When designing for punching shear using stud rails at an interior column in a PT flat plate slab (ACI318-11), the stud rail section limits the maximum shear stress to 8sqrt(f'c). However, the shear provisions for pre-stressed members limit the maximum shear stress to 70 psi based on available...
What would one use for a parapet wind pressure on a low roof adjacent to a tall building? Calculating this load per ASCE7-10 would you take h as 250' or 50' (specifically for the parapet design in question)?
Would your answer change in any way if the low roof height was closer to the upper...
Referencing ASCE7-10:
When calculating torsional irregularity per table 12.3-1, is it necessary to calculate the drift for the entire structure or each individual story? The example situation is one where a shear wall stops one level below the top of the building (call the top level "roof")...
Hi all - I am looking for some guidance on the correct way to design stressing blockouts for PT slabs. We have a situation where our tendons cannot be stressed outside of the slab edge due to an adjacent structure. We have typical details showing the general reinforcement arrangement, but I...
There was a time when we could purchase a PDF of a building code, put it on our server, and our whole office would have access to the file. I don't see this as being any different than an office purchasing a hard-copy and placing it on their bookshelf for everyone to share. Now, it seems like...
We are calculating the wind force on a structure using Chapter 29 of ASCE7-10. The equations give the force as "F", which is essentially the pressure times the area of the structure. I would have taken F as equal to W for purposes of using the load combinations in Chapter 2, where we would...
Hi - not sure if this is the right forum but wanted to see what kind of response I got. I'm investigating a "sink-hole" issue where a building owner is saying that a water pipe broke under his building, causing it to settle, shift, etc. The evidence of damage is some minor cracking in the...
I'm in a jurisdiction that uses IBC 2015 and requires a minimum seismic design category of B. I'm curious how other engineers are implementing minimum requirements.
I'm currently working on a project that would be SDC A based on the soil site class and acceleration parameters. Do you...
According to ACI318-11, my understanding is that column splices must conform to section 12.16.1 in that the compression lap splice length shall be 0.0005fy x db, which corresponds to roughly 30x db (for 60 ksi bars). This is, of course, assuming that there is no tension or bending in the column...
I am using Profis to check an anchor design and came across something in the code that seems confusing.
The application is a shear force applied along a concrete slab edge, but you could draw a parallel to any wood or light gage shear wall anchored to the top of a concrete stem wall. The force...
I'm somewhat new to PT design, and have a question about service stresses. We use an FEM program to do final calculations (after performing preliminary calcs by hand). I often find that we will end up with a design section or 2 that exceed permissible stresses, just slightly. Our typical...
This question is for a 1-story building, akin to a residential structure.
We have a concrete wall (used for bearing and shear) which changed sizes between the time the footings were poured and when the final documents were released. For the purposes of this question, assume it went from a 14"...
I've read several posts on the design checks for 2 conditions that are sometimes seen in concrete flat plate construction: walking columns and transfer slabs.
My understanding is that walking columns use a minimum of 1 floor of full overlap between the columns above and below (like a short...
In the IBC 2015 table 1607.1, what is the purpose of footnote 'm' on live loads of 100 psf or less? We are having some internal discussions about whether or not you can reduce these loads. Although footnote m states that these loads cannot be reduced, it goes on to say "unless specific...
We have a concrete shear wall with vertical concentrated steel at the ends (something like boundary elements). My question is related to the spacing requirements for ties in these elements.
I was told that ties for these elements would only be required if:
1) The reinforcement is required for...
(This is strictly a theoretical topic. I would never design a shear wall assuming it takes no in-plane loading.)
My question is this: is it theoretically possible, by analysis, that you could have a shear wall supporting a rigid diaphragm and determine that the wall takes a shear force of...
We have a detail where a masonry wall will be built around a 4x4 steel column, so the column is essentially "embedded" in the wall. The masonry will be fully grouted. The structure is an exterior trash enclosure, in an environment where the temperature ranges from below 0 F in the winter to...
I'm reviewing a project and it has a framing detail similar to the attached sketch. This condition isn't really covered under any AISC design guide or typical detail that I've ever seen, and I was wondering if anyone has any insight. The concern is that the brace being connected to the face of...
I'm curious what ASTM others are specifying for anchor bolts. I was told by someone from the NCMA that F1554 is not a recognized bolt designation by the masonry people, and that it should be either A36 or A307. However, the steel manual does not list either of these as applicable designations...
Hi all - wondering if you would consider the framing in the attached sketch a "susceptible bay" in accordance with ASCE7-10 8.4. The issue being that while the slope is 1/4" per ft, the overflow scuppers are by their nature controlling drainage of the rainwater in the case of the primary drains...
