I got this in the Milwaukee Road FB Forum.
You know this looks somewhat similar to the pictures from China of their high speed rail viaduct building machine.
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Note that that is actually a short panel (spanning a bent). The machine is capable of placing the longer span girders as well…
There is a very similar picture of a Canadian equivalent in a recent thread here.
One of the modern equivalents is the Rcrane, which was effectively used in rebuilding the NYC-to-Albany corridor to high speed under traffic. It is capable of handling 82’ girder panels built to Cooper E90 rating.
They used to have an extraordinary video with details of that project, showing how the internal worked… which I no longer find on their site – it may still be on YouTube or Vimeo.
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This?
Lethbridge Alberta 1905 Bridge by Edmund, on Flickr
Click image to enable enlargement.
Regards, Ed
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That.
If I understood their website correctly the Rcrane works only when replacing bridge spans as the Rcrane uses the railroad track to move forward.
During construction of the high-speed rail line in Taiwan the construction companies used different but similar machinery to place about 900 tons precast concrete girders bridging empty gaps. I think it comes closer in functionallaty to the OPs crane. Here is a video:
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As I recall from the Empire Corridor video, the system worked a bit like the boom of the old Warner & Gradall; there was an inner truss that telescoped into the outer truss, and did the panel launching. It could run extending the other way to pick up a panel from a trailing car. I don’t remember if it was arranged to support the outer end of the main truss like a Paola di Nicola crane.
That’s a damn good video. Obviously the Chinese have also improved the practice of self-launching long spans, and I believe constructing some or all the viaduct piers as well. A very good precedent, I think, was the approach used to build the Millau viaduct in France, which could be an alternative to the typical Chinese-style concrete-column viaduct structure.
Seems like you need a lot of space for that around the construction side. Curious what they would do in a constrained area like over a city?
I think you are mistaking the construction yard for the actual placement of the voussoirs on the supports. They note in the video that the casting is done directly adjacent to the line being constructed ‘because of the safety concerns inherent in 800-ton segments’ but that is only at the site where the sections are being fabricated. The actual construction ‘width’ required is only marginally outside the finished clearance of the deck structure (mostly due to the portal-frame construction of the Paola di Nicola crane) and there is no protrusion below finished deck height, so I don’t see what your concern is ‘in crowded city sites’.
It was not stressed in the video but the segments were ‘transported’ a considerable distance over the completed viaduct structure – possibly several miles or more – to be placed. This is clear from at least one scene in the video (see 10:50ff)
There was an OSHA report about problems with one of these cranes used on a project in Ohio in the early 2000s:
https://www.osha.gov/sites/default/files/publications/shib050106.pdf
The general consensus was that care needed to be taken to follow the manufacturer’s instructions and not cut corners. Looking more closely – yikes! These things need positive anchoring prestress, and at a minimum that should be Superbolted if not hydraulically prestressed a la Doxford! That’s a cautionary tale for those who would ‘stock’ multiple cranes and TLMs for organized large-scale HSR construction here (as I have advocated).