fibre reinforced polymer prestressing tendons and their anchorages

Young Engineers Colloquium

Hamburg 1st April 2016

Katarzyna Zdanowicz: Fibre Reinforced Polymer Prestressing Tendons and their Anchorages

International Association for Bridge

and Structural Engineering

1

Fibre Reinforced Polymer Prestressing

Tendons and their Anchorages

Katarzyna ZDANOWICZ, M.Sc.

Leibniz Universität Hannover

Institut für Massivbau






FRP tendons: properties

CFRP GFRP* BFRP** AFRP Steel tendons

Tensile strength [MPa] 1800 – 2500 400 – 1600 1100 – 1350 1200 – 2100 1700 – 1900

E-modulus [GPa] 137 – 150 30 – 60 45 – 70 60 – 70 195

Ultimate strain [-] 0.013 – 0.017 0.012 – 0.037 0.022 – 0.030 0.015 – 0.037 0.05 – 0.10

Density [kg/m³] 1500 – 1700 1700 – 2100 2000 – 2200 1200 – 1400 7850

** GFRP tendons are not accepted by all standards

*** BFRP tendons are in testing phase and are not included in any standards for prestressing

1x7 (φ12.5 mm)

1x37 (φ40 mm)

BFRP [RockBar, MagmaTech]CFRP [CFCC, TokyoRope] CFRP [Leadline, Mitsubishi]






FRP tendons: durability issues

CFRP

GFRP

SEM images, 3000x

NaOH

solution,

28 days

Source: Sim, Park et al. 2005






FRP tendons: applications

1980: 7 m span bridge, Lünen’sche Gasse

in Düsseldorf, prestressed with 12 GFRP tendons

1983: AFRP prestressing tendons in the posts of a

noise barriers along highways (Netherlands)

1988: the first bridge worldwide prestressed only

with FRPs (CFCC; 24 girders), Shinmiya Bridge (Japan)

1991: Ludwigshafen, the first road bridge

prestressed with CFRP tendons: 85 m long,

4 CFRP tendons used with steel tendons

2001: the Bridge Street Bridge (Michigan,

USA) – the first structure completely reinforced

with carbon FRP reinforcement






FRP tendons: applications

façade beams, poles, hexagonal marine structures

Source:

Karbhari 1998,

Terrasi 2012






FRP tendons: codes and standards

• Japan:

– Recommendation for Design and Construction of Concrete Structures Using

Continuous Fibre Reinforcing Materials, Japanese Society of Civil Engineers,

1995

• Canada:

– CAN/CSA S6-00 Canadian Highway Bridge Design Code, 2000 (2014)

– CAN/CSA S806-02 Design and Construction of Building Components

with Fibre-Reinforced Polymers, 2002 (2012)

– Design Manual Prestressing Concrete Structures with Fibre Reinforced

Polymers, The Canadian Network of Centres of Excellence on Intelligent

Sensing for Innovative Structures (ISIS), 2007

• USA:

– ACI 440.4R-04, Prestressing Concrete Structures with FRP Tendons, 2004

(2011)






• Europe (fib):

Bulletin No. 40 FRP reinforcement in RC structures (2007):

“it was decided not to include design approaches

for prestressed concrete members”

Model Code 2010 for Concrete Structures (2013):

“The prestressing tendons considered in

this Model Code are made either

of prestressing steel [...]

or of FRP materials.”

FRP tendons: codes and standards






FRP tendons: permissible tendon stresses

CAN/CSA

S806-12

CAN/CSA

S6-14 ACI 440.4R-04

Model Code

2010

at jacking

CFRP 0,70 0,70 0,65 ---

AFRP 0,40 0,40 0,50 ---

GFRP * --- 0,30 --- ---

at transfer

CFRP 0,65 0,65 0,60 0,80

AFRP 0,35 0,35 0,40 0,50

GFRP * -- 0,25 --- 0,30

* – GFRP tendons are permitted only by CAN/CSA S6-14 and Model Code 2010






Anchorages: bond anchorages

Source: Schmidt, Bennitz et al. 2012






Anchorages: HEM (highly expansive material) anchorage

Source: Rohleder et al. 2008

Penobscot Narrows Bridge, Maine, USA (2006)






Anchorages: bond-type anchorage for multiple FRP tendons

Source: Fang et al. 2013

Aizhai Bridge hangers (2012)

