1. ODOT’s Seismic Policy One Year Later
Sean Meddles, P.E.
Assistant Administrator
Office of Structural Engineering
November 15, 2017

2. Session Outline New Bridges Existing Bridges Ductility Requirements
Pier Crossframes
Horizontal Connection Force
Structural Analysis
Existing Bridges
BDM Section – “Seismic vulnerability of a structure shall be considered for rehabilitation projects requiring complete deck or superstructure replacements”
Seat Width
Column Ductility
FHWA – “Seismic Retrofitting Manual for Highway Structures: Part 1 – Bridges”
ODOT's Seismic Update

3. New Bridges Column Ductility – Spiral Pitch
[LRFD ] [BDM S ]
Typical 3-ft Diameter Column: #5 p = 3”
[BDM S ] ρs =
[LRFD ] =
ODOT's Seismic Update

4. New Bridges Column Ductility – Tie Spacing (Circular Column)
𝝆 𝒔 = 𝑽𝒐𝒍𝒖𝒎𝒆 𝒐𝒇 𝑹𝒆𝒊𝒏𝒇𝒐𝒓𝒄𝒆𝒎𝒆𝒏𝒕 𝑽𝒐𝒍𝒖𝒎𝒆 𝒐𝒇 𝑪𝒐𝒏𝒄𝒓𝒆𝒕𝒆 𝑪𝒐𝒓𝒆 = 𝟒 𝑨 𝒔 𝒅 𝒄 𝒑
Typical 3-ft Diameter Column: #5 p = 3”
ρs =
[LRFD ] =
ODOT's Seismic Update

5. New Bridges Column Ductility – Tie Spacing (Rect. Column)
𝝆 𝒔 = 𝑽𝒐𝒍𝒖𝒎𝒆 𝒐𝒇 𝑹𝒆𝒊𝒏𝒇𝒐𝒓𝒄𝒆𝒎𝒆𝒏𝒕 𝑽𝒐𝒍𝒖𝒎𝒆 𝒐𝒇 𝑪𝒐𝒏𝒄𝒓𝒆𝒕𝒆 𝑪𝒐𝒓𝒆 = 𝟐 𝒂+𝒃 𝑨 𝒔 𝒂 𝒃 𝒑
Typical 3-ft Square Column: #5 p = 3”
ρs =
[LRFD ] =
ODOT's Seismic Update

6. New Bridges Column Ductility Plastic Hinge Regions High Zone 1:
(0.15 ≥ SD1 ≥ 0.10)
LRFD: d e
ODOT's Seismic Update

7. New Bridges Column Ductility – Plastic Hinge Regions
ODOT's Seismic Update

8. New Bridges High Zone 1 BDM Fig. 301.4.4.1-1 Site Class D, E & F
ODOT's Seismic Update

9. New Bridges Pier Crossframes
Provide a direct load path from bearings to deck where transverse restraint exists
Guided & Fixed Elastomeric Bearings
Guided & Fixed Multi-Rotational Bearings
Rockers, Bolsters, Fixed Pin & Sliding Bronze Plate Bearings
Design Frames for Strength & Service Loading
ODOT's Seismic Update

10. New Bridges Pier Crossframes
Low Skew
High Skew
ODOT's Seismic Update

11. New Bridges Horizontal Connection Force
LRFD
As < 0.05  0.15 (Tributary Dead Load)
As ≥ 0.05  0.25 (Tributary Dead Load)
Tributary = Area contributing Dead Load to the connection
Extreme Event I Load Combination
Live Load: ϒEQ = 0.0
ODOT's Seismic Update

12. New Bridges Structural Analysis
Not Req’d in Zone 1
Zone 2 analysis could be used to determine seismic design where Zone 1 Connection Force is considered too excessive
LRFD &
ODOT's Seismic Update

13. Existing Bridges Abutment Seat Width
BDM Fig a-1
Overlap between superstructure & bearing seat
Measured Normal to Abutment centerline
Assume maximum thermal contraction
ODOT's Seismic Update

