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COMPOSITES & POLYCON 2007

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American Composites Manufacturers Association

October 17-19, 2007Tampa, FL USA

FRP Composites for Retrofitting of

Existing Civil Structures in Europe:State-of-the-Art Review

by

Masoud Motavalli and Christoph Czaderski,Empa, Swiss Federal Laboratories for Materials Testing

and Research

Ueberlandstrasse 129, 8600 Dbendorf, Switzerland

[email protected]

Abstract

A substantial number of structures in Europe are

more than 30 years old. Whilst they require continuous

maintenance, they also require strengthening due to lackof strength, stiffness, ductility and durability. Because

FRP composites are light-weight and easy to install on

site, they are considered to be the most favoured materialin many strengthening applications.

The paper will present the state-of-the-art of the

FRP composites for strengthening of existing civil struc-

tures in Europe. Existing techniques for flexural and

shear strengthening, near surface mounting reinforce-ment as well as column confinement of Reinforced Con-

crete (RC) structures will be discussed. Furthermore, a

few applications for FRP strengthening of historical ma-

sonry buildings will be presented.FRP pre-stressing techniques for retrofitting of existing

structures will be presented as an emerging market inEurope.

Introduction

There are several situations in which a civil struc-

ture would require strengthening or rehabilitation due tolack of strength (flexure, shear etc.), stiffness, ductilityand durability. Some of the common situations where a

structure needs strengthening during its lifespan are:

seismic retrofit to satisfy current code require-ments;

upgraded loading requirements; damage causedby accidents and environmental conditions;

initial design flaws and change of usage.

Because FRP composites are light-weight and

easy to install on site, they are considered to be the most

favoured material in many strengthening applications.

The overall cost of the whole strengthening job usingFRP materials can be as competitive as using conven-

tional materials, in addition to being quick and easy to

handle on site with minimum interruption to use of facil-

ity.

In some situations, FRP composites are the onlyplausible material that could be used for strengthening,

especially in places where heavy machinery cannot gainaccess or closure of the use is not practical.

Urs Meier and his team at the Swiss Federal Labo-

ratories for Materials Testing and Research (Empa) be-

gan research on the use of carbon FRP composites as ex-ternal reinforcement for strengthening structures in the

mid 1980s. This was the first worldwide research work

in the field of FRP composites for strengthening.The comprehensive research work done at Empa

between 1984 and 1989 (Kaiser 1989), enabled the con-

sequent wide spread use of carbon FRP external rein-forcement to strengthen structures. Based on these de-

velopments, the first application of carbon FRPs to

strengthen a bridge took place in Lucerne, Switzerland in

early 1990s. Ibach Bridge is a multi-span continuous box

bridge, which had one of its pre-stressed tendons dam-aged during drilling to install new traffic signals (Meier

et al. 1992).

Although the material cost of carbon FRPs was

several times more than that of steel plates, the fact that6.2kg of carbon FRPs could be used in place of 175kg of

steel is sufficient to explain the advantages of carbon

FRPs over steel plates. The entire work was carried out

in two-night shifts from a mobile platform eliminatingthe use of scaffolding.

A substantial number of bridges on European

highways and railways are more than 30 years old.Whilst they require continuous maintenance, they also

require strengthening for increased loads due to heavier

vehicles and traffic volume. Strengthening for upgradedloading is now common in bridge engineering and a sig-

nificant portion of funding is spent on this. Since 1999,

all bridges in Europe are required to carry 40 tonne vehi-cles, and consequently a number of old bridges needed

strengthening. The traditional steel plate bonding to the

decks was not viable in some cases due to various rea-

sons including, significant weight increase, access diffi-

culties and longer construction times. Over 30 bridgesand other structures in the UK have been strengthened

during 1997 alone, using about 6km of carbon FRP

plates. Carbon FRP plates or sheets have been used toincrease the flexural and shear capacity of decks and

beams of the upgraded bridges (Loudon June 2001).In mid 1990s, the Highways Agency in the UK

investigated and later implemented the use of aramidFRP composite material to increase the resistance of

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bridge columns that were at risk due to accidental ve-

hicular impact. Following a successful, trial site applica-

tion of column wrapping with FRPs in 1997, the High-

ways Agency commissioned the Transport ResearchLaboratory (TRL) to conduct a series of tests to establish

design rules and guidance, which will be published as a

formal standard (TR55 2004).

