Search results for query: *

I would agree regarding redistribution if there is a lid on the system, but you mentioned that the top is free. How does the moment redistribute up the wall? If there is less than fixity at the base, the wall is not stable. As for the analogy to the snow on the slab - I've never really...

------"the member is part of a redundant structural system that allows substantial redistribution of load and will therefor display adequate ductility"------ If the entire wall sees the maximum load at the same time (and in a constant fashion) is it really a redundant system? If the...

Many of FM's design criteria are more strict than the governing building codes. This seems to be especially true for roofing components. We have binders and binders full of FM data. It's a pain in the neck, really. You think you have it licked using ASCE, ACI, AISC, NFPA, and the governing model...

Could the 48" be the grouting lift height (i.e. low lift grout)?

Do you have the new ACI code? There is a quite extensive appendix having to do with the strut and tie models. No "punching shear" to worry about. It doesn't sound like you have a cantilever or corbel (right?). There are some special ACI provisions for a "regular" beam if...

One problem is that you often don't know if you have control joints or other cracks at the section in question. Owners always see to be interested in putting slab-supported mezzanine columns on existing column lines which have saw cuts along them. Use a big base plate and be very conservative!

I believe the reason for the development of the strut and tie model was to provide a load path which is more accurate than a deep beam model. To this end you have tension and compression forces but no shears.

Depends on the nature of the bolting to the cap plate as to whether I would consider it "fixed" to the plate. What do you mean by "simply bolted"?

Things to keep in mind: The capacity of the tee will be a small fraction of the capacity of wide flange beam from which it was cut. The section moduli for tension and compression in a tee are very different from one another! Be careful which one you are using when checking the lateral buckling...

Single-angle flexural members are very touchy and complex. They make my brain hurt too. Methinks a 6x4 spanning 20' won't work, regardless of the loading!

Ack! I guess I need to read more carefully. My apologies! The HSS Connections Manual (1997) contains the OLD "AISC Specification for the Design of Steel Hollow Structural Sections" and is a supplement to the LRFD manual. It has no provisions for ASD (but you already knew that :) ). I...

AISC has an entire new manual devoted to Hollow Structural Shapes. The "Black Book" has everything you'll need for HSS connection design.

I'm guessing he assumed total fixity when he "computed" the deflection. Model in the actual beam with its corresponding rotation at the support and the deflection may go up considerably. While I agree that clients don't understand shears and moments, they sure can see deflection...

There are many companies that manufacture slide bearings. I've used Con-Serv on rare occaision ( http://www.con-servinc.com ).

It seems to me that the easy part might be the analysis and the hard part deciding what your allowables will be. Anything with "Hool" in the title is a good place to start!

You can fill it or fix it. Epoxy injection may fill it so that water won't get in, but filling it will not prevent further cracking or fix the cause of the crack. If the structure was improperly designed, God onlt knows what you might need to do.

When the required wall thickness gets to be too extreme, you may want to consider going to heavy wall mechanical tubing. If the exact OD is important, it can be turned down from a larger size. This may not be practical for longer pieces, but I have seen it done for larger sizes of pipe (e.g...

Getting your PE in many different States is a simple matter of reciprocity. A handful of States, such as California and Illinois, register structural engineers apart from civil engineers. Getting Structural authority in those States is much more difficult - especially if you are not working in...

I see ungrouted pole base plates around here (Ohio) all the time. Each one I come across I think to myself: Hmmm. I'd like to see the structural calculations on that base plate and those anchor bolts.

The Hollowcore guy I talked to last week called their process "extrusion" but then described it like JAE mentioned above. It's really more of a slipforming than a true extrusion. They place a very very stiff mix over a rotating auger which tapers down into a solid mandrel. The mandrel...