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  • Users: DMcGrath
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  1. DMcGrath

    Half-Moon Baffle in culvert calculation

    I have a 48" culvert with a steel plate installed in the lower half that blocks flow until the water level is at least two feet deep before it would overflow this plate and enter the culvert. How would I go about calculating a rating table for this culvert? I don't see an option for anything...
  2. DMcGrath

    Permeability testing with oil

    Does anyone have an idea of what (if any) correlation can be drawn between permeability testing of soil (ASTM D2434 or D5084) with water vs. oil? I would think the predominant factor would be viscosity, so could a correlation be made based on the viscosity ratio of water to oil? The reason I...
  3. DMcGrath

    Fuel Costs vs. R.S. Means Data

    Any idea what the baseline fuel cost ($/gallon) is in the RS Means "Construction Cost Data" is? I am looking primarily at Section 02315 for Hauling. I presume that the estimators could not have forecast the recent meteoric rise in fuel costs when the book went to press. What I am looking for...
  4. DMcGrath

    Flow Capacity in Gravel Underdrain

    How would one go about computing the flow capacity in a gravel underdrain (Dewatering groundwater)? For an example, a constructed underdrain is 3 feet wide, 2 feet deep, has a bed slope of 1% or so, and is filled with gravel (AASHTO 57 or something like it, then topped with soil. Soil clogging...
  5. DMcGrath

    Old concrete non-deformed rebar

    At my father-in-law's house, we stumbled across an old concrete foundation with exposed, non-deformed rebar. Any idea approximately when the transformation to deformed from plain rebar was made? (1920s?) This is in southeastern USA.
  6. DMcGrath

    Water Tank Settlement

    If you haven't seen this over in the "Structural Engineering - Other Topics" forum, you might want to check it out. A recently constructed tank in Kentucky had to be removed before it was finished due to exceptional ground movement underneath.
  7. DMcGrath

    Metallic Aggregate Topping

    I have a project where roll-off garbage containers will be placed and recovered at a public convenience center station. The plans call for 2" of metallic aggregate topping to serve as a wear surface for the steel wheels on the roll-off containers. The remainder of the surface is 6" standard...
  8. DMcGrath

    Groundwater Well Removal

    We have three groundwater monitoring wells that need to be abandoned and removed from the ground to a depth of at least 26' below ground surface. They must be removed due to a future landfill on top. The wells have multiple steel casings, each with the annular space filled with grout. From...
  9. DMcGrath

    Shear Stress Calculation - Spillway

    I am looking at alternative linings (other than riprap) for an auxiliary spillway for a small embankment dam. I am thinking along the lines of a vegetated TRM. As a first look, I calculate the velocity and shear stress in the downstream section of the spillway to use as a guide for selecting a...
  10. DMcGrath

    Paint in lieu of Galvanizing

    Folks, I am not a structural guy, but I have a structural problem of sorts. At an ongoing project, I received a call first thing this morning from the GC that "the steel arrived, but it isn't galvanized." By steel, he means about 250 feet of W21x73 to be used as a pipe bridge across a creek...
  11. DMcGrath

    ASCE Considering Measuring Engineering Experience

    Looks like ASCE is considering getting into the experience verification business. http://enr.ecnext.com/free-scripts/comsite2.pl?page=enr_document&article=nefiar070115c
  12. DMcGrath

    Voodoo Hydrology

    An interesting article from Stormwater Magazine. Good fodder for discussion. http://www.stormh2o.com/sw_0607_voodoo.html
  13. DMcGrath

    72-Hour Rainfall Distribution

    I will likely soon be asked to analyze a basin and spillway for the 72-hour 1/2 PMF. I can easily find the rainfall amount for that storm, but when it comes to modeling the runoff, where can I find (or create) the 72-hour rainfall distribution for my region (central Virginia)? The drainage...
  14. DMcGrath

    HEC-RAS Channel "forcing"

    I have a project where the first 6 or so cross sections have a parallel channel configuration. The channel with the higher invert is the "main" channel and the lower channel is where the overflow will go. Can I force the program to start the flow in the upper channel section, then overflow...
  15. DMcGrath

    HEC-RAS Output Quirks

    I'm relatively new to HEC-RAS, and I have built a model of a small system to simulate the passing of a discharge (100-Yr) hydrograph of a large stormwater basin. In the first few time increments, the model computes huge flows (about 1000x what the input hydrograph, sometimes negative). After...

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