph that could cause misinterpretation or misunderstanding of the report. At least two general photographs of every structure are provided in the appendix. One of these depicts the structure from the roadway, while the other photo is a view of the side elevation (see Figures 4.6.1 and 4.6.2). Captions are provided for each photograph. Photographs are numbered so that they can be referred to in the body of the report. Sketches may also be a substitute for missing as-built plans.

Photograph of the near approach facing toward the bridge

Figure 4.6.1 Near Approach - Toward Bridge

Photograph of the downstream elevation of the bridge

Figure 4.6.2 Downstream Elevation

Drawings and Sketches

Sketches and drawings needed to illustrate and clarify conditions of structural elements or serve as as-built plans are included or referenced. Sketches may be able to convey information not readily identified in a photograph (ie. remaining web thickness). Original drawings are very helpful during future investigations with determining the progression of defects and to help determine any changes and their magnitude. Drafting-quality plans and sketches, sufficient to indicate the layout of the bridge and bridge site, may be included as an appendix.

Some reports combine photographs and sketches or text boxes together to accurately describe and document a particular deficiency.

Inspection Forms

The inspection forms contain the actual field notes, as well as the numerical condition and appraisal ratings by the inspector. The inspection forms are normally signed by the inspection team leader. A complete SI&A form or equivalent is included in the appendix. Compare previous inspection forms to current conditions for inventory data accuracy.

Load Capacity Analysis

A load rating analysis is performed on the structure to determine the load-carrying capacity of the bridge. It includes the investigation of primary load-carrying members of the bridge. Such analysis is normally performed by engineers in the office, not by the inspector. Also, not all inspections require a new load rating analysis. A new load rating analysis is performed if the condition of the primary members has changed considerably since the last inspection. The report also includes recommendations for a new load rating analysis when maintenance or improvement work, change in strength of members, or dead load has altered the condition or capacity of the structure.

Field Inspection Notes

Include the original notes taken by the inspectors in the field or photocopies thereof in the appendix section of the report. The original field notes are source documents and as such are typically included in the bridge record.

Underwater Inspection Report

If an underwater inspection of the substructure has been performed, a separate report is usually prepared by the dive team. If applicable, include the underwater inspection report in the appendix or cross-reference the location of the report.

Material Testing Results

Material testing may be performed on a structure in order to determine the strength and properties of an unknown or suspect material. Include the testing lab’s report in the appendix.

4.6.3 Basic Components of a Comprehensive Routine Inspection Report

Location Map

A map with a scale may be included to help positively locate the structure. Some agencies may choose to use GPS coordinates or latitude/longitude descriptions to supplement or replace the location map.

Inspection Procedures

The procedures used to inspect the bridge may be documented in the inspection report. For inspection reports that include the inspection procedures, it is advantageous to inspect structures in the same sequence as the load path (i.e., the deck first, then the superstructure, and finally the substructure).

As with in-depth inspections, some routine inspections cannot follow this sequence due to traffic and lane-closure restrictions. Therefore, it is useful to document whatever sequence was used during the inspection. This information will be useful in planning future inspections and will also serve as a checklist to make sure that all elements and components were inspected. The following information is typically included:

When structure plans are not in the bridge records and a load rating has not been calculated, it may be necessary to obtain field measurements to assist in the calculation of the load capacity of the structure.

Inspection Results

The results of the inspection are documented within the inspection forms. Narrative descriptions of the conditions are typically not included for routine inspection reports. As with in-depth inspections, use agency-approved forms consistent with similar inspections. Note all signs of distress, failure, or defects with sufficient precision so that a deterioration rate can be determined. This is very important for determining estimated remaining life and an optimal preservation strategy. Take photographs in the field to show deficiencies and cross reference in the report or on forms where deficiencies are noted. Supplement written notes with sketches and photos to show location and physical characteristics of deficiencies, including a known object in the photograph for scale reference.

Note any load, speed, or traffic restrictions on the bridge. Indicate if the signs are missing or damaged. Take approach roadway photograph to confirm placement of load posting signs that includes the approach roadway, bridge and sign. Check for advanced warning signs. Include information about high water marks and unusual loadings. Note the weather conditions such as temperature, rain, or snow. Note all work or repairs to the bridge since last inspection. Verify or obtain new dimensions when improvement work has altered the structure. New streambed profiles and cross sections are taken to detect scour, channel migration, or channel aggradation and degradation. Note any channel restrictions (e.g. debris) that could impact stream flow and increase scour potential. State the seriousness and amount of all deficiencies at the bridge site.

Load Rating Summary

For routine inspections, a load rating may be conducted. If performed, a load rating summary is included in the report and may also be included on the inspection forms. The summary is presented in a table or chart. Governing load ratings are shown for both inventory and operating levels for all types of loadings used in the analysis. Identify the governing member for each rating. The governing member is the one that has the lowest capacity for a given type of loading.

Conclusions

A routine inspection report may or may not contain conclusions of the inspection. If conclusions are included, explain in detail the type, severity and extent of any deficiency found on the bridge and point out any deviations or modifications that are contrary to the “as-built” construction plans. The depth of the report is consistent with the importance of the deficiencies. Not all deficiencies are of equal importance.

