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RE: PENNSYLVANIA BUILDING CODE - Historic Live Load Specification

[Subject Prev][Subject Next][Thread Prev][Thread Next] Bill,

Some designers and software developers make some wondrous assumptions in their design methodologies. Some defy normal engineering logic and are not conservative for flexural strength or serviceability calculations. They do not use "basic methodology" which I define to be design by first principles. They use short cut methods to save calculation time which is unnecessary in the days of computers plus some also seem develop theories and calculation methods based on erroneous assumptions.

At 10:33 PM 26/04/2005, you wrote:
The notion that design LLs haven't varied by much as far as the Code(s) is concerned is likely true. However, I'm not sure what you mean by "a load applied which is greater than that which they can adequately carry even though they may have been 'designed' for the correct load."
 
Do you mean that the methodology of that time may have been erroneous? Just as you point out in the case of the prescribed LLs, it is not likely that the basic methodology of prestressed concrete design is that different currently compared to the 1960s, at least not in the simple case that I'm looking at. In fact, as far as I know P/S design is the "last bastion" of allowable stress design in the concrete world. Outside of a rudimentary check for "flexural strength," it's all stress and service deflection analysis.


From: Gil Brock [ mailto:gil(--nospam--at)raptsoftware.com]
Sent: Monday, April 25, 2005 12:41 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: PENNSYLVANIA BUILDING CODE - Historic Live Load Specification

Bill,

With some of the interesting design theories and methods that have been and are still floating around it may be a case of them having a load applied which is greater than that which they can actually adequately carry even though they may have been "designed" for the correct load. Design loads have not really varied by a lot over the last 30 years in most cases.


At 02:25 AM 26/04/2005, you wrote:

I'm looking at a problem structure in Pennsylvania (Lancaster CO, to be more precise). Floor framing consists of p/s beams that have almost certainly seen a live load in excess of that for which they were designed. The current Pennsylvania Uniform Construction Code (IBC 2003) is pretty clear on what the minium design LL ought to be, but I'm wondering how that compares with what was in force (if any) when the structure was designed.

Does anyone possess any information on the Pennsylvania building code in effect during the early to late 1960s?

Thanks.


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Regards  Gil Brock
Prestressed Concrete Design Consultants Pty. Ltd. (ABN 84 003 163 586)
5 Cameron Street Beenleigh Qld 4207 Australia
Ph +61 7 3807 8022               Fax +61 7 3807 8422
email:            gil(--nospam--at)raptsoftware.com
email:            sales(--nospam--at)raptsoftware.com
email:            support(--nospam--at)raptsoftware.com
webpage:         http://www.raptsoftware.com

Regards  Gil Brock
Prestressed Concrete Design Consultants Pty. Ltd. (ABN 84 003 163 586)
5 Cameron Street Beenleigh Qld 4207 Australia
Ph +61 7 3807 8022               Fax +61 7 3807 8422
email:            gil(--nospam--at)raptsoftware.com
email:            sales(--nospam--at)raptsoftware.com
email:            support(--nospam--at)raptsoftware.com
webpage:         http://www.raptsoftware.com