Proposed Changes in National Bridge Inventory

This is a special edition of Modern Inspector dedicated to the proposed changes to the National Bridge Inventory (NBI).   The previous bridge specifications were adopted in 1995 and entitled the "Recording and Coding Guide for Structure Inventory and Appraisal of the Nation's Bridges".    The new draft copy is entitled "Specifications for the National Bridge Inventory".  Note: that when reading some of the documents in this email the 1995 edition is often referred to simply as the "Guide" while the proposed new edition is referred to as "Specifications".

It should be noted that these proposed changes are open for comment until January 27, 2007.   At the bottom of the email is information on where to send any comments or feedback.   

As always InspectTech is committed to serving our customers needs.  We strive to stay at the leading edge of bridge related news from FHWA and the industry and pass relevant information along to our customers.   InspectTech will fully support all changes that are finalized in our popular BridgeInspect^TM software.   

Overview of Main Changes

Condition Ratings 

The condition rating fields of Deck (58) - Culverts (62) will retain their 0-9 coding scale.  After extensive comments FHWA determined that the value of converting to a more condensed scale, as first proposed in 2005, would not justify the cost involved.  While the condition rating scales are remaining the same, additional descriptions, charts, and quantitative guidance have been added to describe each value and remove some of the current subjectivity.

Calculated Appraisal Ratings 

While the condition ratings may have escaped the proposed scale change the appraisal ratings from Structural Evaluation (67) to Approach Roadway Alignment (72) have not.   The current 0-9 scale is proposed to be replaced by a new 0-4 scale.    The new values are as follows: 
      4 - At or above desirable criteria
      3 - Better than present minimum criteria
      2 - At, or slightly better than, present minimum criteria
      1 - Below present minimum criteria

Length Units (Metric/English) 

All fields containing length in the proposed Specifications will now contain dual units of English and Metric for usage.  The Federal government will still store data in a Metric format, however states will be able to work entirely in English if desired.   The method of converting and submitting the data have yet to be determined/finalized in this draft edition.

Elimination of Fields

A number of fields are proposed for elimination.   Some of these fields are redundant or seldom used.  Others such as Type of Work (75), Length of Structure Improvement (76), Bridge Improvement Cost (94), and Total Project Cost (96) are commonly used by many entities at the local and state level, but not the FHWA.   If these items are eliminated at the federal level many states or counties may desire to still require that the information be collected, but simply not submit to the Federal government.

 Addition of Fields 

Several new fields have been added.  These fields are primarily related to the substructure and will require similar collection of data as is currently done for the superstructure.   As substructure inventory data does not change frequently this will likely require an added effort on the first inspection cycle to use the revised Specifications, but minimal work in additional cycles.

Other Changes

A number of other changes are present throughout the NBI.   Several fields are expanded to include increased options.   The inclusion of more specific information for Fracture Critical Inspection dating has also been added along with more fields for load rating (load rating date, posting factor, and controlling vehicle for posting).  

Document Length

Create a little bit more room on your bookshelf for the new edition!    The 1995 edition contained 124 pages while the new edition (minus the comparison Appendix F) adds another 61 pages to be a total 185 pages in length.

Many state DOT bridge engineers are assembling comments representing views of those in the entire state and are requesting that any comments also be sent to them.  Specifically, Indiana (Bill Dittrich), Maryland (Dave Logan or Joe Miller), and West Virginia (Frank Liss).