In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

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INTERNATIONAL JOURNAL OF CIVIL AND STRUCTURAL ENGINEERING Volume 2, No 4, 2012 © Copyright 2010 All rights reserved Integrated Publishing services Research article ISSN 0976 – 4399 Received on March, 2012 Published on May 2012 1144 In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study Freeda Christy C 1 , Tensing D 2 , Mercy Shanthi R 3 1- Karunya University, Coimbatore, TamilNadu, India, 641 114 2- ASL Paul’s College of Engineering, Pollachi, TamilNadu, India 642 109 3- Karunya University, Coimbatore, TamilNadu, India, 641 114 [email protected] ABSTRACT Masonry buildings are brittle in nature and one of the most vulnerable among the different types of structural buildings under strong earthquake shaking. Horizontal loads, induced by earthquake causes severe in-plane and out of plane forces in wall. A wall topples down easily if pushed horizontally at the top in a direction perpendicular to its plane (out – of plane), but offers much greater resistance if pushed along its length (in-plane). The lateral load resistance of masonry buildings is mainly due to in-plane shear resistance of the masonry elements/piers. Therefore detailed investigation on the in-plane shear behaviour of masonry thus becomes necessary. Earthquake performance of a masonry wall is very sensitive to the properties of its constituents, namely masonry units and mortar. The shearing strength of masonry mainly depends upon the bond or adhesion at the contact surface between the masonry unit and the mortar. Thus, it is very important to improve the shear behaviour of masonry buildings. The primary gap identified through literature review was the lack of experimental research that addressed the response of masonry shear walls. This paper contains a review on the shear test conducted to improve the lateral load resistance of masonry walls. 1. Introduction Housing is one of the basic requirements for human survival. For a normal citizen owning a house provides significant economic and social security and status in society. In India 83% of the population live in villages and about 73% of the rural population reside in unreinforced masonry structures. Masonry is a composite material of brick units and mortar joints and interface between mortar and unit. The behaviour of masonry is based on the properties of brick units and mortar joints. Brick masonry is unified mass obtained by systematic bonding arrangement of laying bricks and bonding them together with mortar. The shear behaviour of masonry can be investigated at different levels as micro level and macro level. At the micro level, the mortar and the bricks are considered separately. At the macro level the wall panels are considered. Brick masonry is the least understood in the aspect of strength and other performance related parameters because of its complex behaviour and its non homogeneity even in deci-scale, (Paulo, 2006). The weaker the mortar the lower the masonry strength (due to the unit-mortar interaction, the masonry strength is always lower than the unit strength). Very few studies have been identified that addressed the effect of mortar type on the in-plane response of masonry walls. Bridging this knowledge gap require additional experimental research. The research review was classified into two different categories: first being the study of physical and mechanical behavior of brick masonry and its assemblages; second the response of the in-plane shear behaviour of the masonry wall elements.

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n-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

Transcript of In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

Page 1: In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

INTERNATIONAL JOURNAL OF CIVIL AND STRUCTURAL ENGINEERING

Volume 2, No 4, 2012

© Copyright 2010 All rights reserved Integrated Publishing services

Research article ISSN 0976 – 4399

Received on March, 2012 Published on May 2012 1144

In-plane shear behaviour of Brick Masonry – A Literature Review on

experimental study Freeda Christy C

1, Tensing D

2, Mercy Shanthi R

3

1- Karunya University, Coimbatore, TamilNadu, India, 641 114

2- ASL Paul’s College of Engineering, Pollachi, TamilNadu, India 642 109

3- Karunya University, Coimbatore, TamilNadu, India, 641 114

[email protected]

ABSTRACT

Masonry buildings are brittle in nature and one of the most vulnerable among the different

types of structural buildings under strong earthquake shaking. Horizontal loads, induced by

earthquake causes severe in-plane and out of plane forces in wall. A wall topples down easily

if pushed horizontally at the top in a direction perpendicular to its plane (out – of plane), but

offers much greater resistance if pushed along its length (in-plane). The lateral load resistance

of masonry buildings is mainly due to in-plane shear resistance of the masonry elements/piers.

Therefore detailed investigation on the in-plane shear behaviour of masonry thus becomes

necessary. Earthquake performance of a masonry wall is very sensitive to the properties of its

constituents, namely masonry units and mortar. The shearing strength of masonry mainly

depends upon the bond or adhesion at the contact surface between the masonry unit and the

mortar. Thus, it is very important to improve the shear behaviour of masonry buildings. The

primary gap identified through literature review was the lack of experimental research that

addressed the response of masonry shear walls. This paper contains a review on the shear test

conducted to improve the lateral load resistance of masonry walls.

