For my EOR estimates, I just use RISA etc and limit myself to #2 SPF for the chords. The #2 SPF tends to keep the designs from being overly aggressive such that plating issues are pretty much non-existent for 2X trusses. This is a good way to keep yourself from doing silly EOR stuff with the...
No, I'm not sure that I want it known that I was there. I just urinated on the side of the chimney to ward of other structural engineers. That, and I've got a wicked addiction to Big Gulps that flares up whenever I have to drive somewhere for work.
The eccentricity associated with supported load delivery usually isn't much. As such, one can often make the argument that the "torsion" is really just eccentric shear. The danger in moment connecting the slab elements, I feel, is in inadvertently creating much greater eccentricity and...
Wood members in torsion are terrible things, truly. Get any mid-section longitudinal checking or cracking and your torsional stiffness and strength drop drastically. To my knowledge, we don't even have codified methods for checking torsion in the US other than resorting to the Timber...
I reviewed an aged hip recently as luck would have it. 16' setback with the short ceiling joists turned about 6' in. Two of the ridge boards are actually snapped flexurally as a result of past loading and poor lumber grading (knots in bad places).
The thing is holding up impressively well in...
I feel that you are considering things in terms of "what can I prove with real engineering".
Instead, consider it in terms of "how does this sketchy thing actually work, which I take to be OP's fundamental question.
The "tie" is often the connection to the diaphragm that is the ceiling gypsum...
That's my feeling as well. The in-plane flexure will be down to a localized compression block at one end of the wall and localized flexural tension steel at the other. In between, all OOP. Fundamentally, the appropriateness of disregarding the combined loading is down to the proportions of...
Yup. In some very old buildings, I've seen complete sets of tension ties across the entire building in both directions. The one set placed above the other. In more modern buildings its usually a turning of the ceiling joists as you say.
With prefab truss systems, it's the corner jacks of...
That. This probably deserves a sketch (and let me know if it does) but I'm short on time so let's try prose first.
1) Often you have some version of a ceiling tension tie both directions.
2) With the tension ties is play, the things almost work like regular tied rafters hitting a ridge board...
Mrs. KootK, who is also a structural engineer, has this home improvement project on the go at this very moment. It's the addition of a main floor mega-pantry. Lot's of canned goods, jars containing fluids, and the lowest level dedicated to dense dog food storage. All the way to the ceiling...
Thanks. It comes with my hosting too, I'd just have to top it up nominally.
Unfortunately, my hosting is GoDaddy and we don't get along so I'm loathe to pay them more.
GoDaddy... if only they had but a single neck that I could get my hands around.
Just a poll here. Is everybody using OneDrive for cloud collaboration with clients?
I'm still rocking Dropbox just because I was an early adopter and I detest change in all of its myriad forms. And my personal & business files are not as separate as they probably ought to be...
But, lately...
Unless you can somehow quantify the amount of shear slip that you can expect to take place, I would think that you would have to do something like this:
1) Estimate the tension strain at the top of the box girder assuming non-composite behavior.
2) Apportion your rebar in the slab for crack...
@GregLocock beautifully done.
That's exactly what I was getting at with the low Ix_truss to Ix_chord ratio. The left hand side of the thing starts to act like a pair of beams rather than a truss. I suspect this is also why the bottom chord is larger than the top which is unusual for these...
Just keep doing what you've been doing (please). Not in this thread, per se, but within this forum. As with most things rooted in perception, it's a slow battle for hearts and minds. And right now, the truss industry has no better ambassador here than you.
I've come to view a great many...
I'm afraid that I am enough of an anomaly that I have to admit that EOR skepticism is not without justification.
The largest problem that I see is not proper structural engineers doing a poor job of it but, rather, non-structural engineers doing a non-job of it. Mechanical engineers, oil and...
Certainly that is the case with me, in my market. I used to be a truss designer, it doesn't pay super well. Being a staff engineer at a truss shop can pay decently but, then, that has some drawbacks as a long term career choice.
I submit that your annoyance ought not be with the truss...