Sometimes, deficiencies in the initial design have

required strengthening to be carried out during the ser-vice life of the bridge. Reportedly, one of the first appli-

cations of bridge strengthening with FRP composites in

Germany was carried out to correct a design flaw on a

bridge [5].

A number of bridges built after the World War IIin Germany consisted of pre-stressed concrete multi-span

construction. These were mostly designed as continuous

box girders and the joints were usually at the points ofcontraflexure where all the tendons were coupled. Many

of these bridges now exhibit cracks at the joints. The

main cause for these cracks is a temperature restraint,which was not taken into account in the initial design. In

combination with other stresses, tensile stresses at the

bottom increase and exceed the concrete tensile strength

at the joint. This necessitated repairs on these cracked

bridges for which Professor Rostasy and his colleaguesfrom Braunschweig developed a technique to strengthen

such joints with bonded steel plates. In 1986-87, this

method was used for the first time with glass FRP plates

on the Kattenbusch Bridge (Rostasy 1987). The Katten-busch Bridge was designed as a continuous, multi-span

box girder with a total length of 478m. It consists of 9

spans of 45m and side spans of 36.5m each. There are 10

joints. The depth of the twin box girder is 2.7m. The bot-tom slab of the girder is 8.5m wide. One joint was

strengthened with 20 glass FRP plates. Each plate is

3200mm long, 150mm wide and 30mm thick. Loading

tests performed by Rostasy and colleagues showed a re-duction in the crack width of 50% and a decrease in the

stress amplitude of 36%, thus extending the fatigue life.

A number of other European countries such as

Sweden (Tljsten et al. 2003) as well as Italy, Greece,

Poland and Turkey (fib April 2006) have applied FRPcomposites successfully for strengthening their existing

structures.

A selection of examples is presented in the next

sections highlighting the wide range of situations whereFRP composites have been implemented to improve

flexural and shear capacity, ductility, and other service-

ability criteria.

Flexural Strengthening of RC Structures Using

FRP Plates and Sheets

Beams, Plates and columns may be strengthened

in flexure through the use of FRP composites bonded to

their tension zone using epoxy as a common adhesive for

this purpose. The direction of fibers is parallel to that ofhigh tensile stresses. Both prefabricated FRP strips, as

well as sheets (wet-lay up) are applied. Figure - 1 shows

the installation of the flexural strengthening of a RC

girder of a building in Poland using CFRP prefabricatedstrips. Figure - 2 illustrates the crosswise application of a

RC deck on the top and bottom side and around the col-

umns. Well established European guidelines and codesare available for engineers for designing purposes (see

section codes and guidelines).

Shear Strengthening of RC Structures Using

FRP Plates and Sheets

Shear strengthening is usually provided by bonding

the external FRP reinforcement on the sides of the webswith the principal fibre direction perpendicular or with

an angle of e.g. 45 to the member axis. For this purpose

prefabricated L-shaped CFRP (Czaderski et al. 2004)

plates were installed for the shear strengthening of the

rump of the Duttweiler bridge in Zurich Switzerland in2001 (see Figure - 3). The L-shaped plates were installed

in combination with CFRP strips for flexural strengthen-

ing. Figure - 4 shows placing of carbon fibre fabrics inthe shear zone of a bridge above the railway to Laziska

power plant in Poland. The strengthening was carried out

in 2003.

