Carbon fibre reinforced laminates Bonded steel ... - Siegwart, Michael

Carbon fibre reinforced laminates 

Bonded steel plates 

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UNIVERSITY OF ULSTER 

- Jordanstown - 

School of the Built Environment 

Introduction 

INTRODUCTION 

A building has to withstand various loads, e.g. the normal vertical loads from its weight, 

different load combinations, etc.. In addition, tall buildings are under attack from lateral 

forces caused by wind and earthquakes or other catastrophic impacts. Buildings are stiffened 

by means of structural elements such as shear walls. These walls are placed in form of a core 

to provide additional stiffness against lateral forces. 

In order to transform the forces that act on shear walls with openings, they are connected by 

means of coupling beams (coupled shear wall system). When a building with a coupled shear 

wall system is under attack by seismic forces, the energy is dissipated along the core of 

coupled shear walls by means of plastic hinges, which occur either in the beam or in the joint 

to the shear wall. After the seismic event, the beams can be repaired in order to restore the 

structural integrity of the building (Figure 1). 

The report presents the effectiveness of structural repair methods such as resin injection, plate 

bonding and glass fibres. To do so, five full-scale concrete specimens, half of a coupled shear 

wall system, were produced and overloaded. Three of them were repaired by of means resin 

injection and structurally strengthened using externally bonded steel shear strips, steel plates 

and glass fibre laminates. After a curing period they were reloaded. Their behaviour was 

recorded and is presented and analysed in this report. 

Michael Siegwart 1




Background Knowledge 

BACKGROUND KNOWLEDGE 

SHEAR WALLS 

Shear walls in seismic regions show good behaviour when seismic forces attack a building 

since they take and dissipate horizontal shear forces. They prevent buildings from collapsing 

during strong earthquakes and also avoid or limit structural damage when the applied seismic 

disturbance is moderate. Structures such as shear walls ensure that in the event of earthquakes 

human lives are protected, damage is limited and structures important for civil protection 

remain operational [8] . Different types of shear walls can be determined according to their 

design. The types are cantilever shear walls, coupled shear walls and slit shear walls (Figure 

4). 

The ultimate strength of such coupled shear walls is reached when a collapse mechanism is 

formed within the system. The collapse mechanism occurs when two plastic hinges develop in 

each coupling beam and one plastic hinge in each cantilever wall (at their base) is generated 

due to the subjected lateral load (Figure 3Figure 4, Figure 5). The sequence of hinge 

formation in a structure depends on the relative strength and stiffness of its components. 

STRENGTH AND BEHAVIOUR OF COUPLING BEAMS 

The deformation of the coupling beams is a combination of shear (Figure 8) and flexure 

(Figure 7). The actions of a beam where shear and flexural stress are subjected is complex 

(Figure 9). There are two different types of behaviour. Firstly, where flexural action governs 

over shear action the behaviour is similar to the behaviour of beams that are only subjected to 

flexural stress. The second type, where shear stress governs, is more complex. The flexural 

deformations that cause a double curvature of the beam and consequently tension along one 

side and stress on the other half, conflict with the shear deformation, which puts the beam into 

tension along both surfaces [31] . At the early state of loading the beam deforms in a flexural 

load manner with a double curvature and a line of contraflexure at the centre of the span. 

When the shear is strong enough to initiate a diagonal crack, the flexural behaviour changes. 

A shift of the points of contraflexure from the midspan towards the supports in the opposite 

direction occurs. Hence, the line of contraflexure rotates anticlockwise as the diagonal crack 





Background Knowledge 

in the concrete progresses. The shift of the points of contraflexure will stop near the end 

supports. At the end supports the conflicting forces of shear and flexure causes the 

reinforcement to kink. The maximum load-carrying capacity of the concrete is reached when 

small parts of concrete in the compression corners of the beam crush. 

