Great question!
I modified my input file to include the command SET SHEAR, which forces STAAD to ignore Shear Deformation. That solved one of our other unrelated questions.
So problem has been mostly solved!
The answer was not at all what I expected.
My model was correct, my math was correct, but the ratio of end mass to beam mass was not.
The Blevins calculation is for a "slender beam with a concentrated end mass". What it doesn't really explain is that...
I'll definitely peak at it tomorrow.
Really, I need to figure out how to model in FEA the Blevins example. That's where I'm at with it. I'm happy to admit my model is wrong. But if that's the case, I really want to know what the correct answer is.
@Denial I'll double check that. It could be exactly that, which means I'll need to look at how to define a large mass at the end of the cantilever.
@GregLocock I'll check my output in the morning once I'm back at the office. I believe we were looking at this and noticing that they didn't...
I am trying to determine why STAAD provides a different frequency for a simple beam with concentrated mass model versus proven classical methods for the same model. The results are different enough to merit a discussion.
If any of you have STAAD, I have attached my input file. You can perform...
I have been looking into the Effective Area Method outlined in NAVFAC DM7-02 for rectangular and circular footings. However, for instances of designing foundations for silos or similar structures, ring type foundations are typically used (circular foundation with an outside and inside radius)...
All of my decking design resources are at the office, but I would imagine one way you could do this is to treat the decking as a pinned column. You have your section properties of your deck and should be able to determine the buckling strength from that. You make a good point, though - I'm not...
I recently came across a report that gave loadings, foundation properties, allowable bearing, and actual bearing for a large water tank. Something comes across as very odd in this design.
Loads
D = 2860 kip
F = 8360 kip
W = 7800 kip*ft
Foundation Dimensions
OR pad = 25'-10"
IR pad = 10'-1"...
Here's a simplified approach of my analysis. I'd be happy to provide additional information to anyone who may be interested in looking at things. I opted to do an upload to Imgur so others can take a peak.
http://i.imgur.com/FaVhL.jpg
I've got a 4' thick pad at the moment. I may look at going to 54" to see how that helps. And you are correct JedClampett - OT on this tank is NOT an issue!
Thanks for the information folks!
@Michel60 - I appreciate the info. I'm making sure to work closely with our foundation department and concrete field head to make sure that we detail and lay everything out in such a way as to help our crew work as efficiently as possible.
@JoshPlum - you...
I've been working on the design for an octagonal mat for a storage tank over the past few days. Originally, I looked at a circular mat, but the rebar requirements were astronomical (the spacing was getting close to 3" c/c on #11 bars...so that won't work). The rebar requirements for my...
I do a lot of concrete and steel, but my structures are non-standard, so we use a lot of specialized procedures. Regarding your licensure, I wouldn't imagine that your PE is revoked if you don't pass the SE!
I'm going to get in touch PPI and NCEES tomorrow. Thanks for the idea.
@SteelPE The reason I'm not taking the Structural exam is because of what I do for a living. Realistically, I don't do enough classical design to feel comfortable with the material being tested. I could possibly take it...