Well established European codes and guidelines are

existing for shear strengthening of RC structures usingFRP (see section codes and guidelines).

Near Surface Mounting Reinforcement (NSMR)

The externally bonded FRP to RC structures is

susceptible to damage from collision, high temperature,

fire and ultraviolet rays. To overcome these drawbacks,

Near Surface Mounted Reinforcement (NSMR) tech-

nique has been proposed. Slits are cut into the concretestructure with a depth smaller than concrete cover. CFRP

strips or bars are bonded into these slits. Tests have

shown that a higher anchoring capacity compared with

CFRP strips glued onto the surface of a RC structure isobtained (fib 2001; Kotynia December 13-15 2006).

Despite the efficiency of the NSMR technique, a

few applications can be found in Europe, where thistechnique was applied. Furthermore, codes and guide-

lines for this technique are missing.

Figure - 5 shows the strengthening of a RC deck

in Stuttgart, Germany applying the NSMR technique.

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Column Confinement

Confinement is generally applied to members in

compression, with the aim of enhancing their load bear-

ing capacity or, in case of seismic upgrading, to increasetheir ductility in the potential plastic hinge region. The

confinement in seismically active regions has proven to

be one of the early applications of FRP materials in in-

frastructure applications.Confinement may be beneficial in non-seismic zones

too, where, for instance, survivability of explosive at-

tacks is required or the axial load capacity of a column

must be increased due to higher vertical loads, e.g. if new

storeys have to be added to an existing building or if anexisting bridge deck has to be widened. In any case, con-

finement with FRP may be provided by wrapping RC

columns with prefabricated jackets or in situ curedsheets, in which the principal fiber direction is circum-

ferential (Bakis et al. May 2002).

Figure - 6 illustrates the confinement of RC col-umns applying CFRP fabric (wet-lay up technique) of

the Reggio Emilia football stadium in Italy, 50 km fromBologna. Analysis of the stadium with the new Italian

seismic code showed that the existing stirrups at the base

of the columns were not sufficient to withstand the seis-mic loads. Therefore, the columns were confined in

March 2006.

Figure - 7 shows the seismic retrofitting of Ai-galeo football stadium in Athens, Greece. The column-

beam joint is retrofitted using CFRP fabrics (wet-lay up

technique). The CFRP fabric is anchored to the RC deck

using steel plates.Well established European codes and guidelines

are existing for designing the confinement of RC col-

umns (see section codes and guidelines).

Retrofitting of Masonry Structures

Practical applications in recent years have shown

the FRPs as an alternative strengthening material for

masonry structures, especially those of considerable his-

torical importance. One of the first research worksworldwide was conducted at Empa, Switzerland

(Schwegler 1994). FRP strips and fabrics were applied to

the masonry shear walls in the laboratory using epoxy

adhesives. The walls were then tested under static cyclicloading. It was shown, that the in-plane deformation ca-

pacity of the masonry shear walls after strengtheningcould be increased up to 300%, if the end of the FRPstrips are anchored properly.

A number of historical buildings especially in It-

aly, Greece and Portugal were retrofitted applying FRP

composites. Aramid and Glass FRP was applied for re-

storing the Basilica of St. Francis of Assisi in Italy. Thehistorical building was severely damaged by earthquakes

and aftershocks in September and early October 1997

(Borri et al. April 22-28 2002).

Figure - 8 and Figure - 9 shows the retrofitting of

one of the masonry towers of the ancient Vercelli castle

in Italy by applying CFRP rods bonded into the space

between the bricks. One of the four towers showed widevertical cracks. A reinforcement of the outer side of the

masonry wall was necessary. It has been done by putting

horizontal CFRP rods around the tower to prevent further

opening of the cracks. Rods were bonded using epoxy

resin. The strengthening was completed in May 2004.Figure - 10 shows the seismic upgrading of the

masonry shear walls of a school building in Bern, Swit-zerland. GFRP fabrics were glued to the walls surface

followed by CFRP strips, which were applied crosswise

on the GFRP fabric layer. The strip ends were anchored

in the RC decks using steel plates.

