Here’s your chance to see the underbelly of the Jacques Cartier Bridge.
Last week, you may have heard that the Jacques Cartier was being closed overnight and seen the scaffolding around piers that hold up a bridge ramp at the northwest corner of Ste. Catherine St. and De Lorimier Ave.
Workers removed the 82-year-old hunk of steel (in the photo above) that helps hold up a 336-tonne section of the bridge. They were making way for a new shock absorber for the span.
Workers were replacing a part of the structure known as a bearing device. It sits at the top of a pier and transfers the load from the deck to the piers.
In this case, the bearing device is of a type that allows for slight movements in the bridge’s superstructure. It acts as a sort of shock absorber for the bridge, absorbing movements due to traffic and changes in temperature, says Jean-Vincent Lacroix of the Jacques Cartier and Champlain Bridges Inc.
The devices being replaced were installed more than 20 years ago. They are rusty and inspections indicate they should be replaced, Lacroix said. These are not emergency repairs, he added. They’re part of regular maintenance.
I went up to watch some of the work on Feb. 23.
The federal bridge agency is replacing bearing devices on 12 sections of the bridgebetween February and June this year. It’s part of a five-month, $3.5-million renovation that will require the bridge to be completely closed for about 15 brief overnight periods over the next four months.
Here’s how you change a bearing device:
1) Install scaffolding under and around two piers (one on either side of the bridge) where the bearing devices will be replaced.
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2) Install support beams next to and attached to the piers in question.
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3) Close the bridge to traffic between 1 a.m. and 4 a.m. Use a powerful hydraulic jack to lift a 336-tonne section of the bridge slightly (up to 10 millimetres).
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4) Reopen bridge to traffic. Motorists won’t notice the fact that part of the bridge is slightly askew.
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5) Cut out and remove the top of the pier. In this case, most of the section removed dates from the bridge’s opening in 1930 (the green part in the photo below), but the rusty bearing device on top of it had been replaced in 1980. All that rust made it less effective.
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6) Install thick new steel plates and bolt them to the structure. The top of the pier has to be removed because of these new plates. The plates will make it easier to replace the bearing device when it’s time is up in about 25 years. Thanks to these plates, next time, they won’t have to install the support beams in Step 2.
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7) Install the new bearing device between the steel plates.
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8) Close the bridge to traffic again from 1 a.m. and 4 a.m. and lower the bridge deck back to its normal location.
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9) Reopen the bridge.
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10) Return in about 2037 to replace the bearing device again.
..............................So there you have replacing a shock on the JC Bridge , Cheers ! HF&RV - Les
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