FDOT Supplement to LRFR | Jan 2005

Revise the “Guide Manual for Condition Evaluation and Load Resistance Factor

Rating (LRFR) of Highway Bridges” dated October 2003 as follows:

1. Add LRFR Appendix E.6.1 – FDOT Supplement to LRFR.

2. Add a paragraph to Section 1.3 Applicability that states the following:

For new designs, the Department will not allow the use of an alternative load rating methodology (Appendix D.6.1) or posting avoidance techniques.

3. Add a definition to Section 1.5 Definitions and Terminology that states the following:

Posting Avoidance Techniques – Applying engineering judgment to a load rating by modifying the code defined procedures through use of Variances and Exceptions (as defined in the Plan Preparation Manual and Vol. 10A “Load Rating Post-Tensioned Concrete Segmental Bridges”).

4. Add the following paragraph to Section 2.2.15 Structures Inventory and Appraisal Sheets as follows:

In addition to the requirements of the State Highway Maintenance Office, report the LRFR ratings on the load capacity information form as follows:

A. HL-93 inventory and operating ratings as rating factors.

B. HL-93 Design Truck, without the lane load, and the T160 permit vehicle (Table 6-1, Permit load) longitudinal operating ratings in tons.

C. HL-93 Design Truck and Design Tandem axles transverse operating ratings in kips – for prestressed concrete box girder decks only.

D. If the inventory rating is less than 1.0, calculate operating ratings for the SU4, C5 and ST5 Florida legal trucks in tons.

E. Provide a sketch indicating the location of the controlling components for both the transverse and longitudinal analysis.

5. Modify Table 6-1 found in Section 6.4.2.2 as follows:

All 5 shaded cells of the table shall be modified from optional to mandatory. For Prestressed Concrete Service III Limit State under Operating Live Load, change the dash to 0.80; under legal load, change 1.0 to 0.80; under permit load, change dash to 0.8. For Prestressed Concrete Service I Limit State under Design Load and Legal Load, change dash to 1.0. For Prestressed Concrete Service I Limit State under Permit Load, 1.0 applies to transverse tensile stresses in the deck and compression stress checks in the longitudinal direction. For general references concerning prestressed “I” girders, see Vol. 10B “Load Rating Post-Tensioned Concrete Beam Bridges.” Volume 10B can be found on the Structures Design web site at the following address:

www.dot.state.fl.us/structures/posttensioning.htm.

For allowable stresses, see Appendix E.6.1, Table 1.5, Allowable Stresses for Concrete Bridges.

6. After the second paragraph of Section 6.1.2 Scope, add the following:

The Florida Department of Transportation has developed specific load criteria to segmental concrete bridges and added Appendix E.6.1 to augment LRFR.

7. Modify Section 6.4.2.4, Table 6-3 as follows:

For two-, three- and four-girder bridges, revise the “phi sub s” factors (Øs) to 1.00.

8. Modify Section 6.4.4.2.1 as follows:

Expand the legal load defined in LRFR Section 6.4.4.2.1 to include SU4, C5, and ST5.

9. Modify Section 6.4.5.4.2.1 as follows:

The HS-32 truck and the T160 permit truck will be considered as routine annual permit vehicles to be used to verify overload capacity of Florida bridges.

10. Modify Table 6-5 found in Section 6.4.4.2.3 as follows:

For all Traffic Volumes, revise all the Load Factors to 1.35.

11. Modify Table 6-6 found in Section 6.4.5.4.2.1 as follows:

For all Permit Types, revise all the Load Factor by Permit Weight values to 1.35.

12. Add a new Appendix E.6.1 Load Rating Post-Tensioned Concrete Segmental Bridges to

Chapter 6. This new appendix is designed to override any applicable provisions in LRFR.

13. Delete Sections 9.2 and C9.2 in their entirety.

Commentary to the revised sections of “Guide Manual for Condition Evaluation and Load Resistance Factor Rating (LRFR) of Highway Bridges” dated October 2003:

Section 6.4.5.4.2.1

The Department has determined the LRFR process for classifying different ADTT in

Sections 6.4.4.2.3 and 6.4.5.4.2.1 are not warranted with Florida truck traffic volumes

and freeway designations.