This document discusses various practical applications of post-tensioned concrete in buildings. It describes different types of post-tensioned slabs such as flat slabs, slabs with drop panels, slabs with post-tensioned beams, waffle slabs, and lightened slabs. It also discusses post-tensioned foundation rafts and transfer structures like beams and slabs. For each type, examples of real buildings are provided along with details like slab depths, spans, and loading capacities. The document aims to illustrate how post-tensioning techniques have been implemented successfully in a wide variety of building construction projects.
1. 09/09/2014 – GBB – Le béton post-contraint
Practical applications of
post-tensioned concrete in buildings
François LEPERS
CEO of GAMACO Ingénieurs-Conseils
2. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
3. Post-tensioned slabs (PT slabs) (1)
2 effects of the post-tensioning on the structures:
• Compression force
• Balanced loads
Global impact on the building design:
• reduced structure height
• No beams needed
Sketches from commercial documentation Freyssinet
PT slabs can be used in all kind of buildings : office buildings , apartment's building, hospital,
commercial center's, parking's, sport infrastructures, …
4. Post-tensioned slabs (PT slabs) (2)
Specific design consideration regarding to PT structures
Sketches from PT-structures.com
The slab has to be able to shorten freely at jacking
(elastic shortening due to the compressive forces)
When unfavorable cases occurs, specific execution details can be adopted to maximize the
compression force in the slab.
5. Post-tensioned slabs (PT slabs) (3)
Execution design studies :
usually in charge of specialized sub-contractors, as it is also the practice in the industry for
precast elements
6. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
7. Flat PT slabs (1)
bi-directional behavior – no beams
Classical Span/depth ratio :
(Hyperstatic slabs)
Overloads Span/Depth
1.5 kPa Up to L/45
2.5 kPa Up to L/40
5.0 kPa Up to L/35
Admissible spans : usually 6 to 12 m, but 16m often used in parking structures
Typical passive reinforcement :
general bottom mesh, top bars over the columns only, punching shear reinforcement and
bursting/edge reinforcement
8. Flat PT slabs (3)
110 000 m² of flat PT slabs: AZ GROENINGE - KORTRIJK
30000m² in 2004 (Cordeel)
75000m² in 2013 (CEI De Meyer & Jan De Nul)
Flat slab 250mm
Typical grid : 8.1m x 8.1m
Typical overloads : 6.0 kPa
Unbonded & bonded system
75000m² = 7 months on site !
+- 600m²/week/crane
(5 cranes)
9. Flat PT slabs (4)
EUROMED CENTER II – MARSEILLE - FRANCE
45 000 m² of flat PT slabs
Mixed building : parking, hotel, gardens, shopping mall & offices
Spans from 6.0m to 8.5m
10. Flat PT slabs (5)
DOCKS DE LYON – LYON - FRANCE
3 000 m² of flat PT slabs (currently in progress)
6 levels of offices
Spans : max 8.5m
Cantilevers : max 3.5m
Slab depth : 300mm, including integrated heating/cooling system (active floor)
11. Flat PT slabs (6)
BANK ACCORD – CROIX - FRANCE
8 000 m² of flat PT slabs (2013)
- parking (2.5 kPa)
- offices (6.0 kPa)
Spans : 10.m x 8.5 m
Slab depth : 250 / 260mm
12. Flat PT slabs (7)
MAISON DES SCIENCES HUMAINES – BELVAL - LUXEMBURG
30 000m² of flat PT slabs (2011-2012)
