PT STRUCTURES IN BUILDINGS

Practical applications of post-tensioned concrete in buildings

09/09/2014 – GBB – Le béton post-contraint

François LEPERS CEO of GAMACO Ingénieurs-Conseils


I. PT slabsI. Flat PT slabsII. Flat PT slabs with drop panelsIII. Slabs with PT beamsIV. Waffle PT slabsV. Lightened PT slabsVI. PT slabs on wide slabsVII. PT Foundation rafts

II. PT transfer structuresI. PT transfer beamsII. PT transfer slabs

III. Special PT applicationsI. Wall prestressingII. HangersIII. External reinforcement of existing structuresIV. Post-tensioned concrete in silo’s

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

PT slabs can be used in all kind of buildings : office buildings , apartment's building, hospital, commercial center's, parking's, sport infrastructures, …

Sketches from commercial documentation Freyssinet


Specific design consideration regarding to PT structures

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.

Sketches from PT-structures.com


Execution design studies : usually in charge of specialized sub-contractors, as it is also the practice in the industry for precast elements

Flat PT slabs (1)

bi-directional behavior – no beams

Classical Span/depth ratio :(Hyperstatic slabs)

Admissible spans : usually 6 to 12 m, but 16m often used in parking structuresTypical passive reinforcement :

general bottom mesh, top bars over the columns only, punching shear reinforcement and bursting/edge reinforcement

Overloads Span/Depth1.5 kPa Up to L/452.5 kPa Up to L/405.0 kPa Up to L/35

Flat PT slabs (3)

AZ GROENINGE - KORTRIJK110 000 m² of flat PT slabs:30000m² in 2004 (Cordeel)75000m² in 2013 (CEI De Meyer & Jan De Nul)

Flat slab 250mmTypical grid : 8.1m x 8.1mTypical overloads : 6.0 kPaUnbonded & bonded system

75000m² = 7 months on site !+- 600m²/week/crane

(5 cranes)

Flat PT slabs (4)

EUROMED CENTER II – MARSEILLE - FRANCE

45 000 m² of flat PT slabsMixed building : parking, hotel, gardens, shopping mall & officesSpans from 6.0m to 8.5m

Flat PT slabs (5)

DOCKS DE LYON – LYON - FRANCE

3 000 m² of flat PT slabs (currently in progress)6 levels of officesSpans : max 8.5mCantilevers : max 3.5mSlab depth : 300mm, including integrated heating/cooling system (active floor)

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 mSlab depth : 250 / 260mm

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 mOverloads : 6.1 kPaSlab depth : 360 mmMain engineer : BEST

12m

12m 8m

Flat PT slabs (7)

ARENDT HOUSE – KIRCHBERG - LUXEMBURG

8000m² of flat PT slabs (2013)Spans : Maximum 17.0mOverloads: 6.0 kPaSlab depth : 35 cmMain engineer : INCA

17m

Flat PT slabs (8)

GHELAMCO ARENA - GENT

10000m² of flat PT slabs (2013)Spans : 10m x 10 mOverloads : 5.0 kPaSlab depth : 300 mm

Flat PT slabs (9)

PUBLIC PARKING – LA GARDE - FRANCE12500m² of flat PT slabs (2012)2 levels of parking1 roof level with high loadingsSpans : 16.0m x 6.0 mOverloads :

Parking 2.5 kPaRoof 22.0 kPa

Slab depth :Parking 350 mmRoof 550 mm

Flat PT slabs (10)

PUBLIC PARKING – BETHUNE - FRANCE

10000m² of flat PT slabs 2 levels of parking1 roof level with high loadingsSpans : 16.0m x 6.0 mOverloads :

Parking 2.5 kPaRoof 25 to 30 kPa

Slab depth :Parking 350 mmRoof 550 mm

Flat PT slabs (11)

PUBLIC PARKING – BETHUNE - FRANCE

Flat PT slabs with drop panels (1)

bi-directional behavior – no beams


Admissible spans : from 10 to 16m

Overloads Span/Depth2.5 kPa Up to L/455.0 kPa Up to L/40

Flat PT slabs with drop panels (2)

COMMERCIAL CENTER IKEA – MOSCOW - RUSSIA

15 000m² of flat PT slabsProject of commercial centerSpans : 16.0m x 16.0 mOverloads : 15 kPaSlab depth : 400mm + capital 4000x4000x300mm

slabs with PT beams (1)

one-directional behavior


Typical example : grid 16.0m x 8.0m

Overloads PT Slab Span/Depth

BeamsSpan/Depth

2.5 kPa Up to L/45 Up to L/255.0 kPa Up to L/40 Up to L/20

bi-directional behavior


Typical example : square grids from 12.0m to 20.0 m

Overloads Slab Span/Depth

BeamsSpan/Depth

2.5 kPa Up to L/45 Up to L/305.0 kPa Up to L/40 Up to L/25

Slabs with PT beams (2)

