So, I am just learning strut and tie and had a three dimension footing over (4) drilled pier footing that is supporting a tower crane. The worse case load case for the tower crane is on the diagonal, where I will get tension on one pier, a big compression on the opposite pier, and two smaller...
So a co-worker has a core wall at an elevator and stair on a six story P/T slab building going up in Seismic Design Category D. This is a crazy postage stamp sized building where the architect is trying really hard to make the floor plan work on a tight lot. On this building, on the first...
On a recent project, there was a mix-up on some exterior architectural concrete elements where air entrainment inadvertantly got left out of the concrete. What would be the mitigation for this (short of removal and replacement) . . . the concrete supplier is suggesting a penetrating sealer to...
I was just looking for some general opinions on the Brittle Element factor in the 2006 IBC . . . Section 1908.1.16. Here they say that if you don't have a ductile steel failure in your anchorage, you have to multiply your design loads by 2.5. Between Omega Loads on drag connections, the 0.75...
I am retrofitting an existing braced frame connection by installing new epoxy anchors. Basically, I was running in to compounding load factors in using ACI Appendix D . . . Seismic anchorage forces are designed for Omega (Ordinary braced frame). For bond strength, you get a regular phi of 0.55...
I have a cantilevered concrete beam, and I want to know what the moment is at the face of the cantilever if I deflect the beam a certain number of inches. Or at the very least, I would like to know if the beam would fail at that amount of deflection.
This is actually an existing concrete...
Just a general question . . . I heard a contractor one time talk about doing the cladding on a 20+ story tower that had P/T Slab floors. He talked about how it was hard to get the cladding to line up from floor to floor as they went up the building, because the building would move back and...
Are there any horizontal snow pressures that build up from deep layers of mountain snow? In all of our research, we have not found any mention of horizontal snow pressures.
I understand that a heated space will melt the snow back from the face of the wall, leaving an air space and no...
In plan review on a few projects, I have noticed that some two way P/T Slabs specify a group of bottom bars centered over the columns that is on par with the total amount of top steel added above the column. I am a little bit embarassed, but I am not sure what this bottom steel is for. On...
I am relatively new at PT Slab design, and always am curious about how to layout Banded tendons and deformed bar reinforcing parallel to concrete shearwalls. In my mind, I think of the ends of shearwalls and the corners of intersecting shearwalls as columns, and try to detail the tendons and...
Just a quick question, is it absolutely required to have flat bundles in a PT 2 way slab? Or can you have stacked bundles to ease congestion over a column (such as two on top and two beneath). This would be in a 12" thick slab.
Thanks,
This is a problem that I am sure somebody else has run into, so I am just throwing this on here to see if somebody else has a ready made solution.
I have a Podium slab with steel stud bearing walls coming down and bearing on the slab. The podium slab is poured, and some of the exterior walls...
I have been using Ram Concept for about nine months now, and one thing that I have run into is that sometimes, when I have lots of walls constraining my slab, I end up getting less precompression on my section. Say I put 20 tendons into a beam, with an expected precompression of 20*26.8 kips...
I have been doing some plan reviews, where I get to see how different companies do their PT designs. I am relatively new at designing elevated slabs, so I was curious as to the overall design philosophy that I see in the projects that cross my desk, and how that relates to people on this board...
I am relatively new at designing elevated slabs (both PT and Conventional), and am working under a senior engineer who has a lot of experience, but says and does some things that I don't always agree with. So I am in a trust but verify mode with this supervising engineer, which leads to the...
