De la Concorde overpass: Before and after the collapse

The contract for the De la Concorde overpass in Laval was awarded in 1968 and by 1980, the first reports of problems began to emerge.

Here's a look at some of the important dates in the overpass's history.

1968

The contract to plan the building of the De la Concorde overpass over Highway 19 is awarded to engineering firm Desjardins Sauriol & Associés (Dessau). Inter State Paving inc. is given the construction contract.

It is opened to traffic in 1971.

1992

The overpass undergoes a major repair job. According to the inquiry's report following the collapse, the work done in 1992 "weakened the structure."

2004

An engineer from the transport ministry inspects the overpass, following a request from a junior engineer. After the two-hour inspection, the engineer concluded no immediate work was necessary and a more detailed inspection wasn't needed.

The report following the collapse later stated that it was a mistake not to follow up with a more detailed inspection.

Sept. 30, 2006

Driving along Highway 19 a little more than an hour before the collapse, Dave Ferrara witnessed a chunk of concrete fall from the De la Concorde overpass, describing it as being as big as a suitcase.

"I called 911 and I told them what I saw," he said.

Jules Bonin, a Transport Quebec patroller, then went to inspect the overpass. He loaded the piece of concrete into his truck, visually inspected the overpass and wrote a report calling for an urgent engineer inspection.

But it came too late.

The overpass collapsed, killing five people and injuring six others.

April 2007

The government's public inquiry into the collapse begins, lead by former premier Pierre-Marc Johnson.

The panel would hear from 58 witnesses as well as expert testimony.

October 2007

The Johnson Commission files its report into the accident, following the inquiry.

According to the report, a 'chain of causes' led to the collapse of the overpass, but no single person or group can be held responsible for the disaster.

The commission found three major causes contributed to the overpass failure:

• Improper rebar support for the design, which caused a "plane of weakness" where cracks eventually occurred.
• Improper rebar installation at the time of the overpass's construction in 1970.
• Use of low-quality concrete to build the overpass.

2007 to today

While the highways and subsequent overpasses belong to the Quebec government, the City of Laval has made a concerted effort to do its own inspections annually.

The city says it regularly receives calls from citizens regarding the state of its roads.