1. Bridge Replacement and Improvement Management Tool for Local Bridges BRIM
David Conkel, MnDOT State Aid Bridge
Davide Hedeen, MnDOT Bridge
Barritt Lovelace, Collins Engineers

2. MnDOT State Aid | mndot.gov
Project Overview
15,821 Bridges in Minnesota owned by local agencies
Local bridges vary widely by type and size
BRIM tool developed in the past year
Offers a risk based approach to bridge improvements
MnDOT State Aid | mndot.gov

3. Goals and Deliverables
Meet FHWA MAP-21 Act Requirements
Develop tool for local bridge owners to aid in managing bridge inventories
Software and database tool
Provide an easy to use tool to local bridge owners
Help local bridge owners make decisions on bridge maintenance, rehabilitation and replacement
MAP 21 requires DOT’s to apply a risk bases approach to maintaining assets.
BRIM aids local bridge owners
The tool is a software and database tool which uses inventory and inspection data.
Tool is easy to use and understand.
Give bridge owners another tool to make risk based data driven decisions.
MnDOT State Aid | mndot.gov

4. Local vs. Trunk Highway BRIM
TH BRIM focused on bridge decks
Local BRIM focused on rehabilitation and replacement
Local BRIM involves almost 200 bridge owners
More bridges on the local system
Bridge Types
Timber
Culverts
MnDOT has successfully implemented a BRIM program.
The local BRIM is similar but key differences:
Local bridges vary more in type, location, ADT etc.
Timber bridge more common on local system
Culverts half of the local inventory
May be used for inspection frequency in the future.
MnDOT State Aid | mndot.gov

5. Local Bridge Inventory
Large variety of bridge types and material on local system. Majority are culverts.
MnDOT State Aid |  mndot.gov/

6. MnDOT State Aid | mndot.gov
Risk Concept
Risk Level for Service Interruption
= Likelihood X Consequence
Service Interruption - When a bridge no longer performs as intended.
If a bridge has an adverse event, some may have a larger consequence than others
Each bridge is not equal, and some bridges are more likely to have an adverse event
We are defining risk based on service interruptions.
Service interruption is when the bridge no longer performs as intended. Not necessary a bridge collapse. Could be reduced service.
Looking at both likelihood and consequence of failure.
Likelihood=The chance that a service interruption will occur.
Consequence=The impact a service interruption will have on the traveling public.
MnDOT State Aid | mndot.gov

7. MnDOT State Aid | mndot.gov
Risk Concept
As we increase the consequence of failure and the likelihood our risk increases.
MnDOT State Aid | mndot.gov

8. MnDOT State Aid | mndot.gov
Risk Concept
Assessing Risk Benefits
Avoid service interruptions
Improve safety
Plan maintenance, repairs, replacements
Spend budgets more wisely
Benefits of using risk to assess our bridge inventory.
Avoid service interruptions
Improve safety
Plan maintenance, repairs, replacements
Spend budgets more wisely
MnDOT State Aid | mndot.gov

9. MnDOT State Aid | mndot.gov
Risk Concept
Collect Data
We are doing this through our inventory and inspection program.
Assess our bridges,
load rating a good example.
Analysis
This is where the BRIM tool comes in.
Decision
Make data driven decisions based on our risk based approach
MnDOT State Aid | mndot.gov

10. Local (Bridge) Planning Index (LPI)
LPI = 100-(Probablility x Consequence) Range from is the Highest Priority 100 is the Lowest Priority
The LPI is a risk score which factors both the consequence of a service interruption and the probability of service interruption.
MnDOT State Aid | mndot.gov

11. MnDOT State Aid | mndot.gov
Probability
Bridge Condition
Vertical clearance
Scour
Load Rating
Fatigue
Fracture Critical Status
These factors contribute to the probability of a failure.
MnDOT State Aid | mndot.gov

12. MnDOT State Aid | mndot.gov
Consequence
Traffic Volume (ADT)
Detour Length
Bridge Length
Local Considerations
Industry/Trade
Agriculture
These factors increase the consequence of failure.
MnDOT State Aid | mndot.gov