REPAIR OF CONCRETE STRUCTURES 

Although concrete is a material which provides high durability and resistance against 

aggressive environmental factors, concrete structures undergo some damage due to physical 

impact or environmental attack and therefore need to be repaired. Damage might occur 

because of the following reasons: cracks in concrete, high permeability or high porosity, 

insufficient cover, carbonation and chloride, abrasion, freeze thaw, thermal shock, fire 

damage, high velocity waters, overloading, chemical reactions and alkali-silica reaction. 

Two basic types of repair work can be classified. The structural repair and the non-structural 

repair (Figure 11). The aim of any concrete repair is to protect the reinforcement from further 

corrosion, to enhance or restore the appearance of the structure, and to restore or increase the 

load carrying capacity. The selected repair method must provide durable repair within an 

acceptable cost range. 

Deep cracks in massive concrete members and cracks, which pass through a member, can be 

repaired by crack injection using a selected polymer such as epoxy resin. It is very important 

that the work is carried out carefully since inadequately repaired cracks cannot be repaired for 

a second time. Once epoxy has filled the cracks, it will rest there and cannot be removed any 

more. The resin is suitable to restore the structure to its original strength and stiffness [1] . 

The strengthening of beams by means of epoxy-bonded steel or composite plates is widely 

used. A major shortcoming of the system is the corrosion of the plates since the surface is 

fully exposed to the environment. An alternative to steel plates is therefore the bonding of 

reinforced plastics, which do not corrode. Other basic advantages are their low weight, which 

makes installation very easy and their greater length since the need for lapping at joints is 

eliminated. The material can be pre-stressed [20] and is fire resistant. [11] . On the other hand the 

material is relatively costly compared to steel. 





Research 

EXPERIMENTAL PROGRAM 

SAMPLES 

The test specimens were designed as a part of a coupled shear wall that is connected by beams 

and cut in the midspan of the beam. The samples exist as a part of a shear wall that has 

dimensions of 1000mm in width, 150mm in depth, and 1200mm in height. The wall parts of 

all five samples were reinforced with 16mm high yield steel bars in the longitudinal direction, 

and with binders in 6mm of diameter @ 120mm. The ends of the wall contained a column 

reinforcement in order to dissipate the expected forces and to limit the failure on the beam. 

The concrete was designed f cu = 50 N/mmÄ. [7] Two different dimensions of coupling beams 

were produced. Two samples, Sample 1-40 and Sample 2-40 had a beam height of 40 cm, a 

length of 80 cm and a width of 15 cm (Figure 13). Sample 1-30, Sample 2-30 and Sample 3- 

30 had a beam height of 30 cm whilst the other dimensions were the same (Figure 12 and 

Table 1). 

TEST SET-UP 

Adjustable stanchions were placed on the surface of the shear wall section of the specimen. 

They supported the specimens vertically. Horizontal support was provided by means of three 

different mechanisms. First, an adjustable stanchion was placed horizontally at the top of the 

shear wall section and screwed onto a vertical rack stanchion. Second, a clamping mechanism 

that pulled the shear wall on the same vertical rack stanchion was applied at the bottom. And 

third, a pushing mechanism was applied to the bottom of the shear wall by means of two long 

adjustable steel beams. The load was applied by using a hydraulic jack with 700mm clearance 

from the wall. Underneath the jack, a 200 kN load cell was installed. To monitor the 

movements and deflections three dial gauges were installed along the surface of the specimen 

(Figure 15). 





Research 

REPAIR 

Sample 1-40 and Sample 2-40 could not be repaired since the achieved crack opening was too 

small due to the failure of the supporting rack. Samples 1-30 to 2-30 were repaired by means 

of resin injection in the failure cracks. Thereafter steel shear strips, steel shear plates and glass 

fibers were externally bonded onto the beams to strengthen them. 

