03-Appendix C - Research Topics.pdf

Appendix C – Research Topics

BROAD AGENCY ANNOUNCEMENT

Federal Highway Administration

Office of Acquisition and Grants Management

Research Initiatives in Support of FHWA Bridges and Structures Programs

Bridge and Tunnel Safety Inspection Program

Topic Number Title Closing Date for

Concept Papers

HIBS10-BTSIP-001

Analysis and Performance Testing of T-1 Steel Ultrasonic

Testing at 12pm ET

(noon)

11/03/2025

Highway Tunnel and Bridge Safety Technology

Topic Number Title Closing Date for

Concept Papers

HIBS40-TUN-001

Safety of Highway Tunnels During and After Fire Events –

Smoke Removal Capability of Ventilation Systems at 12pm ET

(noon)

11/03/2025

HIBS40-TUN-002

Safety of Highway Tunnels During and After Fire Events –

Structural Component Assessment at 12pm ET

(noon)

11/03/2025

HIBS40-TUN-003 Scanning Technologies for Highway Tunnels at 12pm ET

(noon)

11/03/2025

Bridge and Tunnel Safety Inspection Program

Topic: HIBS10-BTSIP-001

Title: Analysis and Performance Testing of T-1 Steel Ultrasonic Testing

FHWA issued a memo on December 13, 2021 entitled “Non-Destructive Testing of Fracture

Critical Members Fabricated from AASHTO M244 Grade 100 (ASTM A514/A517) Steel.” This memo required bridge owners to verify their fabrication quality control records of butt welds in tension with these high-strength steels to ensure that hydrogen cracks could be detected. If quality control records could not be verified, then nondestructive evaluation had to be performed on in-situ welds to ensure there were no “rejectable” defects within in-service welds. The

AASHTO/AWS D1.5 Bridge Welding Code was cited for inspection procedures and acceptance/rejection criteria.

There were 55 bridges in 19 states subject to the memo. In all instances, bridge owners performed ultrasonic inspection of in-situ welds. For many welds, rejectable defects identified by the testing were cored out of the weld as either a temporary or permanent resolution depending on the reserve strength of the member. Studying those cores with internal defects offers a unique opportunity to gain further information on the reliability of ultrasonic testing (UT) inspection using the AASHTO/AWS D1.5 Bridge Welding Code. This is because as each core could be linked to an individual UT operator’s inspection report documenting size, location, and maybe type, to the reality if the if the core was destructively examined.

Some bridge owners performed forensic evaluations of cores to help validate UT inspection findings. These forensic evaluations involved cutting open a core and performing metallography to physically evaluate the size and types of the rejectable defects. However, only a limited set of cores were evaluated, and the forensic evaluations may not have been consistently performed among bridge owners.

The purpose of this project is to collect and synthesize an academic-grade evaluation of data collected in response to the December 13, 2021 memo, and/or perform forensic evaluation on any cores that remain to support that analysis. The goal of this effort is to put data in the public domain that can be used to enhance national specifications in terms of ultrasonic inspection and bridge design for fracture.

FHWA is seeking solutions that address one or both of the following two objectives:

1. Link the decibel rating of rejectable defect(s) within a core to a forensic evaluation of the defect(s) type, size, and orientation. Summarize that data to in an attempt to better answer the following questions:

o Is the AASHTO/AWS D1.5 Bridge Welding Code UT inspection severity class

(Class A, B, C, or D) correlated to the defect’s real size and type?

o Can the data provide insight into probability of detection of UT technicians? That is, what size of defect can UT operators detect at a certain bound of confidence

(e.g. smallest defect size with 50% or 95% confidence).

o Did defect detection vary with thickness of the weldment?

2. For quality control, some owners specified performance testing of UT technicians, and/or instituted multiple levels of UT inspection of the same weld by different UT technicians to validate indications before officially reporting them as “rejectable.” Can the QC data attempt to answer the following questions:

o Did performance testing of UT technicians increase confidence of the inspection?

