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Post by fivendime on May 20, 2010 16:17:37 GMT -8
This will be the section for us to explore the ideas of types and kinds of bridges that may suit our needs now or in the future.
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Post by toyrocs on May 20, 2010 17:01:44 GMT -8
Thought I would post this where it belongs ( in this new Thread). -------------------------------------------------------------------------------- Do we actually need a traditional bridge? Can some other form of structure, fulfill the same function? Bridges are a way to get from one point to another point. Usually spanning an obstruction below. Like a roadway overpass/ underpass, or creek/ river/ canyon. How about a concrete " bridge" ? By this I mean a concrete structure that is on the bottom of a stream/ creek bed. All the water flows over the concrete & vehicles drive on the concrete across the creek. The vehicle tires do not touch the stream beds natural surface. This sort of " bridge" does not "dam up" or hold water behind it. This type of bridge will not restrict fish movement across the bridge area.
This type of concrete bridge has been in use by the US BLM in various locations for decades. These bridges are used by motorcycles, ATV's,4x4's, heavy construction vehicles & even 2wd cars ! Super low maintenance, low user risk, easy to engineer/ build. I can't think of a cheaper solution, if this type of bridge will work for the proposed DNR trail location.
I have personally used these types of bridges ( on BLM lands) with M/C's & 4x4's with no problems. No stalled out vehicles due to wet ignitions etc with normal crossing speeds. The water depth flowing over the bridge is usually not critical, but would have to be calculated for a specific site/ water flow conditions . The wider the bridge the lower the depth of water flowing over it, would be a general engineering rule for these. Most stock 2wd vehicles have no problem with water depths of 8" or so, let alone M/C, ATV's & lifted 4x4's that can easily handle over two feet or more!
Hardened bridges like the above are used on many 4x4 trails in the west. Some use constrained rocks instead of concrete as the bridge material. A metal mesh " enclosure", that is full of rocks/ small boulders are used . The mesh enclosure used is similar too chain link fence material. These are also similar to the rockfall ( avalanche control) rock fences that protect cars. These types of meshes are used by WDOT on some of the Highway Mountain passes. The rock filled bridges are also used by the Tahoe National Forest as ATV /4x4 bridges , on the eastern part of the Rubicon trail. They have been durable & effective as an environmentally sound bridge.
Toyrocs
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Post by toyrocs on May 20, 2010 18:37:50 GMT -8
Here is a sample of a Railway Flatcar that could be used as a Bridge. The light weight car would be way more than enough capicity for our needs.
Flat Car Back to Top
Use Flatcars are designed to transport oversize goods and cargo that must be loaded from the side or top. Standard cargo for platform trailers includes: ocean freight containers, intermodal truck trailers, machinery, farm equipment, heavy construction equipment, lumber, plywood, steel, steel products, spooled wire, pipe and rebar. Features and Options Available in numerous lengths. Features large flat cargo surface that will accommodate virtually any commodity that is not subject to damage from the elements. Multiple tie downs. Notes Different railcar manufacturers worldwide produce a variety of models designed for different container and stacking configurations. Weight and capacity data are a function of railcar manufacturer, railcar model, and rail system requirements. The following Dimensions, Weight/Capacity, and Curve Negotiability Radius data are valid for the Greenbrier Heavy Duty Flatcar.
Dimensions Length, over end sill 85' 21/2" 25.97 m Length, over couplers 90' 61/4" 27.59 m Length, between truck centers 66' 0" 20.12 m Height, rail to pedestal support 3' 11" 1.2 m Width, extreme 9' 101/4" 3 m Width, over side sills 9' 1" 2.77 m
Weight/Capacity Light weight 60,000 lbs 27,216 kg Gross rail load 286,000 lbs 129,727 kg Load limit 226,000 lbs 102,512 kg toyrocs
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Post by fivendime on May 20, 2010 18:48:21 GMT -8
I know all to well about the rail cars. Its the single best idea in my opinion. My brother in law and father in law both work for BNSF and I just got to pick there brain about this exact topic at dinner tonight. The mentioned the longest one they have is 94' long and is about 10 feet wide, and is WAY more then capable of handling anything that can park on it as far as weight is concerned. The only problem we would have is transporting it to the site. You can easily get it to the gravel roads but through the forest is another question.
