Posttensioned CFRP‐plates

StressHead - CarboStress

10. December 2019

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Schedule

Company StressHead Ltd System References

Bridge strengthening Industrial- and high-rise buildings Earthquake strengthening

Tests & Design Discussion

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Speaker

Dr. Gregor SchweglerDr. sc. techn. Dipl. Ing. ETH /SIACEO / Owner

Marcel ReyBSc. Ing. FHTechnical and Business Development Manager

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Company

Company established since 1999

Located in Switzerland (Lucerne)

International active Partner of Sika

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Experience

Switzerland

International

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System

Bridge strengthening Strengthening of industrial and high-rise buildings

Earthquake strengthening

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System

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System

Standard anchor Type III

Fixed anchor side movable anchor – tensioning side

P0 = 220kN

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System

Standard anchor Type III

Fixed anchor side movable anchor – tensioning side

P0 = 220kN

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System

StressHeadType StressHead 220Material CFRPWeight 550 gDimensions Ø 80 x 110 mm

PlateType SIKA CarboDur S626Material CFRPWeight 250 g/mDimensions 60 x 2.6 mm = 156 mm2

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System

Characteristics StressHead-CarboStress SystemPost-tensioning force FP0 = 220 kNGuarantied anchored force FPsk,min = 300 kNTendon testing in factory (if requested) P0 + 10% = 242 kN

Characteristics of Plate (SIKA CarboDur S626)Post-tension at FP0 = 220 kN σP0 = 1‘410 N/mm2

Tensile strength σu = 2'800 N/mm2

Post-strain at FP0 = 220 kN εP0 = 0.85 %Longitudinal modulus (standard modulus) Emin = 165’000 N/mm2

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System

Benefits of CFRP

Light weight Easy to install Noncorrosive Unlimited length Less labor than conventional steel solutions

Additional benefits of CarboStress

Active external post-tensioning Structure safety and serviceability problems Application under operational conditions

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Anchor Types

Standard anchor Type III

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Anchor Types

Standard anchor Type II (Through ceiling or wall)

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Anchor Types

Various anchorages

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Application (e.g. Typ III)

Define location Drilling Installation & injectionChipping

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Application (e.g. Typ III)

Installation of tendon Appling of adhesive(if bonded)

Protection (optional)Tensioning of tendon

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Protection (optional)

Protection against fire (e.g. Promat Plates)

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Protection (optional)

Protection of plates against mechanical impact

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References

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Strengthening of Bridges

Strengthening of bridges:

1. Shear

2. Widening of the super

structure

3. Wind / noise barrier walls

4. Longitudinal and transverse

5. Pier heads

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Pontcharra (FR) – Small space, precast elements

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Pontcharra (FR) – Small space, precast elements

Two CarboStress-Systems per beam

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Pontcharra (FR) – Small space, precast elements

Two CarboStress-Systems per beam

(16’’)

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Qatar (QA) – High reinforcement with multilayer

Bridge N29 in Qatar: Compensation of lost post-tensioning force

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Qatar (QA) – High reinforcement with multilayer

Bridge N29 in Qatar: Compensation of lost post-tensioning force

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Qatar (QA) – High reinforcement with multilayer

The solution: 16 Prestressed CFRP-Plates and Sika-Wrap on the outside

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Qatar (QA) – High reinforcement with multilayer

The solution: 16 Prestressed CFRP-Plates

Stacks of5 systemsStack of

6 systems

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Spreitenbach (CH) – Bridge strengthening

Sandacher-Bridge in Switzerland: Built in 1969/70

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Spreitenbach (CH) – Bridge strengthening

Cross-section

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Spreitenbach (CH) – Bridge strengthening

Longitudinal Section

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Spreitenbach (CH) – Bridge strengthening

Arrangement of 18 Prestressed CFRP-Plates (18 plates=3’960kN)

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Spreitenbach (CH) – Bridge strengthening

Arrangement of 18 Prestressed CFRP-Plates (18 plates=3’960kN)

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Strengthening of Industrial and High-rise buildings

Industrial and high-rise buildings:

1. Slab and beam strengthening

2. Earthquake strengthening

3. Strengthening due to changes

Ideal application criteria:

- High strengthening degree

- Serviceability problems

- Strengthening of prestressed

structures

- Cracked concrete

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Vienna (AT) – Serviceability problem

Casino – Romoval of existing pillars

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Lucerne (CH) – Extend span of beam

Paper plant Perlen, new columns

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Lucerne (CH) – Extend span of beam

New situation with displaced columnsnew columns

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Trainstation. New pedestrian tunnel

Bern (CH) – Structural change

New tunnel

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Trainstation. New pedestrian tunnel

Bern (CH) – Structural change

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Würenlingen (CH) – Silo strengthening

Silo strengthening

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Earthquake Strengthening

Strengthening of masonry walls

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Bern (CH) – Precast concrete elements

Fellergut – Lack of reinforcement in the joints

Source Pläne: W2H Architekten AG

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Windisch (CH) - Earthquake Strengthening

Object: Office building Switzerland Refurbishment: 2 Basements Ground floor 7 floors 1 additional floor

Problem: Earthquake safety Compliance factor according to SIA 2018 αeff = 0.10

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Windisch (CH) - Earthquake Strengthening

Dimension 14 x 34 m Height 25 resp. 30 m

Structure Skeleton structure with concrete columns and core Durisol masonry system

Problem Big eccentricity between centre of mass

and centre of rigidity West-Facade (αeff = 0.10)

ConcreteMasonry

General floor layout

Ground floor

Nord

Süd

West

Nord

Süd

West

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16 StressHead CarboStress Systems

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Muotathal (CH) – Earthquake strengthening

School building

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Muotathal (CH) – Earthquake strengthening

School building

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Muotathal (CH) – Earthquake strengthening

School building

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Visp (CH) - Earthquake Strengthening

Hospital Visp (Building class III)

4 concrete wallsL = 2.4 – 4.5mH = 21 – 22m

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Design

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Tests

University of Lucerne (CH) Different anchors, strengthened slab

Politecnico di Milano, Italy (I) Under fatigue (2 Mio cycles)

StressHead Ltd, Lucerne (CH) Long Term Tests since 10years with overtensioning-> To extrapolate to 50 years (Creep, relaxation, etc.)

Applied expierence on site 20 years

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Tests

Long Term Test at 240 kN since 2009 -> Relaxation: max. 2mm / 50 years & head

0 1 10 50 1002mm

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Summary StressHead-CarboStress System

Active strengthening

Restriction of deformation of the structure

High reinforcement forces / very limited space between anchors

Concentrated introduction of force

Minimum interferences into the structure

Simple and fast application

Corrosion protection

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Discussion!