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Do you get to design bike trails (or rail trails) at all, or is that something handled by a private company?
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Jul 31, 2009 22:32
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Cichlidae posted:I design those, yes. They're generally 10 feet wide with two lanes, and the MUTCD has a special section dedicated just to them. Bike paths are super easy to make, since the speeds and loads are so low relative to what the tracks are designed for (trains). How long are they designed to last? Just curious, the trails out by me are all concrete so I assume they will last, essentially, for forever.
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Aug 1, 2009 02:15
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Best thread ever, and thanks for answering my bike trails question wayyy earlier. So you want to learn about our cities eh? Welcome to Lincoln, Nebraska. 250,000 people and no traffic engineer (fired ours cause of budget cuts about a decade ago). As you might be able to predict, traffic is kind of a mess in our humble little town. It's Nebraska, so we have no hills or anything crazy like that (although to the west of the city there is a fairly major floodplain and lots of railroad tracks) so you'd think it would be easy Of course, there are a few issues. As the screen shot here of google maps should be fairly clear, there are no freeways or expressways through the city.  I-80 runs to the very far north. Highway 34 cuts directly through the middle of the city and is a congested mess that can't be widened due to historical buildings and the like. You might also notice there are only two direct north to south routes that go through the entire city - 27th street and 84th. 27th street is 2 lanes in most of the south end of town due to a historical district/rich person neighborhood. Highway 2 is covered in stop lights and is routed directly through downtown Lincoln/residential streets. The homestead "expressway" has 5 at grade stop lights on a 65mph "expressway" All you people living in big towns, at least you folks HAVE traffic engineers. Please come work pro bono and fix my city or at least fix this intersection:  http://maps.google.com/maps?f=q&sou...006968&t=h&z=18 that's 3 4 lane roads meeting. There are stop lights at warlick/old cheney, old cheney/14th and old cheney/Brook ridge circle. Yield signs/stop signs where 55w and 14th street merge onto warlick. It's a god awful mess the city can't fix because they literally have no one capable of fixing it. /sob adaz fucked around with this message at 07:47 on Aug 5, 2009 |
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Aug 5, 2009 07:37
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Random but was driving through Iowa earlier this week (flooding,etc) and wondered - are there specific formulas for determining how much water/flow rate it takes to flush away an interstate? Are they designed to handle a certain amount of water coming across the road?
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Aug 27, 2010 01:07
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Cichlidae posted:It depends on the current state of the road. One embankment might wash away because it was built on clay, the one next to it might be fine because it's all gravel. Bridges and culverts, though, are designed for specific flows. We design our bridges to let 50-year floods pass under the bridge with some freeboard, so it takes a 100-year storm or more to really damage them. Another critical factor is scour, which is when the water washes away all the sediment around the abutments and causes the bridge to collapse. The scour line is some distance below the streambed (it's the bottom of the footing, if I'm remembering correctly). Does that depend on the length of the bridge? I mean, are all interstate bridges required to withstand a 50 year flood but longer/more critical bridges might be designed for bigger floods? I remember in 1993 during the huge floods in the midwest driving on the bridges over the Missouri/Mississippi where the water was hitting the bridge deck and that was way over 100 year flood levels. However the jist of what you're saying is the interstate isn't designed, at all, to withstand any specific amount of water or flow rate coming over it, it's only the culverts/bridges that might have specific codes.
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Aug 27, 2010 02:32
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| # ¿ May 3, 2024 12:15 |
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Cichlidae posted:Yeah. We try not to build things in flood plains, but there are always exceptions. Most bridges these days are built with 30- or 50-year lifespans, because it's assumed they'll either be functionally obsolete or structurally deficient at that point and need to be replaced. No point in designing a bridge to withstand that 500-year storm it'll never see, right? Fair enough, one of the big problems in Nebraska is a lot of the interstate bridges are hitting their lifetime limits and have to be replaced and nobody has the money to replace them. Since all these were "new" back when the interstate was being built I guess they have to be rebuilt to the standards or they aren't qualified for federal money. It's just kind of interesting - I'm sure in Connecticut the amount of bridges you have over interstates or interstate bridges that are over 50 years old you can probably count on one hand since they have either been replaced or expanded over the years. Out here I-80 is a lonely strip of pavement that hasn't been touched for decades other than the occasional resurfacing (and some parts have only been resurfaced once in 60 years). e: One of those things you'll never have to deal with but as an example it has taken 10 years to make I-80 between Lincoln and Omaha (About 45 miles, one major river) go from 2 lanes each way to 3. The state just doesn't have the money to spend on the huge costs it requires so they just have to slowly build it up, not like there is anything in the way but farmland. adaz fucked around with this message at 02:51 on Aug 27, 2010 |
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Aug 27, 2010 02:48
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