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RE: Tilt Up systems

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Title: RE: Tilt Up systems

Walter Sheen wrote:

We would think about a 4 inch thick panel with one wwm in the middle.

Walter:

Your walls bring back some old memories.  A few years ago, we designed an industrial park with nine warehouses in suburban Monterey, Mexico.  Our first choice was concrete tiltwall construction, since we annually design millions of square feet of tiltwall warehouses in Texas.  However, the client (who also was the owner, the developer, and the contractor) insisted on cast-in-place concrete walls because she had fabricated a fleet of large, reusable steel plate wall forms (a.k.a., molds).  She invited us to Monterey to tour her last industrial park, which apparently did not involve any engineers.  What we observed were cast-in-place concrete walls that were approximately 4" thick.  It was obvious that the walls were reinforced with 4"x4" WWF because the tell-tale grid was frequently visible on the inside or outside wall surfaces.  I jokingly commented that a swift kick might puncture the walls, and she admitted that this occasionally had happened but that the WWF prevented any intruders larger than rodents!

Finally, I explained that we could not possibly produce a similar design without substantially violating good engineering judgment and numerous (US) building code provisions.  It addition, the corrugated metal roof deck wasn't even close to acting as a diaphragm for lateral loads, etc.  I again proposed tiltwall construction.  She responded that tiltwall was unknown technology in Monterey and she didn't want to be first.  In addition, she didn't have access to a large enough crane to lift the wall panels, but she had unlimited access to cheap labor.  We ended up designing her new warehouses with 6" cast-in-place walls (with legitimate steel rebars) designed to accommodate her modular "molds".  It took a long time to construct all of the buildings.  Meanwhile, she soon started calling us complaining that two new competing industrial parks were now under construction not far away.  Both were tiltwall construction and were started long after but finished long before our project.  We concluded that this virtually guaranteed that we would be able to design her next industrial park as tiltwall construction.  Wrong!  She reverted back to her original scheme, with no engineering.

Tiltwall is a very economical way to construct durable buildings up to 3-4 stories, but only if you have appropriate local infrastructure.  Specifically, there must be a community of hungry contractors who are both knowledgeable and experienced with tiltwall construction, as well as readily available cranes with adequate capacity and reach.

Best regards,

Stan R. Caldwell, P.E., F.ASCE
Vice President
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Halff Associates, Inc.
8616 Northwest Plaza Drive
Dallas, Texas  75225
Phone:  (214) 346-6280
Fax:  (214) 739-0095
Email:  scaldwell(--nospam--at)halff.com
Website:  http://www.halff.com
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