Currently, no design codes and guidelines areavailable in Europe for strengthening of masonry apply-

ing FRP.

RILEM has recently established a new technicalcommittee (TC) entitled Masonry Strengthening with

Composite Materials. The preliminary work of the TC

will be the systematization of the current knowledge onthe structural behaviour of masonry constructions and

components strengthened with composite materials with

the final aim of a possible proposal of international rec-

ommendations including design tools, quantitative and

qualitative evaluation measures, limitation parameters ofefficiency and simple experimental procedures (RILEM

Technical Committee (TC) 'Masonry Strengthening with

Composite Materials (MSC)', www.rilem.net, Interna-

tional Union of Laboratories and Experts in ConstructionMaterials, Systems and Structures)

Prestressed Systems

Prestressing of composite strips prior to the bond-

ing procedure results in a more economical use of mate-rials but requires special clamping devices. Prestressing

results in stiffer behavior; delaying the crack formation;

closing cracks in structures with pre-existing cracks andtherefore improving serviceability and durability.

There are several prestressing methods, which are

currently applied in Europe. Examples are as follows:

A sport hall roof in Austria had to be retrofitted dueto large deformations under dead loads and insufficient

load capacity for high snow loads. The reduction of the

deflection and increasing of the load bearing capacity

was achieved by applying prestressed CFRP strips(Figure - 11). The details of the clamping device are il-

lustrated in Figure - 12.

Figure - 13 shows the strengthening inside the boxgirder of a bridge in Croatia applying prestressed CFRP

strips with different clamping device than the previous

example.

Cracks at the coupling joints of Neckar highwaybridge in Heilbronn, Germany (built in 1964) were the

reason for the rehabilitation of coupling joints applying

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prestressed CFRP strips with steel plates for clamping

the strip ends (Figure - 14).

Above-mentioned mechanical anchorages are ex-

pensive, difficult to install and subjected to corrosion. Toovercome these anchorage problems, the prestressing

force can be anchored using gradient method (Czaderski

et al. 2007; Aram et al. accepted for publication, Feb

2007; Meier et al. November 21-23, 2005). In this

method the prestressing force is reduced gradually atboth ends to zero by using a special processing tech-

nique. Figure - 15 shows a RC deck, which is retrofittedapplying prestressed CFRP strips with the gradient an-

chorage technique without any end anchorage plate. Yet,

few applications are available, where this technique is

applied. More experimental and analytical research work

is required to optimize the gradient anchorage techniquethat could replace the mechanical clamping systems in

near future.

In Figure - 16 columns of a storage building in Por-tugal are shown that are seismically upgraded using

prestressed wrapped aramid fibres. Only a few examples

are available, where prestressed column confinement isapplied.

Yet, there have been no codes and guidelines avail-

able for designing prestressed strengthening systems.

It can be concluded that the strengthening methodswith pre-stressed FRP are not so well established yet. It

will take more development work before they are suit-

able for practical applications since the pre-stressing

methods are still complicated to use and installationtechniques, both manual and automatic, have yet to be

perfected. These include surface preparation, pre-

stressing, placing and bonding, forming end anchorages

and vacuum bonding. Automatic application methodswill offer advantages in hazardous areas, where there is

danger from traffic and will reduce traffic management

and traffic delay costs. It is a need to make in the future

better use of the high strength of CFRP with pre-stressedapplications (Meier August 2004).

Codes and Guidelines

Although the technique externally bonded rein-forcement is quite new, there are already several Euro-

pean codes and guidelines available for responsible engi-

neers for planning a retrofitting project. However, it has

to be noted that in some respects the existing design phi-losophies differ distinctively and various topics are still

under research and development. Therefore, the

strengthening techniques should be planned very care-fully by experienced and educated engineers.

