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  1. MikeDB

    An unusual retaining wall application - I think

    Have you considered using screw anchors? Cheap to install and they could be unscrewed at the end of the project. Depending on the load and the size of the anchors, it may take several anchors fanned out.
  2. MikeDB

    Guy Tower Anchor Block Modification

    Make sure the anchor rod is not the limiting factor. Use dowels to tie the new concrete to the existing. Increase the width and hight as needed.
  3. MikeDB

    Tube-Steel Tower Frame

    If this tower is in the US, TIA-222-G is the standard for the design of communication towers. The standard is an LRFD design and somewhat follows AISC 360 and ASCE 10. The standard requires a check of wind from three directions, normal to the face, on the apex and along the face. As such, leg...
  4. MikeDB

    Thoughts on Substation/T-Line Engineer

    As a civil/structural I try to stay away from black boxes or anything else with smoke in it for fear of letting it out. There are all kinds of work in the electric utility industry so what you pursue will depend on what your interests are. You could spend all day programing "what-if" scenarios...
  5. MikeDB

    Helical Anchors

    Chance makes a wide variety of screw anchors for different soils and holding strengths. Your loads are very light, so I would go with what can be installed cheapest with the equipment and tools you have available. For those loads you could bury a board with a rope tie.
  6. MikeDB

    Plate section modulus

    I would assume an effective plate width "b" equal to the width of the tire plus 12 times the plate thickness. One could use the plastic section modulus, but since this is a moving load with people involved, I would want my results to be on the conservative side. It is not uncommon to use a...
  7. MikeDB

    Thoughts on Substation/T-Line Engineer

    robertplant22, I would avoid the State of California, but there may be some good employers within the state. I like Texas and am registered there, but have not done a lot of work there. They are in the midst of another oilfield boom, which is a boom for the electric business. There is a lot of...
  8. MikeDB

    Thoughts on Substation/T-Line Engineer

    The electric utilitiy industry is not a glamorous field to work in. However it has provided an above average income and very stable employment for many engineers. I have been in the industry for 34 years and have seen some ups and downs, but not the extremes that some fields experience. There...
  9. MikeDB

    V String Insulators

    I think you will always want some tension in each leg of the V string to minimize TV and Radio interference and to reduce wear. Most suspension insulators, like a rope, don't do well in compression. The maximum line angle will be a function of the vertical load, the horizontal load and the...
  10. MikeDB

    Tower types selection

    It would be unusual to add a guy to self-supporting tangent structure for small angles. The deflection of lattice towers is not consistent with the elongation in guy wires. Depending on the conductor size, tension and support method, you may find that the conductor will be deadended at angles...
  11. MikeDB

    Deadman anchor of Guy tower

    I normally use the approach you have suggested, ie the weight of the concrete block and the overlying soil. The 20 degrees sounds conservative for a granular or cohesive soil. I am not aware of any "code" for guy anchors other than the NESC in the US.
  12. MikeDB

    Questions for transmission line design

    The dashed line represents the extension of the parabolic (or catenary) curve to determine the low point of the conductor sag curve. The weight span or vertical span is determined by the distance between the low points on the curves. Any time the vertical span is negative, it means you have...
  13. MikeDB

    Questions for transmission line design

    As transmissiontowers said, it varies a lot from one company to the next. I have worked for a utility that used all civil engineers in the transmission line group and each designed all aspects of a project. I have worked for a utility were I was the only civil engineer in the electric group...
  14. MikeDB

    Wind Turbine Foundation Design Standard

    TIA-222 is not applicable to wind turbines.
  15. MikeDB

    Mat Foundation Question

    Here is a link to where you can download bulletin 1724E-300 "Design Guide for Rural Substations". Beginning on page 483 is a design method for spread footings subject to moments. I think it will address some of your concerns and perhaps clarify it for your...
  16. MikeDB

    Strength reduction factor in ASD and LRFD?

    If you are doing a linear analysis you should get the same results either way. However, once you start to include secondary moments (P-delta or non-linear) then it does make a difference because putting it on the load side increases deflection.
  17. MikeDB

    Steel Pipe Grade and Strength

    You did not say how old the tower was. Did they have HSS when the tower was made. It is not uncommon for tower manufacturers to use a higher yield strength than standard, hopefully because they spec and receive steel at that strength level. I have seen this on several makes of towers. I...
  18. MikeDB

    Catenary Lightning Protection - Grounding Electrode

    If your overhead groundwire is effective, the grounds at the locations the overhead groundwire terminates may be more important than at the buildings. Checking the resistance of the grounding system will tell you if you need to add more runs of buried wire or if you need to add a grounding well.
  19. MikeDB

    Transmission Design books

    Try the same place you downloaded the RUS bulletin. It is all right there.
  20. MikeDB

    Hooked Anchor Bolts

    For those of you who are doing tower re-analysis, how are you dealing with hooked anchor bolts? There have been thousands of hooked anchor bolts installed for communication towers over the last 30-40 years. ACI 318-08 Appendix D, equation D-5 limits the pullout strength of hooked anchor bolts...

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