Pontoon Bridges, Miracles Of Engineering!!

[JPK Huson 1863]

It seems they used them as wharfs fairly frequently, which would make sense? An awful lot of time would go into constructing a wharf, if you think about it. Found one where it seemed to be half permanent wharf half pontoon, pretty cool. Must have save a huge amount of time- and I just thought of something! Our docks on the lake in Maine have to be aken in each year or the ice breaks them up- it's a chore. Plus of course have to be replaced regardless every 7-10 years. Wonder why no one has come up with a pontoon affair since these are all what amount to temporary?

One of these had a ton going on, so I kept picking it apart.

James, with a camp across the bridge, a steamer ( gunboat? Transport? ) and something floating in the water

And then another landing, pretty cool -look at this one! The right leg has 2 boats at the end taling the stress for what, 25 or 30' of span? Or is this bridge unfinished and those long poles are intended to be pounded into the riverbed? Still- no pontoon for that length and supporting a horse? Also became distracted by the man who got that horse out on a pontoon bridge and convinced it to turn around. They don't like bridges on the best day, bet they looked at pontoons funny.....

SOOO much going on in this broken photo, even with bits missing! PLUS we get the name pf yet another steamer/transport, very cool. " George WE......" ( Or " WA ? " in which case it's easy )

There's the bridge and ships and what is occurring on the ships and a c amp and a wagon train....... I'm in love with this whole photo.

I ' think' this was titled " magazine wharf ", seems an awful lot of camping going on right under the nose of a magazine wharf but ok........

 

[John Hartwell]

The engineering expertise developed during the ACW had very far-reaching influence. I was once shown a WWII period Imperial Japanese Army manual for Engineers that had illustrations of bridges and trestles lifted directly from US manuals of the 1860s. I wouldn't be surprised if the text was cribbed as well.

 

[Ray Ball]

It seems they used them as wharfs fairly frequently, which would make sense? An awful lot of time would go into constructing a wharf, if you think about it. Found one where it seemed to be half permanent wharf half pontoon, pretty cool. Must have save a huge amount of time- and I just thought of something! Our docks on the lake in Maine have to be aken in each year or the ice breaks them up- it's a chore. Plus of course have to be replaced regardless every 7-10 years. Wonder why no one has come up with a pontoon affair since these are all what amount to temporary?

One of these had a ton going on, so I kept picking it apart.

James, with a camp across the bridge, a steamer ( gunboat? Transport? ) and something floating in the water

View attachment 58240

And then another landing, pretty cool -look at this one! The right leg has 2 boats at the end taling the stress for what, 25 or 30' of span? Or is this bridge unfinished and those long poles are intended to be pounded into the riverbed? Still- no pontoon for that length and supporting a horse? Also became distracted by the man who got that horse out on a pontoon bridge and convinced it to turn around. They don't like bridges on the best day, bet they looked at pontoons funny.....
View attachment 58246

View attachment 58244

SOOO much going on in this broken photo, even with bits missing! PLUS we get the name pf yet another steamer/transport, very cool. " George WE......" ( Or " WA ? " in which case it's easy )

There's the bridge and ships and what is occurring on the ships and a c amp and a wagon train....... I'm in love with this whole photo.

View attachment 58242
View attachment 58245

View attachment 58241

I ' think' this was titled " magazine wharf ", seems an awful lot of camping going on right under the nose of a magazine wharf but ok........

JPKHudson,
Thank you for posting these outstanding photos. I looooove seeing these. I have some insights which you might find interesting. The long poles you mention in pic #2 are called Birago Trestles. They are an important part of the bridge equippage. Most people do not realize that the most difficult portion of the bridge to construct is often the approaches. Getting the banks of the river where the approach exists to match the level of the crossing sections can more than a little tricky. The same is true of shallows near shore. There may not be deep enough water to allow for adequate displacement that will support the ponton. In that case a trestle or other support that reaches out to the floating pontons is required. The Birago Trestle is a brilliant invention that allows the bridge height to be equated to the approach by the use of a set of chains which can be raised or lowered as needed. They are temporary and very portable, although I do understand that if not assembled with care, they are prone to malfunction.
The tenting is also a very common thing near a bridge. A bridge of this type- or a wharf, requires constant upkeep and maintenance, not to mention supervision. Those things are the duties of the Engineers and they would have been stationed there as long as the bridge was in place. If a section should fail, or be potentially misused/ damaged, the results could be catastrophic to the mission, not to mention the personnel.