The main focus of these codes and guidelines is the

strengthening of reinforced concrete (RC).

The European codes and guidelines for the

strengthening of RC include following topics:

- Basis of design and safety concept,

- Flexural strengthening,- Shear strengthening,- Confinement,- Seismic applications,- Execution and quality control.The European task group fib9.3 FRP (Fibre Rein-

forced Polymer) Reinforcement for Concrete Structures

(fib) was one of the first publishing a guideline in thefield of externally bonded reinforcement (fib 2001). The

fib(International Federation for Structural Concrete) taskgroup comprises experts in the field of FRP as structural

reinforcement for concrete structures. The work per-

formed byfibTG 9.3 is published asfibBulletins. Meet-

ings are held twice a year. Started as a CEB (Comit

Euro-International du Bton) Task Group in September1996 and converted, with the merger of CEB and FIP in

June 1998, into fib TG 9.3, the group forms part of

Commission 9 'Reinforcing and Prestressing Materialsand Systems'. The task group consists of about 50 mem-

bers, representing most European universities, research

institutes and industrial companies working in the fieldof advanced composite reinforcement for concrete struc-

tures. The work of fib TG 9.3 is organized in 2 sub-

groups: (1) FRP reinforcement (RC/PC) and (2) Exter-

nally bonded reinforcement (EBR). The work on an up-

dated bulletin of (fib 2001) for EBR is under process.

In Switzerland, a precode (SIA166 2004) for exter-

nally bonded reinforcement was published in 2004. In

England, already the second edition of TR55 Designguidance for strengthening concrete structures using fi-

ber composite materials(TR55 2004) was also published

in 2004. In addition, since 2004, the Guide of the design

and construction of externally bonded FRP Systems forstrengthening existing structures (CNR 2004) is avail-

able in Italy.

Only less information can be found in Europeancodes and guidelines about prestressed strengthening

methods using FRP materials. Furthermore, the strength-

ening of structures made of wood, masonry, aluminumetc. is also not very well documented.

The above list of European codes and guidelines isnot complete but contains important documents in the

area of FRP applied as external reinforcement of con-

crete. Main weaknesses in these documents are lack of a

unified design approach.

Several topics relevant to the use and design of FRPas externally applied reinforcement are not dealt with or

are poorly covered in the above documents. Research

needed in these areas may be summarized as follows: (a)Better understanding and development of unified and

simple design models for mechanical anchorages and

mechanisms associated with debonding; (b) development

and verification of systems for the protection of exter-nally applied FRP at high temperatures; (c) derivation of

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material safety factors; (d) better understanding of FRP-

strengthened masonry, (e) development of simple design

models for prestressed systems with mechanical anchor-

age, as well as for gradient anchorage technique withoutmechanical anchorage.

Conclusions

The use of FRP in civil and building structures isnot uncommon anymore: structures have successfully

been strengthened or retrofitted with FRP materials in

many European countries. FRP composites are readily

used for strengthening applications mainly due to the

relative ease of installation. Strengthening with FRPcomposites have mostly been either the lowest tendered

price or the only plausible solution available. The mate-

rial costs of the FRP composites are several times morethan that of conventional materials (e.g. steel and con-

crete). However, the life-cycle cost, including fabrica-

tion, application, protection and projected maintenancecosts, is comparable and can be less than that of conven-

tional materials.Many engineers believe that FRP composites must

be used as a complementary material and not as a substi-

tute for concrete and steel. FRP composites have signifi-cant advantages over conventional materials in particular

situations, but composites cannot replace steel or con-

crete in every single application.Design guidelines and recommendations are essen-

tial for the wider use of FRP composites in strengthening

of civil and structural engineering. In the last few years,

European engineering institutions and societies in col-laboration with researchers and practitioners in the field,

either have developed or are in the process of developing

codes and recommendations for professional engineers.Education of engineers is necessary to reap the full

potential and the appropriate use of FRPs.Similarly, training is vital for people who fabricate

and install FRP composites in the construction industry.

