02/22/07 Memo: Attachement B

Load Rating and Posting Reports

All structures meet the criteria for a bridge based on Federal definition (Item 112 = Y; 5a=1; 49 > 6.1 meters; 42A = 1, 4, 5, 6, 7 or 8).

1. Bridges with Item 64 (operating rating) less than 32.4 metric tons with no load posting

UPACS Report Title: Operating rating < 32.4 metric tons, no posting

Criteria:
Item 41 = A or B and
Item 64 < 32.4 metric tons (User will be prompted to insert the posting load. 32.4 is shown as an example.)

OUTPUT – Numerical Count of Bridges meeting criteria, Items 2 (Highway District), 3 (County Code), 5D (Inventory Route Number), 6A (Feature Intersected), 7 (Facility Carried), 8 (Structure Number), 22 (Owner), 26 (Functional Classification), 27 (Year Built), 31 (Design Load), 41 (Open, Posted and Closed), 43 (Structure Type), 59 (Superstructure), 63 (Rating Method), 64 (Operating Rating), 66 (Inventory Rating), 70 (Bridge Posting), 90 (Inspection Date), 103 (Temporary Structure Designation), 104 (Highway System), Sufficiency Rating

Supporting Documentation:
As stated in the commentary section of the AASHTO Manual for the Condition Evaluation of Bridges, Section 7.4.1, "In no case shall the load levels used be greater than those permitted by the Operating Rating."

As stated in the 1995 Recording and Coding Guide for the Structure Inventory and Appraisal of the Nations Bridges for Item 70, Report No. FHWA-PD-001, December 1995, "Although posting a bridge for load-carrying capacity is required only when the maximum legal load exceeds the operating rating, highway agencies may choose to post at a lower level."

Commentary:
Item 41 - Structure Open, Posted or Closed to Traffic – If coded as A (Open) or B (Open, posting recommended but not legally implemented) and Item 64 - Operating Rating is less than HS-20 (32.4 metric tons). If the operating rating is less than HS-20, the bridge may require posting. The input value for Item 64 can be adjusted by the user. This will not capture states legal vehicles that may generate larger live load stresses than HS-20.

This will not capture properly coded structures with a low operating rating that are shored or have temporary structures (Item 41 is coded as D or E for structures with temporary shoring.)

2. Bridges with Item 64 (operating rating) less than maximum legal loads with no load posting

UPACS Report Title: Operating rating < max legal, no posting

Criteria:
Item 70 < 4 and
Item 41 = A

Supporting Documentation:
As stated in 23 CFR 650.313(c), "Post or restrict the bridge in accordance with the AASHTO Manual or in accordance with State law, when the maximum unrestricted legal loads exceed that allowed under the operating rating or equivalent rating factor."

Commentary:
Item 70 - Bridge Posting – If coded as 4 or less (Relationship of Operating rating to max legal load - % below) and Item 41 coded as A (open, no restriction). Structures meeting these criteria will likely require posting. This check should capture the state legal loads.

This will not capture properly coded structures with a low operating rating that are shored or have temporary structures (Item 41 is coded as D or E for structures with temporary shoring.)

3. Bridges with no rating analysis performed

UPACS Report Title: No operating rating performed

Criteria:
Item 63 = 5 (no rating analysis performed)

Supporting Documentation:
As stated in 23 CFR 650.313(c), "Rate each bridge as to its safe load-carrying capacity in accordance with the AASHTO Manual."

Commentary:
Item 63 – Method Used to Determine Operating Rating - If coded as 5 (no rating analysis performed). The number of bridges captured in this query may be large since structures where engineering judgment was used to determine the rating when no plans are available will be identified. However, it should also capture structures which may have been overlooked for load ratings. In the future the number of bridges identified should be reduced as the proposed changes to the Coding Guide provide for "field evaluation" as an additional load rating method.

