Pre-Fabricated Pedestrian Bridge 3

[STrctPono]

I'm working on a design-build job and we are designing a shared use path with a 550 foot long bridge. We are going to go with a pre-fabricated steel truss bridge. Spans are 125, 150, 150, 125.

We are responsible for designing the piers and abutments. I need to reach out to some pre-fabricated steel truss bridge manufacturers and start working through some of the details with them. I've got Contech, Bridge Brothers, and ACROW on my list. I know ACROW extremely well for all the work we do with them for temporary vehicular bridges but they are lacking a bit in the aesthetics category. Do you guys have any more experience with other manufacturers? Any good things to say about working with them?

As a side note, the discussion of using an FRP pedestrian bridge came up. I don't have any experience with FRP bridges but I don't think there's a chance that they're going to get a 150ft span to work. Everything I see is mostly under 100 ft.

 

[oldestguy]

Since there surely are costs involved here, I question that this post is suitable for our site, specially when the names of various firms are listed. We don't promote anyone.. Specific structural details, but names???

 

[Guest090822]

You didn't specify what kind of bridge, but for truss type check "Big R Bridge" out of Colorado. I just did a project with a few 140' spans. The trusses come in 3 pieces. We assembled the truss in a parking lot and then lifted and set it in place as one. You can also try "U.S. Bridge" out of Ohio - used a 125' truss from them. Many moons ago there was the Steadfast Bridge company out of Alabama, but they may have been bought out by Contech now. You could go the route of having custom design, but I'd be careful. I've been involved in a handful of them and some of the designs were not that great as the firms didn't really understand bridge design too well. The larger commercial players that I mentioned are like the "Walmarts" of pedestrian bridges. Their designs are very well thought out and the connections for the pieces seems well planned as compared to the small firm custom designs where they overthink everything.

I just remembered "Mabey Bridges" too - I think they are a British company but do make things in the U.S.

 

[PEinc]

I also did a 240' long pedestrian bridge in NJ with Big R. Here are a few photos. I believe that most, if not all, of the companies (except Big R and Contech) mentioned supply "Bailey Bridge" style, panel truss bridges. Acrow does have beam bridges also, but probably not in the span lengths you need.

http://www.PeirceEngineering.com

 

[STrctPono]

Rick/PEinc,

Thank you for the insight! I'm looking at either a bowstring or pratt truss. I was not aware of Big R. A quick look into their website and it appears that they have been acquired by Contech. It's also good to see that BigR can do longer spans as well since that option is not off the table on our project.

I just looked up Mabey bridges and they seem to be part of the ACROW family. The whole modular bailey bridge system is really nice for cost, ease of installation, and how quick you can get a bridge up and operational but we will lose points in this competition on the aesthetics category. It may still yet be our choice as cost is the biggest factor in the competition.

@oldestguy. I don't claim to be an expert with eng-tips rules but there are threads all over the structural forum were someone is looking to purchase a proprietary structural analysis program and is seeking advice from others on what to choose. How is that any different than what I am doing? Costs associated either way.

 

[PEinc]

Acrow fairly recently bought Mabey's truss bridge division. The Mabey and Acrow truss panel bridges looked extremely similar, maybe identical. Acrow's trusses were made in the USA, Mabey's were not US-made.

http://www.PeirceEngineering.com

 

[STrctPono]

Thanks PEinc!

 

[bridgebuster]

@PEInc - is that the Atlantic City Expressway?

 

[PEinc]

Yes. Pleasantville Toll Plaza.

http://www.PeirceEngineering.com

 

[bridgebuster]

Thanks PE, drove under it plenty of times.

 

[MIKE_311]

that's going to be a big truss. I have a similar size pedestrian bridge in working on, and we ended up going with a three girder system. The truss needed top laterals and the client didn't want that tunnel feel for a shared use path for such a long distance.

 

[bridgebuster]

@MIKE 311 - how long was your bridge? There were 5 recent projects in NYC involving 6 ped bridges; they're all tied arches. The longest is about 270'. The others are in 150' range. I guess arches are the "ped bridge du jour" in NYC these days; used to be cable stayed.

 

[MIKE_311]

It's still in design, its 4 span, 390'. 62.5'-132.5'-132.5'-62.5'. Client didn't want a truss, tied arch or cable. From The EA, they didn't want this bridge to be seen above the tree canopy. The park setting required simple.

The other structure types are flashy but this is its own simple yet elegant appeal to it.

 

[bridgebuster]

Thanks Mike, sometimes simple is better than flashy.