In need of a bridge

[sandman2234]

A stretch flatbed such as used with prestressed concrete and steel beams for Interstate construction would be great but probably expensive.
Another option would be an extendable container frame.
David from jax

 

[em14]

Sandman
Thanks for the links and the information ... very interesting!
Leo

 

[sandman2234]

Your welcome!
David from jax

 

[mopacman]

A mobile home frame is not strong enough to hold any thing but its self up unless you do a lot of fab work on it.

 

[BTDT]

As some of you have read, my 1/2 mile road is under way, and I am now in need of a bridge. The creek is about 50 feet across, and I have been kicking around the idea of a suspension type bridge. This will be for foot traffic only, and no heavy loads, (except my big butt). I suppose I should position and bury 2 large poles on each side to hold up the cable, but time is short, and I do have 2 trees on each side that would work pretty good for now. The cable I am looking at is 1/2" or 5/8" from Webriggingsupply, for less than a dollar a foot. I do have 2 lengths of utility pole guy wire that would be long enough, but not sure if it would work for this, it is very strong though. Has anybody else built this type of bridge? Any help would be appreciated. BEAR

So sorry I didn't see this before now. My bridge is 121' long, 4'wide. The support cable is 5/8", the cables holding up the floor are 1/4". The weights (4 total) are concrete blocks bought from a concrete supplier. They were $60 each. The angle iron is the lightweight 1/8" thick by 1 1/4x 1 1/4, bought in 20' lengths. The floor is 3/4" expanded metal panels, 4x8 sheets. I use it to get my mower across creek (on average about 15' above the water). Here is the link. When you click on the attatchment, use the rotate feature at the top toward the right to rotate picture. When I submitted pics, I had them laying wrong, so they are sideways when opened. I already had the support cable (I used to work for an equipment co. and could have all I wanted) and the 4" pipe for supports on one side of bridge, so no cost there. I think total it was (in 2001) about $800.00 to build. Ask any questions.

http://www.tractorbynet.com/forums/photos/90164-bridge-pics.html

 

[tuolumne]

That's great. Designing traffic bridges is OK, but my dream has always been to make a simple long span pedestrian bridge for my own use in the woods somewhere. OP, do you have clearance under the bridge? The simplest thing you could do for a 50' span would be a king or queen post truss using the utility poles and cable. This would be more straigtforward to errect and is self-supporting - with the suspension type bridge your most difficult task will be adequate anchorage of the backspan cables...you'll need a lot of concrete or other weight hauled out. With the king post, drop 2 60' utility poles across the creek...at mid span attach a downward leg (I could run the calcs for how far down, but let's use 4' for this conversation) and provide a horizontal brace between the two. Now run your cable from one end, under the king post and up to the other end. Jack up the center from the creek, firmly fasten the cable, and release the jacks to get the cable tight. Now just nail decking on top of the utility poles. The poles act as the compression top chord of the truss, and the cable is in tension as the bottom chord. A queen post is similar, but with two downward posts at the third points. It would be quite simple in this fashion to have a much stiffer bridge than the suspension variety, that could easily accomodate a bunch of people on it, atvs or snowmobiles etc.