KootK, I agree about the strutting. In the NDS, you can ignore shear on a wood joist if it is within d from the support because of this effect. However, what do you make of ACI's exclusion of a point load between FOS and d?
Most of us are familiar with the concept of designing a concrete beam for Vu @ d, that is for the shear at a distance 'd' from the face of the support. At this critical distance, the shear in a simple span beam is typically less than at the end or face of support (FOS) which results in a...
Just realized I copied the link for the NY State building code by mistake above. Here is the link to the NYC code, page 257...
https://www.nyc.gov/html/dob/downloads/bldgs_code/bc27s11.pdf
The NYC Building code gives presumptive load bearing values for soil types that are considerably higher than the presumptive bearing values of the IRC/IBC codes. The Data Book for Civil Engineers by Elwyn E. Seele cited these values from the NYC code back in the 1940s-1950s in a manner that...
NDS Equation C12.2.5-2 for fastener head pull-through uses "Fastener Head Perimeter", P-sub-H. What is "fastener head perimeter" and how is this obtained for common hex head bolt sizes? And, how does using a washer come into play when used with fasteners with other than round heads such as hex...
I don't disagree, but what's the difference between this mechanism, and an embedded headed anchor that is imparting its load on the concrete through the head of the bolt?
Thanks Koot, you get it! By applying the one-way shear to the punching shear frustum, do you mean using Vc = 2 f'c^(1/2) * bo * d ?
Interestingly, if I look at this as plain concrete (very little reinforcing actually), then I get a result that is very near to what I get by considering it a...
So the interesting thing about punching shear, which I know a lot of engineers use for through-bolts, is that is returns a less conservative result. Since 17.1.5 gives us a pass on Ch. 17, I think using punching shear could be justified. My only hang-up with that is that it is counterintuitive...
I will add that I know this is not precisely in the scope of ACI 318 Ch. 17 since 17.1.5 excludes though-bolts, which is what this is. So we need to use some engineering judgment to model some capacity from this situation, and best I can tell this will behave like an embedded headed bolt.
Yes, this is exactly the scenario. The sketch shown here is almost identical to the ACI figure showing a headed anchor bolt (Fig. R17.6.2.1). The only difference is that a cast-in headed bolt is embedded in the concrete whereas this one passes through it. The load is transferred from the bolt...
Guys, this is getting rather over-complicated. It is simply a headed stud that is in a pre-formed hole rather than cast in to the concrete. There is no adhesive or need to roughen anything. This is done by a pre-caster and has been done tens of thousands of times. Just looking to establish...
Let's say a 3/4" hole is formed in precast concrete slab so that a 1/2" or 5/8" bolt can later be inserted through the hole to be an anchor. Would this anchor be considered cast-in or post-installed for the purpose of determining factors per ACI 318-19 Ch. 17?
An argument for considering the...
I will add that if you look at the section of ACI 530 that governs anchorage, Equation 9-1 gives a result for breakout that is unconservative as compared to ACI 318 17.6.2.
Can Chapter 17 be applied for anchorage to masonry such as solid grouted CMU? The provisions of ACI 530 to calculate axial and shear strength for anchor bolts embedded in grout seem rather basic and are only a function of f'm and assumed breakout cone, so it would seem that ACI 318 Ch. 17 could...
