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  1. 655321

    Exposed pipe in creek stabilization options

    Thanks, it would defiantly be a bad day if the pipe broke, but I think we have time to weigh our options. I like the articulated block idea and I'm looking into it.
  2. 655321

    Exposed pipe in creek stabilization options

    A large water main has become partiality exposed in a good sized creek due to bank erosion and channel movement. Its happened over the last 40 years since it was installed. I’m looking at ways to add cover to protect the pipe and stabilize it. Riprap, sheet piles and gabions have all been...
  3. 655321

    Storm Sewer Systems and the Energy Grade Line

    In my preliminary designs I also use manning's formula, I match crowns, and I try to stay over 1% with my pipes. I've also found that it almost always works when I run the HGL. Our Design criteria specifically says no pressurize pipes (unless we have a really really good reason), so we do it...
  4. 655321

    Storm Sewer Systems and the Energy Grade Line

    Thanks cvg. do you think this requirement was developed only to mitigate the effects of debris and blockages or could there be some other issues it relates to? Just trying to understand the motivations and thinking behind the guidance. Our local drainage manual is under revision and this...
  5. 655321

    Storm Sewer Systems and the Energy Grade Line

    Many jurisdictions have a storm sewer system design requirement that the calculated energy grade line be below the rims of manholes and the throats of inlets. This is in additional to the requirement that the hydraulic grade line be 2' (or something close to that) below rims and throats, which...
  6. 655321

    Spring Cans - Hot Settings

    I have several spring cans that I will need to verify the hot setting, trouble is that when its hot, I can't get anywhere near the pipe or the cans to look at them. Any ideas how to do this?...Looking for an alternate to setting up cameras. I can cool them back down later and check what...
  7. 655321

    Purpose of Double Manhole Lid

    According "The Electrical world, Volume 32, page 72", dated 1898 (found on Google books), Its not practical to seal manhole lids watertight when they are exposed to vibration and impacts of street traffic. So the outer manhole is intended to take the impacts of traffic, while the inner manhole...
  8. 655321

    Purpose of Double Manhole Lid

    Thanks Bimr, I do know exactly whats under the lids, deep concrete vaults containing cables and splices and sump pumps. See, what I'm trying to figure out is why the original designer used double manhole lids. You can order a watertight and locking frame with a single cover. After doing more...
  9. 655321

    Purpose of Double Manhole Lid

    There's actually a number of manholes of varying size and depth containing a number of different power and control cables, they're located around a power plant. The old drawings show a detail for the ring and "double" cover (an inner cover and outer cover). The detail references a "Flockhart...
  10. 655321

    Purpose of Double Manhole Lid

    There is an electrical manhole with a cover frame designed for an inner and outer solid cover, one below the other. The inner cover is locking. Does anyone know what the purpose of using the double manholes?
  11. 655321

    Is a new Geotech Investigation needed.

    The new units are pretty massive, they weight about 550 Kips a piece. I've come up with 7 ksf max contact pressure applied on one side of the foundation, and less than 1 ksf on the other. Its about 3.5 ksf with the current arrangement (evenly distributed).
  12. 655321

    Is a new Geotech Investigation needed.

    We have a couple of 30-year transformers with pads that are 4.5' deep, 10'long and x 20' wide. We are replacing the transformers, but want to reuse the pads. The new transformers are about 20% heavier, and has its center or gravity shifted off the center-line in the short direction of the...
  13. 655321

    Earthwork Calc w/ variable shrinkage

    Since Civil 3d gives you the total cut / fill volumes…what you need to know is the volume of cut from 0”* to -18”. You could do this by generating cut/fill ticks, drawing polylines around the cut regions to get the area, estimating the average depth of cut (with 18” as your lower bound)...
  14. 655321

    Extreme Flood Event Erosion

    How could you estimate the potential for an extreme flood on a major river to erode the soils in the overbank and floodplain? Thank you.
  15. 655321

    Heavy Haul Spec

    No, were not responsible for local roads. The company I work for owns the roads in on-site. These particular pieces of equipment will be shipped up the river to us and delivered to a nearby port. From there it will brought in pieces to the staging area on site, where finally it will be...
  16. 655321

    Heavy Haul Spec

    Does anyone have suggestions how to write a max wheel load spec for a heavy haul move (contract to move transformers at a power plant)? I'm concerned about damage to pavements and underground pipes/conduit. Tranformers are about 100,000lbs filled with oil, and will be crossing a mish-mash of...
  17. 655321

    liquefaction Boundary

    How would you explain, conceptually, to a "non-geotechnically" trained civil engineer what occurs in saturated soils at the boundary between dense (non-cohesive AND non-liquefaction prone) soils; over, looser (non-cohesive) soils that are susceptible to liquefaction? For example: -what keeps...
  18. 655321

    Street Drainage Flume Entrance Loss

    I'm trying to determine the capacity of a concrete drainage flume at the end of a reverse-draining cul-de-sac. (A cul-de-sac that drains to the back.) I've calculated its capacity as an open channel, but I don't think that adequately represents the situation since I'd expect losses at the...
  19. 655321

    Aircraft Hangar Apron Grades

    Thanks CarlB, Here's a excerpt from FAA Advisory Cricular 150/5300-13, Chapteper 5, Page 54: "To ease aircraft towing and taxiing, apron grades should be at a minimum, consistent with local drainage requirements. The maximum allowable grade in any direction is 2 percent for Aircraft Approach...
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