The quality of the workmanship is a critical factor andthus specifications must address proper fabrication and

installation criteria for composites.

Acknowledgements

To Mr Reto Clenin from SIKA Company AG, whoprovided application examples in Europe carried out by

SIKA.To Mr Josef Scherer from S&P Clever Reinforce-ment Company AG, who provided application examples

in Europe carried out by S&P.

To Professor Renata Kotynia from Lodz University

in Poland, who provided application examples in Poland.

Figure - 1. Flexural strengthening of concrete

girders of a cement manufacturing building in

Poland using CFRP strips

Figure - 2. Strengthening of a concrete deck of a

building using CFRP strips on the top and un-

derside of the deck

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Figure - 3. Installation of prefabricated CFRP L-

shaped plates (shear strengthening) over already

installed CFRP strips for flexural strengthening;

Duttweiler bridge ramp in Zurich, Switzerland

Figure - 4. Placing of CFRP fabrics for shear

strengthening of DK 81 bridge above railway to

Laziska power plant in Poland

Figure - 5. Flexural strengthening of a concrete

deck in the region of negative bending moment

using Near Surface Mounting Reinforcement

(NSMR) technique by cutting a slot in the con-

crete deck and placing the CFRP into the slots;

industry plant in Stuttgart, Germany

Figure - 6. Application of CFRP fabrics on con-

crete columns for seismic retrofitting of Reggio

Emilia football stadium in Italy

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Figure - 7. Seismic retrofitting of column-beam

joints of Aigaleo football stadium in Athens,

Greece, using CFRP fabrics with steel anchor-

ages

Figure - 8. Carbon rods bonded into the space

between the bricks as reinforcement, Vercelli

Castle, Italy

Figure - 9. View into the castle and at the tower

under strengthening and repair works, Vercelli

Castle, Italy

Figure - 10. Seismic retrofitting of a masonry

shear wall using GFRP fabric and additional

CFRP strips, which are anchored in concrete us-

ing end plates; school building Zollikofen in

Bern, Switzerland

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Figure - 11. Reducing deflections and strength-

ening of a sports hall roof in Thrl, Austria by

presstressed CFRP strips

Figure - 12. Detail on prestressing anchorage

Figure - 13. Strengthening of a bridge box girder

using prestressed CFRP strips with steel end an-

chorage; Bakar bridge, Croatia

Figure - 14. Rehabilitation of coupling joints of

the Neckar highway bridge in Heilbronn, Ger-

many using prestressed CFRP strips with steelend plates

Figure - 15. Strengthening of a concrete deck us-

ing prestressed CFRP strips with recently devel-

oped gradient end anchorage technique without

any additional end anchorage plates

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Figure - 16. Prestressing of aramid fibers

wrapped around a column for seismic retrofit-

ting of a storage building in Portugal

Authors:

Masoud Motavalli:

Professor and Head of the Struc-tural Engineering Research Labo-

ratory at Empa, Swiss Federal

Laboratories for Materials Test-ing and Research

(www.empa.ch); Lecturer at the

Swiss Federal Institute of Tech-nology, ETH-Zurich and at the

University of Tehran, Iran

Christoph Czaderski:

Researcher, Project leader and

PhD student at the Structural En-

gineering Research Laboratory atEmpa, Switzerland. Member ofthefibTask Group 9.3 FRP rein-

forcement for concrete struc-

tures

References

Aram, M. R., C. Czaderski, et al. (accepted for publication, Feb2007). "Effects of gradually anchored prestressed

CFRP strips bonded on prestressed concrete beams."Journal of Composites for Construction, ASCE.

Bakis, C. E., L. C. Bank, et al. (May 2002). "Fiber-ReinforcedPolymer Composites for Construction- State-of-the-Art Review." Journal of Composites for Construc-tion: 73-87.

