Echague, together with dozens of other engineers and technicians, is in constant triage mode. The damage is as bad as he’s ever seen on a North American bridge, but his experience in overcoming geographic hurdles, such as deep ravines in high-seismic-risk areas, helps him to think creatively. His team scopes out a problem, puts out a request for proposals from engineering companies, peer reviews submissions, then issues the contract. It never ends. “There’s so much to correct,” he says, explaining that, as they close in, crews are constantly finding new cracks and fissures in the piers. “You can’t do it all. There are judgment calls all the time-that’s the hardest part of the job.” Complicating matters, the most visible signs of decay, such as delaminated concrete (where the exterior has fallen away, leaving rusted rebar to jut out), are not always the most pressing problems. Lately, Echague has focused on shoring up the girders that run parallel to traffic.
We get back in Amiot’s boat so Echague can show me what he means. He points to a trapezoidal truss, known as a queen post, that drops down from the I-beam supporting the outer edge of one part of the deck. The Champlain was never expected to deteriorate so severely after just 50 years, but JCCBI contractors had to take the unusual step of fitting these expensive steel braces to stop heavily corroded beams from sagging.
As a further fail-safe, they reinforced the new concrete, coating those beams with bands of tightly cinched steel cables. Finally, the bridge authority installed motion detectors at regular intervals along the underside of the deck. The sensors, which look like crossed PVC pipes with wires threaded through them, can pick up vibrations of even a few microns-a micron is one-thousandth of a millimetre-and relay the data back to the JCCBI’s computers, which analyze the pattern in real time and can warn agency officials of beyond-normal traffic load. In response, they can mechanically adjust the queen post to counteract the shearing effect of the vibrations on the main beams.
Amiot guides us toward another pier. When we pull up, four burly workers at the end of their shifts are standing on the dock with their lunch boxes, waiting for a ride back to shore. Echague directs me to a five-storey staircase that leads to a plywood platform suspended below the deck of the bridge. As we climb, the structure rattles and sways. About three metres beneath the platform, the steel-grate staircase ends abruptly, and we clamber the rest of the way on the bars of the scaffolding.
This exposed climb, with the St. Lawrence River churning below, is part of the morning commute for the crews who labour on some of the most damaged portions of the Champlain. The platform has railings and is shielded from the sky by the deck above. Still, dozens of men stride around without harnesses in bone-chilling winds. “Every worker on the bridge is proud,” Echague says. “The conditions are very hard.
The dilemma with the Champlain arose because it was stricken well before its time-major bridges are today expected to last from 75 to 100 years. Much of the wear and tear stems from years of deferred maintenance, the scourge of Canada’s major civic structures. Consequently, JCCBI officials must brainstorm unusual solutions to ensure the bridge stays in service until the new span is completed.
Last year, one of the Champlain’s most urgent problems involved the thick rubber pads, or bearings, squeezed between the tops of the piers and the deck’s underside. Bridges need to be able to flex so they can withstand the freeze-and-thaw cycle; sawtooth grates between segments of the deck allow the Champlain to expand and contract. But bridges also need shock absorbers to survive the barrage of passing vehicles, hence the rubber pads.
When Echague’s inspectors discovered that many of these bearings were heavily damaged from corrosion and compression, they had to figure out how to replace them. They decided to use high-power jacks to lift the deck in 22 separate locations along the length of the bridge. The jacks, resembling oversized coffee cans topped by anvil-like heads, raised the deck by about 10 centimetres-just enough clearance to peel away each rotted, doormat-like bearing and fasten a new one.
The hydraulic jacks, moreover, were connected to a single unit of valves, allowing a single operator sitting at a control panel to carry out the operation. Each replacement required about half an hour to complete, and the work took place over a few days late last fall. It’s almost certain the thousands of drivers zipping across the span had no idea it was being hoisted up mechanically beneath their wheels.
Echague opens a plywood trap door over the construction platform, and we gingerly make our way down the scaffolding staircase to the bottom. Before we board Amiot’s skip, we lift our gaze. “It’s a beautiful structure,” Echague says.
For those lucky enough to see the Champlain up close, there’s indeed a sense of awe about this immense, man-made object and how it has defied water and the elements. Yet the Champlain’s shocking fragility calls to mind bridge collapses in other cities. In 2007, the I-35W Mississippi River Bridge in Minneapolis-Minnesota’s fifth busiest at the time-toppled during rush hour. It not only killed 13 travellers, but severely disrupted the local economy, causing an estimated $43-million decline in productivity in 2008. Echague argues that any fears the Champlain will collapse just as completely-and take with it a portion of the 160,000 vehicles that pass over it daily-are unfounded. The Champlain, he explains, is more at risk for a partial road depression (with one or two lanes affected) than a sudden collapse of a section. Even so, that kind of mishap would render the span off limits. South Shore commuters would have to resort either to the Jacques Cartier Bridge, the Honoré Mercier Bridge or the Louis-Hippolyte Tunnel. It would also hobble Montreal’s economy, as trucks travelling between Montreal-area factories and destinations in the United States would be forced to find alternatives. A 2011 study by the Federal Bridge Corporation on the closure of the Champlain-should it ever occur-predicted losses of $740 million a year.
Echague and his team are determined not to let that happen. It will be a fight to the finish-one that will end with the total destruction of their work. Once the new bridge is open for traffic, the JCCBI will likely dismantle Montreal’s dilapidated marvel of postwar engineering, at an estimated cost of $155 million. The three-year demolition will produce about 180,000 tonnes of concrete and steel-the weight of a mid-size oil tanker.
Until then, Echague has a job to do. “It’s all about getting people home,” he shouts over the sound of Amiot’s boat. As we plow through the waves, the massive bridge recedes, and the piers-broad and high-dwindle, looking like so many poles sticking out of the water.