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 (under design load). We arrived first at a size 6.75 in. x 27 in., but it was not quite sufficient. …
Tag: sag
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 …
Jamming Jack Studs
The nice thing about a stiff beam is that it won’t sag much. The not-so-nice thing is that it won’t `give’. In new construction, wood framing more or less starts from the ground up; wood members are placed on top …
Deflections of Wood Beams
When we examine deflections of wood members (beams, joists, rafters, girders, etc.) we generally look at two kinds, actually three … the deflection due to the `live load’, e.g., people walking on a floor, wind on a wall, and so …
Differential Displacements and the SST SDPW Deflector Screw
Differential Deflections … and the Simpson Strong-Tie Strong-Drive® SDPW Deflector Screw (c) Jeff R. Filler, May 2022, Pell City, AL I haven’t tried one out yet … the Simpson Strong-Tie Strong-Drive® SDPW Deflector Screw … but the idea is fascinating …
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Case(s) in Point
In the example (here) I discussed a person standing on a wood plank, and `examining’ the deflection. Talk is cheap. I grabbed three pieces of lumber (that I milled) in my shop: one piece a 1 x 5 Southern Pine …
Shear Deflection – Prefab Wood I-Joist
Shear Deflection – Prefab Wood I-Joist Example Calc (c) Jeff R. Filler, Pell City, 2022 Continuing our discussion on shear deflection of wood beams (joists, etc.), let’s look at a prefabricated wood I-joists. Basic design information for prefabricated wood I-joists …
E min
E min (c) Jeff R. Filler, Pell City, Alabama, 2022 But First, E apparent and E true `E min’ is calculated wood property used in the design of structural wood members (beams, columns, etc.). It is a derived property, derived …
Accuracy of Deflection Calcs (and Eee)
In the example above (link) we calculated a deflection of 0.599 in. How accurate is this number? (I showed it to three significant figures … accurate to half a percent?) Leaving out, for now, the accuracy/precision of the other input, …
E app (Apparent Modulus of Elasticity)
E app (`Eee app’, `Eee apparent’, Apparent Modulus of Elasticity) is a design property for wood construction. It comes from the Modulus of Elasticity of the wood (E, MOE, Young’s Modulus). It’s not a `true’, or `pure’ property, and it …