Borri, A., M. Corradi, et al. (April 22-28 2002). New Materialsfor Strengthening and Seismic Upgrading Interven-tions. International Workshop Ariadne 10, Arcchip,

Prague, Czech Republic.CNR (2004). Guide for the Design and Construction of Exter-

nally Bonded FRP Systems for Strengthening Exist-ing Structures, CNR-DT 200/2004. Rome, Italy,CNR - Advisory Committee on Technical Recom-

mendations for Construction.Czaderski, C. and M. Motavalli (2004). "Fatigue Behaviour of

CFRP L-Shaped Plates for Shear Strengthening ofRC T-Beams." Composites Part B: Engineering 35:

279-290.Czaderski, C. and M. Motavalli (2007). "40-Year-Old Full-

Scale Concrete Bridge Girder Strengthened with

Prestressed CFRP Plates Anchored Using GradientMethod." Composite Part B: Engineering 38: 878-

886.fib. Task Group 9.3 homepage:http://www.labomagnel.ugent.be/fibTG9.3/.

fib (2001). Externally bonded FRP reinforcement for RC struc-tures - Bulletin 14, International Federation for Struc-

tural Concrete (fib), Switzerland.fib (April 2006). Bulletin 35, Retrofitting of Concrete Struc-

tures by Externally Bonded FRP's, with Emphasis onSeismic Applications, International Federation for

Structural Concrete (fib).Kaiser, H. (1989). Bewehren von Stahlbeton mit

Kohlenstoffaserverstrkten Epoxidharzen, DoctoralThesis, ETH No. 8918, Swiss Federal Institute ofTechnology, ETH Zurich.

Kotynia, R. (December 13-15 2006). Flexural Behavior of Re-

inforced Concrete Beams Strengthened with NearSurface Mounted CFRP Strips. CICE2006, Miami,Florida, USA.

Loudon, N. (June 2001). "Strengthening Highway Structureswith Fibre-Reinforced Composites." Concrete: 16pp.

Meier, U. (August 2004). "External Strengthening and Reha-

bilitation: Where from - Where to?" IIFC FRP Inter-national, The Official Newsletter of the InternationalInstitute for FRP in Construction 1(2): 2-5.

Meier, U., M. Deuring, et al. (1992). Strengthening of Struc-tures with CFRP Laminates: Research and Applica-tions in Switzerland. 1st Intl. Conf. on AdvancedComposite Materials in Bridges and Structures, p243,

Sherbrooke, Canada.Meier, U. and I. Stcklin (November 21-23, 2005). A Novel

Carbon Fiber Reinforced Polymer (CFRP) Systemfor Post-Strengthening. International Conference on

Concrete Repair, Rehabilitation and Retrofitting(ICCRRR), Cape Town, South Africa.

Rostasy, F. S. (1987). Bonding of Steel and GFRP Plates in theArea of Coupling Joints, Talbrcke Kattenbusch, Re-

search Repost No. 3126/1429. Braunschweig,Germany, Federal Institute for Materials TestingBraunschweig.

Schwegler, G. (1994). Verstrken von Mauerwerk mit

Faserverbundwerkstoffen in seismisch gefhrdeten

8/13/2019 Mota Valli 183

10/10


10

Zonen. Dbendorf, Schweiz, Empa Dbendorf,Bericht Nr. 229.

SIA166 (2004). Klebebewehrungen (Externally bondedreinforcement), Schweizerischer Ingenieur- undArchitektenverein SIA.

Tljsten, B. and A. Carolin (2003). Strengthening Two LArge

Concrete Bridges in Sweden for Shear using CFRPLaminates. Structural Faults and Repair, 03, London,UK.

TR55 (2004). Design guidance for strengthening concretestructures using fibre composite materials, SecondEdition, Technical Report No. 55 of the Concrete So-ciety, UK.

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