14. Existing Bridges Abutment Seat Width - Retrofit
ODOT's Seismic Update

15. Existing Bridges Seated Hinge Seat Width
ODOT's Seismic Update

16. Existing Bridges Seated Hinge Seat Width
ODOT's Seismic Update

17. Existing Bridges Restrainers
Shall be designed to resist Horizontal Connection Force
Permit Expansion/Contraction/Flexure movement
Prohibit excessive movement during seismic event
ODOT's Seismic Update

18. Existing Bridge Limited Travel Multi-Rotational Bearing
ODOT's Seismic Update

19. Existing Bridges Ductility vs. Restraint
For substructure units where superstructure Restraint exists, substructure Ductility shall be provided.
ODOT's Seismic Update

20. Existing Bridges Removing Restraint
Non-seismic loads applied to superstructure (e.g. Wind on Structure) need to be transferred to substructure
Typically occurs at fixed or guided bearings
Can This Fixity Be Relocated?
“Friction is not considered a positive connection” – LRFD C
ODOT's Seismic Update

21. Existing Bridges Removing Restraint
Exp.
Exp.
Replace bearings with exp. Elastomeric
Convert to Semi-Integral Abutment
ODOT's Seismic Update

22. Existing Bridges Moving Restraint
Fix.
Exp.
Exp.
Exp.
Replace Fixed bearings with Exp. Elastomeric
Move Fixity to either abutment
Design Joints for revised movement ranges
ODOT's Seismic Update

23. Existing Bridges Keep Restraint
Exp.
Exp.
Fix.
Exp.
All bearing types remain same
Improve Ductility of Fixed Pier
ODOT's Seismic Update

24. Existing Bridges Ductility for Wall & T-Type Piers
ODOT's Seismic Update

25. Existing Bridges Ductility for Wall & T-Type Piers
ODOT's Seismic Update

26. Existing Bridges FRP Wrap
PN 519
Pays for wrap and surface prep for wrap.
Does not pay for concrete repairs!!!
Engineering performed by Contractor/Supplier
Uses products listed by International Code Council (ICCES)
BDM b
Specify FRP wrap from top of footing to bottom of cap
SD1 < 0.10: Specify Min. Confining Stress = ksi
SD1 ≥ 0.10: Specify Min. Confining Stress = ksi in Plastic Hinge Regions per LRFD e
Dewatering required until product fully cures
Specify disposition of all attached appurtenances
ODOT's Seismic Update

27. Existing Bridges FRP Wrap
ODOT's Seismic Update

28. Existing Bridges Other Ductility Options
Concrete Jacket with Threaded Couplers
ODOT's Seismic Update

29. Existing Bridges Other Ductility Options
Steel Jacketing
ODOT's Seismic Update

30. Existing Bridges Other Ductility Options
External Prestressing
Utilizes special anchorages originally designed for prestressed water tanks.
0.6” diameter strand
ODOT's Seismic Update

31. Questions? ODOT's Seismic Update
BDM b states “The tributary permanent load defined in LRFD represents the factored dead load of the superstructure…” The referenced section of AASHTO does not specifically indicate the tributary dead load should be a factored dead load, and the factored dead load appears to be very conservative. Why has ODOT decided to use a factored tributary dead load? The connections shall be designed at the Extreme Event I Limit State which using factored loads. BDM b does define ϒEQ as 0.0.
Is that factored tributary dead load supposed to include the future wearing surface? Yes include Future Wearing Surface in the determination of factored tributary load. The idea is to design the connection force for the tributary load in place at the time of the seismic event. Without knowing when this will occur, defer a time when the FWS will be in-place.
Site Class requirements and using historic borings: Certainly, if information is available from a previous subsurface investigation, then that information can be used to determine the Site Class. It is not ODOT’s goal to require new subsurface investigations for rehabilitation projects. As a default per BDM , Designers may assume As > 0.05 which correlates to a 0.25 connection force factor and SD1 < 0.10 which correlates to the lesser column ductility requirements.
ODOT's Seismic Update

32. MASH What Does It All Mean?
Sean Meddles, P.E.
Assistant Administrator
Office of Structural Engineering
November 15, 2017

33. Manual for Assessing Safety Hardware
Purpose:
To present uniform guidelines for the crash testing of both permanent and temporary highway safety features and recommend evaluation criteria to assess test results.
An AASHTO publication provides a platform to update for vehicle fleet. As an NCHRP report, new research would need to be sponsored to issue updates.
MASH – What Does It All Mean?