RESIN INJECTION 

The tension and shear cracks were injected using TamRez 210 . Before the cracks were 

sealed the surface area around them was cleaned mechanically. Thereafter, holes were drilled 

along the major cracks at distance of approximately 10 cm. The sealant (TamRez 310) was 

placed over the cleaned area. Tam plastic injection ports were then glued, using TamRez 

310, over the drilled holes (Figure 14). The bond of the injection ports to the concrete failed 

during the injection process after about 40 seconds, although the pressure was only 3 bar. The 

resin came out of small cracks around the injection ports. The degree of filling by the resin is 

therefore assumed to be very low and mainly dependent upon capillary effects rather than 

injection pressure. An investigation of the specimen using the ultrasonic method, in order to 

prove filling of cracks, did not succeed. 

PLATE BONDING 

Sample 1-30 was the strengthened by means of two shallow shear plates that were bonded on 

the surface of both sides of the beam by means of TamRez 220. To achieve adequate bond 

the plates were pressed onto the surface of the sample using weights until the resin was cured 

(Figure 16, Figure 17). 

Sample 2-30 was strengthened against shear failure using shear strips. The strips were placed 

above the surface using a cover meter in the same spacing of 120 mm. The joint to the shear 

wall was covered by means of T-shaped steel plates The dimensions were 30 mm x 300 mm 

for the beam section and 45 mm x 500 mm for the wall section. The plate thickness was 3 

mm. The steel was the same as used for the shear strips (Figure 18). 





Research 

Sample 3-30 was strengthened using the Tyfo Fibrwrap System. Two layers of glass 

fibres (TyfoS / SEH) were wrapped around the beam section. The joint was strengthened 

using two layers of Tyfo BC. The glass fibres were pre-cut and manually saturated by 

means of epoxy resin Tyfo S. The dimensions of the T-shaped Tyfo BC layers were 100 

mm x 500 mm bonded to the shear wall section and 100 mm x 300 mm bonded to the beam 

section of the specimen (Figure 19). 

The installation was carried out according the proposal of Fyfe Co. LLC, USA. The beam was 

wrapped in such a way that both sides and the underside were covered by the TyfoS / SEH 

glass fibres. The surface was not covered in order to simulate a non-accessible surface. The 

fibres were allocated vertical direction in order to strengthen against shear failure. Therefore 

the effect of the layers bonded onto the underside (flexure) is likely to be marginal. The 

Tyfo BC glass fibres are allocated in a grid of 45 degrees inclined against the horizontal in 

each direction in order to transfer the forces from the beam to the shear wall. The thickness of 

one layers (Tyfo BC and TyfoS / SEH) was approximately 1 mm. Before the glass fibres 

were installed the surface of the specimen was cleaned using a needle gun. Dirt and dust was 

removed by means of vacuum cleaning. The surface was coated using the epoxy resin Tyfo 

S before the glass fibres were bonded onto the specimen. After one day, the saturated fibres 

were bonded onto the surface. The fibres were not anchored. Due to the nature of the 

installation process, which does not require any clamping of the bonded material, the 

specimen was repaired in its testing position. 

EXPERIMENTAL RESULTS 

Sample 1-30 

The main cracks during the first test were a tension crack in the joint to the shear wall and a 

diagonal shear crack in the beam section (Figure 20). The crack width reached during the first 

test is very small. Only crack 13 reached a width of 0,2 mm at a load of 73 kN. The vertical 

displacement is high compared to Sample 2-30 and Sample 3-30. The sample was repaired by 

means of an externally bonded shear plate. The repair was effective although the calculated 

load capacity was not reached since the joint to the shear wall failed at a load of 84 kN. No 

cracks occurred until the load of 42 kN was reached then a flexural crack opened at a distance 





Research 

of 15 cm from the shear wall section until the shear plate was reached. The crack opened at a 

place that was previously undamaged. The reason for this is the difference in the initial 

stiffness due to the shear plate. However, as the load increased to 48 kN hairline cracks 

appeared at the border to the steel plate in the lower part of the T-shaped end section of the 

shear plate in the resin layer. The cracks were found from the middle axis downwards. No 

other cracks developed. The sample failed suddenly at a load of 84 kN. The failure occurred 

in the concrete. The bond of the plate to the concrete did not fail (Figure 22). The ultimate 

capacity of the reference sample (sample 3-30) was reached at a load of 80 kN. The test of 

sample 1-30 was stopped at a load of 74 kN. 

Sample 2-30 

The first crack, crack 1 occurred at a load of 28 kN at the joint to the shear wall. This crack 

proceeded further as the load increased and reached its final length of 25 cm at a load of 42 

kN. The crack opened wider as the load increased. The crack width was 0,6mm at a load of 71 

kN. The early occurrence of a tension crack in the shear wall can be put down to the fact of a 

much stiffer test set-up as for sample 1-30. However at 30 kN two further cracks, crack 2 and 

crack 3 occurred. Crack 2 stopped to increase at a load of 56 kN. The crack opening was 

between 0,1 mm and 0,2 mm. Crack 3 increased until 60 kN were reached. At this load stage 

a 12 cm long shear crack grew of crack 3 towards the bottom face of the beam. At a load of 

50 kN the last tension crack, crack 5 developed from the bottom face of the beam. This crack 

did not increase any further. As the load increased by 2 kN to 52 kN the diagonal shear crack, 

crack 6, started to develop. It stopped at a load of 70 kN at a distance of 3 cm from the top 

face of the beam. As the load increased to 72 kN spalling of the concrete cover occurred at 

crack 6 in the middle axis of the beam. The slope of the test graph became 0 so that the test 

was stopped. The displacement of the beam increased at a load of 30 kN from 2,5 mm to 6 

mm. This was due to the uplift of the supporting rack due to the insufficient lateral support of 

the shear wall section. 

Sample 2-30 was externally reinforced by means of high yield steel strips for shear. Although 

the dimensions of the shear strips were small compared to the shear plate of sample 1-30, the 

repair was successful. A flexural crack occurred between the joint plate and the first shear 

strip of the beam section at a load of 26 kN. It increased to a length of 15 cm as the load was 





Research 

increased to 34 kN. When the load reached 56 kN the crack width between the T-plate and the 

shear strip increased further. 

The original shear crack (crack 6) that was repaired by means of resin injection reopened at a 

load of 60 kN. This did not affect the performance of the beam since the stiffness did not 

decrease. The failure occurred at a load of 82 kN. The initial crack between the joint plate and 

the first shear strip increased in its length. It stopped 5 cm from the top face of the beam. The 

opening of the crack was 3 mm (Figure 23). 

Sample 3-30 

The tension crack in the joint of the beam occurred at a load of 22 kN. It increased until a load 

of 30 kN was reached. The crack length was 20 cm at this load stage. As the load increase the 

crack width increased to 1 mm at 72 kN. Cracks 2, 3, 4 and 5 occurred at 40 kN. Crack 3 did 

not proceed any further as its initial length of 7 cm. Crack 2 did not proceed further as well. 

At a load of 48 kN crack 4 reached its final length of 14 cm and crack 6 occurred. As the load 

increased to 68 kN the crack length of crack 6 increased to its final length of 25 cm. The 

diagonal shear crack occurred at a load of 52 kN and reached its final length of 40 cm at a 

load of 62 kN. The crack opened wider as the load increased. It reached a width of 1mm. At a 

load of 80 kN the sample failed at the beam joint to the shear wall and the slope of the test 

graph became zero. The early occurrence of a tension crack in the shear wall can be put down 

to the fact that there was very effective lateral support. As the load was taken away the cracks 

closed and were only visible as hairline cracks on the surface of the beam. The crack at the 

joint and the shear crack (crack 1 and crack 7) did not, however, close as far. The crack 

opening of the latter cracks after the load was taken away were 0,5mm. Sample 3-30 was the 

only specimen that reached a wide opening of cracks at its failure load. 