How many UT technicians were screened out?

o How much did defect rating, size, and location vary amongst all the UT technicians?

o Were there merits in performing the multiple levels of UT inspection, that is, did the extra cost and time associated with that increase the level of confidence of finding rejectable indications?

FHWA seeks proposals from entities that collected data as part of an effort to address the

December 13, 2021 FHWA memo, including bridge owners and the contractors that worked for them. Proposals should address which questions above could be addressed with the data proposers already have or could attain, other questions they think the data could help address not mentioned above, and their overall technical approach. Proposals should include no more than 30 forensic evaluations of cores removed from any individual bridge. Entities should base proposals on the data and cores they have available.

Topic: HIBS40-TUN-001

Title: Safety of Highway Tunnels During and After Fire Events - Smoke Removal Capability of Ventilation Systems

Fires in highway tunnels can result in significant consequences. Fires can produce a large amount of smoke, which can reduce visibility, hinder evacuation efforts, and result in the inhalation of toxic substances. Ventilation is a critical system for fighting fires and dispersing smoke in tunnels. However, the ventilation systems for many older highway tunnels may have been designed for air quality, not smoke removal. These systems have some capacity for smoke removal, but many highway tunnel owners may not have the expertise or resources to evaluate the capabilities of those systems.

The intent of this project is to categorize tunnel ventilation systems and then demonstrate the smoke removal capabilities of various tunnel ventilation systems. The ventilation demonstration should allow tunnel owners and inspector to safely experience the impact of fire event and the capabilities of the ventilation system to remove the smoke.

The FHWA seeks solutions to address the following objectives:

1. Develop a summary of existing ventilation systems used in highway tunnels in the U.S., including but not limited to the type of ventilation system and design criteria.

2. Develop a testing plan for physical smoke tests in existing tunnels. Discuss the type of instrumentation to be used to evaluate the capability of the existing ventilation system.

Determine the amount of smoke to be generated, how the smoke will be generated, the most appropriate location(s) within the tunnel to perform the demonstration and the fire size simulated by the smoke generated.

3. Perform physical testing that demonstrates the capabilities of various tunnel ventilation systems with cost-effective smoke test exercises showing the impact of a fire in a tunnel.

4. Produce a report that illustrates the effectiveness of existing ventilation systems based on the physical demonstration performed.

Topic: HIBS40-TUN-002

Title: Safety of Highway Tunnels During and After Fire Events – Structural Component Assessment

Fires in highway tunnels are a significant concern for tunnel owners. A vehicle fire in a tunnel with sufficient fuel can result in temperatures exceeding 1000 °C, causing severe damage to structural materials. Steel and concrete may lose up to 50% of the original strength at 500 °C.

After a fire, tunnel owners seek to quickly determine the impact of the fire on the tunnel structure. However, performing extensive material testing to accurately determine the structural integrity of the tunnel may force the tunnel to remain closed for an extended time.

Visual inspection and acoustic impact testing are techniques commonly used in the post-fire inspection of structures, though a more comprehensive set of non-destructive tests may be used onsite to determine the condition of tunnel structures after a fire event with these methods. Non-destructive methods may be able to provide information about the integrity of the structure without the need for material testing to be performed at a laboratory.

The intent of this project is to develop post-fire inspection guidelines to provide inspectors information to allow them to visually assess the structural components onsite and determine if material samples are needed to fully assess the condition of the structure.

The FHWA seeks solutions to address at minimum the following objectives:

1. Provide a history of bridges and tunnels damaged by fires. Provide a summary of the subsequent post-fire assessment and describe the resulting condition of the structure.

2. Develop guidelines for performing a visual inspection of tunnels after a fire event.

3. Develop a visual reference for inspectors to determine the extent of the fire damage to the structure based on the tunnel component, material, estimated fire intensity or other factors, including suggestions for when additional nondestructive or material testing may be needed.

4. Provide a summary of onsite nondestructive techniques that can be used (or have been used) to evaluate the condition of a tunnel after a fire event.