34. Safety Features Tested to MASH
Longitudinal Barriers – flexible/rigid & transitions
Terminals
Crash Cushions
Support Structures – breakaway signs, traffic control devices & utility poles
Work Zone Attenuation & Channelizers – TMA’s
Traffic Gates
Drainage Features
ODOT's Seismic Update

35. MASH – What Does It All Mean?
MASH Test Levels
Test Level
Test Vehicle
MASH Test Conditions
NCHRP 350 Test Conditions
Δ Impact
Severity
(%)
Speed
(mph)
Angle
(degrees) 1
Passenger Car
Pickup Truck 31 25 20
166%
114% 2 44 3 62 4
Single-Unit Truck 56 15 50
141% 5
Tractor-Van Trailer
100% 6
Tractor-Tank Trailer
MASH – What Does It All Mean?

36. Small sedan weighing 2420-lb
MASH Passenger Car
Small sedan weighing 2420-lb
(previously 1540-lb)
MASH – What Does It All Mean?

37. 2-wheel-drive pickup with 4 full-size doors
MASH Pickup Truck
2-wheel-drive pickup with 4 full-size doors
GVW = 5,000-lb
(Previously 4400-lb)
MASH – What Does It All Mean?

38. MASH – What Does It All Mean?
MASH Single Unit Truck
GVW = 22,000-lb
MASH – What Does It All Mean?

39. MASH Tractor-Van Trailer
GVW = 80,000-lb
MASH – What Does It All Mean?

40. MASH Tractor-Tank Trailer
GVW = 80,000-lb
MASH – What Does It All Mean?

41. FHWA/AASHTO Implementation Agreement
Dated January 7, 2016
FHWA will continue issuing eligibility letters for hardware tested to MASH but not NCHRP 350
Agencies urged to replace hardware not tested to NCHRP Report 350 or later
Agencies urged to upgrade existing hardware to MASH when damaged beyond repair
MASH – What Does It All Mean?

42. FHWA/AASHTO Implementation Agreement Dates
Only MASH hardware shall be used for contracts on the NHS with letting dates after:
December 31, 2017: w-beam and concrete barriers
June 30, 2018: w-beam terminals
December 31, 2018: cable barriers & terminals
December 31, 2019: bridge railing & all other longitudinal barrier including portable barrier
NCHRP 350 PCB manufactured before 12/31/2019 may continue to be used throughout its normal service life.
MASH – What Does It All Mean?

43. MASH – What Does It All Mean?
FHWA Open Letter May 26, 2017
To qualify for an FHWA Federal-aid eligibility letter, all roadside hardware devices must complete the full suite of recommended tests as described in AASHTO MASH.
FHWA will no longer provide eligibility letters for modifications to MASH accepted hardware.
FHWA will not “grand-father” NCHRP Report 350 eligible hardware.
Modifications to proprietary system will need to be addressed at the state and local levels.
Creates the need for “State Certification” of hardware.
MASH – What Does It All Mean?

44. MASH – What Does It All Mean?
“Self Certification”
States assume responsibility for determining railing eligibility for Federal-aid in FHWA’s absence
No FHWA guidance for determining eligibility
50 different opinions - one State’s certification does not provide certification for all states
No central clearing house
MASH – What Does It All Mean?

45. MASH – What Does It All Mean?
ODOT Bridge Railing
36” BR-1-13
42” BR-1-13
BR-2-15
DBR-2-73
DBR-3-11
PCB-91
SBR-1-13
SBR-2-13
TBR-91
TST-1-99
MGS-2.3
MASH – What Does It All Mean?

