Forensic & Structural Investigations Archives - Atlas /project_tag/forensic-structural-investigations/ Tue, 12 May 2026 19:58:44 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 Caltrans, San Francisco-Oakland Bay Bridge /project/caltrans-san-francisco-oakland-bay-bridge/ Wed, 20 Aug 2025 18:34:19 +0000 /?post_type=project&p=246881 The east span of San Francisco-Oakland Bay Bridge (SFOBB) is the world’s largest Self-Anchored Suspension (SAS) Bridge, and is also the first bridge of its kind constructed with a single tower.Ìý Atlas provided materials and coating testing, analysis and inspection services, and oversight for the fabrication and installation of the cable system. Our team was […]

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The east span of San Francisco-Oakland Bay Bridge (SFOBB) is the world’s largest Self-Anchored Suspension (SAS) Bridge, and is also the first bridge of its kind constructed with a single tower.Ìý Atlas provided materials and coating testing, analysis and inspection services, and oversight for the fabrication and installation of the cable system. Our team was responsible for managing all mechanical, chemical, metallurgical and specialty testing for numerous high-strength anchor rods, suspender ropes and wires, including full-size ultimate capacity testing and fatigue testing. In addition, Atlas performed all inspections on the steel deck including the newly adopted Phased Array Ultrasonic Testing (PAUT) method by AWS welding code. Atlas managed the fabrication of suspender ropes, cable bands, high strength cable band bolts and various cast steel components for the cable system. Our team provided ASNT NDT Level II and III services in UT, MT, and PT testing of cable system cast split collars and zinc saddles and provided summary and analysis reports.

Atlas’s approach to maintaining quality during fabrication of this bridge, which occurred in China, Japan, South Korea, the United Kingdom, and throughout the United States, was based on proactively identifying issues and resolving them as early as possible in the fabrication process. Our structural materials representatives provided field erection support by managing inspection resources and generating analysis reports throughout the cable system component erection and coating application activities. This included erection of cable deviation and jacking saddles, erection of main cable strands, compaction of main cable, wire wrapping of main cable, erection of cable bands, tensioning of cable band bolts, erection and load transfer of suspender ropes and erection of numerous components related to the cable system on the bridge.

For the Skyway portion of the project, Atlas was responsible for the development of inspection protocols, training programs, and the coordination of all materials submittals, RFIs and shop drawings. In addition, the team oversaw all inspection activities related to the steel fabrication being performed. Atlas worked collaboratively with the contractors, designer, and owner to re-engineer systems and implement new processes that resulted in improved quality, fewer repairs and reduced labor costs.Ìý Atlas was also instrumental in the acceptance of the $1.2 Billion project without a single claim. Our team assisted Caltrans in the resolution of over $600 million potential claims by developing, organizing and serving as the Department’s primary presenter on eleven Dispute Review Boards. Our staff developed position papers and formal PowerPoint presentations for each fabrication issue.

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Foresthill Bridge Weld Inspections: Advancing Safety Standards for T-1 Steel /project/foresthill-bridge/ Wed, 20 Aug 2025 18:12:05 +0000 /?post_type=project&p=246880 The post Foresthill Bridge Weld Inspections: Advancing Safety Standards for T-1 Steel appeared first on Atlas.

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The Foresthill Bridge, the tallest in California and fourth highest in the U.S., stretches 2,428 feet across the American River canyon and carries more than 50,000 vehicles daily. Built in 1973 with T-1 steel, the bridge became the focus of a Federal Highway Administration (FHWA) and Caltrans initiative in 2024 to assess fracture-critical welds and guide national safety standards.

Placer County selected Atlas to perform non-destructive testing and documentation on all 288 butt welds. Using a combination of snooper trucks, custom scaffolding, and advanced ultrasonic methods, Atlas inspectors accessed welds more than 700 feet above the canyon while keeping the bridge open to traffic.

Initial results showed a defect rate much higher than the anticipated. Atlas quickly scaled operations, adapting inspection techniques for difficult locations, coordinating with Caltrans and FHWA oversight teams, and delivering real-time data to support timely repair decisions. Despite rain delays and challenging conditions, all work was completed in compliance with AWS D1.5 Bridge Welding Code and without safety incidents.

The findings from this project are already informing FHWA guidance for evaluating T-1 steel structures across the country. For Placer County, the work reinforced immediate safety, while nationally it advanced a proactive approach to bridge management.

 

In the numbers

288Ìý·É±ð±ô»å²õ

Inspected using advanced non-destructive testing methodsÌý

44 repairsÌý

Welds stabilized through targeted repairs and metallurgical review to ensure long-term safetyÌý

730 feetÌý

Maximum working height during inspectionsÌý

0 safety incidentsÌý

Maintained across months of elevated operations and weather-related delaysÌý

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