Research Experience - CoMSIRU · Research Experience Laboratory tests ... Strengthening beams in shear . ... Mineral Based Strengthening systems

Research Experience

Research – Experience

by

Björn Täljsten

Anchor tests with

NSMR rod

Research Experience

Material Science Components Structures

10-6

10-9

Si2 OH-

OH-

OH-

C 10-3

Overlapping area Overlapping area

Phase I Phase II Phase III

From “Nano” to Macro and Full-Scale Demonstrations

Research Experience

Ideas

needs

Process

Systems

Concepts

Decisions

Resources

Output

Output

Experiences

Ideas

Needs

Input

Research Experience

Laboratory tests

• Bending

• Shear

• (Torsion)

• Full-Scale tests

DP

P1 P2

Bending

q DP

Shear

Laboratory tests are essential

Research Experience

A strengthen concrete beam and possible failure modes

1. Compressive failure

2. Yielding, tensile reinf.

3. Yielding, compressive reinf.

4. Tensile failure, laminate

5. Anchorage failure

6. Peeling failure

7. Delamination

Research Experience

Shear - and peeling stresses - Principles

0 ,0

1 ,0

2 ,0

3 ,0

4 ,0

0 5 0 1 0 0 1 5 0 2 0 0

F E M - a n a ly s

A n a ly t is k b e rä k n in g

-0 ,5

0 ,0

0 ,5

1 ,0

1 ,5

2 ,0

0 50 100 150 200

F E M - ana ly s

A na ly t is k be räk n ing

Research Experience

Theory: Shear - and peeling stresses - Equations

2

12

2

x

cc

a ea

a

ba

WsE

PGx

22

2

44

32

11

3 41

12

4 IsE

ab

IE

a

a

baP

s

Ex a

z

xe

a

WEIsE

tbG

WE

tG

IE

E x

ccfcfc

fcfca

cc

fca

cc

a

cos1

22 22

xe

WE

tG

IE

E

IsE

ab

IE

a

a

baP x

cc

fca

cc

a

fcfccc

sin24

12

4 2

2

44

2

2

x

cc

fca

cc

a

fcfc

fcx

cc

eWE

tG

IE

E

a

ba

IsE

abPe

a

a

ba

IE

P

2

2

42

2

2 2442

where

where

ccccfcfc

fca

WE

z

AEAEs

bG02 11

2

0

cc

fca

WsE

zbG

4

fcfc

fca

IsE

bE

Peeling stresses

Shear stresses

Research Experience

Test set-up and test specimens

RB - Reference beam

SB1 - Ef = 155 GPa, a = 150 mm

SB2 - Ef = 155 GPa, a = 200 mm

SB3 - Ef = 155 GPa, a = 300 mm

MB2 - Ef = 210 GPa, a = 150 mm

HB2 - Ef = 300 GPa, a = 150 mm

FB1 - Ef = 95 GPa, a = 150 mm

SIKA and BPE Composite®

Research Experience

Measurements

Measurements were taken of the deflection at the supports and the

midsection, and of the strains at various points over the laminate plate.

Research Experience

Laboratory tests Results from laboratory tests – Load – Deflection curves

Typical crack pattern and failure mode

0 5 10 15 20 25 30 35 40 45 50

Mid-deflection, , [mm]

0

20

40

60

80

100

120

140

160

Lo

ad,

F,

[kN

]

H1

Ref

S1

S2

S3

M1

A higher Young´s modulus of the

laminate plate gives a stiffer load-

deflection behaviour. H > M > S >F

Research Experience

Comparison between Test, Simulations and Theory Beam S1, 80 % of the failure load

0 400 800 1200 1600 2000

Distance from CFRP cut off end, [mm]

-1

0

1

2

3

Sh

ea

r str

ess,,

[M

Pa

]

0

1000

2000

3000

4000

5000

Str

ain

, ,

[

m]

(x), Experimental

(x), Analytical

Beam S1, 80%, 114.6 kN

(x), Numerical

Research Experience

Strengthening beams in shear

Research Experience

0 10 20 30 40 50

0

200

400

600

800

1000

Deformation, ,(mm)

Beam S5

Beam S4

Lo

ad

, F

, (k

N)

Beam R2

Beam R2

Beam S5 Beam S4, Beam S5

Shear Test

Research Experience

Beam R1

Beam SR1

0 10 20 30 40 50

Deformation, ,(mm)

