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Do you folks include a maximum allowable fly ash limit in your standard concrete specifications? I know Table 26.4.2.2(b) of ACI 318-19 has a limit of 25% for Exposure Class F3 concrete uses. I wasn't sure if anyone puts any other stricter limits than that? A few things I have come across is...

I'm working on a precast parking garage with a cast-in-place topping slab applied over the precast double tees. I found the PCI Parking Structure Manual which has some good information on durability considerations including a geographical zone map and table shown below. For reference, this...

Unfortunately, this is an existing pre-topped double tee building that does not meet 2% ADA requirements, and they are now trying to go back and get it to meet the limits. So we are looking at repair options at this stage. No chance to install them as field topped anymore. Thanks for that...

Good to know, thank you for the response. Do you have any thoughts on my question #3? Is it safe to assume the new topping can re-bond with the original concrete deck and act compositely for the final compression flange loading condition? Not sure if you guys have to do assumptions like that...

I have a project where a client wants to adjust the grading/slopes inside one area of a precast parking garage to meet ADA accessibility slope limits. To achieve this they are proposing raising the deck surface by anywhere from 0" - 4". I still need to check if this extra weight of concrete on...

I expect the column will have lateral loads that will need to be resisted by this connection. Have you considered this? Yes, the connection is supposed to resist the lateral loads that the column would see. The connection can be installed initially with the bolt near the upper end if live load...

Thank you for the responses. That's good to hear it should have the same strength as a standard long slotted hole. I'll look into the AISC Section 3.11b check when I'm back by my handy dandy steel manual.

See detail below for a general question I have. In the detail I am trying to brace the top of a new HSS column to the underside of an existing slab on metal deck. I don't want the slab or structure above to apply load to this new column. I am assuming that the floor above and the floor below...

If a multi-ply wood beam is unbraced for lateral torsional buckling, how do y'all calculate the beam stability factor for this beam, like a (4) 1 3/4" x 16" LVL? Do you consider the entire built-up 'composite' beam, thus when you calculate Rb=sqrt((le*d/b^2)) per equation 3.3-5 of the NDS...

I don't have any exact stress ranges at the moment. This question came from a fellow engineer who was wondering if they should check combined shear, and I didn't have a good response as to why they should or should not. We looked at the design programs we have access to including Enercalc...

If you refer to the diagram below, I'm showing example surfaces where I think the shear stress parallel to grain is developing on the member under both loading cases. Does the fact that one happens on xy planes and one on xz planes help anything or are those parallel to grain shear stresses...

I was wondering if shear stress parallel to grain vs perpendicular to grain had anything to do with it. When you load a beam on both the strong and weak axis, are the shear stresses parallel to grain additive in terms of mechanics and materials? Or is it only the shear perpendicular to grain on...

Yes, I was thinking a rectangular section like a 2x8. Thank you for doing that. Please report back with what they say.

If you are designing a wood beam with bending in two directions (strong axis and weak axis), how come you only need to check the shear stresses in each axis independently? Is there no sort of resultant or combined shear stress that develops on the beam cross section face? Seems like this...

Interesting. I was under the assumption that the typical party wall details I see on townhomes are IRC 302.2.2 common walls, but not my area of expertise so I'm probably wrong. I typically see the detail shown below. Do you know if that is a "double wall" or a "common wall"? I just tried...

Sounds good. I think we are in agreement. I was just hoping a residential engineer on here may have a trick that they have used or a code section that allows an entire townhome building to always be designed as one big IRC braced wall building. But I'm guessing no such thing exists. For your...

I did notice the structural independence provision R302.2.6. I believe these townnhomes would meet the exception #5 of that part of the IRC (Townhouse units separated by a common wall as provided in Section R302.2.2, Item 1 or 2), so I don't think that code section needs to be met in this case.

I'm working on IRC townhomes and trying to implement IRC braced wall line methods for checking lateral. I'm not a pro with the braced wall line methodology, and I'm coming across some nuances with how townhomes/rowhomes are built that relates back to lateral resistance. Refer to example plan...

Definitely like the simplicity of detailing argument if it doesn't cause any harm like you said.

Sounds good, thank you. That 4ft distance was the exact sort of thing I was looking for.