PARKING & COMMERCIAL CENTER LECLERC – ROQUES (TOULOUSE) - FRANCE

35 000 m²Spans : 16.0m x 8.0 mOverloads : 2.5 kPaSlab depth : 200 mmBeams : 1000x600mm

Slabs with PT beams (3)

PARKING OF THE AIRPORT – ISTANBUL - TURKIE

35 000 m²Spans : 16.0m x 16.0 mOverloads : 5.0 kPaSlab depth : 30cmFlat beams : 300x60cm

bi-directional behavior


Admissible spans : up to 16m

Waffle PT slabs (1)

Overloads Span/Depth2.5 kPa Up to L/305.0 kPa Up to L/25

Parking 28 000 m²Grid 16.0m x 7.0m Waffle slab 400mm

Waffle PT slabs (2)

PARKING OF A COMMERCIAL CENTER - AIX-EN-PROVENCE - FRANCE

Ovoïdal shape in plan view Waffle slab with variable thickness

Waffle PT slabs (2)

ERNST&YOUNG - KIRCHBERG - LUXEMBURG

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.

http://www.google.be/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=CNz4CymT8rQq8M&tbnid=LAAx3buPrDALYM:&ved=&url=http://www.bubbledeck.com.vn/quytrinhthicongsanBD.html&ei=P1XvU6byBuyh7Aamv4GACw&bvm=bv.73231344,d.ZGU&psig=AFQjCNE8f-KJU6VYQWB_Mub68QDob9t0Uw&ust=1408280255516387


PARKING ARLEQUIN – GRENOBLE - FRANCE

11 000 m² of lightened slabs (2013)Isostatic spans : 10.5 mOverloads : 2.5 kPaSlab depth : variable from 30 to 35 cmLightening elements : Uboot


TWARDA TOWER – WARSAW - POLAND

25 000 m² of lightened slabs (2012)High-rise building – 44 floorsmax spans : 9.20mSlab thickness : 230 mm + Cobiax SL 120Overloads : 5.0 kPa

PT slabs on wide slabs (1)

MAISON DU SAVOIR – BELVAL - LUXEMBURG

Cable profile

Typical section


BRUSSELS AIRPORT - ZAVENTEM

Terminal & Pier B150 000 m²

Grid 8.0m x 8.0m

PT Foundation rafts (1)

WATER TREATMENT PLANT OF BRUSSELS NORTH - BRUSSELS

Foundation raft on piles : 25 000 m²Other PT slabs : 50 000m²General contractor : Jan De NulPiled raft supporting 10m of water

PT Foundation rafts (2)

HALA CZYZYNY - POLAND

Sport hall (Hockey)Foundation raft : 12 500m²Spans : up to 12m Thickness : 1000mm

PT transfer structures (1)

Particularities : • Initial stage is often critical (reversed moment conditions)

• Staging of the construction / jacking sequences

High tensile stresses + cracks

Finitial = 0

Finitial = 0

100% PT force

50% PT force

Finitial = 40%

100% PT force

Finitial = 100%

50% PT force

Finitial = 40%

100% PT force

PT transfer beams (1)

AUDITORIUM - BORDEAUX8 isostatic beams 32 mSuperior building with 4 concrete level to support over a spectacle hallBeams 200 x 220 cm

PT transfer beams (2)

HOTEL DE REGION – TOULOUSE - FRANCE

PT truss beamPT in the tie elements of the trussCantilever 6.0m

PT transfer slabs (2)

APPARTMENT BUILDING - TEMSE

PT transfer slabs240 mm

PT transfer slabs (2)

CITE JUDICIAIRE - LUXEMBURGBi-directional flat slabMax spans : 17.0mSlab thickness : 130 cmLoadings : 6 levels height building

Wall post tensioning (1)

MAISON DU SAVOIR – BELVAL - LUXEMBURG2 cantilevers : 25m each1 central span > 50mMain engineer : Jan Van Aelst



2 facade walls2 inner walls


MAISON DU SAVOIR – BELVAL - LUXEMBURGInner walls

Central span 50 m Tower basement Right cantilever25 m

Dilatation joint


MAISON DU SAVOIR – BELVAL - LUXEMBURGInner walls


MAISON DU SAVOIR – BELVAL - LUXEMBURGFacade walls

Central span 50 m Tower basement Right cantilever25 m

Dilatation joint

Hangers TWARDA TOWER – WARSAW - POLANDHigh-rise building (160m)

44 levelsCantilever 11m PT Hangers

External PT reinforcement of existing structures (1)

Legend:Main beamsCarbon fiber reinforcement of the main beamsExternal PT reinforcement of the secondary beams

EXHIBITION HALLS - CHARLEROI

Vertical component of the equivalent loads due to PT



Particular anchor system have been developed for reinforcement of existing structures


Annular compression = reduced cracks

PT concrete in silo’s (4)

WATER TREATMENT PLANT – BEAURADE - FRANCE

Thank you for your attention


www.gamaco.eu

PLATINIUM TOWERS - WARSAW POLAND

PT STRUCTURES IN BUILDINGS

Engineering

Transcript of PT STRUCTURES IN BUILDINGS