SacreBleu
Structural
- Apr 7, 2005
- 427
At work, we are having a difference of opinion.
Design of uniform thickness PT slab, on very expansive soil. The usual designs in this area are almost always 7.5" thickness, with tendons spaced to produce about 50-60 psi final (after friction losses) compression. Unfortunately, this project's soil report shows much more expansive soil, and the developer of the project is a tightwad. He may go ballistic if we design a 10" thick slab.
Therefore, an engineer here designed the usual 7.5" thick slab, but spaced the tendons 12" on center, which, in my opinion, is absurd. Also, my opinion is that providing so much posttensioning provides only a slight increase in slab capacity, as opposed to increasing the thickness. If the slab is increased to 10", however, the tendon spacing does get closer to maintain at least 50 psi compression.
I would rather risk the ire of the developer, and go with the 10" slab.
Any opinions?
Design of uniform thickness PT slab, on very expansive soil. The usual designs in this area are almost always 7.5" thickness, with tendons spaced to produce about 50-60 psi final (after friction losses) compression. Unfortunately, this project's soil report shows much more expansive soil, and the developer of the project is a tightwad. He may go ballistic if we design a 10" thick slab.
Therefore, an engineer here designed the usual 7.5" thick slab, but spaced the tendons 12" on center, which, in my opinion, is absurd. Also, my opinion is that providing so much posttensioning provides only a slight increase in slab capacity, as opposed to increasing the thickness. If the slab is increased to 10", however, the tendon spacing does get closer to maintain at least 50 psi compression.
I would rather risk the ire of the developer, and go with the 10" slab.
Any opinions?
