Does anyone know of a standard or guideline regarding the relationship of the EOR to the P/T designer? Does PTI or ACI address this anywhere such as a "Code of Standard Practice", describing the responsibilities of all parties?
miecz, I'm not so sure about your statement that f'm is unrelated to the grout strength.
If the unit strength method is used (typical for my firm), then you are correct. As long as all the criteria is met regarding masonry unit strength, bed joint thickness, and grout and mortar proportions...
I see your point that it doesn't amplify much in Section 12.8.4.3. But the other reference sections of Table 12.3-1 come into play also, such as the Increase in Forces and for higher Occupancy Categories whether Equivalent Lateral Force is allowed (Table 12.6-1).
The way I understand it is you either:
1) specify that the grout must meet the proportions of ASTM C476; or
2) specify the compressive strength.
You shouldn't do both. If you choose the latter, you must test it. Tests must be in accordance with C1019 (4 blocks with paper). We have...
Did you specify that the grout must be tested? If so, was the grout tested in accordance with ASTM C1019? If some other method was used, the results are probably not valid if the mold does not match the absorption rate of the masonry units.
We typically do not require grout compression tests...
JoshPlum, thanks for the reply. It isn't perfectly symmetrical, but close. And yes, the 5% accidental eccentricity is applied.
My point is that when the magnitude of the drift is very small, there does not have to be much difference from one corner to the other to exceed the 1.2 limit. As...
When you say "in order to bring it up to Code" do you mean for strength or for seismic detailing requirements? If the former, we have added interior steel girts (CMU spanning vertically) or pilasters (CMU walls spanning horizontally between pilasters). If the latter, we have heard of...
Does anyone know of an exception based on the magnitude of the story drift? I have a two-story building with special concentric braced frames relatively symmetrical, seismic design category D. When I calculate the Torsional Irregularity, I am outside of the 1.2 limit, but the seismic drifts...
Thanks to all for the input. I am very skeptical of the composite approach also. Just wanted to check whether there is an accepted procedure for this that I didn't know about.
DavidStructural08, perhaps I misunderstood your initial response, but I think the original question from kk88818 was about direct uplift, not uplift due to a lateral element.
DavidStructural08, I'm not sure what you mean. The tributary area getting to a column footing would be the same for DL or uplift.
One thing that must be considered though is vertical, downward DL vs. "real DL" used to resist uplift. You may choose to use a heavier DL for the gravity design...
DaveAtkins, good point about the discontinuity of the sheathing. If we were able to determine that no joints occur in the sheathing though, do you know of an established procedure? Have one of the wood organizations addressed this?
I have been asked to review an existing wood-framed building. My client wants to look at the wall studs as composite with the exterior OSB sheathing. I have never analyzed a wood-framed wall in this way and have a few concerns. One is the shear stress transfer to ensure composite action...
One thing to make sure of is your safety factor. If your DL has the 0.6 factor applied for allowable stress design, in my opinion, this includes the safety factor for uplift. So, you wouldn't need to multiply by that again. Also, check your uplift number - 30 psf is pretty high, depending on...
Thanks to all for your input. I agree that ideally the chords should be continuous - and it is easier to design that way. However, the previously-mentioned thread got me thinking about some of the construction I've seen in the field. I've seen "continuous" angles butted together with no...
UcfSE, interesting analogy. However, in my scenario, the individual little "beams" are each horizontally supported by the individual shear walls. In other words, each shear wall provides a reaction equal and opposite to the chord force at that location, which does not allow the force to...
In reading thread507-104685, it got me wondering about the necessity of diaphragm chords being continuous. Suppose you have a steel deck diaphragm attached to a CMU wall (200' long) via a “continuous” angle bolted to the wall. The wall is designed as a shear wall when the shear force is...
Of the prequalified connections (FEMA 350 and AISC 358), some have weld access holes, some have backing bars, etc. Not all of these items are used in each connection. I believe what is intended is that when you choose a connection with one of those items, you have to do it a certain way. The...
