what are the chances?
In a previous post (here), we determined the size glulam roof beam required to not deflect more than 1.00 inches. We arrived first at a size 6.75 in. x 27 in., but it was not quite sufficient. So we ended …
Ex min or Ey min
This will probably be my shortest post. … In the determination of wood beam stability (lateral torsional buckling) with respect to bending about the X-X axis, use Ey min (not Ex min). The context here is structural glued laminated timber …
E min and `Never’
I continue to be mesmerized by this thing called `E min’. E min is the `minimum modulus of elasticity’ used in stability calculations in wood engineering design. E min (hereafter just Emin) is based on `regular’ modulus of elasticity, E. …
Absolute Deflection
Let’s look at a situation where, after construction, it is required that a certain roof beam experience a deflection of not more than 1.0 inches (in.). The deflection limitation comes about by a required clearance between the ceiling and some …
Dimension versus Dimensional
I design structures. I am an engineer. In this day and age we design buildings so that they don’t fail; don’t fall down, and, in a sense, just barely don’t fall down. Seldom do we `overbuild’. And as such, it’s …
Glulam MBF
So, in another post we looked at `board feet’ (BF), or `board foot measure’ (BFM). Now we’ll look at BF for structural glued laminated timber (glulam), and MBF, or MBFM. From the earlier post, amount of lumber is often described …
Board Foot Measure (BFM)
We had a windstorm recently … some big trees down. After cutting up most of the fallen ones on my property (taking a couple weeks), I started in on one of my neighbor’s. One of `em is a big oak. …
weight of wood (posts)
Yesterday I went to the building supply store to get some pressure-treated 4 x 4 posts. (for more fence … gates, etc.!). I’m always amazed by how `wet’, and heavy, pressure-treated posts are, at the store. I pulled them from …
floor (joist) vibration
Other than a project or two where I looked at vibration from machinery, I never worried too much about vibration in floor / floor framing design. Typically, I never had to. Manufacturers of floor joists (e.g., prefabricated wood I-joists) worry …
Bounce on the Movie Set
was called once to a movie set. It was in an old house, out in the country. There was considerable `bounce’ in the upper story floor, and they wondered if it was `safe’ (… to do their filming). I did …