huangyhg

1865 bridge photo
just a cool photo of a view down the chain bridge over the potomac at washington circa 1865.
cool photo! looks like it is being guarded by union troops.
daveatkins
looking at those yankees, i wonder how they won the war. guess by that time, our boys looked even worse.
here's a side view.
awesome pics!
looks like the designer couldn't decide on a truss bridge or an arch bridge, so he used both. i wonder how long a timber bridge like that lasted. looks like pine from virginia, not exactly a durable timber. the rods would have been cast iron, so would have outlasted the wood.
here's a website with some short history of this bridge (there were many at this site) this one apparently was destroyed in a flood.
hokie66 - it's actually called a burr bridge after theodore burr; a combination arch & truss.
if you're ever in the allentown pa vicinity, go to covered bridge state park. there are two well preserved burr bridges from the 1850's - and still open to traffic.
thanks bridgebuster, that's a new one for my vocabulary. will look him up. what materials were used in the allentown bridges?
they're timber bridges. a lot of covered timber bridges in southeast pa.
we just completed a bridge much like the one in the photo. ours was a 128' single span. all timber. hs20 loading. the only steel in it was the bolts and plates at the connections.
those were some fun shop drawings to check.

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