Pierre-Marc Johnson did not hide his exasperation on the subject of "extraordinarily bad work" related to the framework, the source of which was never established.
(Photo: Jacques Pharand Courrier Laval)
Laval is not to blame
The overpass tragedy is attributed to a variety of causes
Ville de Laval does not figure among the people or organizations blamed by the Commission inquiring into the Concorde bridge collapse, but Chairman Pierre Marc Johnson was particularly critical of the Quebec Ministry of Transport.
During the public hearings that extended over four months, Laval was hung out to dry by a government engineer. The city, said this engineer, had been lax in relation to the maintenance of structures of shared jurisdiction with Transport Quebec. The city was also sermonized by the chairman of the Commission for failing to rectify a drainage problem that produced permanent water pools on top of the bridge joints, near the area that broke apart. Laval is nonetheless exonerated in the report.
The pool
The presence of this notorious pool of water, framed within a problem of structural drainage, is noted in the Johnson Commission's final report.
"The drainage of the Concorde overpass roadbed did not conform to current standards of good practice," says the report. "The bridge is too flat and has no drains." At the time the overpass was built, there were no norms for drainage.
By virtue of the shared responsibilities in bridges such as the one that collapsed, the city has to see to the maintenance of the surface, including drainage. Could the problem have been resolved during the useful life of the bridge?
"It's more difficult with an existing bridge, explains an expert of the Commission. A drain would have had to be installed. It would have been better, but it would not have prevented the collapse."
The three causes
The experts consulted by the Johnson Commission agree on three principal causes of the tragedy. They point the finger at the framework, which was noted to be inappropriately designed and installed. With respect to this, Pierre Marc Johnson was unable to camouflage his exasperation in front of the media, describing the work as "extraordinarily bad" and as "incredibly negligent".
The use of concrete of mediocre quality is another element deemed partly responsible for the collapse of the Laval bridge, concludes the commission.
The blame
Although the designers at Desjardins, Sauriol et Associes (DSA), who respected the code for bridge-building of the day is not blamed, the consulting firm itself is, for having failed to fulfill its legal and contractual obligations.
DSA was responsible for "overseeing the entire work done on the bridge," which it failed to do, notably when the framework columns were installed, say the members of the commission. Retired engineer Marcel Dubois, 73, who was in charge of the viaduct worksite, is personally pointed the finger.
Elsewhere, together with the Transport Ministry (MTQ), DSA shares the responsibility for selecting concrete which was inadequate for the type of structure spanning Highway 19.
But DSA is not wholly to blame. Inter State Paving (ISP) shares the blame with DSA for not delivering construction work that conformed to the plans and designs, the Commission maintains. And lastly, the Acier d'armature de Montreal (AAM) and its president, a sub-contractor of ISP, also earned a reprimand.
Secondary causes
Vulnerability to an abrupt rupture (shearing), the absence of an impermeable membrane on the surface of the paving stone, and the weakening of the structure during repair work done in 1992, are all cited as contributing factors to the falling of a part of bridge roadbed.
The three commissioners blame engineer Tiona Sanogo, responsible for the 1992 work, for his bad management of the work. A second engineer of the MTQ also merits reproach: Christian Mercier, of the Direction des structures (Structures Directorate), called in by the regional directorate following an inspection of the viaduct conducted in 2004.
"The Commission, while wholly deploring the lack of rigour exercised by Mr. Mercier in conducting the 2004 inspection, blames above all the MTQ," can be read in the 200-page report.
The list of recriminations against the MTQ is long. The Ministry did not take into account the particular nature of the Concorde bridge (its cantilever design, with no central support beams), was negligent in its maintenance of the files, tolerated non-adherence to its inspection manuals and tolerated ambiguity between engineers and administrative units, notes the Commission.
Photo:PMJ rapport
(Photo: Jacques Pharand Courrier Laval)
Météo: Laval, 18 juillet 2008 / 19°C
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/ Vents: 11 Km/h / Humidité relative: 88 % 
Steven Guilbeault - Chronique environnement
Richard Cléroux - Le fouineur politique
