Page 280 - Bridge and Highway Structure Rehabilitation and Repair

CHAPTER 6 APPLICATIONS OF BRIDGE DESIGN AND RATING METHODS 255

Figure 6.5 Use of transverse steel box beam to eliminate pier permitting through traffi c (similar concept used
by the author on I-80 and Route 23 intersection in northern New Jersey). For curved steel girder design, refer to
AASHTO Guide Specifi cations for Horizontally Curved Steel Girder Highway Bridges.

6.5 RATING PROCEDURES FOR CONCRETE AND STEEL BRIDGES*
6.5.1 Rating of Composite Single Span Steel Bridge

The following steps need to be computed:
1. Section properties of composite section.
2. Dead load moments for DC1, DC2, and DW.

3. Distribution factors for flexure for one lane loaded.
4. Distribution factors for shear for one lane loaded.

5. Distribution factors for flexure for two or more lanes loaded.
6. Distribution factors for shear for two or more lanes loaded.
7. Maximum design moments for HL-93 live load.
8. Maximum design shear for HL-93 live load.
9. Web slenderness.
10. Ductility requirements.
11. Plastic moment of resistance.
12. Yield moment of composite section.
13. Nominal fl exural resistance.
14. Nominal shear resistance.
• General load rating equation and evaluation factors.
• Design load rating for Strength I (inventory and operating level).
• Design load rating for Service II (inventory and operating level).
• Rating factors for fatigue limit state.

*For detailed design of concrete and steel girders, refer to AASHTO LRFD Specifications Section 5, Ap-
pendix A5; Basic Steps for Concrete Bridges and Section 6, Appendix C6; Basic Steps for Steel Bridge Super
structures.