It was repaired by means of wrapped glass fibres. The wrapping was done in such a way that 

made the observation of crack development in the beam section not possible since the side 

section and the bottom section of the beam were fully covered. As the load reached 20 kN and 

was increased, a cracking sound could be heard. This had, however, no influence on the 

stiffness since the slope of the load/deflection curve did not change. At a load of 86 kN 

Sample 3-30 failed suddenly at the joint of the beam to the shear wall. The failure occurred 

similar to that in Sample 1-30. The external reinforcement did not fail. The failure occurred 





Research 

due to tension failure in the concrete in the shear wall section underneath the T-shaped glass 

fibre (Figure 24). 

DISCUSSION 

The tests have shown the ways in which way different structural repair and strengthening 

methods are suitable to restore the structural strength and stiffness of damaged reinforced 

concrete structures. The test elucidated the complex behaviour of a coupled shear wall system 

under static loading conditions. 

Sample 1-30, Sample 2-30 and Sample 3-30 are compared under consideration of different 

aspects. The stiffness, ultimate strength, the plate bonding by means of shallow shear plates 

and shear strips and the bonding of glass fibres and the effect of resin injection are now 

discussed. 

Stiffness 

The initial stiffness is evaluated using the deflection measured at a load of 20 kN. The final 

stiffness is found by dividing the load at failure by the deflection at this load stage. 

In the original test of Sample 1-30 the corrected initial stiffness was 100 % higher than in all 

other tests procedures. This can be put down to the fact that there was provided a stronger 

vertical support for the tests of the other samples (Graph 1). 

The initial stiffness of Sample 1-30, Sample 2-30 and Sample 3-30 increased after repair. The 

shallow shear plates of Sample 1-30 gave the best performance since the stiffness increased 

by 124 % compared to the original. Sample 3-30 increased by 83 % in its initial stiffness. The 

stiffness of Sample 2-30 increased by only 16 %. This behaviour can be explained when the 

repair mechanisms are examined. Sample 1-30 and Sample 3-30 had strong shear 

reinforcement after repair. The samples were over-reinforced. The opening of previous shear 

and tension cracks had no influence on the stiffness of the specimens since the load was 

completely carried by the additional reinforcement. Sample 2-30 carried weak external 

reinforcement. The shear strips enabled the opening of unrepaired cracks, so that the stiffness 

could not be increased to the level of the other specimens. 





Research 

These results can be explained as follows. The initial tests of Sample 1-30 and Sample 2-30 

did not load the specimen until failure. Therefore Sample 2-30 with the weakest 

reinforcement reached the best performance of all specimens. The shear plate of Sample 1-30 

transformed the forces from the beam into the shear wall. The shear wall section was weaker 

than the beam section. Hence the final stiffness was only 117 %. Sample 3-30 was the only 

specimen that was tested providing full vertical and lateral support. It was the only sample 

that was overloaded. The loss in the final stiffness can be explained because of the elongation 

of the glass fibre material that is higher than that of steel and the successful original test that 

loaded the specimen until failure (Graph 2). 

Ultimate Strength 

The test of Sample 1-30 and Sample 2-30 was interrupted early so that the failure could not 

develop to its full extent. Therefore a comparison of the “ultimate” strength before and after 

repair is difficult. However, the ultimate strength of Sample 3-30 increased by 7,5 %. The 

failure mode of all samples was a diagonal shear failure in the beam section at the final load 

during the first test. This changed after repair. Sample 1-30 and 3-30 did not fail in the beam 

section. The failure occurred at load of 84 kN and 86 kN in the joint of the beam to the shear 

wall section. The failure mechanism was tension failure in the concrete. Sample 3-30 failed 

after repair at a load of 83,5 kN due to a flexural crack near the joint to the shear wall. 

