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Experimental Work for Mechanical Properties of Brick and Masonry Panel

Article in Journal of Science and Engineering · August 2018

DOI: 10.3126/jsce.v5i0.22372

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 EXPERIMENTAL WORK FOR MECHANICAL PROPERTIES OF BRICK AND
MASONRY PANEL

Saroj Phaiju1, Prachand Man Pradhan2

1
Department of Civil Engineering, Khwopa Engineering College, Libali-8, Bhaktapur, Nepal
2
Department of Civil & Geomatics Engineering, Kathmandu University, Dhulikhel, Nepal

Abstract
The use of Masonry panels in building construction has been popular in most of the parts of the world. However,
the use of bricks and brick masonry in different parts of the world being of different nature in terms of quality,
size, workmanship of construction, etc. It is yet a topic of interest to researchers to identify the mechanical
properties, like Young’s modulus of elasticity and shear modulus of brick masonry panels. It is essential to know
the characteristic of brick masonry panels in order to evaluate the responses of masonry walls for any kind of
loading. Individual bricks do possess better compressive capacity as compared to masonry walls. Masonry walls
are bound together with either mud mortar or by cement sand mortars of various mixes as per the strength
requirements. The essential strength properties in engineering are basically the compressive strength and the
modulus of elasticity. The American Society for Testing and Materials (ASTM) standard is the most popular for
testing bricks and brick masonry for these properties so far. Here, the study has been concentrated in finding the
compressive strength of brick, mortar and brick masonry. The study is also done for Young’s modulus of
elasticity of brick as well as that of masonry wall. Similarly, the study is extended to find the modulus of rigidity
of brick masonry panel. The study is done experimentally for the samples that are generally used in Kathmandu,
Nepal. The samples include bricks, cement and sand particularly available in Kathmandu region.

Keywords: Masonry panel, Mechanical properties, Compressive strength, Modulus of elasticity, Shear modulus

1. Introduction
The value of mechanical properties; compressive biaxial tensile strength of brick, the failure criteria
strength, modulus of elasticity, shear modulus are for a brick under a triaxial state of stresses, the
required to analyze and design the masonry uniaxial compression strength of mortar, behavior of
structures. Depending on the quality of materials, mortar under triaxial loading and the coefficient of
size, workmanship of construction, these values non-uniformities due to joints and brick properties.
have wide range of adaptability. This research is Thus, it is seen that there are many factors that
focused on the finding of these values in local affect the strength of brick masonry and as such
context. various researchers have suggested the Young’s
modulus of elasticity of brick masonry in their own
Sahlin (1971) suggests that within practical limits, ways. The range of Young’s modulus thus varies
the wall strength is dependent on mortar strength as extremely. If fb is the compressive strength of
well as brick strength. Thus, the brick wall strength individual brick, Glanville & Barnett (1934) suggest
is about 25% to 50% of individual brick strength. that the Young’s modulus of individual brick is Eb =
The factors that affect the masonry strength 300*fb. Most of the empirical expressions suggested
according to Hilsdrof’s theory include the uniaxial by various researchers fall within the range Em =
compressive strength of brick, 400*fm and 1000*fm, where fm is the compressive
*Corresponding author: Saroj Phaiju strength of masonry panel and Em is the Young’s
Department of Civil Engineering, Khwopa Engineering modulus of elasticity of Masonry panel (Sahlin,
College, Libali-8, Bhaktapur, Nepal
1971). Sahlin also suggests that the rough estimate
Email: joras0816@gmail.com
(Received: Nov 5, 2017 Accepted: May 10, 2018)
of the modulus of elasticity of masonry in

JScE Vol. 5, August 2018 Saroj Phaiju 51

compression may be considered as Em = 700*fm.

