13. Load Rating

This section performs load rating per AASHTO Manual for Bridge Evaluation (MBE) to determine the safe load capacity of the bridge.

Load rating determines rating factors for design, legal, and permit vehicles to assess the bridge's load-carrying capacity.

Load Rating Checks

Rating	Description
Steel I Girder Load Rating	Rating factors for girder capacity

Rating Levels

Level	Purpose
Design Load Rating	Rating at Inventory and Operating levels using HL-93
Legal Load Rating	Rating for legal trucks (Type 3, 3S2, 3-3)
Permit Load Rating	Rating for overweight permit vehicles

Rating Factors

Rating Factor (RF) = (Capacity - Dead Load Effect) / (Live Load Effect)

• RF > 1.0: Bridge can safely carry the rated load

• RF < 1.0: Load posting may be required