Spans :
12.0m isostatic & 12.0m x 8.0 m
Overloads : 6.1 kPa
Slab depth : 360 mm
Main engineer : BEST
12m
12m 8m
13. Flat PT slabs (7)
ARENDT HOUSE – KIRCHBERG - LUXEMBURG
8000m² of flat PT slabs (2013)
Spans : Maximum 17.0m
Overloads: 6.0 kPa
Slab depth : 35 cm
Main engineer : INCA
17m
14. Flat PT slabs (8)
GHELAMCO ARENA - GENT
10000m² of flat PT slabs (2013)
Spans : 10m x 10 m
Overloads : 5.0 kPa
Slab depth : 300 mm
15. Flat PT slabs (9)
PUBLIC PARKING – LA GARDE - FRANCE
12500m² of flat PT slabs (2012)
2 levels of parking
1 roof level with high loadings
Spans : 16.0m x 6.0 m
Overloads :
Parking 2.5 kPa
Roof 22.0 kPa
Slab depth :
Parking 350 mm
Roof 550 mm
16. Flat PT slabs (10)
PUBLIC PARKING – BETHUNE - FRANCE
10000m² of flat PT slabs
2 levels of parking
1 roof level with high loadings
Spans : 16.0m x 6.0 m
Overloads :
Parking 2.5 kPa
Roof 25 to 30 kPa
Slab depth :
Parking 350 mm
Roof 550 mm
17. Flat PT slabs (11)
PUBLIC PARKING – BETHUNE - FRANCE
18. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
19. Flat PT slabs with drop panels (1)
bi-directional behavior – no beams
Classical Span/depth ratio :
(Hyperstatic slabs)
Overloads Span/Depth
2.5 kPa Up to L/45
5.0 kPa Up to L/40
Admissible spans : from 10 to 16m
20. Flat PT slabs with drop panels (2)
COMMERCIAL CENTER IKEA – MOSCOW - RUSSIA
15 000m² of flat PT slabs
Project of commercial center
Spans : 16.0m x 16.0 m
Overloads : 15 kPa
Slab depth : 400mm + capital 4000x4000x300mm
21. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
22. slabs with PT beams (1)
one-directional behavior
Classical Span/depth ratio :
(Hyperstatic slabs)
Overloads PT Slab
Span/Depth
Beams
Span/Depth
2.5 kPa Up to L/45 Up to L/25
5.0 kPa Up to L/40 Up to L/20
Typical example : grid 16.0m x 8.0m
bi-directional behavior
Classical Span/depth ratio :
(Hyperstatic slabs)
Overloads Slab
Span/Depth
Beams
Span/Depth
2.5 kPa Up to L/45 Up to L/30
5.0 kPa Up to L/40 Up to L/25
Typical example : square grids from 12.0m
to 20.0 m
23. Slabs with PT beams (2)
PARKING & COMMERCIAL CENTER LECLERC – ROQUES (TOULOUSE) - FRANCE
35 000 m²
Spans : 16.0m x 8.0 m
Overloads : 2.5 kPa
Slab depth : 200 mm
Beams : 1000x600mm
24. Slabs with PT beams (3)
PARKING OF THE AIRPORT – ISTANBUL - TURKIE
35 000 m²
Spans : 16.0m x 16.0 m
Overloads : 5.0 kPa
Slab depth : 30cm
Flat beams : 300x60cm
25. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
26. Waffle PT slabs (1)
bi-directional behavior
Classical Span/depth ratio :
(Hyperstatic slabs)
Admissible spans : up to 16m
Overloads Span/Depth
2.5 kPa Up to L/30
5.0 kPa Up to L/25
27. Waffle PT slabs (2)
Parking 28 000 m²
Grid 16.0m x 7.0m
Waffle slab 400mm
PARKING OF A COMMERCIAL CENTER - AIX-EN-PROVENCE - FRANCE
28. Waffle PT slabs (2)
Ovoïdal shape in plan view
Waffle slab with variable thickness
ERNST&YOUNG - KIRCHBERG - LUXEMBURG
29. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
30. Lightened PT slabs (1)
Basic solution : polystyrene blocs (IMEC tower)
Other solutions : Cobiax, Uboot, Bubbledeck, …
The self-weight reduction is typically about 20% to 30% with this kind of solution.
This allows to reduce the PT and RC ratios in the slabs.
The economical balance has to be checked between material earnings and weight-reducing element
costs.
