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  1. jrbaus

    Minimum design actions to AS4100

    sdz - if you read the preface for the 2012 commentary you will see it mentions to delete the wording "for the minimum size of member" of clause 9.1.4. It was changed to reflect the intentions of the original panel I believe (I found a publication stating this but cant for the life of me...
  2. jrbaus

    natural frequency from eigen analysis

    Its been too long since I took a look at dynamics from first principles (due for a refresher), but I can remember solving eigenvalues using Sturm's method. I have attached my algorithm from my university days which is implemented in Matlab. I can email m file if it is more helpful. I believe...
  3. jrbaus

    critical flange for continuous beam using AS4100.

    geopat, interesting post. Has me thinking (I now understand exactly what it is you are asking).... Thanks KootK & Trenno for your input.
  4. jrbaus

    critical flange for continuous beam using AS4100.

    If the outer supports act as vertical supports only, with tension throughout the entire length of the top flange, I would treat the outer segment as a cantilever with the outside support considered as a load at or below the shear centre of the section: alpha_m = 1.25 -> 2.25 [Table 5.6.2] kt =...
  5. jrbaus

    What would you consider the unbraced length of this double angle to be?

    Sorry, Just seen slickdeals post with list of references. Most appreciated. Jake
  6. jrbaus

    What would you consider the unbraced length of this double angle to be?

    KootK, Interesting point you make there. I would appreciate any references you might be able to point me towards. All the angle cross bracing sets in large industrial structures I have reviewed used tension-only members in their models.
  7. jrbaus

    What would you consider the unbraced length of this double angle to be?

    What happens if you analyze only the member that is in tension and neglect the compression member? I typically neglect the compression member in bracing sets comprised of slender members such as angles. In saying that, you need to ensure you treat the members as "tension only" in your analysis...
  8. jrbaus

    Safety Factor For Lifting Lugs

    For ULS designs in Australian refineries, I have seen a live load factor of 1.5 in combination with a dynamic load factor of 2.
  9. jrbaus

    Coefficient of drag for Rectangular Hollow Sections

    Another extract from AS1170.2 (see attached), however this time for rectangular prisms. For an aspect ratio of 2:1, I calculate a Cd of 2.78/1.6 depending on wind direction. Regards Jake...
  10. jrbaus

    Wind loading spreadsheets

    medeek - nice calcs on your website. Very impressive. For what it is worth, I have found the avoiding vlookup functions in your spreadsheets greatly improves their accuracy since they rely on the data being sorted. Instead, use index(XXX,match(XXX,XXX,0)) which will work regardless of the data...
  11. jrbaus

    [Australia] Uplift in Shallow Piers

    asixth, jayrod12, thank you for your comments. The 20-30 kPa in my previous post for undrained shear strength did not have any FOS applied so will correlate roughly with the 10 kPa shaft adhesion that you mentioned. For residential footings, Australian Standard AS2870 Clause G5.3 states "No...
  12. jrbaus

    [Australia] Uplift in Shallow Piers

    Inspired by a recent post on this board, I would like to ask for some more opinions regarding "post/pole" and bored pier footings. In my location (Queensland, Australia) it is common to see houses and portal frame buildings supported on shallow pier footings. Mostly the soils I deal with are...
  13. jrbaus

    Post Hole Foundations

    Assuming these are analogous to "post footings" typically used in Australia where steel posts are cast into bored piers to support residential construction (i.e. clad frame buildings elevated above ground level) I will share what I have found from my research: 1) cantilever action can be relied...
  14. jrbaus

    Curved Rafters

    Indeed it is an interesting subject - one which I don't yet fully grasp to be honest. I remember deriving the shear forces, axial force and bending moment equations for a catenary shaped beam in university and had a few big 'aha' moments when it all came together. I suspect the same would occur...
  15. jrbaus

    Slope deflection method

    @Zaes1980: pygal looks nice. I will keep that one in mind to for next time and might see how well it plays with pyqt. @RFreund: I gained a lot of good insight into python programming during my university days where I took an introductory course. I did get started with Python before I had any...
  16. jrbaus

    Curved Rafters

    Trenno, Like 90% of what I have been quoting on lately - I still haven't got the green light from the client to do the detailed design. I managed to undertake some preliminary member sizing using the literature you put me on to (thanks for that). This allowed the client to get an estimate to...
  17. jrbaus

    Slope deflection method

    Thanks for the feedback. Agree Python tools are good for repetitive tasks. I have a few small tools put together with PyQt however always looking for better ways to solve certain problems. Your matplotlib output is very clean, gives me a some ideas to consider next time I need to show some...
  18. jrbaus

    Slope deflection method

    Zaes1980, I am not familiar enough with this method to comment on where the error lies, however I would like to commend your efforts with Python. May I ask what libraries you used to produce the graphic output? That is quite impressive. I have thought of doing something similar in Python...
  19. jrbaus

    Stub Column For monorail

    I would be concerned about lateral deflection. Some client sites I have worked for require an allowance of 10% of the rated capacity for lateral loading which in your case would result in considerable deflection unless you have some method of providing lateral restraint to the top flange and...
  20. jrbaus

    Von Mises Yield Criterion

    Most FEA and working stress checks I have seen/undertaken on steel structures compare the Von Mises stress to Fy/FOS where Fy = yield strength and FOS=1.5. The FOS of 1.5 came from the old (Australian) steel design code before ultimate limit state was adopted. A FOS of 1.075 is very low. That...

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