46. ODOT Bridge Railing 36” Concrete NJ Shape Barrier
Has not been crash tested to MASH
ODOT not interested in crash testing or self-certification
Alternative: 36” Single Slope has been crash tested to MASH TL-4
MASH – What Does It All Mean?

47. ODOT Bridge Railing 42” Concrete NJ Shape Barrier
Has not been crash tested to MASH
ODOT not interested in crash testing or self-certification
Alternative: 42” Single Slope
MASH – What Does It All Mean?

48. ODOT Bridge Railing Concrete Sidewalk Barrier
Has not been crash tested to MASH
ODOT not interested in crash testing
ODOT considering self-certification
Alternative: Some states are considering all metal systems for crash testing
MASH – What Does It All Mean?

49. ODOT Bridge Railing DBR-2-73 & DBR-3-11
Have not been crash tested to MASH
ODOT not interested in crash testing or self-certification
Alternative: New ODOT side-mounted railing
MASH – What Does It All Mean?

50. ODOT Bridge Railing PCB-91
Has not been crash tested to MASH
ODOT not interested in crash testing or self-certification
Alternative: ODOT approved proprietary portable barrier (i.e. Zoneguard) or new PCB design from others
MASH – What Does It All Mean?

51. ODOT Bridge Railing 42” Concrete Single Slope Barrier
Has not been crash tested to MASH
Evaluated by Texas DOT/TTI
Self-certified by Texas as TL-5
ODOT will wait for testing by others or self-certify based on TxDOT/TTI evaluation
MASH – What Does It All Mean?

52. ODOT Bridge Railing 57” Reinforced Single Slope Median Barrier
Has not been crash tested to MASH
42” Evaluated and self-certified by Texas as TL-5
ODOT will wait for testing by others or self-certify based on TxDOT/TTI evaluation
MASH – What Does It All Mean?

53. ODOT Bridge Railing 57” Un-Reinforced Single Slope Median Barrier
Has not been crash tested to MASH
ODOT currently scheduled to test with MASH TL-3 pickup truck
ODOT will self-certify to TL-3 based on results
MASH – What Does It All Mean?

54. ODOT Bridge Railing TBR-91
Has not been crash tested to MASH
ODOT not interested in crash testing or self-certification
Alternative: 36” or 42” Single slope concrete barrier
MASH – What Does It All Mean?

55. ODOT Bridge Railing TST-1-99
Has not been crash tested to MASH
ODOT not interested in crash testing or self-certification
Alternative: New ODOT side-mounted railing
MASH – What Does It All Mean?

56. ODOT Bridge Railing New ODOT Side-Mounted Railing
Scheduled to be crash tested to MASH TL-4
Expect FHWA acceptance letter
MASH – What Does It All Mean?

57. ODOT Bridge Railing Long Span Guardrail
FHWA accepted to MASH TL-3 (B-189)
ODOT SCD MGS-2.3
Max Span = 25-ft c/c posts
MASH – What Does It All Mean?

58. MASH – What Does It All Mean?
NHS vs. Non-NHS
ODOT is considering different standards for the two systems:
NHS  MASH accepted hardware
Non-NHS  MASH or NCHRP Report 350 accepted hardware
Allows the use of DBR-3-11 upgrade for existing DBR on rehab projects.
Benefits local projects
MASH – What Does It All Mean?

59. Existing Barrier Systems
If the existing railing system was crash-tested design, no upgrade is required until deck is replaced.
Example: 36” BR-1 does not need to be replaced with a rigid overlay project, but will be upgraded to SBR-1-15 on new deck
If the existing railing system was not crash tested design, upgrade with rigid overlay or deck replacement
Example: AR-1-57 railing shall be upgraded to SBR-1-15 with a rigid overlay project
MASH – What Does It All Mean?

60. MASH – What Does It All Mean?
Questions?
MASH – What Does It All Mean?