Satellite offers new clues about what went wrong with the Washington Bridge

by: Tim White, Ted Nesi

PROVIDENCE, R.I. (WPRI) — One year after Rhode Island officials abruptly closed the westbound Washington Bridge, data from a European satellite is offering new insight into what was happening to the bridge in the months before it shut down.

ORIGINAL NOTE: https://www.wpri.com/target-12/satellite-offers-potential-clues-about-what-went-wrong-with-the-washington-bridge/

Target 12 asked Value.Space, a technology firm with offices in London and Estonia, to analyze data from the European Space Agency’s Sentinel-1 satellite in search of clues about the bridge’s final months. Value.Space uses the satellite data to monitor dams, bridges and other infrastructure on behalf of governments, insurers and other organizations.

Sentinel-1, which was launched in 2014, sends a radar signal down to the earth’s surface that bounces back like an echo, with new readings gathered every 12 days. That allows engineers to evaluate whether there has been any movement of a piece of infrastructure or landscape — down to the millimeter.

“Think of it as a policeman measuring your own driving speed,” Agu Leinfeld, Value.Space’s founder, told Target 12 in a Zoom interview from Estonia. He said the satellite radar can pick up noteworthy changes that an inspector on the ground might miss because they’re so small to the human eye.

And sure enough, Value.Space’s analysis of the westbound Washington Bridge discovered small but potentially telling signs that something unusual was occurring there.

The Sentinel-1 data shows a section of the bridge began to rise slightly in June 2022, then stayed put until May 2023, when it began to rise more significantly for the next six months — by 27 millimeters total. Leinfeld suggested any movement greater than 3 millimeters is abnormal.

“So in this specific spot, it definitely stands out when you compare it with the historical baseline,” he said.

The section of the bridge flagged by Value.Space is the same section — cantilever A over Pier 7 — where an engineer working on the bridge in December 2023 discovered a broken anchor rod that was supposed to be holding down that part of the bridge. R.I. Department of Transportation Director Peter Alviti closed the bridge three days later, citing safety concerns, and subsequent analysis found the bridge needed to be replaced.

“Twenty-seven millimeters is significant movement when it comes to materials like concrete,” Leinfeld said. “They don’t have very high tolerance of moving.”

Yet the data only shows that movement has occurred; it can’t say what caused the movement. “The satellite picks up the changes in the infrastructure,” Leinfeld said. “They’re not indicating the underlying cause.”

RIDOT spokesperson Charles St. Martin said the agency had nothing new to share about what caused the bridge’s failure, partly because the state is suing over a dozen companies that worked on the span over the years.

“The causes and assessments of the failure of the westbound side of the Washington Bridge are part of ongoing litigation and those questions would need to be directed to the legal team,” St. Martin told Target 12.

Value.Space’s ability to analyze Sentinel-1 data for information about the Washington Bridge was first flagged by Casey Jones, a professional engineer who hosts a YouTube channel that focuses on infrastructure issues around the country. Jones has done a series of videos about the Washington Bridge crisis, and has been increasingly critical of RIDOT and its leadership.

“I don’t think they’re transparent at all,” Jones said in a video posted on Nov. 11. “And saying they’re not being transparent is giving them the benefit of the doubt. Quite frankly, I think a number of their statements … have been outright misleading.”

St. Martin indicated RIDOT wasn’t familiar with the use of satellite imagery for infrastructure monitoring.

“Neither the Federal Highway Administration nor AASHTO, the organizations that advise or regulate bridge construction and inspection, have ever suggested the use of satellites,” he said. “RIDOT has not used satellites and, after making inquiries of several other states, we were not able to identify another state DOT that has used this technology.”

Leinfeld said the satellite data reinforced that Alviti made the right decision by closing the bridge. He said the alternative could have been a disaster similar to what happened in Dresden, Germany, three months ago when a concrete bridge partly collapsed there.

“They were really lucky because it just happened in the middle of the night,” Leinfeld said. “So there was no traffic at the bridge at this moment.”

A postmortem analysis of the Dresden bridge by Value.Space shows the section that eventually failed began sinking two years before it collapsed, suggesting the problem could have been prevented or mitigated if it had been spotted earlier.

“I think discovering these kinds of things should not be a matter of luck, but a matter of knowledge — especially because the tools are there and usable today,” Leinfeld said.

Concerns are now being raised about the long-term health of the eastbound Washington Bridge, a newer structure that has been carrying traffic in both directions since the closure of the westbound span. The eastbound bridge is also carrying more weight because cement barriers have been installed on it as part of the traffic changes.

Jones, the Kansas engineer, asked Value.Space to examine satellite data on the eastbound bridge and found some signs of concern.

“I wouldn’t suggest using this data right now in an absolute sense to say, yes, they definitely have a problem,” Jones said in his video last month. “But it’s definitely a red flag.”

Leinfeld echoed that caution, saying that more time is needed to make any judgments about data on the eastbound bridge. “The traffic load is different, and also the structure itself behaves differently because of the new elements and ongoing construction on site,” he said, suggesting the issue should be revised six months after construction ends.

Both Alviti and Gov. Dan McKee have maintained that they have no concerns about the eastbound bridge’s ability to handle the increased load while the westbound bridge is out of commission. RIDOT pointed Target 12 to a February letter from an engineering firm that deemed the extra lines and barriers “structurally acceptable,” and the agency is also installing a new weight-monitoring system on the span.