1. Virtis Opis User Group Meeting, August 6, 2013
Effect of 2013 Interim Revisions to the MBE on Legal, SHV and Permit Vehicles
August 6, 2013
Bryan J. Silvis, P.E.
Structure and Bridge Division
Engineering Services Section

2. VDOT Load Rating Background
Original purpose was to run a test suite to track changes in release versions.
When investigating changes in ratings for legal routine, legal SHV and permit (unlimited crossing) vehicles, became aware of more general effect of the changes to the MBE.
All tables shown are taken from the AASHTO 2013 Interim Revisions to the Manual for Bridge Evaluation, Second Edition.

3. Sample Set 8 Bridge Types (3 structures selected for each type):
Type 1 - Simple span concrete slabs
Type 2 - Continuous concrete slabs
Type 3 - Simple span concrete T-beams
Type 4 - Simple span rolled beams
Type 5 - Continuous rolled beams
Type 6 - Simple span plate girders
Type 7 - Continuous plate girders
Type 8 - Simple span prestressed AASHTO I-beams

4. Legal - Routine

5. Legal - Routine

6. Legal - SHV

7. Legal - SHV

8. Permit – Unlimited Crossings
BP-115:

9. Previous MBE - Permit

10. 2013 Interim - Permit

11. Summary 2013 Changes (very general):
Legal (Routine): Modest increase in rating for lower ADTT’s to substantial increase for higher ADTT’s
Legal (SHV): Slight decrease in rating for lower ADTT’s to modest increase for higher ADTT’s
Permit (Unlimited Crossing): General increase in ratings. Rating increase percentage increases with ADTT. Percentage increase where entire vehicle fits on structure is larger than where only a portion of the vehicle can.

12. Questions??
Contact: