Post-Tensioned Slab-On-Grade
Post-Tensioned Slab-On-Grade
(OP)
Hi,
I am new to this subject, but am designing a 125*100 foot rectangular foundation on expansive soil (with post-tensioned slab on ground with ribs in Houston, TX. PTI-DC10.1-08 gives several design examples for Extreme dry, Extreme Suction profile and wet climate. Do I have to do the design for all conditions or only one? If only one condition? which and how should I select it? Please advise.
Depth to water table is 9feet. Given constant suction, velocity of moisture flow, thronwaite moisture index, effective PI (29%)
I am new to this subject, but am designing a 125*100 foot rectangular foundation on expansive soil (with post-tensioned slab on ground with ribs in Houston, TX. PTI-DC10.1-08 gives several design examples for Extreme dry, Extreme Suction profile and wet climate. Do I have to do the design for all conditions or only one? If only one condition? which and how should I select it? Please advise.
Depth to water table is 9feet. Given constant suction, velocity of moisture flow, thronwaite moisture index, effective PI (29%)






RE: Post-Tensioned Slab-On-Grade
RE: Post-Tensioned Slab-On-Grade
RE: Post-Tensioned Slab-On-Grade
Sounds like you have it right with the conventionally reinforced, ribbed slabs. I wouldn't use PT in those situations, as the crack control provided would be close to nil.
RE: Post-Tensioned Slab-On-Grade
Restrained unbonded PT is not much use for crack control. Bonded PT is not much better. The PTI logic that the PT slab is much stiffer only works if the concrete is uncracked. There is little chance of that, considering the low levels of P/A used and also the restraint that reduces this effectively to zero and the section is in tension. And if it is cracked without any bonded PT, it will be much less stiff than a conventionally reinforced section of the same shape.
Have not seen the other method mentioned.
Bonded reinforcement is required at relatively close spacings.
RE: Post-Tensioned Slab-On-Grade
Dik