Part of Kingston causeway bridge 'buckled instantly' when supports removed, report says

On the evening of March 30, 2024, workers were removing a criss-crossed lattice of supports along part of a steel truss that held up the LaSalle Causeway's massive counterweight.

The project was supposed to strengthen the crossing and add decades to its lifespan.

Instead, just as the last piece of lattice was removed, the"member" a diagonal element that helped carry the heavy load "buckled instantly."

That moment, described in a health and safety incident report obtained by CBC through access to information laws, spelled the end forthe century-oldlift bridge that thousands of people relied on to cross the Cataraqui River every day.

The document, prepared by Landform Civil Infrastructures Inc. (LCI) for Ontario's Ministry of Labour, provides a glimpse into the damage that led to thebridge's demolition.

What followed was months of frustration for residents and downtown businesses, estimatedmillions in losses for local cruise boat and tourism operators, and daily traffic gridlock.

The demolition of the green metal structure, known as the "singing bridge" for the sound it made as vehicles drove across, also drew an emotional response, with many on social media sharing their love and sense of loss.

Others shared their feelings more directly. One message, penned on the bridge in permanent marker with the damaged member in the background, read, "I'll miss the sound of your rumbling heart."

Federal department has shared few details

Public Services and Procurement Canada (PSPC), the federal department that owns the causeway, has shared little about what happened March 30,beyond issuing a statement five days later that an element of a "diagonal steel truss" was "damaged while carrying out work to strengthen it."

The member that buckled was part of that truss, which in turn supported thecounterweight that could be used to raise and lower the Bascule bridge to let boats through.

No one was injured when it failed. The crossing was already closed to traffic at the time because the scheduled rehabilitation work was underway.

A now-deleted description on the federal government's website said the rehabilitation project would "extend the service life of each of the components by another 30 years." The work would "improve the condition and operation of the BasculeBridge," it said, and "ensure the safety of bridge users."

But, rather than improving the span, the project endedwith the entire structure being scrapped.

In late May, following the buckling and a laser survey that found "key elements" of were misaligned, PSPC announcedthe bridge'sremaining life was "significantly reduced."

It was demolished in June.

11:00LaSalle causeway's 100 year legacy comes to a close

Public Services and Procurement announced Tuesday that Kingston's LaSalle causeway will need to be demolished and rebuilt from scratch, ending over 100 years of service.

'Removal activities' led to buckling:internal messages

Emails from PSPC staff reacting and responding to the bridge damage were among the 95 pages of documents provided to CBC.

One message sent by the department's chief engineer for bridge and transportation structures, roughly an hour after the incident, starts tersely.

"Just happened," the message began."Removal activities during construction caused one of the main members supporting the counterweight of the Bascule Bridge of the LaSalle Causeway to buckle."

That phrasing is echoed in a "heads up" summary from 5:30 p.m. on March 30, again stating the construction activity caused the damage.

However, that same summary along withupdates shared among staff in the following days lists the root cause of the "abnormal bending of the bridge structural steel" as "unknown."

Plans called for lattice to be removed

LCI, a Hamilton-based company, was awarded the$8.7 million contract to repair the crossing in 2023.

"Our mission is to leave bridges better than we found them, and our experience and dedication enable us to," the company says onits website,under a section on rehabilitation.

Parsons Corporation is listed as the design and engineering consultant. They state on the website for their Canadian operation that they offer expertise in various areas, including Bascule bridges.

Drawings from Parsons outlining the work that was to take place were alsoincluded in the documents obtained by CBC.

They call for the lacing or lattice along the top and bottom of the member that buckled to be removed and replaced with cover plates.

The drawings note the maximum unsupported length for the member should remain under 1.45 metres at all times.

The plans direct that interim "diaphragms" lateral bracing between the two pieces that make up amember should be spread out at the same interval.

Based on the documents CBC reviewed, it'snot clear whether the diaphragms were considered enough support or if some or all of the lattice was also meant to remain during the replacement.

Photos of the buckled member shared by LCI anddated April 2appear to show the diaphragms in place and no lattice along the top.

Small elements can play 'critical role': professor

MarkGreen, a civil engineering professor at Queen's University, reviewed the documents and pictures acquired by CBC.

Speaking generally, Green saidlattice are used to link parts of members, making them act as oneand providingsupport to prevent them from failing.

The cover plates described in the Parsons drawings would serve a similar function, bracing the memberto stop buckling, according to Green.

"There are sometimes very small elements of structures that play a very critical role," heexplained. "That is very true in buckling behaviour."

Green described the damage to the member shown in site photos as "significant," adding it appears to have buckled while work was underway to change its bracing system.

LCI's health and safety report states crews were removing the top lattice so the member could be "blasted and primed that night, with intentions of installing the new reinforcing plate the next day."

Following a conversation with Amson Welding, LCI's subcontractor, it became apparent that "after the last lattice was removed from the top the member buckled instantly," the report said.

The health and safety report did not address why the member failed when it did.

Representatives for Parsons, LCI and Amson Welding did not respond to requests for comment about the causeway damage.

Loss a 'tremendous challenge' for city

A federal webpage about the causeway estimates 23,000 vehicles used the bridge daily. They've since been pushed onto other city streets, causing daily traffic jams.

Kingston Mayor Bryan Paterson described losing the bridge as a "tremendous challenge" for the city, with downtown businesses reporting a sharp drop in spending and hospitals raising concerns about ambulance response times.

Cruise boat companies faced challenges too. Several vessels were caught on the wrong side of the causeway at the start of the busy tourism season, forcing them to cancel more than a month's-worth of trips before the demolition allowed their ships to be released.

By the time a temporary bridge is expected to be assembled in September, allowing traffic to resume,six months will have passed.

PSPCsaid it plans torentthat replacement for three years whilea permanent span is procured andconstructed.

Paterson said knowing what killed the causeway is "important" information and something Kingstonians want to understand.

Investigation into cause continues

PSPC also did not directly respond to emailsabout what it believescaused the member to buckle. The departmentsaid it's hired a risk management and claims specialist to investigate the failure.

A spokesperson declined to comment on any potential financial liabilities or legal matters related to the incident.

In a message to staff the morning after the member failed,PSPC's chief engineer wrote it"buckled without warning"just as a hockey game was letting out at an arena around the corner.

Workers were able to quickly secure the site, the engineer said.

"We received a stark reminder on how our line of work is serious business with real impacts on public safety and the communities we serve," they wrote.

"Luckily no one got hurt."