Details
Type: Bulletin
Topic or Program: Highway Design Manual and the Bridge Design Manual
Final Number: TSB22-01(B)
Effective Date: 06/01/2022
Updated Date: N/A
Signature on File: Michael Kimlinger, P.E., Interim Chief Engineer
Purpose
The purpose of this document is to provide guidance on roadside safety feature design requirements for Major Bridge Maintenance (MBM) projects. Managing ODOT’s bridge and roadway assets requires balancing risks. Funding limitations require programs within the Agency to make decisions to provide effective and equitable use of their resources to perform the program’s mission. At times, that means addressing only the greatest risk and leaving others, such as roadside safety features, for a different project.
Guidance
Decision Workflow:
Use the following decision tree when considering the inclusion of safety devices on MBM projects.
1. Do no harm:
Avoid degrading the effectiveness of existing roadside safety devices, bicycle or pedestrian facilities. Design deviations are not required to document substandard devices if they are not negatively impacted during the project. Concrete deck sealing and multi-layer polymer concrete overlays (MPCO’s) are examples of deck preservation activities that are considered to have a negligible impact on roadside safety features. Guardrail height adjustment is not required for resurfacing treatments that do not impact guardrail height.
2. Reductions in effectiveness:
When maintenance needs necessitate minor reductions in the effectiveness of a roadside safety device, document this decision with a design deviation or design exception depending on the feature. Although each situation will be unique and require individual approval, the below criteria will be considered as minimum values allowed for approval:
a. Bridge Rails:
- Final height is greater than 27 inches (measured from riding surface or top of sidewalk).
- No portion of bridge rail is rated Condition State 4 (serious). Railing coded Condition State 4 indicates a portion of the railing failed. Include repairs to failed railing as part of the project.
b. Guard Rails:
- Where the impacted height is lower than 28 inches, refer to the Highway Design Manual Part 400 for guidance on adjusting guardrail height.
- Rail elements are not torn or separated.
c. Curb:
- Curb height is greater than or equal to 4 inches.
d. Geometry:
- Maintain positive drainage and existing flow spread.
- Cross-slope does not exceed 8%.
Does not result in an algebraic difference greater than 11% at ADA ramps.
Removed rumble strips are replaced.
Does not change existing striping.
3. Roadside safety features not addressed by MBM Program:
- Blunt bridge rail ends: The limited scope and resources of the MBM program do not accommodate addressing blunt bridge rail ends within MBM projects. The 1R Roadside Safety Feature Upgrade Program prioritizes blunt bridge rail end upgrades.
- Transitions: The limited scope and resources of the MBM program do not accommodate addressing substandard transitions within MBM projects. The 1R Roadside Safety Feature Upgrade Program prioritizes upgrades to transitions.
While MBM program funding will not be used to address blunt ends or transitions, both of these safety features will be addressed in the following ways:
- a. Seek additional funding to upgrade bridge rail end treatments
- b. Where it is not possible to include bridge rail end treatments in the project, prioritize and address in a future project through the 1R Roadside Safety Feature Upgrade Program (contact the Sr. Roadside Design Engineer in the Engineering and Technical Services Branch/Traffic-Roadway for more information). Where unprotected bridge ends cannot be upgraded due to site conditions, document with a design exception. Due to the limited time available to add bridges to maintenance paving projects, the process must be completed within two weeks (standard templates for typical site conditions requiring a design exception will be made available to help expedite the process).
4. Curb ramps:
There are no programmatic exceptions for curb ramps. If the proposed work is considered an alteration and the existing ramp is not compliant, it must be replaced before or within the MBM contract.
b. Reference
BDM Appendix 2 and operational notice
MG100-107 to determine if the proposed project meets the criteria of an alteration.
Background/Reference
The Major Bridge Maintenance Program was established in 1990 to specifically address major and emergency bridge repairs. The program is intended to fill the funding gap between STIP and District funding.
The volume of bridge defects and associated maintenance recommendations has substantially increased since the MBM program’s inception. To assist the Maintenance Districts with identifying priority work, the MBM Engineer reviews the maintenance backlog and provides annual program priority lists. The priorities include structurally deficient bridges, urgent and high-priority maintenance recommendations, scour repair, and cost-effective preservation actions.
The program’s function in the Agency is an important consideration in determining the level of investment for a given project. Maintenance focuses on maintaining functionality through targeted repairs and replacement in kind, while the STIP is a strategic investment to broadly improve infrastructure. MBM projects typically have a narrow scope of work. The objective of the program is to keep structures in service by addressing localized deterioration. Although the objective may be focused, the magnitude of repairs may be large; at times rivaling a STIP project. Even though the scope of repairs may be similar to a STIP project, the objective of the MBM program is much more surgical. There is a large population of existing roadside safety devices that do not meet current design standards. Some of these have their own programs that prioritize work based on the greatest risk. While it may be desirable to upgrade these devices to meet standards, incorporating these upgrades into maintenance projects reduces funds available for the backlog of defects, and may delay the operationally critical repairs needed to keep the facility open to traffic. This guidance is intended to balance the risks between bridge and roadside safety feature conditions.
Action Required
The above guidance will be used to update the Highway Design Manual and the Bridge Design Manual as appropriate.