Reactive powder concrete

grout as expansive material






Anchorages: bond anchorages

Bond materials:

epoxy resins,

mortars (normal or expansive),

reactive powder concretes

Problems:

ageing,

creep,

maintenance,

long-term performance






Anchorages: clamp anchorages

Source: Burningham et al. 2014

suitable when there are neither

special aesthetic demands

nor necessity of compact devices,

possibility to differentiate

the torque for each row

of the bolts






Anchorages: transverse strength problem






Anchorages: transverse strength problem

end of anchorage






Anchorages: sleeve-wedge anchorages

Source: Schmidt, Smith et al. 2011

Sleeve:

usually aluminium or cooper,

uniform distribution of radial

compressive stresses around

the tendon circumference






Anchorages: integrated sleeve-wedge anchorages

Source: Schmidt et al. 2010, 2011

consisting of one piece

with a gap and two slits

grips the tendon both

circumferentially

and longitudinally






Anchorages: gradient anchorages

Source: Meier 2012






Anchorages: gradient anchorages

Source: Meier 2012

Elasticity modulus

modified through

combination of

aluminum oxide ceramic

(Al2O3) granules and

epoxy resin

Stork Bridge in

Winterthur, Switzerland

(1996)






Anchorages: CFCC anchorages

Source: CFCC Manual 2014






FRP materials: economical issues

Source: Lux Research, Inc. Report






Conclusions

Research areas:

anchorages, which will not induce

too large transverse stresses on the tendons,

prestressing devices and procedures

deviators to shape the

tendon profile without

any damage risks

relaxation and

long-term behaviour






24

Fibre Reinforced Polymer Prestressing

Tendons and their Anchorages

Katarzyna ZDANOWICZ, M.Sc.

Leibniz Universität Hannover

Institut für Massivbau

Thank you

for your attention!






ReferencesACI 440.4R-04, 2004 (2011): ACI 440.4R-04 Prestressing Concrete Structures with FRP Tendons.

Burningham, C.; Pantelides, C.; Reaveley, L. (2014): New unibody clamp anchors for posttensioning carbon-fiber-reinforced polymer rods.

In: PCI Journal 59 (1), S. 103–113.

Fang, Z.; Zhang, K.; Tu, B. (2013): Experimental investigation of a bond-type anchorage system for multiple FRP tendons.

In: Engineering Structures 57, S. 364–373.

Fédération international du béton (fib) (2013): fib Model Code for Concrete Structures 2010. Berlin.

Karbhari, V. M. (1998): WTEC study on use of composite materials in civil infrastructure in Japan. Baltimore: International Technology Research

Institute World Technology (WTEC) Division.

Meier, U. (2012): Carbon Fiber Reinforced Polymer Cables. Why? Why Not? What If? In: Arab J Sci Eng 37 (2), S. 399–411.

JSCE-CS23, 1997: Recommendation for design and construction of concrete structures using continuous fiber reinforcing materials.

Rohleder, W. J.; Tang, B.; Doe, T. A.; Grace, N. F.; Burgess, Ch. J. (2008): CFRP Strand Application on Penobscot Narrows Cable Stayed Bridge.

In: Journal of the Transportation Research Board 17 (2050), S. 169–176.

CAN/CSA S6-14, 2014: S6-14 Canadian Highway Bridge Design Code.

CAN/CSA S806-12, 2012: S806-12 Design and construction of building structures with fibre-reinforced polymers.

Schmidt, J. W.; Bennitz, A.; Täljsten, B.; Goltermann, P.; Pedersen, H. (2012): Mechanical anchorage of FRP tendons – A literature review.

In: Construction and Building Materials 32, S. 110–121.

Schmidt, J. W.; Smith, S. T.; Täljsten, B.; Bennitz, A.; (2011): Numerical Simulation and Experimental Validation of an Integrated Sleeve-Wedge

Anchorage for CFRP Rods. In: J. Compos. Constr. 15 (3)

Sim, J.; Park, C.; Moon, D. Y. (2005): Characteristics of basalt fiber as a strengthening material for concrete structures.

In: Composites Part B: Engineering 36 (6-7), S. 504–512.

Terrasi, G. P. (2012): Prefabricated Thin-walled Structural Elements Made from High Performance Concrete Prestressed with CFRP Wires.

In: JMSR 2 (1).