1. Introduction

Housing is one of the basic requirements for human survival. For a normal citizen owning a

house provides significant economic and social security and status in society. In India 83% of

the population live in villages and about 73% of the rural population reside in unreinforced

masonry structures. Masonry is a composite material of brick units and mortar joints and

interface between mortar and unit. The behaviour of masonry is based on the properties of

brick units and mortar joints. Brick masonry is unified mass obtained by systematic bonding

arrangement of laying bricks and bonding them together with mortar. The shear behaviour of

masonry can be investigated at different levels as micro level and macro level. At the micro

level, the mortar and the bricks are considered separately. At the macro level the wall panels

are considered. Brick masonry is the least understood in the aspect of strength and other

performance related parameters because of its complex behaviour and its non homogeneity

even in deci-scale, (Paulo, 2006).

The weaker the mortar the lower the masonry strength (due to the unit-mortar interaction, the

masonry strength is always lower than the unit strength). Very few studies have been

identified that addressed the effect of mortar type on the in-plane response of masonry walls.

Bridging this knowledge gap require additional experimental research. The research review

was classified into two different categories: first being the study of physical and mechanical

behavior of brick masonry and its assemblages; second the response of the in-plane shear

behaviour of the masonry wall elements.

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In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

Freeda Christy C, Tensing D, Mercy Shanthi R

International Journal of Civil and Structural Engineering

Volume 2 Issue 4 2012

1145

1.1 Study on the behavior of brick masonry and its assemblages

The unreinforced masonry is brittle in nature. Earthquake performance of masonry wall is

very sensitive to the properties of its constituents, namely masonry units and mortar. Shear

rupture occurs either as a diagonal splitting or as step-pattern sliding along the mortar joints,

depending on the characteristics of the constituent materials (mortar and bricks). Therefore,

in order to predict properly the masonry shear capacity, it is necessary to first identify the

failure mechanism based on the knowledge of the involved materials. Masonry mechanical

properties depend on the characteristics of the constituent elements (bricks and mortar) as

well as on the workmanship and the interface interaction within the assemblage.

1.2 Brick

A variety of masonry units are used in the country using clay bricks (burnt and unburnt),

concrete blocks (solid and hollow), stone blocks. Burnt clay bricks are most commonly used.

The properties of these materials vary across India due to variation in raw materials and

construction methods. The main mechanical properties of the bricks were compressive and

tensile strength. The characterization and the properties of local low modulus bricks, table

moulded bricks and wire cut bricks, mortars and masonry were compared (Sarangapani etal,

2002). Maximum flexural strength was obtained by immersion of bricks in water for ten

minutes before use which influenced the flexural tensile strength (Choubey, 1993). the usage

of flyash in bricks was introduced, as it has good shear strength properties and relatively less

compressibility, (Dayal, 1995). The flyash bricks are of two types: (i) non-calcinite bricks

(flyash mixed with bonding agent) and (ii) calcinite bricks (flyash clay brick). The use of

flyash offered a considerable saving of coal consumption which had been found to vary in the

range of 3t – 7t of grade I coal per 105 bricks. The bricks cannot be manufactured with highly

swelling soils without additives and flyash were added to soil for making good bricks with

the soil in varying ratio’s as 0%, 10%, 20%, 30%, 40% and 50%, (Krishnamoorthy et al,

1994). The properties of strength and water absorption of bricks made with replacement of

soil by 50% of flyash were reasonably good and the strength were ranging from 9.8 to 11.5

N/mm2

but for the country brick it was about 3.5N/mm2 and no marked improvement was

there with more addition of flyash. good quality of light weight bricks were produced from

the flyash of Seyitomer power plant, Turkey, (Tayfun Cicek and Mehmet Tanrıverdi, 2007).

