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  1. oldrunner

    500 Hz power transformer noise

    If it is a core clamping issue or a windings clamping issue, do you know if the clamping system on the windings has some sort of a hydraulic compression system? The coil stack column may have shrunk due to degradation and now is loose. Helpful if we know the age of the transformer and whether...
  2. oldrunner

    Short circuit forces used for structural design of the gantry structure

    When the electrical engineer designs the transformer coil windings assembly, the physical design is for the wind assembly not to fly apart when a fault goes through the system. For axial loadings of the assembly, he provides a force value that the tie rods must resist - say 300,000 lbs. This...
  3. oldrunner

    Design and construction of 126m tall flagpole Design parameters

    Raj6: I am the EOR on a number of tall flagpoles. https://en.wikipedia.org/wiki/Aqaba_Flagpole Your latest summary of the criteria required for the design is very good and is what I used on my “monster” poles as these flagpoles were initially called. Today the highest flag pole is the Cairo...
  4. oldrunner

    HP 15c re-release, Anyone still using calculators

    Once before I said some of these things - but my introduction to big numbers for multiplication and division was a about a 3" thick logarithm book that required looking up large numbers and just adding them together and then getting the result from consulting the book. (1961) Remember putting...
  5. oldrunner

    A mis-named forum!

    IEEE 693 concerns the seismic design of substations including transformers. The California PUC requires that transformers are able to operate during an earthquake and continue operation. The document does not consider degradation of the insulation and what condition the insulation is when the...
  6. oldrunner

    Good reference book for the vertical and horizontal distribution of seismic loads

    https://www.iccsafe.org/about/periodicals-and-newsroom/international-code-council-and-seaoc-release-new-seismic-design-manuals/
  7. oldrunner

    Using Shop Drawings as Leverage

    Could you hold the approval until the special solution is provided to you for approval as per the contract? I have had the concrete trucks sent away because the geotech and I were having an argument. Can get messy.
  8. oldrunner

    Does anyone know where I could find

    Probably should have been in your original specifications and then he could have price this detail accordingly. Might be an extra now.
  9. oldrunner

    Coefficient of Friction for Steel on Concrete

    Dik: That's the point. What is the maximum variation? The coefficient of expansion of concrete and steel are different and the concrete value is probably not what is in the back of the steel manual. Take the maximum differences in the maximum possible coefficient of expansion of concrete and...
  10. oldrunner

    Coefficient of Friction for Steel on Concrete

    Should also check the thermal stresses. Might have to let one end slide and the other end be an anchor. The COTE of the concrete is unknown because you probably don't know which quarry the aggregate came from. This is currently a contentious discussion concerning transformers and their...
  11. oldrunner

    Ancient spread sheet formats

    We started with Visacalc. It ran on a Radio Shack Model II. Later we moved over to Lotus 123. Have many files in WK1. Can open with Excel and Libre and save to Excel. The macros don't work. Have about 200 templates, many that were "production" templates, that is they would do 7 problems per...
  12. oldrunner

    Sister Full Length Joists Instead of New Beam

    Just sister on each side without going to the support. Make sure you have enough fasteners to transfer the end shear to the original joist and check the main joist for adequate shear capacity.
  13. oldrunner

    Cable try Ice loads

    It depends where in the country the cable tray is. Does your contract provide a thickness? I've worked with ice from 1/2" to 5". Had one project in North Dakota where the BR said 1/2" and the local building department said 3". I used the 3" and was chastised by the BR plan checker. But I...
  14. oldrunner

    NYC Parking Garage Collapse

    In addition: 2022 NYC building code: Basic garage load is 40 psf with a concentrated load of 3000 lbs on a 4.5 x 4.5 inch square area. Ground snow load is 25 psf and the ice load references ASCE 7. Many of the NY codes are web accessible.
  15. oldrunner

    NYC Parking Garage Collapse

    Per page 19 of the New York City 1922 and 1929 building codes: Floor Loads: "120 psf for any other purpose...." Roof loads are 40 psf. Could not find a reference to combined roof load (which can be snow and ice) and the 120 psf floor load.
  16. oldrunner

    NYC Parking Garage Collapse

    I don't understand how the last few responses have missed the previous graphic that showed a 120 psf live load. To me, a 40 psf load is typically for a residence. Also there is a factor of safety built into the design analysis - even in 1927 or 28 - but I'll have to check my dad's old codes for...
  17. oldrunner

    NYC Parking Garage Collapse

    Interesting that there would be "stacked" cars as shown in one of the pictures. Might be ok in the cellar.
  18. oldrunner

    Earthquake

    FaceEngrPE: Your building inspector is your last line of defense! Hiring your own inspector is really a good recommendation. I have suggested that to clients years ago. But good inspectors have called the EOR and saved a lot of grief. In LA an inspector called me about a 6 foot diameter...
  19. oldrunner

    Autodesk Outage

    Erasing mistakes is easier in autocad. You can't go through the tracing sheet.
  20. oldrunner

    Structural Steel building never torqued, hand tight bolts only

    From the manufacturer's web page: "Inspection after Snug Tightening Perform routine observation of the snug tightening process to verify proper techniques are followed as described in Step 1: Snug Tightening Verify that the plies in the connection are in firm contact. Verify that the...
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