Simplified analysis for connections

[awa5114]

In my work, I am frequently faced with the problem of transferring loads from larger structures to connections. It is not always easy to determine how a loaded element will transfer its load to an adjacent connection.Also, the standard "stick modelling" approach taught in most universities (based on Euler Bernoulli bbeam theory and the general stiffness method) really doesnt apply to connections. Does there exist any literature on the subject of load transfer and distribution to connections? I am specifically looking for simplified procedures that structural engineers can use in a non-academic context to quickly determine loading on bolts, screws, welds etc, without resorting to finite elements. Something one can do by hand or spreadsheet...

 

[BadgerPE]

I think a sketch or an example of what specifically you are looking for, would be quite helpful.

 

[SAIL3]

pick up a few books by Omar Blodgett and study them.....

 

[awa5114]

Omer Blodgett's book on welds is excellent, but he has little, if any, work on bolted connections, which are my main concern.

 

[KootK]

Tamboli: Link
Salmon & Jonhson: Link
AISC Design Guide 17: Link
Kulak (free): Link
RCSC (free): Link
AISC Design Guide 29: Link

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[awa5114]

Kootk, thanks for the suggestions. I'm looking for something more on the analysis rather than design side... Something agnostic to the type (Steel or otherwise) connection. I'm looking for a general theory on how to translate boundary/loading conditions on elements to local stress distributions on connections...

 

[KootK]

I'm looking for something more on the analysis rather than design side..

Me no understando. For typical connections and loads, the design and analysis processes are essentially inseparable.

Something agnostic to the type (Steel or otherwise) connection.

Agnostic... I like that. Unfortunately, there's no such thing. Connection load distribution is very dependent on the parent material (steel, concrete, wood, chewing gum).

I'm looking for a general theory on how to translate boundary/loading conditions on elements to local stress distributions on connections..

For the love of all that that is agnostically holy man, follow Badger's advice and give us a sketch/example to work to.


I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[MacGruber22]

The answer is to satisfy the equations of:
1. Equilibrium
2. Compatibility
3. Constitutive relation



"It is imperative Cunth doesn't get his hands on those codes."

 

[awa5114]

MacGruber... That sounds like FEM to me... is there a simplified FEM procedure for connections?

 

[Lomarandil]

For specific cases (e.g. a shear tab connection, or corbel bracket), sure, you can develop some strain compatibility procedures that will act a lot like FEM without being FEM "proper".

Generally? No. Not that I've heard of at least.

 

[BUGGAR]

I have a spreadsheet.

 

[KootK]

You might get some satisfaction looking into the "Component Method" that seems to be emerging out of Europe. Here's an example for base plate connections: Link. Two caveats:

1) It's steel very much material specific and;
2) Personally, I'm not yet sold on it.

The best statements of connection design philosophy that I've encountered come from the Tamboli book that I mentioned above. I've posted those below. Even this stuff only really applies to ductile materials however. It works for steel, aluminum, and concrete (usually). It would not necessarily work for wood, cast iron, or glass.

Looking at MacGruber's list:

1. Equilibrium
2. Compatibility
3. Constitutive relation

For routine connection design, I would change that to:

1) Equilibrium fo' sure.
2) Some rough accounting of the relative stiffness of things.
3) Some provision for ductility if there's any to be had.

Compatibility and constitutive relations get a pretty rough treatment, if any, in the design of most connections.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[awa5114]

Lomarandil: Im interested in these strain compatibility procedures. Also, Buggar, do you mind sharing it or at least the reference documents you used to develop it?

Thanks guys

 

[Guest262653]

There´s an italian software for the design of connections (Castalia CSE) that may what you're looking for. I haven't tested it yet but it seems that it is basically an environment for the creation of full 3D FEM models of the connections.

Here's the link:

http://www.steelchecks.com/connections/home.asp#.VyjJw_krKUk

 

[Trenno]

Following on from KootK's comment regarding the component method.

Link below to software developed on the back of that theory/method. I believe it's the same guys who came up with the method in the first place.

Link