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Recent content by ldeem

  1. ldeem

    ratline design

    I used to do quite a few of these (we also used the term rat line on site). Watch your sag specification to make sure contractor follows your design. Contractors always seem to want to pull these tight, thinking that is better, but it will drive your anchor point loads way up. I don't know...
  2. ldeem

    PEMB Splice Modification

    Try to stich weld the beam reinforcing. That will help reduce costs. Provide a detail on beam reenforcing splice (I usually do full pen welds) Think about making the bottom plate wider than the beam flange. This will avoid a difficult overhead weld. 3/8" plate is pretty heavy for column...
  3. ldeem

    Submerged plate design

    How wide of a plate strip are you using to calculate the composite section properties? I have always found this to be a challenge. When I have designed similar items I lean toward a narrow strip and then look at plate bending between stiffeners. In this case, assuming it is a critical item to...
  4. ldeem

    Von Misses and Local Buckling

    Make sure you read up on how STAAD is showing results. You can see a Von Mis stress in results but that is a calculated stress RESULT. I tried to find a link to the STAAD technical reference but couldn't. The value in the results has nothing to do with any calculated allowable stress. In my...
  5. ldeem

    Von Misses and Local Buckling

    I am not sure what you are designing but plate buckling is a complex subject. I typically use Blodget to get an idea of buckling stress and then stay well away from that.
  6. ldeem

    Weathering Steel vs HDG

    Thank you to everyone for your replies and sharing your experience. Client isn't sounding too keen on the idea right now. Mainly because it is nearly impossible to keep structures cleaned off in the field. I am still going to rough out cost differences and will update the thread.
  7. ldeem

    Weathering Steel vs HDG

    I work in mining and am in the process of designing a replacement 90' truss. This is a limestone facility and the truss will be part of material handling system. Corrosion is a significant problem at the site. In the past we have used a lot of HDG but that can be hard to do on larger trusses...
  8. ldeem

    Tourist submersible visting the Titanic is missing

    TugboatEng regarding the epoxy joint. My first thought is the differential movement of the Ti and CF hull due to different thermal coefficients and E would have to be taken in the joint. Either creating large stresses across the joint surface or (if the epoxy is strong enough) large forces in...
  9. ldeem

    Tourist submersible visting the Titanic is missing

    Regarding liability in one of the videos the CEO talks about working with Boening on the pressure hull. I wonder how long before they try to distance themselves from this fiasco.
  10. ldeem

    Tourist submersible visting the Titanic is missing

    I was looking around and found this article on the carbon fiber hull maker. https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters Link Quite a read, delegated design and six weeks to do it. I assume that is design and fabrication. Now I am...
  11. ldeem

    Tourist submersible visting the Titanic is missing

    When I read about the pressure hull construction (Ti end's with carbon fiber composite middle section) I had a gut reaction this is not a good idea. Two different materials, differing modulus of elasticity and thermal expansion coefficients would make for a very challenging analysis. Then...
  12. ldeem

    Old to new foundation

    I don't do a lot of work like this but when I do I try and use smooth bars to connect between foundations. My thinking is I want to prevent differential vertical movement and transfer some out of plane loads. I also want to avoid vertical shrinkage cracks past the dowels. By using smooth dowels...
  13. ldeem

    What is the antidote for sloth and torpor in life ?

    It looks like I missed the entire point of the original post. To clarify I am not suggesting use of prescription drugs as a cure all. My point as that we can think of ourselves as complex machines and apply engineering thought process to improving ourselves. One of many ways to approach this...
  14. ldeem

    Invoicing and Accounting Solutions

    I am a one-man operation myself and used to use Quickbooks until it went to subscription then I changed to Quicken but now that has gone to subscription so I am looking for another option. Right now I am planning to give Bookkeeper a try. I mainly need to make invoices and track expenses for...
  15. ldeem

    What is the antidote for sloth and torpor in life ?

    I don't want to sound like a late-night infomercial but you might go get your testosterone level (assuming your male) or perhaps similar female hormone level if that is the case. I did a bit of research on this topic and TRT, I'd suggest first going to LabCorp (assuming you are in the US) and...
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