As per FEMA273 the masonry compressive strength mechanical properties of masonry panels. According
may be taken as at the most 900psi for masonry in to him, the Young’s modulus of infilled masonry is
good condition, 600psi for masonry in fair condition 3939.41 MPa and shear modulus of half full brick
and 300 psi for masonry in poor condition. It is also infilled masonry wall is 2643.43 MPa.
suggested that the Young’s modulus of elasticity of
masonry wall may be considered as Em = 550*fm. Eurocode 06 prescribes the empirical relation for
shear modulus of rigidity of brick panel as G = 0.4
Pauley & Priestley (1992) uses Em = 600*fm where Em. This shows that the shear modulus is about 40%
fm is compressive strength of masonry (in MPa or that of Young’s modulus of masonry panel.
psi). Pradhan, 2012 has used fm as 5.6 N/mm2 and
the Young’s modulus as 2750 N/mm2 his study 2. Experimental Set-up
which further indicate that the relation chosen
approximately as Em = 490*fm. The test specimens chosen were red colored,
metallic ringing sound, hand-made chimney kiln
Rodrigues, Varum, & H. Coasta (2010) have tested burnt clay bricks that are generally available and
experimentally for bricks, mortar joints and panels used in Kathmandu valley. Similarly, the ordinary
for Young’s modulus as well as for Shear modulus portland cement and sand which are usually
and suggested the values for them. Brick’s available in the market are taken for testing purpose.
compressive strength perpendicular to the bed joints The structural testing laboratory of Khwopa
is 2.8 N/mm2. Similarly, the mortar joints tensile Engineering College which houses Universal
strength is 0.59 N/mm2, while compressive strength Testing Machine (UTM) of 40 Tonne capacity was
is 1.33 N/mm2. Their results for masonry wall used for loading purpose. Dial gauges of least count
compressive strength is 1.1 N/mm2. The Young’s 0.01 mm were used for deflection measurement. The
modulus of masonry wallets perpendicular to the loads and sizes of panels needed to be conveniently
bed joints is given as 1.873 GPa (1873 N/mm2). The handled within the UTM, thus the specimens were
shear modulus is given as 0.657 GPa (657 N/mm2). scaled down to 1:3. The sand and brick samples
were accordingly scaled down; even the mortar
Bergami (2007) has done experimentation for thickness was also scaled down correspondingly.

Table 1. Physical characteristics of prototype samples

S.N Items properties Length (mm) Breath (mm) Depth (mm)
1 Brick First class 230 110 50
2 Sand 4.75mm sieve passed
3 O.P.C 53 grade
4 Brick panels density 17KN/m3 1200 230 1200
5 Mortar Mix 1:4 12

Table 2. Scaled down model data

SN Items properties Length (mm) Breath (mm) Depth (mm)

1 Brick First class 77 34 17
2 Sand 2mm sieve passed
3 O.P.C 53 grade
4 Brick panels density 17.3KN/m3 400 77 400
5 Mortar Mix 1:4 4

JScE Vol. 5, August 2018 Saroj Phaiju 52

2.1 Brick Compression Test

The prototype brick sample and Scaled down brick

samples were of sizes 230mm x 110mm x 50mm
and 77mm x 34mm x 17mm respectively.
The brick compression test was performed as per the
ASTM standards. Total of seven samples were
tested with the UTM. The force application was
very slow at the speed of 14 N/mm2 so that the
displacement of brick on load increment could be
easily measured. The force–deflection curve were
plotted in order to identify the Young’s modulus and Fig. 3 Cement sand mortar cube test
the compressive strength of individual brick.
2.3 Brick Masonry Compression Test

Three brick panels of dimensions as per Table 2

with mortar thickness 4mm have been tested under
UTM with very slow application of loading
increment. A dial gauge was used to measure the
displacement as the compressive force was applied
to the brick panel as shown in Fig 4. The force-
displacement curve was plotted to identify the
Young’s modulus as well as the compressive
strength of brick panel. The force required for initial
crack, and also the crack pattern was studied as the
loading increased. In order to apply the loads
uniformly, two supporting beams of mild steel were
Fig. 1 Brick compression test prepared as shown in Fig 5. The panels were
installed between the beams.

