@sandman In Section 12.10.2.1, I'm interpreting "vertical elements" as shorthand for "vertical elements of the SFRS" (i.e., the braces not gravity columns). Doing a CTRL+F through Ch. 11 and 12, this is consistent with how the term "vertical elements" is used throughout the chapters and makes...
@Deker - Thanks for your insight and answers to my question. I agree with your answers, generally, and maybe you hadn't gotten to my rant in my last post, but let me ask a more pointed question. I apologize in advance for being such a stickler on code language.
Does Section 12.10.2.1 of ASCE...
Out of curiosity I looked at ASCE 7-22 and confirmed the subject provision remains unchanged, but the whole section on diaphragms, chords, and collectors looks to have increased in length and complexity. BUT so long as the system for determining Site Class hasn't changed, I would be in SDC B...
@DL - I was actually giving that nerhrp document a thorough read through last night. While it does give credence to the limited-depth collector conapt, it also gives a few reasons why you may not want to do that (like you and @sandman mentioned in your replies), and I'm inclined to heed that...
Thanks @DL - No, as a rule I make no decisions based on the results of analysis model alone. I learned too much about FEA during grad school to ever trust it blindly. As mentioned, I was fully onboard with the collector strategy until I started see the size of the connections and I got some...
Consider if you will the 6-bay frame arrangement (attached) utilizing chevron bracing as the LFRS elements along with the following parameters/assumptions:
1) The structure is SDC C.
2) R = 3 for structures not specifically detailed for seismic resistance (i.e., AISC 341 requirements are not...
@RobertHale Thank you very much for your feedback. A section like the one you've mentioned was precisely what I was envisioning for the clearest way of invoking the Ch. 17 requirements.
What is the typical way that the IBC Chapter 17 Special Inspections, specifically the Statement of Special Inspections (SoSI), get invoked in construction specifications? If we already have a concrete testing and inspection specification, for example, which includes all the required tests and...
@phamENG - Architectural constraints make that a bit tricky. Even if I was able to get a brace or two on the west side of the foyer, I'd still be counting on the flexural resistance of the warehouse columns on the east to transfer the foyer's lateral reactions either directly to the ground or...
@phamENG - Agreed that separating it is not preferable. The concern is that the foyer portion will act as a completely different structure that the remainder of the structure (considering it's half the the warehouse's height, utilizing a different LFRS) despite sharing structural elements...
I submit for discussion a large warehouse with a relatively small foyer area, half the height of the warehouse. The warehouse is a steel braced-frame structure. In the interest of avoiding an additional row of columns (i.e., design the foyer as a structurally independent "addition"), I'm...
@steveh49 I'm coming around to that line of thinking. After reading through DG28 again, they seem to indicate the factor only comes into play for "heavily-loaded beam-columns". Running some numbers on the structures I'm working on, the Pu/A doesn't get anywhere close to 50% (two-story moment...
@le99 - Right. The user note below C3(a) recommends applying the 0.8 factor to all member stiffnesses across the board to avoid artificial distortions. This is no big deal, easy to accomplish. The τb factor, however, is a function of the axial demands on each particular member the provision...
The Direct Analysis Method is nothing new, so when I started digging around for interpretations of the subject requirement, I was surprised I didn't find any verbiage in any of the spec commentary, the front matter of the manual, existing eng-tips posts, AISC DG28, etc... to satisfy my...
The load combinations presented in Section 1605.2 and 1605.3 of IBC 2018 for LRFD and ASD, respectively, are generally equivalent to those presented in ASCE 7-16 Sections 2.3 and 2.4 for strength design and ASD, respectively, albeit arranged differently. When examining them in detail, however...
