In 2024, the New Mexico Department of Transportation (NMDOT) faced an urgent need to inspect and repair the Rio Grande Gorge Bridge—the seventh-tallest bridge in the United States, spanning 650 feet above the Rio Grande River—without a full shutdown.
As a National Register landmark, the bridge’s historic integrity had to be preserved throughout the project. This required coordination among multiple agencies and stakeholders.
NMDOT engaged Ulteig as a consultant and agency partner to ensure the project was completed as promised: maintaining the bridge’s historic character (a unique specialization in itself), addressing abnormalities with agencies and consultancies and ensuring traffic flow with minimal downtime.
Project Background
The Rio Grande Gorge Bridge provides a vital connection between Taos County, NM and surrounding communities. It serves as critical infrastructure for tourism and for transporting goods and services throughout the area.
Its T-1 steel butt welds were installed before modern weld shielding standards were identified and implemented, creating the potential for hidden discontinuities. After the Federal Highway Administration (FHWA) issued guidance on T-1 inspections, NMDOT moved quickly to confirm weld integrity without forcing a full closure, as any shutdown would have diverted heavy trucks onto winding mountain routes, adding time, cost and safety concerns.
Ulteig was selected because of its proven ability to coordinate multi-disciplinary specialized teams on historic structures, our teams’ Non-Destructive Testing (NDT) expertise in T-1 steel, finite element analysis capabilities and local New Mexico–licensed engineering presence to streamline approvals.
Project Goals:
- Preserve the bridge’s historic character
- Verify weld performance per AWS D1.5 criteria
- Keep traffic moving safely across the bridge and support the establishment of a long-term asset management plan utilizing advanced data models
Ulteig’s Role and Responsibilities:
- Project management
- Coordination services
- Structural analysis
- Repair design
- Oversight for each task
The project required coordination with multiple other agencies and consultancies who were responsible for:
- Performing non-destructive testing (NDT)
- Lead paint abatement and repainting
- Providing rope access support
- Performing in-situ repair services via coring
- Conducting traffic control
- Providing an A-62 under-bridge inspection access vehicle
- Analysis support
Project Overview
The Ulteig team, along with our partners, began by developing a finite element analysis (FEA) model to simulate hypothetical weld discontinuities under live loads, defining thresholds that allowed NMDOT to keep one lane open throughout inspection and repair.
With a phased approach established and in place, Ulteig’s on-site coordinator oversaw sequential lead paint abatement and NDT activities, designed targeted repairs and managed final coating work. At the same time, a drone-based digital twin was created to support any repair design, future construction, and reduce future inspection efforts
Key Deliverables:
- FEA‐Driven Phasing Strategy
- Modeled T-1 steel weld scenarios to quantify defect tolerance under live loads
- Established criteria for one-lane vs. short-term closures based on inspection findings, minimizing traffic disruption
- Lead Paint Abatement & NDT
- 1 Priority Environmental removed existing lead coatings on the south truss, followed by Fickett Structural Solutions scanning welds using an A-62 Under Bridge Inspection Vehicle suspended 650 feet above the gorge
- Repeated the process on the north truss, inspecting 92 weld locations and performing QA scans on critical locations
- Documented 12 localized discontinuities in a Critical Inspection Finding Memos for NMDOT and FHWA
- Repair Design & Execution
- Partnered with Purdue University’s S-BRITE Center to validate coring as a minimally invasive repair technique
- An engineering partner completed coring on January 7, 2025—drilling out defective weld material
- An environmental abatement partner performed repainting under heated enclosures to ensure proper curing despite winter temperatures and high winds
- Drone‐Based Digital Twin
- Collaborated with an international technology company to capture overlapping imagery over four days via FAA Part 107-certified drone pilots
- Delivered a sub-centimeter-accurate 3D mesh for NMDOT’s virtual inspections, corrosion monitoring and future design support
Challenges and Innovations
Maintaining Historic Status
Working on a National Register-listed structure meant zero tolerance for visible alteration. By selecting coring over full-section replacement, Ulteig preserved original member profiles and avoided any change to the bridge’s appearance.
Drone Modeling
To reduce repeated daytime closures for visual inspection without the use of access equipment, Ulteig’s drone-based digital twin offered NMDOT a high-resolution model for virtual site visits, repair design support and condition monitoring.
Weather Challenges
Accessing welds 650 feet above the gorge required an A-62 UBIV and rope-access support, all coordinated under phased, one-lane closures. Winter repainting posed a risk to proper paint curing; we collaborated with agencies and consultancies to arrange heated enclosures and adjusted work schedules to meet the manufacturer’s specifications.
Results
By developing an FEA-driven phasing plan, managing national specialist partners on-site and leveraging drone technology, Ulteig delivered a solution that preserved a historic landmark, reopened traffic flow crucial to tourism and logistics and provided a digital roadmap for the bridge’s future maintenance.
- Preservation-Friendly Repairs: Coring removed all 12 discontinuities without altering member profiles; repainting matched the original finish, maintaining historical status.
- Continuous Traffic Flow: One-lane closures during abatement, NDT and coring kept freight and commuter vehicles moving; no full bridge shutdown was necessary.
- Digital Asset Delivered: The drone-derived model supports virtual inspections, corrosion monitoring and design simulations—eliminating future daytime closures solely for visual checks. This efficient, innovative process is currently being tested to be used on future transportation projects.
- On-Schedule Completion: Coring repairs concluded on January 7, 2025, and repainting was completed by May 2025, allowing NMDOT to fully reopen for summer traffic.
To learn how Ulteig can support your initiatives with comprehensive bridge engineering solutions, get in touch with our team today.
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