Page 264 - Bridge and Highway Structure Rehabilitation and Repair

CHAPTER 6 APPLICATIONS OF BRIDGE DESIGN AND RATING METHODS 239

When 3 1, both equations are the same.
i
Example of load modifi er value used for reinforced concrete bridge design: (1.3.2.1)
6.2.3 Resistance Factors

Minimum value is 0.85, and maximum is 1.0 (Table 5.6).

Table 6.2 AASHTO recommended values for resistance factors.
Material Limit State R (1 2V ) *
R
LFD
Noncomposite steel Moment 0.90 0.90
Noncomposite steel Shear 0.90 0.85
Composite steel Moment 0.90 1.00
Composite steel Shear 0.90 1.00
Reinforced concrete Moment 0.85 0.90
Reinforced concrete Shear 0.85 0.85
Prestressed concrete Moment 0.90 0.90
Prestressed concrete Shear 0.85 0.85
* Strength reduction factor

Resultant
load

Resultant
load

Resultant
load

Figure 6.1 AASHTO recommended legal loads.