The inspector’s experience and judgment are called upon when interpreting inspection results and arriving at reasonable and practical conclusions. Improper and misinformed conclusions will lead to improper recommendations. The inspector may need to play the role of a detective to conclude why, how, or when certain deficiencies occurred. Seek advice from more experienced personnel when you cannot confidently interpret the inspection findings.

Recommendations

Recommendations are made by the inspector that constitutes the “focal point” of the operation of inspecting, recording, and reporting. The inspector reviews previous inspection recommendations and identifies any recommendations that have not been addressed, particularly if urgent. A thorough, well-documented inspection is essential for making informed and practical recommendations to correct or preclude bridge deficiencies.

All recommendations for preservation work, load rating, postings, and further inspection are included in this portion of the inspection report. Carefully consider the benefits to be derived from completing recommended work and the consequences if the work is not completed. List, in order of greatest urgency, any work that is necessary to maintain structural integrity and public safety. Recommendations concerning work are typically classified between three to five distinct prioritization levels, which range from the most severe or significant (critical) to a maintenance item that is considered routine or may only require monitoring (non-critical). The specific prioritization levels are set forth by each bridge-owning agency. Examples of agency priority maintenance procedures are listed in Topic 4.5.2.

The inspector decides whether a deficiency is a critical finding and needs immediate action using agency procedures. Usually this is easily determined, but occasionally the experience and judgment of a professional engineer may be required to reach a proper decision. A large hole through the deck of a bridge obviously needs attention, and a recommendation for immediate action is in order. Communicate the critical finding immediately and document actions taken in the report. By contrast, a slightly deteriorated bridge bearing may not be critical. A condition such as this would appropriately call for a recommendation for a preservation action.

Typically, most work recommendations submitted by the bridge inspector will be in the category of non-critical work. The recommended work is carefully described in the report along with a cost estimate.

The recommendations section of the report summarizes the following:

Some state and local agencies designate separate personnel, not the inspector in the field, to prepare recommendations and cost estimates.

Report Appendices

To achieve maximum effectiveness of the inspection report, the report appendices contain any back-up information used to substantiate the inspector’s findings, conclusions (if included) and recommendations. Typically, the appendices include photographs, drawings and sketches, and inspection forms. See Topic 4.4 for record keeping and documentation. Note that for routine inspections, inspection forms comprise the report, itself. Appendices may also include copies of any field notes used and specialist reports (e.g., underwater, nondestructive evaluation (NDE), and survey), or these documents may be referenced in the report. Although typically not conducted for routine inspections, a load capacity rating analysis of the structure may also be incorporated into the report appendices if performed. It is important to have the inspection report and all supplemental information, including report appendices, accurate with clear and concise descriptions or explanations.

Photographs

Photographs are a great asset to anyone reviewing reports on bridge structures. It is recommended that pictures be taken of any problem areas. Take pictures even if you think you can explain it completely in writing. It is better to take several photographs that may be considered unessential than to omit a photograph that could cause misinterpretation or misunderstanding of the report. At least two general photographs of every structure are provided in the appendix. One of these depicts the structure from the roadway, while the other photo is a view of the side elevation (see Figures 4.6.1 and 4.6.2). Captions are provided for each photograph. Photographs are numbered so that they can be referred to in the body of the report. Sketches may also be a substitute for missing as-built plans.

Drawings and Sketches

Sketches and drawings needed to illustrate and clarify conditions of structural elements or serve as as-built plans are included or referenced. Sketches may be able to convey information not readily identified in a photograph (i.e., remaining web thickness). Original drawings are very helpful during future investigations with determining the progression of defects and to help determine any changes and their magnitude. Drafting-quality plans and sketches, sufficient to indicate the layout of the bridge and bridge site, may be included as an appendix.

Some reports combine photographs and sketches or text boxes together to accurately describe and document a particular deficiency.

Inspection Forms

The inspection forms comprise the actual routine inspection report and contain the field notes, as well as the numerical condition and appraisal ratings by the inspector. The inspection forms are normally signed by the inspection team leader. A complete SI&A form or equivalent is included in the appendix. Compare previous inspection forms to current conditions for inventory data accuracy.

Load Capacity Analysis

A load rating analysis may or may not be performed on the structure to determine the load-carrying capacity of the bridge. For routine inspections without a load capacity analysis, the results of the previous load capacity analysis are typically included in the report. If a load capacity analysis is performed, it is normally performed by engineers in the office, not by the inspector, and represents an investigation of primary load-carrying members of the bridge. A new load rating analysis is performed if the condition of the primary members has changed considerably since the last inspection. The report also includes recommendations for a new load rating analysis when maintenance or improvement work, change in strength of members, or dead load has altered the condition or capacity of the structure.

Field Inspection Notes

Include the original notes taken by the inspectors in the field or photocopies thereof in the appendix section of the report. The original field notes are source documents and as such are typically included in the bridge record.

