几何尺寸与公差论坛

 找回密码
 注册
查看: 655|回复: 0

1865 bridge photo

[复制链接]
发表于 2009-9-6 22:36:41 | 显示全部楼层 |阅读模式
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.
您需要登录后才可以回帖 登录 | 注册

本版积分规则

QQ|Archiver|小黑屋|几何尺寸与公差论坛

GMT+8, 2024-9-29 06:56 , Processed in 0.035995 second(s), 19 queries .

Powered by Discuz! X3.4 Licensed

© 2001-2023 Discuz! Team.

快速回复 返回顶部 返回列表