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  1. LeoSC

    Pier type footing stability

    I believe VAD is correct. In the case of an earthquake the soil around the structure may not provide sufficient support to the pier, as it could move independently of the piers. Consequently, the pier would not have lateral support. Therefore, it is necessary to tie them together to ensure...
  2. LeoSC

    Hydraulic Capacity of Back pitched pipes

    The correct way of modelling this problem is how RWF7437 or bltseattle suggested. Gravity flow is pushed by the difference in total energy, so what will happen here is that the flow will build up a head to push the flow through the pipe. This will happen even when the pipe is not flowing full...
  3. LeoSC

    uplift on spillway chute

    I suggest "Design Of Small Dams" U.S. Bureau of Reclamation as the start. If the information in it is not sufficient, it has excellent references.
  4. LeoSC

    Elastromeric bearings

    As crossframe recommended, try thread507-80259. You'll probably need to get the AASHTO codes recommended there.
  5. LeoSC

    developing runoff hydrograph

    I suggest the following document for a very useful explanation of the SCS unit hydrograph method: www.info.usda.gov/CED/ftp/CED/neh630-ch10.pdf Once you understand the method, then you can apply a computer model such as HydroCAD. What you will find in hydrograph methods, is that the...
  6. LeoSC

    Design Storm

    I believe that it makes more sense to design the overall system taking into account the concept of minor and major systems: the minor system conveys the more frequent storms, say up to a 5-year storm, and the major system is designed so that the 100-year storm can be conveyed safely. This...
  7. LeoSC

    Hydraflow doesn't compute supercritical flow

    Don't let the structural scare you, I know what I'm talking about (15 years of hydraulic engineering practice on top of 10 years as structural): In the standard step method, the calculations proceed from downstream to upstream for subcritical flow and vice versa for supercritical flow. If the...
  8. LeoSC

    Gravity wall design aides

    I design retaining walls using spreadsheets or MathCAD. In all cases, though, I have to do a trial-and-error method to arrive at the structure dimensions. Some structural manuals will give you some general ideas based on past problems.
  9. LeoSC

    Rain on snow event

    Usually the rain part on rain-on-snow events is less intense than for usual runoff calculations. This is because the large, high intensity storms occur during the non-frozen part of the year. So in effect, you should calculate the n-year storm using peak rainfall data applicable for the months...
  10. LeoSC

    How do I find stream depth given flow rate ?

    I agree with Iha. Do you have photos of the reach? The Manning equation will give you an approximation, but would not be correct in a reach where the flow is gradually variable.
  11. LeoSC

    Cynical Question

    For practical purposes, the 101-year flood is equal to the 100-year flood is equal to the 99-year flood. We must not forget that the 100-year flood is the flood that has a probability of 0.01 of being equalled or exceeded in one year. However, in most cases we don't have enough records to...
  12. LeoSC

    HEC-RAS Flood Study

    I agree with bltseattle. Most of the time the problem is due to the program not being able to converge to a solution on the section downstream of the crossing. In addition to more sections, you should check the elevations you input for the ineffective flow areas on each side of the culvert...
  13. LeoSC

    Industrial mixer support structure

    The first thing that should be done is to provide intermediate supports to reduce the beam spans. From your description, you have a "failed" support structure, which may be still working due to redistribution of the load. It is reasonable to assume that the dynamic torque will be transmitted...
  14. LeoSC

    Spectral response Acceleration Ss & S1 for areas other than U.S.

    I suggest that you contact the local university's Civil Engineering Department. The structures section likely has the required data, or data from which you could develop the S1 and S2 values.
  15. LeoSC

    Tailwater and Headwater as they pertain to Floodwalls

    gman1, For dams the headwater and the tailwater numenclature are as explained by flame. However, it seems that for floodwalls there is no consistency in numenclature. My own inclination is to call the "headwater" where the water is, and "tailwater" where I want it to go. In the case of a...
  16. LeoSC

    Bulk Density fo Dewatered Sewage Sludge

    I did a Google search, and found the following article, indicating a bulk density of 1.27 g/ml at 21% solids. www.geotubes.com/PDF/tech%20docs/sewagesludge.pdf Hope this helps.
  17. LeoSC

    Is part of a footing 3' 1" below grade OK?

    The Ontario Building Code, 1997, Section 9, Table 9.12.2.2, Minimum Depths of Foundation, indicates that the minimum depth of foundation for a foundation containing no heated space is as follows: For foundations with good soil drainage, on rock - no limit on coarse grained soils (e.g. gravels...
  18. LeoSC

    detention volume Calculation

    The storage volume of pipes and other appurtenances are physically used by storm water as it moves in the system. This is usually modelled in a sewer routing computer routine, which takes into account the slope of the hydraulic gradient. This is a similar to flood routing in a river reach...
  19. LeoSC

    Frost Line Depth Under Berms

    Generally frost depth is assumed to occur at the design frost depth, measured normal to the exposed areas. In this particular case, the soil in the berm would be expected to freeze 4' from the top and 4' from the sides. The soil under the berm itself would freeze 4' measured normal from the...
  20. LeoSC

    Pavement Design reference book

    I am not an expert, but a quick Google search suggests that the following textbook is fairly common in pavement design courses in North American universities: "Pavement Analysis and Design," by Yang Huang, Prentice Hall You may also want to try the following link...
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