Lo

ad

, F

, (k

N)

Beam R1

Beam SR1

0

200

400

600

800

1000

Shear Tests

Research Experience

F

0

200

400

600

800

1000

Lo

ad

, (

kN

)

0 5 10 15 20 25 30

Deformation, (mm)

R1

C4

C2

C1

C3RC1

C5

Fiber angle important

Shear Tests

Research Experience

LVDT

Orgin

Rosette strain gauge

Centre of beam

LVDT

250 250 500

12

90°

No:

1

2

3

4

5

x

50

150

250

350

450

y

50

150

250

350

450

L T

5

4

3x

y

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

Fibre Strain, [s]

C1, 125 g/m2

C2, 200 g/m2

0

100

200

300

400

500

600

700

Loca

tio

n o

n c

rack f

rom

bo

tto

m,

[mm

]

C2C1

Shear Tests

P

P

y)

1

23

45

V

V

Steel

CFRP

1, 5

32, 4

S1, S5

C1, C5

C2, C4

C3

S2, S4

S3

x

x

x

x

x x x

V1

V2 > V1

1

2

34

5

fsy

f()

Research Experience

0 100 200 300 400 500

Load, [kN]

-2000

0

2000

4000

6000

8000

10000

Str

ain

, [*

10E

-5]

Strain gauges3:90

3:135

3:45

F

Strengthening for Shear

1

2

3

4

5

Laboratory tests

Research Experience

Strain fields

Laboratory testing: Speckle pattern analysis

Research Experience

Mineral Based Strengthening systems

To create a more environmental friendly and sustainable

strengthening systems with the benefits of CFRP strengthening but

avoiding the drawbacks of epoxy.

Introducing Mineral Based Composites (MBC)

Motivation

Research Experience

Laboratory testing – pilot tests: slabs

Research Experience

MBC, t = 15 mm t = 100 +15 mm


Research Experience

0 50 100 150 200

Mid-span displacement, d, [mm]

0

10

20

30

40

50

60

To

tal L

oa

d,

P,

[kN

]

No.1. Reference

No.2. Extra steel

No.3. NSMG 1 layer, sanded

No.4. NSMG 1 layer, no sand

No.5. Composite

No.6. NSMG 2 layers, no sand

No. 1

No. 2

No. 3

No. 4

No. 5

No. 6


Research Experience

The demand for strengthening in torsion is quite low. However, it

still exist and an application may be strengthening for increased

torsional capacity of box bridges

Strengthening for torsion

Research Experience

Similar to shear –

however, a different

crack path

Examples for

strengthen in torsion

Strengthening for torsion

Research Experience

Test set up

Loading side Clamped side

LVDT

A

Stirrups 8 cc 50

600

Bending reinforcment 12

4 000

2 500500

150

60

0

50

35

1

LVDT

B A

53

0

P3

5

5002 500

2

3

4

5

6

1 000 1 000

Research Experience

Test Specimens

Research Experience

During Loading

Very ductile, the test equipment

stopped at the floor level. A angle of

approximately 30°. Elastic

behaviour.

RCG7

RCC8

Also ductile, the crack pattern

during loading could clearly be

seen. After the test the glass fibre

fabric was removed. The concrete

was completely crushed.

Research Experience

Load-Rotation Curves

RCC8

Radians

To

rsio

na

l M

om

en

t, M

, (

kN

m)

RCG7

v

0.00 0.05 0.10 0.15 0.20 0.25 0.30

0

10

20

30

40

RCG7

Radians

To

rsio

na

l M

om

en

t, M

, (k

Nm

)

RCC8

v

0.00 0.05 0.10 0.15 0.20 0.25 0.30

0

10

20

30

40

RCC6

Radians

To

rsio

na

l M

om

en

t, M

, (k

Nm

)

RCC6

v

0.00 0.05 0.10 0.15 0.20 0.25 0.30

0

10

20

30

40

RCC4

Radians

To

rsio

na

l M

om

en

t M

,

(kN

m)

