Recent content by NKT

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.

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...

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...

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.

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...

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.

Can you post a sketch of the shearwall layout?

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...

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...

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...

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...

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

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...

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...

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...