structural help for a foot bridge...

teg · Apr 14, 2016

Need some quick help. I need to turn this 20' old fire escape ladder into a 20' bridge to hold up a 180 pound graduate student. The "brackets" were used to hold it to the building. I was hoping to either use a 20 foot flat stock and bolt it to it (#1). ...or (#2) I can use 1/4" angle iron or other suggestions??? ...or (#3) use a 20 foot treated 2x6 or 2x8" bolted to this AND along the side rail. Gotta get done by Sunday!!!

It's pretty heavy but so far we can deal with it.

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bcp · Apr 14, 2016

Flat stock, maybe 2 x 1/8, run as in the red line in the drawing. Remove or disregard the end brackets.

Bruce

teg · Apr 14, 2016

bcp said:
Flat stock, maybe 2 x 1/8, run as in the red line in the drawing. Remove or disregard the end brackets.

Bruce

I wondered about that, makes sense... I can do that. So 1/8" is enough? Price doesn't matter (but weight does a little bit).

Cataclysm · Apr 15, 2016

I would add a hand rail on one side. Wet or frosty mornings carrying anything could be difficult.

Is the weight an issue because you have to haul it to the location by hand?

teg · Apr 15, 2016

We may add a rope to assist. It will only be used by the graduate student. Weight concerns are since we have to drag it across a drainage ditch. I'll have photos after Monday.

QUESTION, Should I bend the ladder before I mount the "red" band of 1/8" metal?

Gary Fowler · Apr 15, 2016

If you are going to add a truss, keep the ladder straight. I think you might be able to use the attachment legs to hold the truss in the middle if there are two of them and then just have to remove the end legs. If done right, you could then attach the flat bar to the cut off legs at each end.

teg · Apr 15, 2016

There are 3 legs in the middle, one on each end. I was going to tie the middle 3 together with 2" x 0.125" cold rolled laid flat. The ends will be hot rolled 2" x 0.125" standing on end from top down to the bottom of the end legs. Bolting everything with Grade 8, 5/16th bolts.
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teg · Apr 15, 2016

It pretty heavy but I can drag it around. It now supports my fat azz, 227 pounds. Feels much stiffer. I was second guessing the 0.125 thickness but that was perfect. I would have over built it and had a boat anchor. Thanks for the help... will have photos of it in place.

Added cross bracing since I had a little left over.

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PS. Don't want to sound like an Ad but Metal Supermarkets opened up a couple of months ago in Raleigh. They are great to buy from. I'm sure they are more expensive. It was $56 for 2x 10ft. hot rolled 2"x 0.125" and 2x 12ft. cold rolled 2" x 0.125". (The span in the middle was 10.5' so I had to get the cold rolled.)

PSS. the original frame was 1/4" 1.5" angle iron with solid rods as rungs.

Streetcar · Apr 15, 2016

I would add a deck and possibly railing .steel can be slippery when wet and fall can be painful
Until I saw last post I was going to ask size of angles