Truckee River Bridges

Solomani
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Re: Truckee River Bridges

Post by Solomani » Thu Jun 17, 2010 10:02 pm

Hi Andrew,

I need to take you up on your offer. If you get a chance could you confirm that the Bridgeport Bridge does not have ties from the arch to the lower chord of the truss? As I recall, the arch was only bolted to the braces and laterals.

thank you in advance,

John

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Andrew Brandon
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Re: Truckee River Bridges

Post by Andrew Brandon » Fri Jun 18, 2010 10:10 am

John,

You have impeccable timing! I just sold my car a few weeks ago and am presently traveling by foot or bus. :lol:

I should be able to get someone to drive me up there this weekend and get some images.
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Andrew Brandon
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Re: Truckee River Bridges

Post by Andrew Brandon » Sat Aug 14, 2010 4:44 pm

I finally made it down to Bridgeport this afternoon.
There are no "ties" in the deck beyond the diagonal flooring.
I took a few detail shots of the center illustrating the location of the support beams on the underside.
Attachments
100_5404.jpg
100_5423.jpg
100_5416.jpg
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An End To Red Domes In Our Lifetime!

Solomani
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Re: Truckee River Bridges

Post by Solomani » Wed Aug 25, 2010 8:35 pm

Andrew,

Thank you very much for the pictures. They help resolve some things I could not remember from my trip to see it last year.

John

Solomani
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Re: Truckee River Bridges

Post by Solomani » Sat Dec 04, 2010 7:35 pm

While surfing to find more info on the ore cars I found some great detail on Howe truss bridges. First a great thank you goes out to David Guise who sent me a copy an industrial archeology magazine that had a transcript of a French manuscript that gives a detailed description of materials and procedures to be used to build a 200 foot Howe railroad bridge. It may have been transcribed into French from an original description by William Howe himself. David also sent me a number of other very useful articles and cutouts in addition to that manuscript copy.

Also, I stumbled across "The Railroad and Engineering Journal" for 1890 which, as part of a series on the use of wood in railroad structures, details Howe bridges and their construction. The Journal gives a detailed part list as well for a number of bridge lengths. Most importantly for me was the drawing of a "brace block" sometimes called a hackmatac, that has a tube attached to the outside edge. This is what I am seeing in the photos of the Truckee river bridges and it is quite satisfying to find detailed dimensions for this part of the bridge and how these parts were constructed.

To find these you can go to google books and google for the 1890 journal.

-John

Solomani
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Re: Truckee River Bridges

Post by Solomani » Wed Jul 04, 2012 9:18 am

It has been quite a while since I have visited my research project but I have done some additional cad work. Next task is to create the angle blocks with the tubes as referenced in the 'Railroad and Engineering Journal'. In the mean time please enjoy a couple of jpegs of my current cad work.

-John
Attachments
closeup of arch at intersection with truss.jpg
Double Truss and Arch.jpg
Closeup of arch separation blocks.jpg

Solomani
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Re: Truckee River Bridges

Post by Solomani » Mon Jul 16, 2012 8:01 pm

Added upper and lower truss bracing, arch rods and seats.

-John
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Central Pacific Bridge - without decking.251.jpg

Solomani
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Re: Truckee River Bridges

Post by Solomani » Sun Aug 12, 2012 12:02 am

I am now largely complete on the through truss. There are still some details to change based on the latest photos I found and there will be some things I will not change unless I can figure them out.

1) Leaving the plates on the truss beams. I can't see anywhere in the photos that there are plates to connect the truss beams but on the other hand I can't really tell if there are not any either.
2) The support plates on the bottom of the lower truss should be narrower.
3) There should be about a quarter of an inch difference in the panel width from the top truss to the bottom truss to induce a camber in the bridge but for the model I will leave them even.
4) I can now see that some of the truss bolts are placed wrong as the connections between the truss beams but I can’t figure out why they are placed as they are since the look like they should be at the joints. Perhaps they are not a butt joint but a lap joint. I have not seen any evidence to think they are anything but a butt joint though so I will leave it as is for now.
5) Spiking down the rail and adjusting the length of the under rail runner timbers so that the joints will be supported
6) Details such as fish plates might happen.

Next I plan to tackle the deck truss bridge. Not too much different except for the interior lateral bracing.

-John
Attachments
view through bridge.254.jpg
Improved Howe Truss Through Bridge side view.259.jpg
Bridge below verdi Hart 278.jpg
Last edited by Solomani on Sun Aug 12, 2012 12:24 am, edited 4 times in total.

Solomani
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Re: Truckee River Bridges

Post by Solomani » Sun Aug 12, 2012 12:05 am

The "bridge within a bridge'" section that spans the area where the arches cross the lower truss is interesting.

The carpenters on these bridges did quite a bit of custom cutting to fit the deck timbers into the braces.

The bridge under-rail-runner timbers and connecting ties is something I have only seen on these bridges and one photo of a civil war era bridge. Quite a lot of cutting and fitting to get these right.
Attachments
Improved Howe Truss Through Bridge interior.257.jpg
Through truss half deck asy.jpg
Improved Howe Truss Through Bridge truss arch detail.260.jpg
Last edited by Solomani on Sun Aug 12, 2012 12:19 am, edited 2 times in total.

Solomani
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Re: Truckee River Bridges

Post by Solomani » Sun Aug 12, 2012 12:11 am

One more Photo from Alfred Hart
Attachments
bridge over first crossing of the truckee river  Hart 250.jpg

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