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RE: STANDARD PRACTICE

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Bill,
What building code is being used in the Dallas area? The reason I ask is that compliance to a design standard is not generally defined by a Professional Act (which I assume is you were referring to) but rather by the minimum standards defined within the adopted building code. I'm used to addressing standards in high risk regions and even the UBC Conventional Construction provision is limited to 80-mph High wind provisions. Beyond this, engineering design is required.
 
I find it difficult to comprehend that a 25,000 square foot custom home could be designed by prescriptive methods when  unless all bearing walls conform with available span tables. Still, I believe that most of the conventional codes limit plate heights to 8'-0" before requiring engineering.
 
Conventional Construction (prescriptive) provisions of the 97 UBC are limited by geometry. Structural irregularities such as non-stacking shearwalls, cantilevers in the diaphragm or discontinuities in lines of lateral resistance (including wind) will require engineering.
 
I'm not arguing this point - I'm confused as the NEHRP drafts for wood design in seismic and high wind regions that is proposed for the next IBC code is pretty specific about the limits of prescriptive construction - as is the HUD standards. This thread has made me aware of facts I never was aware of in the past. While I'm sure it is a shock to those of us in California, it explains many of the comments from engineers back east who don't appear to understand that lateral design is not simply a seismic provision but is considered wherever Wind occurs.  Conversely, it is understandable in areas of the country where seismic risk is low or non-existent and low-rise buildings are typically veneered in brick rather than siding or stucco. These homes are not at risk of seismic or wind as the weight of the brick works to the homes advantage. Having grown up in Chicago it is understandable why prescriptive methods are used more often in residential construction than full-engineering design.
 
Dennis
-----Original Message-----
From: Bill Polhemus [mailto:bill(--nospam--at)polhemus.cc]
Sent: Thursday, June 14, 2001 10:16 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: STANDARD PRACTICE

-----Original Message-----
From: Caldwell, Stan [mailto:scaldwell(--nospam--at)halff.com]
Sent: Thursday, June 14, 2001 11:26 AM
To: 'seaint(--nospam--at)seaint.org'
Subject: RE: STANDARD PRACTICE

 
The reality in California is obviously different than elsewhere.  The vast majority of single family homes east of the Rockies are not engineered structures, not even the expensive ones.  In Dallas, the local home builders are building $5 million (25,000 s.f.) spec homes without any engineering whatsoever, except for the foundation.  In fact, I don't think that I've ever even met a local engineer who works with stick-built wood frame construction.
From the Texas P.E. Board Enforcement FAQ:
 
Q. How does an individual know when is engineering required?
 
A. Refer to Section 19 of the Texas Engineering Practice Act (TEPA).
Private dwellings that are exceeding eight units for one-story buildings or exceeding four units for two-story buildings. Other buildings having more than one story and containing a clear span between supporting structures greater than 24 feet on the narrow side and having a total floor area over 5,000 square feet. (See Section 20 (d) of the TEPA).

William L. Polhemus, Jr., P.E.
Polhemus Engineering Company
Katy, Texas
Phone 281-492-2251
Fax 281-492-8203