Tuesday, December 6, 2011

RE: Structural Design with Bronze

Bronze for structural design is a bit problematic without ASTM's for all of their product lines.  The yield stresses vary from 16 ksi to 35 ksi.  Modulus of elasticity is 14,000 ksi.  The most common bronze for architectural applications is called Bronze 385.  The extruded Bronze 385 is ASTM B455.  There was also the ASTM E54 for analysis, but this document was superseded with no replacement and officially withdrawn by ASTM. 
If you build it out of bronze, I would suggest a load test for verification.  Although the Hyatt walkways failed in 1981, the cantilevered steel stair in the atrium is still in place after over 30 years of service primarily because it was load tested for verification.   
I would use the lower bound for stresses. 
Now for the nitty gritty; go to http://www.juliusblum.com/downloads/Catalog.pdf , download a copy of the catalog, and go to "Engineering Data".  Your welding spec will be interesting.  I would suggest you reference The Procedure Handbook of Arc Welding by Lincoln Electric, Section 10.1. 
You can weigh this against making it out of steel and cladding the stair in bronze. 

Regards, Harold Sprague

To: seaint@seaint.org
Subject: Structural Design with Bronze
From: fsrahbar@aol.com
Date: Tue, 6 Dec 2011 10:59:43 -0500

Does anyone know where we might be able to find structural properties for Bronze? A client of ours would like to build a stairs in a commercial building out of Bronze!
Thank you,

Farzin S. Rahbar, SE
Vice President
David C. Weiss Structural Engineer & Associates, Inc.