Analysis of cast iron column's seat

[U4ENIK]

Hi Everybody,

I am working on a building having cast iron columns supporting girders by means of triangular
stiffened seats.
Has anyone analysed such seats?
Is there any literature with examples of how to go about checking the capacities of such supports?


Thank you for your time.

 

[JAE]

Bump,

U4ENIK, you might try posting some photos or drawings of what you are looking at.

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[CANPRO]

In "Design of Welded Steel Structures" by Blodgett, there are design equations for the capacity of a stiffened seat. Nothing specific to cast iron, but it might be a good start.

 

[U4ENIK]

Thank you all.
I will post some photos next week.
The seat is made of horizontal plate on top and supported by two/ or one/two vertical rib(s) that are shaped like a triangle.

 

[U4ENIK]

Hi Everybody,
I have uploaded a photo of the connection so you can see what I am talking about.
Thank you again for your time.

 

[KootK]

There are several references that can be used for the design methodology. In my library, I've got:

- Blodgett as mentioned above.
- AISC Manual 14ed, figure 10-10.
- Salmon & Johnson: Link
- Lambert & Beedle: Link

In your opinion U4ENIK, are we seeing a plate assembly that is welded together? If so, my main concern would be with the weld quality as welding cast iron is difficult (Link). The plate elements look pretty thick so I doubt that they'll give you much trouble.

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.

 

[SlideRuleEra]

U4ENIK - Do you have a date, even an approximate one, for original installation of the cast iron column?

What are the shape and dimensions of the column?

Have you determined the column's original safe load rating? If so, what method was used and what value was obtained?

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[bookowski]

You didn't say if you were trying to modify or add load to the connection.

There is a lot of info out there, you need to look in restoration/preservation texts. I have dealt with a lot of these. My opinion is that there is no reliable way for you to predict the capacity. The usual logic is to not make it any worse, i.e. don't add load or change loading patterns or modify the connection.

If you look at historic values you will see cast iron allowable values get progressively lower until it was removed as a building material. It is very unpredictable.

There has been testing done on these types of connections. In general they were heavy with the seat and stiffener so it doesn't fail through shearing of the connection but rather tear out from the P x e moment on the wall of the cast iron.

Look at this thread and photo that I had posted for an example of a typical brittle failure that I have encountered with these.

http://www.eng-tips.com/viewthread.cfm?qid=380253