shear capacity and crack pattern of reinforced and plain ...10 n/mm2) amount, shape, type and plac...

Shear capacity and crack pattern of reinforced and plain masonry walls

Presenter: ANITA FÓDI, PhD Student

Budapest University of Technology and EconomicsFaculty of Civil EngineeringDepartment of Structural Engineering

Supervisor: István Bódi, Associate Professor

Presenter: ANITA FÓDI, PhD Student

Contents

1) Purpose of research

2) Goals and characteristics of the experiments carried out

3) Presentation of the results

8th fib International PhD Symposium in Civil EngineeringTechnical University of Denmark, Kgs. Lyngby, 20-23 June, 2010

3) Presentation of the results

4) Conclusion

5) Further plans

2/34

Aim of the test series

What are the effects of reinforcement application in masonry walls due to shear?

1. Analysis of reinforced masonry shear walls


Aims to analyze:

� Shear capacity

� Displacements

� Crack patterns

� Failure modes

3/341 4 6 Aim of the research1 2 3 4 5 6

Shear failure of reinforced masonry

Up to the present� Cored, concrete blocks

Proper experiments� Solid, clay bricks

� Advantage: compressive strength isalmost the same in each direction


� Reinforcement bars in concrete infill of the cores

� The head joints do not serve as a place for vertical reinforcement

� EC6 does not contain the effect ofthe vertical reinforcement on thebearing capacity of walls

� Reinforcement bars in mortar infill

� Small size of the vertical mortar joint

� The effect of vertical reinforcement can be analysed

� Vertical bars go through head jointsthat can be filled with mortarbecause of the size of the joints

Aim of the test series1 2 3 4 5 6

almost the same in each direction

4/34

Solid reinforced masonry wall

185,5

Developed bond of bricks

250x120x65


46,75 46,75

185,5

172

46,75

25

1 2 3 4 5 6 Aim of the test series5/34

HEA200

20t

U300

20t50 70 50

Layout of the test setup

Horizontal force

Vertical compression (2x100 kN)

Steel loading frame


U300

121,5

172

1 2 3 4 5

Changes of the height due to vertical force

Displacement

Displacement

Displacement

6 The experiments carried out 6/34

Failure: after 28 days

Aim of the experiments carried outPlain Vert. reinforced Horiz. reinforced Vert. and horiz.


1 2 3 4 5 The experiments carried out6

PURPOSE: find out for both reinforcement directions whether it can

• enhance the load bearing capacity (if yes, to what extent),

• decrease the width of the cracks,

• modify the type of the failure of the wall,

• alter the crack pattern.

3 walls 2 walls 2 walls2 walls

7/34

Test specimens

250x120x65Header bond

A) PLAIN MASONRY WALLS C) VERTICALLY REINFORCED

B) HORIZONTALLY REINFORCED D) HORIZONTALLY AND VERTI-CALLY REINFORCED


Strecher bond

3Ф8 /joint (46,7 cm) deformed bars, S500B

Murfor RND/Z-5-200, in every second joints

2Ф5 head joints

1 2 3 4 5 6

0,1%

0,14%

The experiments carried out 8/34

Characteristics of the experiments

� Geometry was the same in all cases (H/L=0,7)

� Vertical compressive force: 200 kN

� Type of the brick was the same (compressive strength: 10 N/mm2)

� Amount, shape, type and placement of the


� Amount, shape, type and placement of the reinforcement were the same in one direction

� Two types of mortar:

�the compressive strength of the mortar is less (3 N/mm2) than that of the brick (10 N/mm2)

�and it is the same

(M30-weaker and M100-stronger mortar)

1 2 3 4 5 The experiments carried out6 9/34

Crack pattern – plain masonry wall, M30

The wall decays completelyafter cracking, the upper

First crack: 145 kN

(3.2 mm)


1 2 4 53 4 Presentation of the results6

Maximal force: 155 kN, (4.6 mm)

Residual force: 130 kN

after cracking, the upper part of the wall slipped on the lower „triangle”.

10/34

Crack pattern – vertically reinforced masonry, M30

The crack pattern is similar

Displacement at the top, after 163 kN: 60.5 mm

First crack: 121 kN (3.4 mm)


1 2 4 53 4 6

The crack pattern is similar to that of the plain masonry.

The masonry does not decay after cracking immediately, it is able to carry load in an amount that is provided by the reinforcement.

The difference is caused by the distinct bond of bricks.

Presentation of the results11/34

Crack pattern – horizontally reinforced masonry, M30

Shape of the crack pattern changes, the way of the

First crack: 173 kN(6.5 mm)


1 2 4 53 4 6

changes, the way of the failure alters partly.

