] [Thread] [Date] [Author]

[Harold Sprague <harold.sprague(--nospam--at)neenan.com>]

Tahir,

There is a lot to reinforcing old steel structures.  First, make sure that
what you have is steel as opposed to cast iron.  Secondly you need to
determine the carbon equivalents by testing the chemistry of the material.
The frequency and location of the testing is crucial.  Older steels had
irregular chemistries from section to section and even within the same
section you can have carbon lenses.  

High carbon equivalents are a particular problem in older steels.  This
makes them a problem for welding and cyclic loading.  They will, in general,
not be a tough steel.  The carbon equivalents will dictate welding
procedure, and whether or not the steel can be welded at all.

The connections will probably be riveted, and you will also need to
determine the type and strength of rivets.

Re: 
1.	AISC Engineering Journal, 4th quarter, Reinforcing Steel Members and
the Effects of Welding, by R. H. R. Tide.  
2.	Proceedings, AISC National Engineering Conference, New Orleans,
April 1987, Basic Considerations When Reinforcing Existing Steel Structures,
R. H. R. Tide.

Tide is with Wiss, Janney & Elstner in Northbrook, IL.

Calculating the revised section properties is the easiest part.  There is an
example in Omer Blodgets, Design of Welded Structures.

Harold Sprague, P.E.
The Neenan Company
harold.sprague(--nospam--at)neenan.com


-----Original Message-----
From: TahirQ(--nospam--at)aol.com [mailto:TahirQ(--nospam--at)aol.com]
Sent: Monday, October 05, 1998 7:25 PM
To: seaint(--nospam--at)seaint.org
Subject: 1903 STEEL BEAM ANALYSIS


STRUCTURAL ENGINEERS;

I am working on evaluating a 1903 Structural Steel Building to load more
weights on the existing beams/girders.  Any body out there has a
sample/example for me.  I have done some work and I want to check my work to
make sure.  The allowable stress is 16 Ksi.  I am particularly interested in
shear stress analysis and how to retrofit the existing beams i.e., adding
steel plates at bottom etc.  A hand written example will do, I have a
spreadsheet to calculate moment of inertia for the old AMERICAN STANDARD
BEAMS (Rolled I-Sections 15" I-60 , etc.)

Also, any ideas how deal with the connections.  There are no as-built plans
to find out existing connection details. Thanks in advance for your help.

REGARDS,
Tahir