Arc bridge

[Skicat]

Can anyone direct me to a source or sources on the topic of Arc type bridges? We have a 160' clear span that we intend to bridge with an Arc type bridge. Conceptually we are going to use two rolled plate girders for the arcs and use hangers to support the deck. Thanks for any help

 

[Qshake]

What type of bridge is this for? Not so sure that one should attempt this without knowing a bit of arch behavior first....and if you can't find that topic in a book from school, that's not good.

Regards,
Qshake

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[bridgedesign222]

There are quite a few more economical solutions than an arch bridge. Unless the client has specifically requested the bridge be an arch I would lean towards a more standard bridge.

 

[Zambo]

bridgedesign222,

this is a nearly 50m span which although no means large does limit the choices. I think the type of bridge proposed by Skicat is worth a look.

A box section using precast postensioned segments would be a good solution, but then the erection scheme could be expensive.

A steel truss bridge with composite deck could also be considered.

Which solution do you propose?

 

[Qshake]

I recently looked at a short span arch bridges of 250 to 400 feet to replace a series of truss spans and found it very difficult to get a solution under $5M. Fabrication is very much a large part of this.

Our company does many arches, tied arches, true arches and spandrel arches. Mostly we don't consider their use until your up around 700' spans.

However this was a special situation where existing road could not be raised over a creek with relatively high water level.

If it can be avoided, I agree with bridgedesign222, use something else.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

 

[TampaBridgeDesign]

Have you considered a steel box girder? Shipping limitations might dictate the need for a field splice. The two segments could be spliced together and then lifted as one piece onto the supports. This would eliminate the need for costly erection towers or other temporary supports. If erection tower costs aren't too significant consider using a post-tensioned Bulb-T. There have been several articles published recently regarding extending the span lengths of prestressed girders. You might want to look into finding these.

 

[graybeach]

It sounds like skicat may need to design an arch bridge for non-structural reasons. I had to design a 240 foot tied arch that could easily have been another less expensive type. But the client wanted a "signature bridge" and that's what he got.

Try to find this old FHWA publication: "Arch Bridges" by Douglas A. Nettleton.

By the way, if the bridge is a tied arch, you need to be careful with fracture critical details and with out of plane bending where the floorbeams meet the tie.

 

[Skicat]

The architect requested an arch type bridge. I would gladly design another type of bridge if the choice were mine. This arch type bridge will be designed to carry two lanes of traffic and a pedestrian walk way on either side of each lane. We have a very close relationship with a steel erector and have been working hard with them to minimize the cost of the structure. Again, I'd like to know if anybody can direct me to any helpful document about arch type bridges. I've already been researching arch behavior but nothing related to an arch bridge yet. We've got the lead time to do the research, we just haven't found any helpful resources yet. Thanks again.