Maximal force: 180 kN(16.9 mm)

Residual force: 163 kN


1 2 4 53 4 6 Representation of the results

Crack pattern – vertically and horizontally reinforced masonry wall, M30


Maximal force: 252 kN(60.8 mm)

Maximal displacement:


1 2 4 53 4 6

The run of the crack pattern changes, the cracked zone is bigger.

The width of the cracksis smaller.

Maximal displacement: 60.8 mm


Force vs. displacement of the plain masonry wall, M30

200

250

Crack: 145 kN

Residual force : 130 kN

at 26 mm


0

50

100

150

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Vízszintes elmozdulás a tet őponton [mm]

Víz

szin

tes

erő [k

N]

M30vasalatlan

Maximal force : 154 kN

at 26 mm

QUESTION: How much is the force that can shift the mortar-free wall during samecompression force?

Horizontal displacement at the top of the wall [mm]

Hor

izon

tal f

orce

[kN

]

Plain masonry, M30

Force vs. displacement diagram of a vertically reinforced wall, M30

200

250

Force at the end of the process: 161 kN

Crack: 121 kNMaximal force : 161 kN

at 60,6 mm


0

50

100

150

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70


Víz

szin

tes

erő [k

N]

M30vasalatlan

M30függőlegesen vasalt


Hor

izon

tal f

orce

[kN

]

Plain masonry, M30

Vertically reinforced, M30

Force vs. displacement diagram of a horizontally reinforced wall, M30

200

250Crack: 173 kN

Residual force: 163 kN at 67 mm


0

50

100

150

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70


Víz

szin

tes

erő [k

N]

M30vasalatlan


M30vízszintesen vasalt


50 kN


Hor

izon

tal f

orce

[kN

]

Plain masonry, M30


Horizontally reinforced, M30

Force vs. displacement diagram of a wall reinforced in both directions, M30

200

250

Crack: 176 kNMaximal force: 252 kN

Force at the end of the process : 252 kN

at 60 mm


0

50

100

150

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70


Víz

szin

tes

erő [k

N]

M30vasalatlan


M30vízszintesen vasaltM30vízszintesen és függőlegesen

50 kN


Hor

izon

tal f

orce

[kN

]

Plain masonry, M30


Horizontally reinforced, M30

Vertically + horizontally reinf., M30

Crack pattern– plain wall, M100

Crack pattern changes: run of the cracks begins lower: under the

Maximal force: 193 kN (4.8 mm)


1 2 4 53 4 6

Residual force: 143 kN, Maximal displacement at the top: 31 mm

begins lower: under the fifth course.



Crack pattern – vertically reinforced wall, M100


Maximal force: 231 kN

(39 mm)


1 2 4 53 4 6

Crack pattern changes: cracks run through the bricks.

Maximal displacement: 42 mm


Crack pattern – horizontally reinforced wall, M100

Crack pattern changes: run of the cracks

First crack: 190 kN(4.4 mm)


1 2 4 53 4 6

Maximal force: 193 kN,

Residual force: 171 kN, maximal displacement at the top: 38 mm

run of the cracks begins lower: under the twelfth course.


Crack pattern – horizontally and vertically reinforced, M100

200 kN compression:Maximal load: 331 kN

Max. displacement: 32 mm

240 kN compression:


1 2 4 53 4 6

Failure can be caused by bending definitely.

First crack: 200 kN

240 kN compression:Maximal load: 378 kN

Max. displacement: 38 mm


Force vs. displacement diagrams for plain masonry

Vasalatlan falazat nyírási ellenállása

160

180

200

M100 vasalatlanM30 vasalatlan

Residual force: 143 kN at 31 mm

30 kN

Plain, M100

Plain, M30Crack: 180 kN


0

20

40

60

80

100

120

140

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Felső pont elmozdulása [mm]

Víz

szin

tes

erő

[kN

]


ab. 13 kN, because of the stronger mortar


Hor

izon

tal f

orce

[kN

]

Force vs. displacement diagrams for vertically reinforced masonry

M100 és M30 függőlegesen vasalt fal

180

200

220

240

260

M100 függvasalt

M30 függvasaltCrack: 176 kN

Force at the end of the process: 231 kN

Vertical, M100

Vertical, M30


0

20

40

60

80

100

120

140

160

180

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62

Felső pont eltolódása [mm]

Víz

szin

tes

erő [k

N]

Maximal load: 231 kN

Force at the end of the process: 231 kN at 42 mm

60 kN


Hor

izon

tal f

orce

[kN

]