From these results it can be seen that the real ultimate strength of the specimen was in the 

range of 80 kN compared to calculated 72 kN. The real ultimate load was only reached by 

Sample 3-30. However the repair methods were suitable to increase the ultimate load capacity 

of the specimen. The tension plate determined the ultimate loading capacity after repair over 

the joint to the shear wall. The dimensions of the tension plates used for Sample 1-30 and 

Sample 2-30 were the same. Therefore, the ultimate loading capacities of Sample 1-30 and 

Sample 2-30 are similar 84 kN and 83,5 kN. The ultimate load capacity of Sample 3-30 was 

greater because the area of the tension glass fibre web was greater than for the other samples. 

The area for Sample 3-30 was 10 x 50 + 10 x 30 = 800 cmÄ compared to 4 x 50 + 3.5 x 30 = 

305 cmÄ for Sample 1-30 and Sample 2-30. 





Research 

Resin injection 

The resin injection was only carried out successfully for Sample 3-30. The crack width of this 

sample was wide enough to enable the full penetration of the crack. This was visible after the 

coating was removed. 

Steel Shear Plate and Steel Shear Strips 

The failure of Sample 1-30 did not occur in the beam nor in the bonded steel plates. However 

the quantity of steel that was used to reinforce the sample was quite considerable (overreinforcement). 

Sample 2-30 reached similar results with much less steel. In order to reach 

maximum bond of the steel plates the installation of the plates and strips was done whilst the 

samples were lying on the structural floor (Figure 17). This is not possible in situ. 

Glass fibres 

The main advantage of the applied glass fibre system Tyfo SEH 51 É was its easy 

application. Sample 3-30 remained in its upward testing position whilst the repair process was 

carried out. The installation process would have been similar for real structures (Figure 21). 

The glass fibre layers were very thin so that voids and air bubbles, which would reduce the 

performance were visible. The ultimate load was the highest of the three samples. The reason 

for the reduced final stiffness of the sample is complex due to a combination of various 

factors. Sample 3-30 was the only sample that reached its ultimate load and failed certainly. 

The voids were not repaired as recommended by the manufacturer. 





Conclusion 

Conclusion 

The experiments were carried out in order to gain an understanding of the complex behaviour 

of the beam coupling shear wall structures. The effectiveness of resin injection and externally 

bonded steel plates and glass fibres were investigated and compared. From this experimental 

work, a number of conclusions could be derived. 

Reinforced concrete sections, namely reinforced concrete coupling beams to shear walls, are 

suitable for the transformation of lateral forces from shear wall section to shear wall section in 

a coupled system. The beams dissipate energy that is created by such events as earthquakes by 

developing hinges either in the beam or in the joint to the shear wall. This is dependent upon 

the embedment length and strength of the beam. 

The repaired samples were able to resist a higher static load than in the first test. This can be 

put down to the fact that the structural strengthening measures were accompanied by the resin 

injection. 

The stiffness of the samples that were strengthened by means of externally bonded metal 

plates (resin TamRez 220É) increased between 17 % and 43 % compared to the original. This 

can be explained regarding the incomplete damage that was reached during the first test of the 

samples. The fully loaded and damaged Sample 3-30 was restored to 80 % of its original 

stiffness by means of the bonded glass fibre system Tyfo SEH 51É. 

The application of the glass fibre system is quick and simple since the installation and 

preparation process is simple compared to externally bonded steel plates. Defects in the bond 

are easy to detect since they are visible. 

The effectiveness of resin injection is well known but could not been proven by this 

investigation due to unsuitable injection procedure, and the fact that each sample that was 

resin injected was also strengthened. 





