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Off-Site Building of Bridges

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Off-Site Building of Bridges
Posted by Track fiddler on Thursday, May 16, 2019 8:39 PM

As many of you somewhat know me,  you have also gathered my interest and fascination for Bridges.

I watched a rather interesting build of an extremely large bridge on an educational channel a while back.  Not only did they build the whole Bridge off-site,  the elaborate measures to move it, followed.

A Worldwide International Company was hired to lift the bridge, move it on-to the river and place it on two barges,  somewhat makeshift connecting the two barges together.  The room for error could not be a consideration.

This International Company moved it down the river (I do believe it was a canal) and put it in it's permanent resting place.

That is a short gist of what I watched.

The bridge was built and sitting on a huge platform by the river.  The international company came in and erected four towers on each corner of the bridge.  They simultaneously jacked up the bridge with their four towers with cables, somewhat similar to lift Bridges.

They parked a series of custom hydraulic lift semi trailers under the bridge on both ends and set this multi-million pound Bidge in motion.

At a specific time in the morning, before the tide started to rise, they had to transfer this bridge from land to the barges.  There was a problem halfway during the transfer,  the tide was rising,  the mid portions of the trailers were bottoming out.

This International Company thought of everything.  This wasn't their first rodeo.  They not only had pumps to pump water out of the barges from which they started to make them rise,  they also had pumps to pump water into the barges to make them sink as the tide came up.

To make a long story short they did get the bridge on the two barges, moved it down river and installed the bridge in place.

When they got to the resting place of the Bridge the Hydraulic semi trailers rose the bridge up, moved it into exact placement and dropped it down on the pins.

The move of this bridge looked awfully expensive.  It must be more cost-effective than building a bridge on site.  I really don't know the pros and cons of all this.

Your thoughts?

Track Fiddler



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Posted by mbinsewi on Saturday, May 18, 2019 9:19 AM

So what kinda' thoughts you looking for, TF?

My first thoughts, what, no links?, no names?,  no location? no solid information for a retired construction worker, who loves big jobs, and big job sites, to go on for a search of what you watched?  Indifferent

I watch a lot of PBS shows, and I missed this one.




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Posted by NVSRR on Saturday, May 18, 2019 11:53 AM

There are a couple reasons tjis is done

logistics.  Getting the materials to the bridge site.  Could be an issue. So can the space avaliable at the site to set up to erect the. bridge.  

Cost.  Sometimes in odd occassions it is cheaper to do that.    

Time.  The location might not be be big enough to do a parallel build.  But also the existing road or railroad can not be taken out of service for any extended period.    So a weekend shutdown is executed.  Where the old bridge is rapid demo.  The new one is slide into place.   If the abutments need to be replaced. A new set is built under the existing structure in front of the old ones.  Since bridges "float" and not secured, the contracture just as to get it lined up on the bearings.  


The most common reason is time of shut down. The new one is built next to the old one on a temp super structure, then Slide in place. 


This is common in the philadelphia area.  Traffic loadings and no good alternative routes.  I did one of the rapid replacements two years ago.  We had 12 hours to do the swap and 12 hours to get the road back to service.  The new one was built next to the existing one. Blew the old one out of the way. Before the dust settled the new one was being moved.  The old bridge was run theough a rock crusher onsite to make the structural fill to fill in the gaps where the old abutments wHere.   This was a full width 4 lane bridge with full width shoulders. 82 feet shoved 2 feet at time.  

Bridges are interesting.  No two projects are the same  it is usually a combination that determines how it is built by which method.  Time being the main driving factor

Wolfie. Infrastructure field engineer

A pessimist sees a dark tunnel

An optimist sees the light at the end of the tunnel

A realist sees a frieght train

An engineer sees three idiots standing on the tracks stairing blankly in space

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Posted by Track fiddler on Saturday, May 18, 2019 6:26 PM

Mike.... sorry.... It is kind of a dud thread I created here.  It was Mega Movers on Quest where I saw this.  It was quite a while ago so I don't remember to many specific details.

I don't know how to do links.. I'm kind of a neanderthal when it comes to computers.  I chucked my computer into a dumpster about 6 years ago and only have a phone now.  

No,  We're all good here,  let's just let-er drift to the second page.  It'll be alright.


Thanks Wolfie for the informative information.  I think you pretty much summed up all my question marks.  Interesting points you made.

Yes  TF

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Posted by gmpullman on Saturday, May 18, 2019 8:05 PM

This is common in the philadelphia area.  Traffic loadings and no good alternative routes.  I did one of the rapid replacements two years ago.

Fascinating to watch. (the "play" arrow is kind of hidden in the title)

They rebuilt a lift bridge a few years back in Cleveland. Barge floated it downriver a couple hundred feet or so to land it for repair work.

When they went to put it back they discovered that the counterweight ropes were five or six feet too short! Somebody didn't check for a revised print and they used dimensions from an obsolete print. Had to remove the bridge again (so river traffic wouldn't be blocked) and it took something like two months to have new wire rope made.

Regards, Ed

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