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Coordinating, Developing, and Delivering Highway Transportation Innovations

 
REPORT
This report is an archived publication and may contain dated technical, contact, and link information
Publication Number:  FHWA-HRT-16-007    Date:  January 2016
Publication Number: FHWA-HRT-16-007
Date: January 2016

 

Long-Term Bridge Performance (LTBP) Program Protocols, Version 1

Long-Term Bridge Performance Program Logo

Calculation of Bridge Ratings
LTBP Protocol #: PRE-ED-BD-007


1.

Data Collected

 
1.1 Information and data related to load ratings of the bridge.  

2.

Onsite Equipment and Personnel Requirements

 
2.1 Equipment:  
2.1.1 Computer.  
2.1.2 Scanner.  
2.2 Personnel: PRE-PL-LO-005, Personnel Qualifications.  

3.

Methodology

 
3.1 Work with the bridge owner to obtain bridge rating information for the year in which the bridge is first load rated and for each subsequent year ratings were calculated (data collection table items8–18).  
3.2 If the bridge information exists only in paper form, scan that information into an electronic format so it can be stored in the LTBP Bridge Portal.  
3.3 Storing data, documents, and images:  
3.3.1 FLD-DS-LS-001, Data, Document, and Image Storage—Local, for local storage.  
3.3.2 FLD-DS-RS-001, Data, Document, and Image Storage—Remote, for remote storage.  
3.4 Reporting: Transfer all metadata, data, documents, and images to Federal Highway Administration (FHWA), and/or upload all metadata, data, documents, and images into the LTBP Bridge Portal.  

4.

Data Collection Table

 
4.1 Table:  
# Field Name Data Type Accuracy Unit Field Description Row Color
1 State
Text
Text
 
State Code; e.g., Virginia = VA
Green
2 NBI structure number
Text
Text
 
Item 8, structure number; from NBI Coding Guide
Green
3 Structure name
Text
Text
 
Descriptive name for the bridge; e.g., Route 15 SB over I–66
Green
4 Protocol name
Text
Text
 
Title of the protocol
Green
5 Protocol version
Text
Month and year
 
Month and year the protocol version was published; e.g., May 2015
Green
6 Personnel performing data collection activities
Text
Text
 
First name(s) Last name(s)
Green
7 Date data were collected
Text
Exact date
 
mm/dd/yyyy
Green
8 Month and year of ratings
Text
Exact month and year
 
mm/yyyy; month and year that ratings were calculated
Blue
9 Rating calculated by consultant, State, or local
Predefined list
 
 
Consultant
State agency
Local agency
Yellow
10 Person(s) rating the bridge
Text
 
 
Name(s) and affiliations
Yellow
11 Method used to determine operating rating
Predefined list
 
 
Load factor rating
Allowable stress rating
Load and resistance factor rating
Load testing
No rating analysis performed
Yellow
12 Calculated operating rating
Numeric
0.1
T
1T = 2,000 lbs
Yellow
13 Method used to determine inventory rating
Predefined list
 
 
Load factor rating
Allowable stress rating
Load and resistance factor rating
Load testing
No rating analysis performed
Yellow
14 Calculated inventory rating
Numeric
0.1
T
1T = 2,000 lbs
Yellow
15 Rating vehicle used
Text
 
 
 
Yellow
16 Was the bridge posted, or continued to be posted, as a result of these ratings/load testing?
Predefined list
 
 
Yes
No
Continued Posting
Yellow
17 Posted load
Numeric
1
ton(s)
Posted load capacity, if any, due to these load ratings or load testing
Yellow
18 Comments
Text
 
 
 
Orange
4.2 Table Key:  
Column Descriptions
#
Sequential number of data item
Field Name
Data field name
Data Type
Type of data, such as text, number, predefined list, binary large object (BLOB), or PDF file
Accuracy
Accuracy to which the data are recorded
Unit
Unit in which a measurement is taken and recorded
Field Description
Commentary on the data or list of items in a predefined list
Row Color Key
Green
Data items only entered once for each protocol for each day the protocol is applied
Pink
Logical breakdown of data by elements or defect types (not always used)
Blue
Data identifying the element being evaluated or the type of defect being identified
Yellow
LTBP data reported individually for each element or defect identified
Orange
Comments on the data collection or data entered

5.

Criteria for Data Validation

 
5.1 None.  

6.

Commentary/Background

 
6.1 This protocol provides guidance for collecting data on calculations performed by the bridge owner to determine the load rating of the bridge.  
6.2 The operating rating is the maximum permissible live load to which a bridge may be subjected for the load configuration used in the rating.  
6.3 The inventory rating is that load, including loads in multiple lanes that can safely use the bridge for an indefinite period of time.  
6.4 See the AASHTO Manual for Bridge Evaluation, 2nd Edition (2010) for descriptions of the following:  
6.4.1 The load factor rating method.  
6.4.2 The allowable stress rating method.  
6.4.3 The load and resistance factor rating method.  
6.4.4 Load testing procedures.  
6.4.5 Rating vehicle for load tests.  

7.

References

 
7.1 LTBP Protocols:  
7.1.1 PRE-PL-LO-005, Personnel Qualifications.  
7.1.2 FLD-DS-LS-001, Data, Document, and Image Storage—Local.  
7.1.3 FLD-DS-RS-001, Data, Document, and Image Storage—Remote.  
7.2 External:  
7.2.1 AASHTO, AASHTO Manual for Bridge Evaluation, 2nd Edition, Washington, DC, 2010.  
7.2.2 FHWA-PD-96-001, Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation’s Bridges, Federal Highway Administration Office of Engineering, Washington, DC, 1995.  
7.2.3 FHWA Memorandum, Bridge Load Ratings for the National Bridge Inventory, Federal Highway Administration Office of Infrastructure, Washington, DC, October 30, 2006.  

 

 

 

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