building bridges

[bgeoffreyburnham]

Hello, and thanks for taking the time to read this....
I have a pond on my property that is about 70 ft across at the point where I would like to build a bridge. I have no idea how to begin such a project...I would like to have a slight arc to it so that is not on the water but you can see below the bridge... the depth of the water varies but I believe its no deeper than 5-6 ft... does anyone have an idea where I should begin? I don't think I can afford to hire someone to build this and am prepared to do the work myself .... and hire someone for any parts of it that I can't do but, as I said above, not sure how to design it or where to begin.. any suggestions would be appreciated.. Thanks

Geoff

[Richard A Hetzel]

This is a design project for a professional. It will be a balance between span distances and foundation requirements. I would think that the fewer foundations that must be built in the water, the better, so maybe something like a truss design can span at least a third of the distance. Such trusses can be made of wood, with careful attention paid to the connections. Question: is it a footbridge, or a vehicle bridge, and what weight of vehicle will be crossing it?

It might look like this:
http://www2.snapfish.com/slideshow/AlbumID=240253648/PictureID=5797983918/a=122549428_122549428/t_=122549428

But there are many details that need to be professionally designed. A structural engineer or a civil engineer or both would be the places to go.

[bgeoffreyburnham]

The bridge would only be for foot traffic, or possibly a lawn tractor at most...since I have no idea what professional engineer services cost, can anyone give me an idea how they charge?? by the job? by the hour? What if I don't care for the design? Will they still charge me? Any further information will be greatly appreciated.. Thanks for your time...

Geoff

[Richard A Hetzel]

Engineers will probably charge either by the hour or by the job. They may ask for a retainer before they begin. They should present a preliminary design and discuss it with you first, or better yet, show you some alternate designs, before proceeding to final drawings. They should never design something you don't like. On the other hand, you are expected to be reasonable and not expect miracles. The engineers can only do what's possible.

[bgeoffreyburnham]

Engineers will probably charge either by the hour or by the job. They may ask for a retainer before they begin. They should present a preliminary design and discuss it with you first, or better yet, show you some alternate designs, before proceeding to final drawings. They should never design something you don't like. On the other hand, you are expected to be reasonable and not expect miracles. The engineers can only do what's possible.

Thanks for the information... hate to sound so stupid but can you give me any idea what might be a reasonable price to pay for a design for a simple foot traffic bridge across a 70 ft span?? Thousands?? I just don't want to further embarrass myself by calling and expecting hundreds and paying thousands.. thanks

Geoff

[Richard A Hetzel]

The best people to answer that would be the engineers you plan to use. I would expect it to be more than a thousand, I'll say that much.

[Rich]

Several engineers that I work with allow me to provide a design for them - hand drawn or in cad - and they verify the spans, beams, etc for around 500 including a stamp. In fact we just finished a design for a small commercial project where I did all the preliminary beam, joist, and rebar sizing and details - he charged me $500 to stamp them for the building permit.
So, if you get so lucky to find an engineer that is willing to let you do that - and you have the time to put together such a package you can save yourself some money. A lot of if's I know - but may be a learning experience for you.

[Richard A Hetzel]

...and in doing so, they leave themselves wide open for state discipline and possible loss of their license to practice engineering. Many states have very strict rules governing such "services", including verifying all structural selections, keeping complete notes of their review of such plans for a period of years, and the big one: they must verify that the person who prepared the plans was not attempting to practice engineering (or architecture) without a license.

There is enormous risk in "stamping plans". I will only do it if I am paid enough to cover my time to do the extensive review, and if the person who prepared the plans was not attempting to practice without a license.

[Rich]

They run that risk anyway with the same documentation requirements. I'm talking about a structural review of a set of documents - not just wet stamping something somebody created on a whim.

[kam11]

I would like to build a bridge. I have no idea how to begin such a project...I would like to have a slight arc to it so that is not on the water but you can see below the bridge... the depth of the water varies but I believe its no deeper than 5-6 ft... does anyone have an idea where I should begin? I don't think I can afford to hire someone to build this and am prepared to do the work myself .... and hire someone for any parts of it that I can't do but, as I said above,

[Willie T]

I would like to build a bridge. I have no idea how to begin such a project...I would like to have a slight arc to it so that is not on the water but you can see below the bridge... the depth of the water varies but I believe its no deeper than 5-6 ft... does anyone have an idea where I should begin? I don't think I can afford to hire someone to build this and am prepared to do the work myself .... and hire someone for any parts of it that I can't do but, as I said above,Start here:
http://images.google.com/images?sourceid=navclient&rls=GGLD,GGLD:2004-20,GGLD:en&q=landscape%20bridges&hl=en&um=1&ie=UTF-8&sa=N&tab=wi

[rwanders]

You might consider a combination of methods that would greatly simplify your structural requirements----use a floating section from each bank using the large foam floats commonly used for marina dock sections. You could then have a much shorter arched center section built on driven pilings, wood or steel pipes, to support a nice arched center span and perhaps even a small deck for a bench or even a BBQ. Engineering the floating sections should be pretty simple and most dock companies would probably provide direction if you are buying the floats and fittings from them.