Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations waross on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  • Users: NKT
  • Order by date
  1. NKT

    Timber Beams Doubled Height

    I wouldn't count on a shear connection between the two (no composite behavior), but I would add the section properties and check bending and deflection before rejecting.
  2. NKT

    Need help estimating project completion time

    I have a lot of experience with the type of project you're describing; they've taken up at least half of my billed hours over the past five years. The following factors must be weighed to arrive at a fee: 1. How long the work will take (more on this below) 2. The value of the work to the...
  3. NKT

    Seismic Forces at Raised Floor (Wood Builiding)

    I second Mike's "don't worry about it too much" sentiment. There are typically very few gaps in the attachments between the first floor diaphragm and the foundation, so the attachment loads are usually very well distributed on the perimeter foundation, and are reduced to a level which is...
  4. NKT

    Rigid Insulation Structural Values

    I wouldn't count on any strength from the insulation: it is very easy to damage, and once it's damaged it has just about zero bending strength.
  5. NKT

    Wood Perforated Shear Wall Design

    It seems that you haven't addressed the horizontal tension forces at the openings. The vertical chord forces as shown are normally not an issue since there is a continuous stud at the edge of each opening. Part of a perforated shearwall design is usually determining connections to transfer...
  6. NKT

    Calculators!!

    Casio CFX-9850G. I got it as a freebie 12+ years ago when I was in school and it's performed well since, even though it's seen plenty of abuse.
  7. NKT

    center of rigidity outside the building footprint

    Can you post a sketch of the shearwall layout?
  8. NKT

    LEED Certification for new construction

    Thanks for the replies, this has been very helpful. I ended up adding 5% to my fee; That translates to about four full days of work for this project. It seems that it's mostly a matter of documenting recycled and locally produced content as I go through the design. I'll definitely add a "no...
  9. NKT

    LEED Certification for new construction

    I am in the final stages of negotiating a scope of work with an architect, and the subject of "Leadership in Energy and Environmental Design" (LEED) certification for the project came up. The architect wants me to add this to my scope of work for the structural engineering. Does anyone have...
  10. NKT

    Calculating Hold Downs at the end of shearwalls

    To get 30k uplift with two stories, you end up with an average of 1500plf in your shearwalls (assuming 10' walls). This is a lot for wood framing; I would try to get more shearwall length or consider another lateral-force-resisting-system. You can get some of the holdown forces to cancel out if...
  11. NKT

    Wood wall stud

    Cp is usually the controlling modification factor for wood stud walls; it will typically be significantly smaller than 1.0. If it's approaching 1.0, you may want to consider increasing the economy of your design by using a smaller column (stud) section. Since you are looking at bending of a...
  12. NKT

    Wood wall stud

    Yes... For typical wall studs I would use CL=1.0 because the sheathing restrains lateral buckling. Gypsum board works too.
  13. NKT

    Best Retaining Wall Book / Reference?

    The retaining wall design reference that comes with the RetainPro software is actually pretty good. I have an older version of the software, but I assume the reference book is basically unchanged. It offers a very clear and concise summary of retaining wall design for local stability and...
  14. NKT

    Enercalc and Retain Pro

    I use RetainPro version 6 frequently. It is a quirky program with numerous bugs, a somewhat cumbersome user interface, and ugly / hard to interpret reports. The positive side is that it allows me to quickly arrive at a workable design for a retaining wall - about 15 min start to finish to...
  15. NKT

    what is correct procedure to 'sister' a new rafter to existing rafter

    I would design it like this: Calculate the portion of the load carried by the new rafter. If they are the same depth, the load carried will be proportional to the width. Determine the capacity of your connection. I would use nails installed with a nail gun. Determine the spacing required to...
  16. NKT

    Solving for impact loading

    "Would it be as simple as f=ma?" Using f=ma is not necessarily a simple way to do it... the acceleration is difficult to determine and requires simplifying assumptions that make the accuracy questionable. A simple way is to use conservation of energy; equate the potential energy of the person...
  17. NKT

    Removal of Load Bearing Wall

    Spans were not mentioned in the question, and I assumed relatively short spans. One way around this would be to jack the channel up incrementally along its length to get the required deflected shape (and corresponding load on the wall). The jacking points and loads would be dictated by the...
  18. NKT

    Removal of Load Bearing Wall

    hokie66: How about drilling the holes in a deflected-shape pattern? The construction sequence might be something like this: 1. Drill the hole at one end and install the channel with one bolt. 2. Lift the channel to an angle such that the center is at its calculated deflected position under...
  19. NKT

    Removal of Load Bearing Wall

    "Just for curiosity, is there any practically way to hold the wall and introducing the new beam to support it, i can't visualize how to insert new beam in load bearing cmu."(ali07) I've seen this done with steel channel sections bolted through the wall before the masonry below the channels is...
  20. NKT

    Give current boss opportunity to match better job offer or just quit?

    I was in a similar situation about two years ago (underpaid by clueless management). Most of the engineering dept at my company evaporated around me seeking opportunities (better pay) elsewhere. When management finally realized that the staff had been underpaid, most had already left. I came out...
Back
Top