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Illustrations 

Figure 1 Building subjected to lateral load 

Figure 2 damaged concrete beam 

Figure 4 types of shear walls 

a) cantilever shear wall b) coupled shear wall c) slit shear wall 

Canadian Concrete Standard CSA 1994 Eurocode 8 (Prestandard) 

M 0 =M 1 +M 2 +P x L 

M 0 =M 1 +M 2 + D x N 

DC = P x L / M 0 (DC= 1/a s ) D x N / M 0 

condsidered as fully coupled: 

Treat as wall if: 

DC > 0.66 1.0 > D x N / M 0 < 2/3 (=0.66) 

condsidered as partially coupled: 

Treat as coupled shear wall if: 

DC < 0.66 2/3 (=0.66) > D x N / M 0 < 1/3 (=0.33) 

minimum for efficient coupling: 

Treat as frame: 

DC = 0.33 1/3 (=0.33) > D x N / M 0 

Figure 3 Location of internal compression resultant 

in flanged low-rise shear wall [24] 

Figure 5 Shear failure of low-rise flanged shear wall [24] 





Illustrations 

Figure 7 Flexural deformation of beam and forces [30] 

Figure 6 close-up of coupling 

beams in the Mount McKinley 

Building in Anchorage [24] 

Figure 8 shear deformation of beam [30] 

Figure 9 combined shear and flexural actions, 

final stage [31] 

Figure 10 Local stress concentrations and deformations 

around beam-wall joint [18] 





Illustrations 

Evaluation 

Repair 

Analysis 

Repair 

Strategy 

User 

Needs 

Cause 

? 

Scope 

Effect 

? 

S c o p e 

Useful Life 

Urgency 

Cost 

Technical 

Performance 

Requirements 

Structural Needs 

Effect of Repair 

on Structure 

Constructibility 

Environment 

Yes 

Protection / Appearance 

(Cosmetic) 

Surface Repair 

Both 

Yes 

Load Carrying 

(Structural) 

Aesthetics 

Safety 

Barrier to 

unwanted 

Environment 

Aesthetic 

Water 

resistant 

Live 

Loads 

Impact 

Loads 

Dead 

Loads 

Figure 11Performance Requirements [10] 

EUROCODE 

BRITISH STANDARD 

SPECIMEN 

EC 2 

BS 8110 

1-40 and 2-40 1-30 to 3-30 140 and 2-40 1-30 to 3-30 

SHEAR 63.3 kN 51.6 kN 69.0 kN 55.0 kN 

ULTIMATE SHEAR 98.8 kN 72.2 kN 75.0 kN 60.0 kN 

TENSION 81.2 kN 63.8 kN 85.1 kN 62.0 kN 

Table 1 Loading capacities of the specimen according to EC 2 and BS 8110 





Illustrations 

Figure 12 Specimen 1-30 to 3-30 (reinforcement) 

Figure 13 Specimen 1-40 and 2-40 (reinforcement) 





Illustrations 

Figure 15 final test set-up 

Figure 14 Sealed cracks with injection ports 

Figure 16 Sample 1-30 with shallow shear plate 

Figure 17 Installation of shear plates 

Figure 18 Sample 2-30 (shear strips) 

Figure 19 Sample 3.30 (glass fibres) 





Illustrations 

Figure 21 installation process (glass fibres) 

Figure 20 Crack pattern sample 1-30 

Figure 22 Sample 1-30 failure 

Figure 23 Failure Sample 2-30 

Figure 24 Sample 3-30 (Failure 

in beam joint to shear wall) 





Illustrations 

Sample 1-30 Sample 2-30 Sample 3-30 

Load [kN] 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

0 5 10 15 20 25 

Displacement [mm] 

Graph 1 Test Results Sample 1-30, 2-30 and 3-30 before repair 

Load [kN] 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Sample 1-30 (T-Plate) 

Sample 3-30 (glass fibre) 

Sample 2-30 (Strips) 

0 5 10 15 20 25 

Displacement [mm] 

Graph 2 Test Results Sample 1-30, 2-30 and 3-30 after repair 

Reference Curve

Carbon fibre reinforced laminates Bonded steel ... - Siegwart, Michael

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