PRESTRESSED CONCRETE PART 3

Bonded PT

Stress transfer is through bond (require cement grouting)
strain compatibility between strand and concrete

Very common in Australia, Middle East, and Europe

Unbonded PT

stress transfer is through anchorage
no grouting required
no strain compatibility
strand and concrete moves independently

Very common in North America

Mono strand system

strands in tendon are stressed separately usually 1, 3 or 5 strands per tendon

Used in slabs or beams

Multi strand system

strands in a tendon are stressed at the same time (16, 19, as much as 37 strands per tendon)

Used in bridges, and in buildings (transfer beams)

PT structures are used in

slab on grade (for houses in expansive soil)
Mat foundation (raft)
parking structures
flat plate
bridges (Girder type, cable stay, suspension)
silos
water tanks
walls (currently becoming common for shear walls in seismic areas)

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