Fig. 2 Scale down Brick compression test Fig. 4 Compression test of brick masonry

2.2 Mortar Testing

The sand sample available was sieved in order to

achieve the 1:3 scaled down requirements. Then the
cement sand mix of 1:4 was used to prepare mortar
test sample cube as per the Indian standards. The
cubes of size 100mm x 100mm x 100mm after
curing for 28 days were tested under UTM for cube
strength. Fig. 5 Supporting beams

JScE Vol. 5, August 2018 Saroj Phaiju 53

2.4 Brick Masonry Shear Test strength of 11.12N/mm2 and that of scaled down
brick had 13.73N/mm2, and the compression
Three brick masonry panels of the size as per Table strength of masonry panel is 2.5N/mm2. The tests of
2 were applied loadings as shown in the Fig 6. The mortar cube suggests that the motar samples had
application of loading was very slow at the speed compressive strength of 3.8 N/mm2. This informs us
rate of 14 MPa per minute, so that the deflection of that the masonry panel would acquire about 23%
panels at two locations was conveniently observed. strength of individual brick. This indicates that the
The displacement of the panel both vertically as brick panel that is constructed in Kathmandu has the
well as horizontally were measured with the support strength within the range prescribed by international
of dial gauges of 0.01mm sensitivity. The standards as compared to the documents suggested
displacement as well as crack propagation by Sahlin.
phenomena and also the crack patterns were studied.
In order to apply the loads, two supporting saddles 3.2 Young’s Modulus of Elasticity of Brick
of mild steel were prepared as shown in Fig 7. The
and Masonry Panels
panels were installed within the saddles.

Fig. 6 Shear testing

strength of 11.12 N/mm2 and that of scaled down

brick had 13.73 N/mm2, and compression strength
of Masonry Panel is 2.5 N/mm2. The test of mortar
Fig. 8 Compression force versus axial displacement
of bricks

The Young’s modulus of masonry panel observed

from the experiment suggests that the value is about
2700 N/mm2. Here, the Young’s modulus of
masonry panel observed as Em = 1085*fm, where fm
is compressive strength of individual brick. The
Fig. 7 Supporting Saddles initial crack was used to identify the Elastic limit
from which the Young’s modulus of elasticity was
identified. After the initial crack, the masonry panel
3. Results and Discussions
could accept significant force beyond the elastic
3.1 Brick, Mortar and Brick Masonry limits. The complete failure occurred at the force
Compression Tests value of 72 KN and elastic limit force value is 7
The test results for brick compression suggest that KN, which was 9.7 % of the complete failure force.
the full brick samples chosen had the compression

JScE Vol. 5, August 2018 Saroj Phaiju 54

 may be taken as G = 0.34*Em which is slightly less
than that prescribed by the Eurocode 06. The failure
pattern was observed as to propagate from the sides
as shown in the Fig. 12. The failure pattern indicated
that the panels would crack or fail mainly by shear
or slipping action within the mortar joints. The
loading was applied till the panel completely failed.

Fig. 9 Compression force versus axial

displacement of masonry panel

Fig. 12 Propagation of cracks

Fig. 10 Graphical representation for

Tangent modulus, Em a

Fig. 11 Stress-Strain curve of Panels

3.3 Shear Modulus of Rigidity of Masonry

Panels

The shear test result showed that the modulus of

rigidity of brick panel can be estimated as 915
N/mm2, which is about 34% of the Young’s c
modulus of elasticity. This further suggests that an Fig. 13 Load displacement curves (horizontal and
empirical relation between Shear modulus and vertical )
Young’s modulus can be established. The relation