RCC4

v

0.00 0.05 0.10 0.15 0.20 0.25 0.30

0

10

20

30

40

RCR1

Radians

To

rsio

na

l M

om

en

t, M

,

(kN

m) RCR1

v

0.00 0.05 0.10 0.15 0.20 0.25 0.30

0

10

20

30

40

Research Experience

Strengthening in openings

Research Experience

Openings in Walls

Priming

Strengthening

Taken up the

opening after

strengthening

Research Experience

Strengthening

Opening

Additional strips

in corners

Openings in slabs

Research Experience

Test Set-up

Airbag Slab placed in the rig

Strengthening bonded

around the opening

Research Experience

Results

Crack pattern for a non

strengthen slab

Brittle failure

0 2000 4000 6000

Strain [str]

0

20

40

60

80

Lo

ad [

kN

/m2

]

H4 (3y)

S5re

(1x)

S7 (1x)

S6st

(1x)

S8we

(3y)

1x

3y

Research Experience

Simulation of traffic load during adhesive hardening

Laminate/Rod 3200 mm

Laboratory testing

Research Experience

Research Experience

0 5Time [s]

0

20

40

60

Lo

ad

[kN

]

Yielding of control beam

44 %

49 %

7 %

• 40 kN load

• (8–6 mm deformation)

• every 108 s during the

hardening procedure


Research Experience

0 5 10 15 20 25Time [h]

0

400

800

1200

1600

2000

Str

ain

[1

0-6

]

0

2

4

6

8

10

Mid

po

int d

efle

ctio

n [m

m]Steel strain

Fiber strain

Mid-point deformation


Research Experience

Testing of beams in cold climate – 28 C

4 000

3 200

1 300200 1 000

200

30

0

64 72

30

16

10 @ 75 mm

Research Experience

Preparation of test beams

Sawing of slots and cleaning Application of adhesive

(epoxy or cement) Bonding and final result

Research Experience

Test Results

Load/Deflection No Strengthening (cold = black, room=Magenta)

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120

Mid-deflection, d , [mm]

Lo

ad

, F

, [k

N]

Research Experience

Test Results

Load/Deflection Cementbond NSMR (cold = black, room=red)

0

20

40

60

80

100

120

140

160

180

0 10 20 30 40 50 60 70 80


Load, F

, [k

N]

Research Experience

Test Results

0

20

40

60

80

100

120

140

160

180

0 10 20 30 40 50 60 70 80

Mid-deflection, d , [mm] ]

Lo

ad

, F

, [k

N]

Load/Deflection Epoxy Bond NSMR (cold = black, room=blue)

Research Experience

Test Results

Load/Deflection Epoxi bond CFRP laminates, black = cold, green = room

0

20

40

60

80

100

120

140

0 5 10 15 20 25 30 35 40 45 50


Load, F

, [k

N]

Research Experience

Failure Modes

NSMR Cement Based NSMR Epoxy Bond

Research Experience

Cold Climate

This is how we have to work in cold climates in Sweden. The arches

are strengthen, the temperature is – 22 °C.

Research Experience

Problem Solving

Problem

Diagnostics

Phase 2 Needs

Analysis

Phase 1

Ideas

Experiences

Information

Phase 3

Solving

Suggestion

Phase 4

Application

Phase 5

User

System Evaluation

Phase 6

“Start”

Research Experience

•Load Bearing capacity

•Change of use

•etc.

Phase 2 •Old and deteriorating infrastructure

•Old buildings

•Reuse of buildings

•etc

Phase 1

•Benchmarking

•Thinking, Theory

•Testing

•etc.

Phase 3

A method

for strengthening

Phase 4 Field applications

Phase 5

CFRP (Carbon Fibre Reinforced Polymers)

Strengthening

Evaluation

Phase 6

Problem Solving

Research Experience

Strengthening of a Over-Head Crane Beam

• Change of Structural system

• Evaluation of Strengthening Method

• Full-Scale Test After Strengthening

The underside of one

of the beams

Research Experience

A section of the Structural system


Research Experience

The beams were to a high degree cracked


Research Experience

Stage 1: Removal of Column, Strengthening for dead load

Dywidag Steel Stays


Research Experience

The static structural system will be changed due to removal of the supporting columns. We

will have a free supported beams instead of a continuous one. Almost no steel reinforcement

is placed in the bottom of the beam in the section where the column connects the beam.

