Limit States

This section defines AASHTO LRFD limit state categories for design load combinations.

Navigation: Combinations > Design Load Combinations > Limit States

For detailed parameter explanations, see the Limit States Reference.

Steps

Step 1: Navigate to Limit States

Navigate to Combinations > Design Load Combinations > Limit States in the tree view.

Step 2: Configure Strength Limit States

Define strength limit states per AASHTO LRFD:

• Strength I: Basic load combination for normal vehicular use

• Strength II: Load combination for owner-specified special vehicles

• Strength III: Load combination for wind on structure

• Strength IV: Load combination for very high dead/live load ratio

• Strength V: Load combination for normal vehicular use with wind

Step 3: Configure Service Limit States

Define service limit states:

• Service I: Normal operational use

• Service II: Steel yielding and concrete cracking control

• Service III: Tension in prestressed concrete

Step 4: Configure Extreme Event Limit States

Define extreme event limit states as needed:

• Extreme Event I: Earthquake

• Extreme Event II: Ice, collision, vessel impact

Quick Tip: AASHTO Limit State Reference

Refer to AASHTO LRFD Bridge Design Specifications Section 3.4.1 for detailed limit state definitions and load factor requirements.

Verification

After completing these steps, limit states are defined for load combination analysis.