cast iron (historic structures) design properties

[PT999]

I am analyzing a historic building with cast iron sidewalk platess which cover basement vault area below. I need the design properties for finite element analysis program

For design properties of this c1860 to 1900 cast iron, I have found properties for modern grey cast iron. Is this the same as my (historic) cast iron. Probably not

Does anyone know what grey cast iron means and what the difference is between regular cast iron and grey cast iron?


Does anyone know properties (E, poissons ratio, Fy, allowable stress, etc of my historic cast iron

There may be something is AASHTO load ratings for cast iron bridges, I don't have a copy of this

Is wrought cast iron different from cast iron? I think so.
Does this have different design properties also

 

[EnglishMuffin]

Wrought iron is ductile, most cast iron isn't. Wrought iron is heavily worked, and in earlier times it pretty much performed the role that mild steel does today. See this link for details on wrought iron :

http://www.nomma.org/support/wrought/wrought.htm

I would say gray cast iron pretty much is regular cast iron, but I could be wrong. It has a lot of free carbon in flake form, and looks gray when fractured.

Can't help much on anything else.

 

[LPPE]

Cast iron is terrible in tension.

 

[bertyboy]

PT999, and ScottishMuffin, hi !
Cast-iron was quite a common ingredient of American truss design, over 100 years ago, when most of the railways were being constructed. During this period 10's of thousands of bridges were being constructed across the US. Many of these bridges used types of trusses that utilised the compressive strength of cast-iron, and the tensile strength of wrought iron, e.g. The Bollman truss, and the Fink truss.

 

[JohnCT]

British Constructional Steelwork Association Ltd has a publication entitled "historical Structural Steelwork Handbook". Their associations address and contact numbers are as follows:

4 Whitehall Court
Westminster
London SW1A 2ES
England
UK
Tel: +44 (0)20 7839 8566
Fax: +44 (0)20 7976 1634


The book has properties of UK and European cast iron, wrought iron and steel sections since the mid 19th century. It includes design, load and stress data. There are figures quoted for ultimate and allowable stresses in the book but I'm not sure how these figures would compare with american iron of the same period.

You can view the book on the BCSA website:

http://www.steelconstruction.org/

or buy it for £27 sterling (+ postage) from BCSA.

 

[Qshake]

Cast-iron was also produced by just about anyone back in those days and so I would expect the properties to be extremely varied.

Anyone having an old sructural engineering handbook by Kirkham may find something. Otherwise a early book on structures from Hool and Kinne...

Just some thoughts.

Also, check out the FAQ for some ideas for old properties.

 

[jheidt2543]

Source:
Handbook of Building Construction
by G.A. Hool & N.C. Johnson
2nd Ed., McGraw-Hill, 1929

Page 64, Article 98 Cast-Iron Column Formulas:

"The most commonly used formulas for allowable stresses in cast-iron collumns are of the straight-line type. The Chicago and Seattle building codes specify an allowable unit stress of [10,000 - (60)L/r] psi, with a maximum of L/r at 70. The New York and Boston building codes specify an allowable unit stress of [11,000 - (30)L/r] psi with a maximum of L/r at 70. The Philadelphia code specifies an allowable unit stress of [11,670/(1+L^2/400d^2)] psi; in which "d" is the least dimension in inches and also specifies a maximum length of 20d."

I should note that L and r are also both in inches.

Source:
Structural Members and Connections
by G.A. Hool and W.S. Kinne
2nd Ed., McGraw-Hill, 1943

Page 299, Article 71 Properties of Cast Iron

"Cast-iron has a very high unit compressive strength - usually considered to be about 80,000 psi. This material however, is not strong in shear or tension, the average ultimate shearing stress being 18,000 psi. and the average ultimate tensile stress 15,000 psi. ...."

I hope this helps.

 

[Grouser]

Here's another source for info: American Foundry Society. I checked the American Iron & Steel Institute web page but didn't see anything that might relate to historic practices. Most metallurgy info seems to be focused on recent developements.
Good luck.