13. MnDOT State Aid | mndot.gov
Example Calculation
A MathCAD Example Calculation is available for download to help bridge owners understand the calculation steps to determine the LPI. There is one version available for bridges and one for culverts.
MnDOT State Aid | mndot.gov

14. Probability Scaling Table
Scaling tables used to determine probability scores
Example shown is the probability for a deck
Based on NBI Condition and Crack Density
Scaling tables use to determine probability scores for deck, superstructure, substructure, scour, fracture critical status, load rating and vertical clearance.
Example shown is for the deck
MnDOT State Aid | mndot.gov

15. Importance Factor Table
Table used to determine importance factors
Example shown is the importance factor for ADT
Tables also used to determine importance factors which include ADT, detour, length and bridge width.
MnDOT State Aid | mndot.gov

16. MnDOT State Aid | mndot.gov
Report Access
Hosted on the MnDOT Website
Results viewed as a report ranking bridges
100 Least Risk
0 Most Risk
A MathCAD Example Calculation is available for download to help bridge owners understand the calculation steps to determine the LPI. There is one version available for bridges and one for culverts.
MnDOT State Aid | mndot.gov

17. MnDOT State Aid | mndot.gov
BRIM LPI Report
Example report from Chisago County.
MnDOT State Aid | mndot.gov

18. MnDOT State Aid | mndot.gov
Benefits
Improvement on sufficiency rating
Easy to obtain data
Data is as current as inspection data
Easier to follow than the sufficiency rating
Another tool for owners to make decisions
Encourages maintenance
The LPI is an improvement on the sufficiency rating from FHWA and uses a more risk based approach. The sufficiency rating is no longer being used by FHWA.
The data is easy for a bridge owner to obtain, just need to download from MnDOT website.
Data is always as current as the inspection data that is in the SIMS database.
Sufficiency rating was more of a black box. Individual bridge calculations can be reviewed by inputting bridge data in the MathCAD workbooks.
The tool will hopefully encourage early and appropriate maintenance.
MnDOT State Aid | mndot.gov

19. Bridge Owner Action Items
Review the workings behind the LPI
Compare the LPI report against existing priority lists
Consider reprioritizing based on LPI information
Work with DSAE, Patti and Dave for funding eligibility
Funding still tied to sufficiency rating and status (SD, FO)
Use LPI list to plan maintenance and repairs
Reevaluate your list annually or as inspection information changes
Review the workings behind the LPI, review MathCAD example calculations to understand factors affecting score
Compare the LPI report against existing priority lists
Consider reprioritizing based on LPI information
Work with DSAE, Patti and Dave for funding eligibility
Funding still tied to sufficiency rating and status (SD, FO)
Use LPI list to plan maintenance and repairs, try to bring scores up
Reevaluate your list annually or as inspection information changes
David Hedeen, Dave Conkel, Moises Dimaculangan or Patti Loken are available to answer questions.
MnDOT State Aid | mndot.gov

20. Accessing Report Available through the Bridge Reports Website
Located the Bridge Lists folder

21. Customizing Report

22. Cover Report

23. LPI Summary Listing

24. Detail/Visualization of LPI Reduction

25. Demonstration of Weight Effects

26. Demo Found in the Bridge Reports Repository
Also linked MnDOT’s Bridge Inventory Page

27. LPI vs Sufficiency Rating

28. MnDOT State Aid | mndot.gov
Project Team
Dave Conkel, MnDOT
Dave Hedeen, MnDOT
Moises Dimaculangan, MnDOT
Brian Homan, MnDOT
Dustin Thomas, MnDOT
Patti Loken, MnDOT
Jake Bronder, Hennepin County
Barritt Lovelace, Collins Engineers
Matt Hemmila, St. Louis County
Lance Robertson, St. Louis County
Willy Rabenberg, Redwood County
Brian Pododzinski, Houston County
Ron Benson, Stonebrooke Engineering
Jamison Beisswenger, SRF
Brent Christensen, City of St. Paul
Jack Yuzna, City of Minneapolis
Jon Siiter, LHB Inc.
Rachel Litfin, St. Louis County
Thank you to the team members who contributed their time and energy to this effort.
MnDOT State Aid | mndot.gov

29. MnDOT State Aid | mndot.gov
Questions?
MnDOT State Aid | mndot.gov