When they started building the Pont de Québec spanning the Saint Lawrence River in 1905, there was a sense of pride. Designed mainly for rail traffic, it was going to be the biggest cantilever bridge in the world, longer than the Forth Bridge in Scotland.
But on Aug. 29, 1907, a riveter noticed that a rivet he’d put in only an hour earlier had broken in half. Minutes later the structure twisted and collapsed with such force that people in Quebec City, 10 kilometres away, thought it was an earthquake.
The engineering challenges of the Quebec Bridge had been daunting. It spanned a shipping lane, so it had to have a 45-metre clearance for ocean-going ships. It was 850 metres long, but needed a single 550-metre span in the centre.
Key to its structural integrity was the ...