Underwater Inspection Report

If an underwater inspection of the substructure has been performed, the summary of findings of the underwater inspection report (typically prepared by the dive team) is usually included in the appendix or cross-referenced to another location of the report.

4.6.4 Importance of the Inspection Report

Source of Information

A well-prepared report will not only provide information on existing bridge and bridge site conditions, but it also becomes an excellent reference source for future inspections, comparative analyses, and bridge study projects. Any conditions that are suspicious but unclear are reported in a factual manner, avoiding speculation. Terms such as “hazardous” or “dangerous” are subjective and are not used in the inspection report or inspection documentation that may be included in the appendix. Further action on such reports will be determined after review and consultation by experienced personnel.

Legal Document

In preparing an inspection report, keep in mind that bridge funding may be allocated or repairs designed based on this information. Furthermore, the inspection report is a legal record which may form an important element in future litigation. The language used in reports needs to be clear and concise and, in the interest of uniformity, care needs to be taken to avoid ambiguity of meaning. The information contained in reports is obtained from field investigations, supplemented by reference to “as-built” or “field-checked” plans. The source of all information contained in a report needs to be clearly stated.

Some state agencies require inspection reports to be signed, dated and sealed by a professional engineer before accepting them. Other state agencies require inspection reports to be signed and dated by the inspection team leader. The AASHTO MBE states (per Article 2.2) that "the components of data entered in a bridge record should be dated and include the signature of the individual responsible for the data presented." No undocumented alterations are allowed to the report once it is accepted. Some inspectors retain copies of their reports for their personal files in the interest of self-protection if there is any litigation.

Critical Findings

Critical findings are documented in the inspection report. However, the inspection report does not provide guidance for the follow-up to critical findings - the inspector does not wait for the inspection report to communicate and take action on critical findings. Instead, the follow-up to critical findings is a separate procedure that is immediately communicated with action taken on the critical findings, in accordance with the requirements of the NBIS. Agency procedures are established to assure that critical findings are addressed in a timely manner. In many instances when the critical finding exists, a plan of action is established and the deficiency is addressed prior to the formal submittal of the inspection report.

The FHWA is periodically notified of the actions taken to resolve or monitor critical findings. Advanced inspection methods for one or more elements may be recommended. The report provides information which may lead to decisions to limit the use of a bridge or close it to traffic; any bridge which the inspection has revealed to be a potential public safety concern.

Maintenance

Another purpose of the inspection report is to provide useful information about the needs and effectiveness of preservation activities. An active preservation program is vital to the long-term structural integrity of a bridge. The inspection report enables bridge preservation to be programmed more effectively through early detection of structural deficiencies, therefore minimizing more costly future work and inconvenience to the traveling public.

Load Rating Analysis

When an inspection reveals deficiencies that may affect the load-carrying capacity of the structure, the findings need to be reviewed by an engineer to determine if a revised load rating analysis is required. A new load rating analysis is performed to determine the safe load capacity for the current condition. It may then be necessary to restrict loads crossing the bridge so that its safe load capacity is not exceeded. It is important that the revised load-carrying capacity (load rating) analysis become part of the bridge record.

Bridge Management

Another purpose of the inspection report is analysis by the bridge owners and the FHWA of the SI&A data. The intent of the analysis is to aid in the decisions for allocating and prioritizing funding.

Another important purpose of the inspection report is the data the report provides for use by the owner in managing the bridge asset. The data provided in the inspection report is important for the identification, prioritization, budgeting and programming of bridge preservation, improvement and replacement work. On a national level the data is used for reporting to Congress on the condition and performance of the Nation's bridges and for determining current and future estimates of funding needs. Furthermore, the data is used to: classify bridges according to serviceability, safety, and essentiality for public use; assign each a priority for replacement or rehabilitation; and determine the cost of replacing each such bridge with a comparable facility or of rehabilitating such bridge.

4.6.5 Quality

The accuracy and uniformity of information collected and recorded is vital for the management of an owner’s bridges for preservation, improvement and replacement, and, most importantly, public safety. Quality cannot be taken for granted. The responsibility of ensuring quality bridge inspections rests with each bridge owner and the inspection team. Two phrases are frequently used when discussing quality; they are quality control and quality assurance.

NBIS regulations require each state to assure that systematic quality control (QC) and quality assurance (QA) procedures are being used to maintain a high degree of accuracy and consistency in the inspection program. Include periodic field review of inspection teams, periodic bridge inspection refresher training for program managers and team leaders, and independent review of inspection reports and computations.

The AASHTO MBE provides guidance for the implementation of appropriate quality control and quality assurance procedures. Quality control procedures include the "use of checklists to ensure uniformity and completeness, the review of reports and computations by a person other than the originating individual, and the periodic field review of inspection teams and their work." Quality assurance procedures include the "overall review of the inspection and rating program to ascertain that the results meet or exceed the standards established" by the bridge-owning agency.

Follow state-wide or agency-wide QC/QA procedures for a higher degree of accuracy and consistency in the inspection program.

See Topic 1.3 for a detailed description of quality control and quality assurance.