Section 1: Condition Ratings

Definition of Condition Ratings

Condition ratings based on field inspections are snapshots in time and cannot be used to predict future conditions or behavior of the structure. However, condition ratings based on inspections along with written comments by a field inspector act as the major source of information on the status of a bridge. Condition ratings also help with planning for necessary repairs or modifications. In addition, the condition ratings are used as flags when performing over-weight permit evaluations.
Condition ratings are one-digit numbers given by the field inspector to the various components of a bridge. They are objective and not opinions.
Condition ratings reflect deterioration or damage and do not measure design deficiency. For instance, an old bridge designed to a low load capacity but with little or no deterioration may have excellent condition ratings while a newer bridge designed to modern loads but with deterioration will have lower condition ratings.
Refer to the Coding Guide and the SNBI for details on different components and corresponding coding descriptions. To support the transition to SNBI and the new coding items the number of components that receive condition ratings has increased.

Recording Condition Ratings

Per Coding Guide
Condition ratings are entered on the Bridge Inspection Record. The Item Numbers relate to the entry of the data in the electronic Bridge Inventory Files, the detailed instructions for which are contained in the Coding Instructions of the Coding Guide
  • Deck (Item 58)
  • Superstructure (Item 59)
  • Substructure (Item 60)
  • Channel (Item 61)
  • Culverts (Item 62)
  • Approaches (Item 65)
  • Miscellaneous (Used for informational purposes only))
Per SNBI:
The detailed instructions for the condition ratings are contained in the SNBI (incorporated by reference) Subsection 7.1.
  • Deck [B.C.01]
  • Superstructure [B.C.02]
  • Substructure [B.C.03
  • Culvert [B.C.04]
  • Bridge Railing [B.C.05]
  • Bridge Railing Transitions [B.C.06]
  • Bridge Bearings [B.C.07]
  • Bridge Joints [B.C.08]
  • Channel [B.C.09]
  • Channel Protection [B.C.10]
  • Scour Condition [B.C.11]
  • Bridge Condition Classification [B.C.12] (automatically calculated)
  • Lowest Condition Rating Code [B.C.13] (automatically calculated)
  • NSTM Inspection Condition [B.C.14]
  • Underwater Inspection Condition [B.C.15]
The rating must equal or exceed the minimum values for each element of a component (shown to the left of the element description on the form). Each element is rated based on independent consideration. For instance, lower or deficient secondary members (bracing, diaphragms, etc.) in a superstructure may cause the Superstructure (Item 59) [B.C.02] component to have a poor rating even though the main members show no significant deterioration. The summary Component Rating must be the least of the element ratings comprising that component.
However, when referencing the Coding Guide, Deck (Item 58) component is independent of its associated element ratings such as joints, railings, wearing surface, etc. The SNBI has joints and railing as their own components.
Do not base condition ratings on the known presence of chlorides in the deck, superstructure, or substructure concrete or low compressive strengths from core samples. Determine the condition rating solely on the observed, materials-related, physical condition of the component at the time of the inspection.
The Bridge Inspection Electronic Form has space for fully supportive written comments for each of the above features. These comments are required for any condition rating of 7 or lower. The form includes a brief summary of the description of each level of rating. More detail on the condition rating for each item number is given in the Coding Guide and SNBI.
For the condition ratings calculated by FHWA, Bridge Condition Classification [B.C.12] uses the lowest condition rating of B.C.01, B.C.02, B.C.03, or B.C.04 to output a classification code and the Lowest Condition Rating Code [B.C.13] outputs the lowest condition rating code from B.C.01, B.C.02, B.C.03 or B.C.04. SNBI Subsection 7.1 has detailed information to explain coding.

Assigning Condition Ratings

Evaluate each element separately based on general considerations for assignment of the ten levels of condition ratings. However, other deficiencies may affect the condition if they are directly related. For instance, instability of an approach embankment may reduce the abutment condition rating but not reduce the Superstructure condition rating.
Consider only permanently installed repairs when assigning condition ratings. Permanent implies that the repair has returned the damaged or deteriorated element to a condition as good as or better than the remainder of the bridge. For instance, a steel beam damaged by an over-height load that reduced the load capacity of the beam is considered permanently repaired when a section is replaced or a bent section is straightened by proper techniques and no residual cracks can be found. The strength of the repaired member is the primary concern. Modifications and repairs that simply improve the appearance of a damaged member are not considered to improve the condition rating.
Do not consider as temporary any repair which remains in place without further project activity for a period of 4 years. Consider the repair permanent and evaluate the structure accordingly. Four years from the repair date is a reasonable amount of time for a District to move a project forward. If the District requires more time, then submit a written justification for continuing to classify a repair as temporary.
Do not consider for condition rating any components with temporary repairs, even though functioning. For instance, a support or brace to a partially undermined column could be susceptible to damage from another flood; therefore, make the condition rating on the basis that the support is not present. Do not consider temporary repairs in determining condition ratings because they directly affect the calculations of the sufficiency ratings.
Condition ratings are still a matter of judgment, which should be made based on experience, knowledge, and consistency with other structures with the same deterioration.