Post-tensioning is simply a method of producing prestressed concrete, masonry, and other structural elements. Post-tensioning is a form of prestressing. Prestressing simply means that the steel is stressed (pulled or tensioned) before the concrete has to support the service loads. Most precast, prestressed concrete is actually pre-tensioned-the steel is pulled before the concrete is poured. Post-tensioned concrete means that the concrete is poured and then the tension is applied-but it is still stressed before the loads are applied so it is still prestressed.

1. POST TENSIONED
FLOOR SYSTEM
Prepared by
Aditya Shah (M.Tech CPM)
Building Construction System

2. INTRODUCTION
Post-tensioning is
simply a method of
producing
prestressed
concrete, masonry,
and other
structural
elements
process of
introducing internal
stress into a concrete
during the
construction process
in order to
counteract the
external loads
applied when the
structure is put into
use
Internal forces are
applied by
tensioning HS
steel

3. WORKINGOF
PT FLOOR

4. EXECUTION
METHODOLOGY
 Construction of post-tensioned slabs on grade is very similar to
using reinforcing steel, except for the tensioning step. Step wise
construction of post tension floor is given below.
 1. Form work setup
 2. Placing of bottom reinforcement
 3. Fixing of bar chair for PT tendon
 4. Placing PT tendon
 5. Fixing anchorage burstling reinforcement
 6. Placing of top reinforcement
 7. Placing anchorage pocket former and grout vent
 8. Fixing slab edge formwork with pocket former
 9. Concreting of slab

5.  10. Removal of slab edge formwork
 11. Remove pocket former
 12. Placing anchor head and wedge in position
 13. Stressing
 14. Cutting end of strand
 15. Capping stressing recess with cement mortar
 16. Grouting
 17. Repeat for next floor slab

6. COMPONENTS

8. ADVANTAGES
OF PT FLOOR
Lighter and
Slender
members are
possible.
remains un-
cracked under
Service load.
improves
serviceability
Fast
construction
can achieved
Flat soffit
reduces
shuttering,
plastering and
painting cost.
Reduces
building height

10. DISADVANTAGES
Chances of
corrosion are
high
Complexity of
work
Lead to
accidents

11. ECONOMICS
• Post-tensioned should
be considered as a
possible economic
alternative for most
structures when spans
exceed 7.0 meters.

12. ECONOMICS
 P-T reduces the concrete volume by 10 to 20%.
 Cost of PT is typically 20 to 30% less as compared to
conventional reinforced structure.
 For flat slab in 8m x 8m or 9m x 9m Grid, P-T costs approximately
Rs. 40 to 50 per sq. ft. with any kind of desired geometry
availed better than R.C.C.
 Since the reinforcement is protected, P-T reinforced structures
have lower annual maintenance costs overtime

13. SPEED OF
CONSTRUCTION
 The comparison of PT and RCC slab is carried out on Strata SE1
project located in center London. The building is a residential high-
rise 147 meters in height with 41 post-tensioned flat slabs.
 The average area of the slab is 630 sqm.
 The floor cycle estimates using the same criteria for PT and RCC
are respectively 5 and 6.5.
 This yields a total increase of 60 working days between PT
and RCC.

14.  Time saving on the PT option is due to less material and hence less
installation time and labor, to stressing of the tendons and
consequently early deshoring.
 The actual floor-cycle achieved on the PT slab was 4.5 days on
average.

15. REFERENCES
 [1] “POST-TENSIONING IN BUILDING STRUCTURES”, Ed Cross1
BE, Grad.Dip(Tech.Mgt), MIEAust, CPEng.
 [2] POST-TENSIONEDSLABS, PUBLISHED BYVSL
INTERNATIONAL LTD.
 [3] Sanfield (India) LTD., PT Slab brochure.
 [4] “A PROJECT-BASEDCOMPARISON BETWEEN REINFORCED
AND POST-TENSIONED STRUCTURES FROMA SUSTAINABILITY
PERSPECTIVE.”,Carol Hayek & Saleem Kalil.
 [5] www.concreteconstruction.net

16. Thank you