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Post by toyrocs on May 20, 2010 19:29:48 GMT -8
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Post by toyrocs on May 21, 2010 7:49:09 GMT -8
I want to clarify the use of a hardened surface (concrete or constrained rock) bridge on a stream bed, as suggested in a previous post.
Thre are many types of bridges & this one would be idenitified as a Ford Bridge. I have seen them annotated just as Bridges on Official government maps in the United States. The vehicle tires do get wet, but only contact the hardened bridge structure, not the original natural surface bottom. These types of bridges are used here in the USA & all over the world year round, including low & high seasonal water-flow conditions.
Toyrocs
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Post by The Black Jeep on May 21, 2010 10:04:32 GMT -8
I seen something in one of the post about emergency vehicles and the width of the bridge for them. Up at TSF, they rely on Trail Patrol, other 4x4s, or on foot(pack outs) to extrac people from trails. As far as fire season, emergency vehicles are usually "Brush Trucks" fire fighting rigs. Look into what Washington is using and consider the width of the bridge for them.
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Post by oltmann on May 21, 2010 10:36:18 GMT -8
I wrote in the other thread asking about the unsupported span length. I'm not familiar with the area we're trying to bridge. Is it a steep gully or a flat marsh?
I really like the idea of a hardened ford/bridge if the intention is to cross a soft swampy area. The low bridge/decks in the Naches area seem to work well too.
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Post by bchutchens on May 21, 2010 16:16:57 GMT -8
I always thought the DNR has the whole state to get ideas from and for sure has built bridges before. And for sure they have Engineers. I found just a small amount of the rules they need to go by. It was on their WA DNR web site. I thought the WAC rules are for that. www.dnr.wa.gov/Publications/fp_rules_ch222-24wac.pdf
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Post by windturbine1 on May 21, 2010 21:07:33 GMT -8
the bolt together bridge is a good idea. i put one together for a river crossing over in zig zag.
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Post by fivendime on May 22, 2010 10:51:06 GMT -8
I'm not familiar with the area we're trying to bridge. Is it a steep gully or a flat marsh? The area I believe is a marshy area that's why it has to be so long.
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Post by bchutchens on May 22, 2010 11:31:56 GMT -8
It has a bunch of wet land area on the north side of the creek. The south area could be a little steep. Thats why they need to build up the area for protection. The low bridge/decks in the Naches area seem to look good for the area. The DNR may not want wood ones because of all the wet weather.
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Post by mikeames on May 25, 2010 15:35:44 GMT -8
FYI, I was told the whole thing must be installed above the 100 year flood plain...which dramatically increases the length. The amount and height of old growth in the area makes a helicopter delivery tough if not impossible and very expensive. That means either building a full on road to truck in a big bridge which would be horrendously expensive, or coming up with a plan that uses a modular bridge that can be haul in in smaller chunks. The DNR is looking into fiberglass as it has been used at other locations by the DNR. I love the idea of a Concrete Ford Bridge. I know where there's one in use in Oregon and it's great. I think getting it past the environmentalists might not be possible...even though it truly is a good solution and really won't be a problem environmentally.
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Post by toyrocs on May 26, 2010 11:48:34 GMT -8
I did some checking today about composite/ fiberglass single span bridges. 10' wide ( total) X 90' long ( available up to aprox 120' long )$2,000 a linear foot. That's FOB ( factory). + truck shipping + site preparation / footings + transport to site + other equipment rentals during erection + other professional services?
90' @ $2,000 ft ( could be greater) = $18,000 Truck Shipping from Midwest = ? Site preparations/ materials = ? Transport on trail system = ? Rental crane? Large backhoe? = ? Volunteer manpower? = ? Professional services? = ?
I could be WAY off ( on the low side) on the Bridge costs so could you guys come up with some other ($)#s.
Toyrocs
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Post by oltmann on May 26, 2010 12:12:04 GMT -8
I think you slipped a zero there, reads like it should be $180,000?
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