JScE Vol. 5, August 2018 Saroj Phaiju 55

 Table 3. Mechanical properties of cement mortar, bricks and masonry

S.N Item Parameters values

Compressive strength (fcm) 3.8 N/mm2

1 Cement mortar
Young’s modulus (Ecm) 2555.5 N/mm2

Compressive strength (fb) 11.12 N/mm2

2 Bricks
Young’s modulus (Eb) 3357.9 N/mm2

Compressive strength (fm) 2.5 N/mm2

Young’s modulus (Em) 2703.2 N/mm2

Shear modulus (G) 915.1 N/mm2

3 Masonry
Poisson’s ratio (ν) 0.32

G = 0.34 Em

Em = 1085 fm

3.4 Poison’s Ratio of Masonry Panel This further indicates that the Young’s modulus of
elasticity as well as Shear modulus of rigidity needs
It was observed from the force displacement data that to be improved. The handmade bricks have been
the longitudinal and transverse strains were obtained found to have density of 17 KN/m3 in dry state,
which is further used to compute the Poisson’s ratio which also indicates that the strength of brick
of the masonry panels. Thus, from the experimental masonry might have been less due to less compaction
work, the Poisson’s ratio for masonry panel is found being applied during moulding work. If the bricks
to be 0.32, which is slightly more than that of were allowed to compact properly during its
concrete’s value. manufacturing, the density could have increased,
which would further be the reason for strength
4. Conclusions and Recommendations enhancement.

The conclusion from the study is that the mechanical However, since there are many factors which affect
properties of locally available handmade bricks of the strength and quality of brick masonry, the
Kathmandu may be considered to have Young’s compact brick is just one recommendation for
modulus of elasticity as 2700 N/mm2, and the Shear improving the masonry’s strength. Besides, as other
modulus may be considered as 34% of Young’s researchers indicate, the workmanship and mortar
modulus of masonry wall. The mortar of 1:4 cement strength are very crucial factors for strength
sand mix may be considered to have compressive quantification.
strength as 3.8 N/mm2. The individual brick may be
considered to have compressive strength as 11.12 References
N/mm2 and that of the brick masonry may be
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strength of brick masonry according to FEMA273 Tension (Shear) in Masonry Assemblages
indicates that the brick masonry is of poor quality.
[2] Bergami, A. V. (2007). Implementation and
Thus, we have to increase the strength of brick experimental verification of models for nonlinear
masonry in order to meet the FEMA standards of at analysis of masonry infilled r.c. frames. Rome, Italy:
least fair condition. Universita degli studi ROMA TRE.

JScE Vol. 5, August 2018 Saroj Phaiju 56

 [3] Eurocode 06: Design of Masonry Structure, Part 1-1,
General Rules for Reinforced and Unreinforced
Masonry Structures

[4] FEMA273. Siesmic Rehabitation Guidelines. USA.

[5] Glanville, & Barnett. (1934). Mechanical Properties of

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Researach Station.

[6] Hilsdorf, H. (1969). "An Investigation into the Failure

Mechanism of Brick Masonry Loaded in Axial
Compression", Designing, Engineering and
Construction with Masonry Products, edited by Dr.
Franklin Johnson. Texas: Gulf Publishing Company.

[7] IS: 3495(Part 1)- 1992, Indian Standard, Methods of

Tests of Burnt Clay Building Bricks

[8] IS:1905- 1987, Indian Standard, code of Practice for

Structural Use of Unreinforced Masonry

[9] IS: 2250- 1981, Indian Standard, code of Practice

forPreparation and Use of Masonry Mortats

[10] IS : 2116 - 1980, Indian Standard, Specification for

Sand and Masonry Mortars

[11] Paulay, T., & Priestley, M. (1992). Seismic Design of

Reinforced Concrete And Masonry Buildings. USA:
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[12] Pradhan, P. (2012). Equivalent Strut Width for Partial

Infilled Frames. Journal of Civil Engineering Research
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[13] Rodrigues, Varum, & H. Costa, A. (2010). Simplified

Macro-Model for Infill Masonry Panels. Journal of
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[14] Sahlin, S. (1971). Structural Masonry. New Jersey:

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JScE Vol. 5, August 2018 Saroj Phaiju 57

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