Post-Tensioned Slab-on-grade Foundations

[Jimerna]

Is there anyone out there designing these slabs to be placed on expansive soils? In other words, on Houston gumbo.

 

[newbuilder]

Are these foundations popular in the states?

I have come across a company named "Elspan" who specialize in this structure along the SE Asia area.

nb

 

[Qshake]

I have only heard of them in the southern US as Jimerna point out. So I don't think they are very popular at all.

I haven't designed one to answer Jimerna's question.

 

[jhall]

Post tensioned slab on grade construction is common in the west coast. The post tension institute (PTI) has a design manual for a post tensioned slab on grade. You may also consider contacting your geotech, he or she could get you more information on other projects they may have down in that area.

 

[kocos]

Post Tensionong Institute has a software for the design. It is worthwile to use it.

 

[swthwdy]

Be careful of Post Tensioned foundations in expansive clay soil, and especially in the unincorporated areas of Texas. There is no licensing of homebuilders in Texas, and no inspections required in Counties outside of City boundaries.
Our Post Tension Foundation is labeled by our Engineers as "extremely non-uniform" and "economically uncorrectable".
Some builders cut corners, run into difficulty because of lack of experience or just plainly don't care about good workmanship, just the $ for a finished product.
Our builder tried to cover up the defects. Our cost of discovery, litigation, anquish we have experienced, and watching our 5 year old model home deteriorate, has been devastating.
We have found one tendon that was not stressed, and broke when the PT Co. tried to stress it after 5 years, one
tendon too deep in the Slab, and the r-meter cannot find any other tendons, re-bar, or mesh anywhere in the
foundation. Therefore, we have interior and exterior differential settlement which Post Tension is supposed to at least minimize if constructed correctly.
The State of Texas and Texas Counties are certainly remiss in not regulating homebuilders and inspections of new construction in unincorporated areas. Professional Engineers and/or ASHI Inspectors should seal all new foundations whether Post Tension or regular residential Slab on Grade.
Any ideas?













Texas is certainly remiss in not regulating licensed inspection in an important arena such as a Post Tension Slab on Grade for residential.
Professional Engineers and ASHI inspectors should seal inspections of all foundations.

 

[geonerd]

PT Slabs are very common in Southeast Louisiana. We have some of the softest soils in the country. But our soils in this area are not typically expansive, they are more compressible.