31. Lightened PT slabs (2)
PARKING ARLEQUIN – GRENOBLE - FRANCE
11 000 m² of lightened slabs (2013)
Isostatic spans : 10.5 m
Overloads : 2.5 kPa
Slab depth : variable from 30 to 35 cm
Lightening elements : Uboot
32. Lightened PT slabs (3)
TWARDA TOWER – WARSAW - POLAND
25 000 m² of lightened slabs (2012)
High-rise building – 44 floors
max spans : 9.20m
Slab thickness : 230 mm + Cobiax SL 120
Overloads : 5.0 kPa
33. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
34. PT slabs on wide slabs (1)
MAISON DU SAVOIR – BELVAL - LUXEMBURG
Cable profile
Typical section
35. PT slabs on wide slabs (2)
MAISON DU SAVOIR – BELVAL - LUXEMBURG
36. PT slabs on wide slabs (2)
BRUSSELS AIRPORT - ZAVENTEM
Terminal & Pier B
150 000 m²
Grid 8.0m x 8.0m
37. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
38. PT Foundation rafts (1)
WATER TREATMENT PLANT OF BRUSSELS NORTH - BRUSSELS
Foundation raft on piles : 25 000 m²
Other PT slabs : 50 000m²
General contractor : Jan De Nul
Piled raft supporting 10m of water
39. PT Foundation rafts (2)
HALA CZYZYNY - POLAND
Sport hall (Hockey)
Foundation raft : 12 500m²
Spans : up to 12m
Thickness : 1000mm
40. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
41. PT transfer structures (1)
Particularities :
• Initial stage is often critical (reversed moment conditions)
• Staging of the construction / jacking sequences
Finitial = 0
High tensile stresses + cracks
Finitial Finitial = = 0
100%
100% PT force
50% PT force
40%
100%
42. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
43. PT transfer beams (1)
8 isostatic beams 32 m AUDITORIUM - BORDEAUX
Superior building with 4 concrete level to support over a spectacle hall
Beams 200 x 220 cm
44. PT transfer beams (2)
HOTEL DE REGION – TOULOUSE - FRANCE
PT truss beam
PT in the tie elements of the truss
Cantilever 6.0m
45. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
46. PT transfer slabs (2)
APPARTMENT BUILDING - TEMSE
PT transfer slabs
240 mm
47. PT transfer slabs (2)
Bi-directional flat slab CITE JUDICIAIRE - LUXEMBURG
Max spans : 17.0m
Slab thickness : 130 cm
Loadings : 6 levels height building
48. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
49. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
50. Wall post tensioning (1)
2 cantilevers : 25m each MAISON DU SAVOIR – BELVAL - LUXEMBURG
1 central span > 50m
Main engineer : Jan Van Aelst
51. Wall post tensioning (2)
MAISON DU SAVOIR – BELVAL - LUXEMBURG
2 facade walls
2 inner walls
52. Wall post tensioning (3)
MAISON DU SAVOIR – BELVAL - LUXEMBURG
Inner walls
Central span 50 m Tower basement Right cantilever
25 m
Dilatation joint
54. Wall post tensioning (5)
MAISON DU SAVOIR – BELVAL - LUXEMBURG
Facade walls
Central span 50 m Tower basement Right cantilever
25 m
Dilatation joint
55. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
57. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
58. External PT reinforcement of existing structures (1)
EXHIBITION HALLS - CHARLEROI
Legend:
Main beams
Carbon fiber reinforcement of the main beams
External PT reinforcement of the secondary beams
59. External PT reinforcement of existing structures (2)
Vertical component of the equivalent loads due to PT
EXHIBITION HALLS - CHARLEROI
61. External PT reinforcement of existing structures (4)
Particular anchor system have been developed for reinforcement of existing structures
62. Practical applications of post-tensioned concrete in buildings
I. PT slabs
I. Flat PT slabs
II. Flat PT slabs with drop panels
III. Slabs with PT beams
IV. Waffle PT slabs
V. Lightened PT slabs
VI. PT slabs on wide slabs
VII. PT Foundation rafts
II. PT transfer structures
I. PT transfer beams
II. PT transfer slabs
III. Special PT applications
I. Wall prestressing
II. Hangers
III. External reinforcement of existing structures
IV. Post-tensioned concrete in silo’s
63. PT concrete in silo’s (4)
Annular compression = reduced cracks
WATER TREATMENT PLANT – BEAURADE - FRANCE
64. Practical applications of post-tensioned concrete in buildings
Thank you for your attention
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PLATINIUM TOWERS - WARSAW POLAND