Building a Bridge

[Andy Hoyt]

Lots of ways to skin this cat.

What's the budget? On the cheap - Nice but, but geez! - Sky's the limit.

Pair of waders might be easiest.

[Ben Grunow]

Rob- I would use pressure treated PSL's or steel depending on your level of comfort with steel. I built a bridge using steel and we bolted 3x12 PT to the top and nailed 3x12 boards across for the deck. 2x would work but the span should be engineered. THe span tables from the manufacturers should be all you need. Look on the timberstrand, georgia-pacific, or who ever supplies engineered lumber to your local lumber yard to see them. THe lumber yard salesman should be able to steer you through this as most of them have computer programs from the mfgrs of the engineered lumber that enables them to size joists and determine spacing for residential jobs.

BTW, make sure to pour some solid (thick and below the frost line if there is one where U live) footings and head walls with anchor bolts. Is there any chance that the stream could wash the bridge out during high flow? Just thinking. Good luck.

[Paul Downes]

Rob, here is another bridge design to consider.
http://pacifi.ca/home.html
this design looks really interesting and somewhat simple to build. I have been considering building one on a friends property so he can get into his woods across a creek. It's a perk for letting me hunt his property.

[Dick Strauss]

Rob,
A suspension bridge might be the least expensive route. In addition, the suspension cable can also be used as a hand rail. Many farmers (who allow snowmobiling across their property) have allowed the snowmobile assoc to build these across the rivers and streams. I know of many that span 100' or more across the Winooski River in Central VT between Burlington and Montpelier. Obviously if they can be built to span 100' and hold a snowmobile alolng with lots of snow/ice, they should be safe for a few people at a 24' length.

[Roger Bell]

If this is to be a footbridge for your children, stop and take the time to develop an adequately engineered design. This is especially the case if the creek is such that structural failure might result in drowning. If this is the case, then this is not a question that should be directed to woodworkers or building contractors, but to a licensed structural engineer.

You absolutely must factor in snow load for your area as well as the dead load of any decking or railing. You might also consider adding a handrail on at least one side. Resist the temptation to cobble something together. Before everyone starts rolling their eyes and muttering, I suspect that a single hour of consultation with an engineer will likely get you what you want as long as you keep it simple.

If there is a National Forest near you, contact their engineering people. They specialize in constructing pedestrian footbridges. Their structural engineers will likely know the snow loading and will likely have quite a few stock plans available incorporating a variety of materials, including logs, dimensional lumber, etc. If you ask them nice, they might be willing help you refine your ideas and come up with something that is consistent with simple and cheap.