4. Bridges with recommended posting but not legally implemented

UPACS Report Title: Recommended postings, no legal implementation

Criteria:
Item 41 = B

Commentary:
Item 41 – Structure Open, Posted or Closed to Traffic – If coded as B (Open, posting recommended but not legally implemented). This should capture structures which should be posted, but are not. This should be even more of a concern if it is coded as B for more than two cycles.

5. Bridges with a superstructure condition rating less than or equal to 4 and no load posting

UPACS Report Title: Superstructure rating <= 4, no posting

Criteria:
Item 59 ≤ 4 and (User may insert other values as needed.)
Item 41 = A and B
Item 103 is blank.

Supporting Documentation:
There is no requirement that bridges with a low superstructure condition rating be posted. This is a reasonableness check to verify that deterioration is accounted for in the load rating.

Commentary:
Item 59 – Superstructure — If coded as less than or equal to 4 and Item 41 = A and Item 103 is blank. The user can change value of item 59 to perform other runs. This is a reasonableness check to verify that as the structure deteriorates, the load posting is still valid.

6. Bridges with Item 64 (operating rating) less than 2.7 metric tons and bridge is not closed

UPACS Report Title: Open, operating rating <= 2.7 metric tons

Criteria:
Item 64 < 2.7 metric tons and
Item 41 = A,B,P,R and
Item 103 is blank.

Supporting Documentation:
As stated in the AASHTO Manual for the Condition Evaluation of Bridges, Section 7.4.1, "A bridge owner may close a structure at any posting threshold, but bridges not capable of carrying a minimum gross live load weight of three tons (2.7 Metric tons) must be closed."

Commentary:
Item 64 less than 2.7 metric tons and Item 41 = A,B,P,R (vehicular traffic only) and Item 103 is blank (Temporary Structure). Any bridge with an operating rating less than 2.7 metric tons must be closed.

7. Bridges with a change in wearing surface and no change in the operating rating

UPACS Report Title: Changed wearing surface, but unchanged operating rating

Criteria:
Item 108 - if a change in coding has occurred from previous inspection report, has a change occurred in item 64. The previous five years of data will be reviewed.

Supporting Documentation:
As stated in 23 CFR 650.315(c), "For existing bridge modifications that alter previously recorded data and for new bridges, enter SI&A data in to 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."

Commentary:
If Item 108 changes (say from monolithic concrete to bituminous) it is likely the load ratings in Items 64 and 66 should change. This is a reasonableness check to verify that as the dead load changes the load rating reflects the change. This check may capture when a bridge gets a bituminous overlay.

8. Bridges which have been reconstructed and no change has occurred in load ratings

UPACS Report Title: Reconstructed, but unchanged operating rating

Criteria:
Item 106 – Year Reconstructed – If this item is coded for the first time (after reconstruction) and the coding of Items 64 and 66 are the same as recorded prior to reconstruction. The previous five years of data will be reviewed.

Commentary:
If Item 106 is coded for the first time (after reconstruction) it is likely the load ratings in Items 64 and 66 should change. This is a reasonableness check to verify that as a structure changes condition following reconstruction the load rating reflects the change.

Output

The output for reports 1 through 6 is broken into two sections, the "Count" and "Details." Only the "Details" tab will be provided for reports 7 and 8.

The "Count" will indicate the total number of bridges which meet the criteria for each of the six reports, broken out by State.

The "Details" will include all of the output data indicated in the description for each of the eight reports. The output data will be shown for each bridge which meets the criteria, thus allowing for further investigation and manipulation of the data. The "Details" will only include the data related to your State.

Contacts

Tom Everett
Office of Bridges and Structures
202-366-4675
E-mail Tom

Gary Moss
Office of Bridges and Structures
202-366-4654
E-mail Gary

Tom Drda
Office of Bridges and Structures
919-747-7011
E-mail Tom

Barry Brecto
Office of Bridges and Structures
360-753-9556
E-mail Barry