Force vs. displacement diagrams for horizontally reinforced masonry

Vízszintes vasalású falak

160

180

200

220

M100 vízszintes

M30vízszintesCrack: 190 kN

20 kN

Vertical, M100

Vertical, M30Residual force: 171 kN at 38 mm


0

20

40

60

80

100

120

140

160

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70

Felső pont elmozdulása [mm]

Víz

szin

tes

erő [kN

]



Hor

izon

tal f

orce

[kN

]

M100 habarccsal készült falak nyírási ellenállása

300

320

340

360

380

400

M100 függőleges és vízszintes

M100_F+V_240kN

M30 függőleges és vízszintes

Uplift: 200 kN

Force at the end of the process: 331 kN at 32 mm

Force vs. displacement diagrams for masonry reinforced in both directions

Horiz. + Vertical, M100,200 kN

Horizontal + Vertical, M30

Horiz. + Vertical, M100,240 kN


0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62

Felső pont eltolódása [mm]

Víz

szin

tes

erő [k

N]

Uplift: 200 kN

Force at the end of the process: 378 kN at 38mm


Hor

izon

tal f

orce

[kN

]

Summary of walls M30

Type of thewall

Appearing first crack

Maximal load Maximal displacement

(residual force)

Forces belonging to

25 mm displacement

Plain masonry without mortar

89 kN 12,6 mm

41 mm (76 kN)

80 kN


Plain masonry 145 kN 3.2 mm

154 kN 4,6 mm

26 mm (129 kN)

128 kN

Vertically reinforced

121 kN 3.4 mm

161 kN 60,7 mm

60 mm (161 kN)

133 kN

Horizontally reinforced

173 kN 6.6 mm

180 kN 16,9 mm

67 mm (163 kN)

166 kN

Vertically and horizontally reinforced

176 kN 6.5 mm

252 kN 60,8 mm

60 mm (252 kN)

189 kN

28/34Conclusions1 2 4 53 4 6

Summary of walls M100

Type of the wall

Appearing first crack Maximal load Maximal displacement

(residual force)

Plain masonry 180-192 kN 3.7 mm 193 kN 4.8 mm 31 mm (143 kN)


1 2 4 53 4 6

Vertically reinforced

176 kN 5.3 mm 231 kN 39 mm 42 mm (231 kN)

Horizontally reinforced

192 kN 4.4 mm 193 kN 4.4 mm 38 mm (171 kN)

Vertically and horizontally reinforced

200 kN 5.0 mm 331 kN(378 kN)

32 mm 32 (38) mm

331 kN (378 kN)


Conclusions I.

� Horizontal reinforcement increases the shear capacity ofmasonry wall and delays appearing cracks in case of theweaker mortar. It modifies the crack pattern anddecreases the width of the cracks.

� In case of stronger mortar the horizontal reinforcement


According to the experiments carried out the following conclusions aredrawn:

� In case of stronger mortar the horizontal reinforcementdoes not provide an extra shear capacity compared to theplain masonry, the attention is attracted to an otherfailure mode that can be prevented by applying verticalreinforcement.

� By applying weaker mortar, horizontal and vertical rein-forcement the extension of the cracked zone is bigger,cracks appear less closely and the width of the cracks issmaller than in case of the plain masonry, at the sameload.

Conclusions 30/341 2 4 53 4 6

Conclusions II.� The new bonded vertically reinforced wall cracks almost at

the same load as the conventional wall independently of thetype of the mortar. However, the masonry does not decayafter cracking immediately, it is able to carry load in an amountthat is provided by the reinforcement.

� The vertical reinforcement does not alter the run of the


� The vertical reinforcement does not alter the run of thecracks. Although using stronger mortar causes a crackpattern running through the bricks.

� The stronger mortar, the horizontal and verticalreinforcement presented a masonry that modified the typeof the failure. It can not be damaged with the test setup.

Conclusions 31/341 2 4 53 4 6

Further plans� Experimental investigation of masonry wall bulit by other special

technologies

� Developing of a numerical model


1 2 4 53 4 Further plans6 32/34

Thank you for your kind attention!


33/34

Acknowledgement

Warm-hearted thanks to our colleagues in the Laboratory of the Budapest University of Technology and Economics,

Dr. Miklós Kálló Mr. Mansour Kachichian Mr. László Kaltenbach Mr.


Dr. Miklós Kálló, Mr. Mansour Kachichian, Mr. László Kaltenbach, Mr. Ferenc Dombi, Mr. Ferenc Hutterer, Mr. Ferenc Szász and to the

Wienerberger Corp.,

that provided the materials used.

34/34

shear capacity and crack pattern of reinforced and plain ...10 n/mm2) amount, shape, type and plac...

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