Column


Research Experience

Stage 2: Strengthening with CFRP

Dywidag Steel Stays

Strengthening for Bending Anchorage Strengthening for Shear

Strengthening for Shear

Strengthening for Bending

Anchorage


Research Experience

In Bending the need for strengthening were approximately 12.5 MNm

In Shear the need for strengthening were approximately 1.0 MN


Research Experience

In Bending 24 layers of carbon fibres were placed in the highest loaded section.

In Shear 3 layers were wrapped around the beams

BPE Composite 300S were used

in all cases. A wrap system with a

standard grade of carbon fiber and

a weight of 300 g/m2.


Research Experience

The result after strengthening and during painting


Research Experience

Full-Scale Testing - Loading

The Over-Head Crane was moved on a predestine path and were

stopped at 10 “destinations” where measurements were taken. The

loads were increased from 274 tonnes up to 494 tonnes in three

steps (The total load to be distributed between the beams).


Research Experience

Full-Scale Testing - Loading

The Full-Scale loading was done with water tanks, steel goods and concrete prisms attached to

the over-head crane. It was possible to apply a load corresponding to 90 % of the ultimate

theoretical load.

Water Tanks

Beam

Up Stream

Beam

Down Stream

Over-Head Crane


Research Experience

Full-Scale Testing - Testing Path

Strain Gauge T5

0 1000 2000 3000

Time, [sek]

0

100

200

300

400

500

Str

ain

, [m

s]

3

2

1

4

6

78

9

6

78

9


1

2

3

4 6

7

8 9

Research Experience

Full-Scale Testing - Recorded Strain and Deflections

Recorded Strain (left) and deflection (right) as a function of time in

point T5 respectively L9 during loading Case C (311 tonnes on one beam)

Strain Gauge T5

0 1000 2000 3000

Time, [sek]

0

100

200

300

400

500

Str

ain

, [m

s]

3

2

1

4

6

78

9

6

78

9

LVDT Gauge L9

0 1000 2000 3000

Time, [sek]

0

2

4

6

8

Defle

ctio

n,

[mm

]

1

2

3

4

67

8

9

67

8

9


Research Experience

Comparison between calculated and measured strains, T5, and deformations, L9

Load Uncracked Cracked Measured

Case C1

P = 247 tonnesStrain, [s]

Composite

Deformation, [mm]

167

4.1

1062

16.9

310

6.2

Case C2

P = 311 tonnesStrain, [s]

Composite

Deformation, [mm]

207

5.2

1343

21.3

420

7.7

The measured values are best in accordance with an uncracked beam. However, the reason

for this is most likely not that the beam is uncracked but that the composite holds the beam

together and in that way increases the stiffness.


Research Experience

Strengthening of a Railroad Bridge

• Need of increased load bearing capacity

• Investigation of the Strengthening Method

• Full-Scale Test before and after testing

Research Experience

Strengthening of a railway bridge

Highly cracked

• Insufficient load bearing capacity

• Low overhead clearance

• Traffic on the bridge

Research Experience

The bridge needed strengthening due to increased axle

loads, from 25 to 30 tons


Strengthening for flange shear, ± 45°, 2 x 3 layers

Strengthening in cross direction, 2 layers

Research Experience

•Post-treatment

•Pre-treatment

•Strengthening


Research Experience

The bridge after

strengthening

The bridge is mainly

strengthen in the cross

direction


Research Experience


•Minimisation of own frequency

•Strains and deformations

•Train weight well known

•Three different train speeds

10 km / h

30 km / h

50 km /h

•Change in humidity

Research Experience


Curves are adjusted for different train weights

0.00

20.00

40.00

60.00

80.00

Str

ain

[e

-6]

Time

Before strengthening After strengthening "Long-term" behavior

Strain measurement on steel and concrete

Research Experience


0.00 0.50 1.00 1.50 2.00

-0.4

-0.3

-0.2

-0.1

0.0

De

fle

ctio

n,

[mm

]

Distance from support, [m]

Deflection in slab

Before strengthening

After strengthening

Measurement of deformations at two locations

Research Experience

Conclusions

• Advanced composite materials are very suitable for strengthen concrete structures.

• Full scale tests verify results from theory and laboratory tests

• Theory for design correspond well with actual test results

• Also very complicated structures and systems can be strengthened with CFRP

Strengthening of Concrete Structures

Research Experience - CoMSIRU · Research Experience Laboratory tests ... Strengthening beams in shear . ... Mineral Based Strengthening systems

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