The compressive strength, unit weight, water absorption and thermal conductivity of the

flyash–sand–lime bricks obtained under optimum test conditions were 10.25 MPa, 1.14g/cm3,

40.5% and 0.34W m-1

K-1

respectively. The brick made of pure flyash was developed by

Henry Liu, (Henry Liu etal, 2009) and the manufacture of the brick does not involve high

temperature heating in kiln, in contrast to manufacturing clay bricks. Consequently, using

greenest brick not only eliminates waste disposal of flyash and saves landfill space, it also

saves much energy and eliminates all the air pollution and global warming problems caused

by burning fossil fuel in kilns to manufacture clay bricks. Flyash bricks made from flyash do

not emit mercury into air. On the contrary, they absorb mercury from air, making the ambient

air cleaner. Flyash brick do not emit radon gas as compared to 50% of that emitted from

concrete blocks. Thus it was considered safe to use flyash bricks more than concrete blocks in

buildings. Leaching of pollutants from flyash bricks caused by rain was negligible. In

addition, long-term observation of the compacted flyash bricks revealed that the long-term

growth of strength in flyash bricks is due to carbonation caused by absorption of CO2 from

the atmosphere and bring relief to global warming. Emeritus and Hendry reviewed masonry

materials clay, concrete and calcium silicate in which a wide variety of brick unit sizes, forms

and colours were produced, (Emeritus and Hendry, 2001). Clay bricks are obtainable in

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In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

Freeda Christy C, Tensing D, Mercy Shanthi R

International Journal of Civil and Structural Engineering

Volume 2 Issue 4 2012

1146

strengths of up to 100 N/mm2 and much lower strengths; say 2 – 4 N/mm

2 are generally

sufficient for domestic buildings and for cladding walls for taller buildings. Concrete blocks

have lower apparent compressive strengths in the range 2.8-35 N/mm2. The tensile strength

of masonry units both direct and flexural has an influence on the resistance of masonry under

various stress conditions but is not normally specified except in relation to concrete blocks

used in partition walls where typically a breaking strength of 0.05 N/mm2 is required.

Although mortar accounts for as little as 7% of the total volume of masonry, it influences the

performance of the masonry. It is inadvisable to use a stronger mix than necessary to meet the

structural requirements. Hardened and sufficiently strong mortar develop adequate adhesion

to the units and also set without excessive shrinkage which would reduce the resistance of the

masonry to rain water penetration or even cause cracking of the units. Masonry wall

construction had undergone considerable change in the course of the last few decades with

the introduction or extended use of lightweight materials and new types of units. In

comparison with alternative materials achieved to an excellent future for the continued use of

masonry construction.

1.3 Mortar

Mortar, a pasty material formed by the addition of water to a mixture composed of an

aggregate (sand) and a binding material (cement or lime) which may be handled with a trowel.

Mortar unites the individual bricks together and takes up all irregularities in the bricks.

Generally, mud mortar, cement mortar, lime mortar, cement lime mortar are in use. Mud

mortar is used for the temporary construction. Cement mortar is used for permanent

structures. Pitre et al utilized the waste materials - flyash, kiln ash, surkhi, cinder and

crushed stone in building construction along with lime and cement (Pitre et al, 1995). Flyash

mortars with un-slaked lime developed more strength than those with slaked lime and mortars

with surkhi and slaked lime gains more than with the un-slaked lime. Lime mortars with kiln

ash attained higher strength than all other mortars therefore, it was recommended as a viable

substitute to cement sand mortar. Lime mortar with surkhi and flyash developed adequate

compressive strength and recommended for use in building construction. The poor bond and

low bond strength is a major weakness of brickwork, (Reda Taha and Shrive, 2010). The

bond was affected by many interrelated factors associated with both masonry units and

mortar. The Lime present in masonry mortar as a by-product of cement hydration,

particularly at the mortar-unit interface where it produces a weak layer. Hence introduction of

varying amounts and types of pozzolans (flyash types F, C and slag) which reacts with the

lime, produce strong calcium silicate hydrates and enhance the bond strength of the masonry

by altering the microstructure of the mortar-unit interface. Statistically significant increases in

bond strength were measured at 28, 90 and 180 days with 20% substitution of flyash in the

cementitious materials. No increases were observed with slag. Pozzolonas as a mineral

admixture in masonry mortar were environmentally friendly and beneficial from the

rheological, economic and structural points of view. The flyash mortar improved the long-

term bond strength in masonry. Partial replacement of the portland cement and lime with

class F flyash significantly improved masonry bond strength. Class C flyash provided limited

enhancement to the long-term bond strength. Both materials provided more cost-effective,

high durable, environmental friendly mortar than mortar without flyash. The flyash and silica

fume showed different surface features compared to Portland cement which effected on

compressive strength of mortar, (Yilmaz kocak, 2010). The ternary use of flyash and silica

fume provided the best performance, when the compressive strength properties of the cement

mortars were taken into account. During hydration of cement mortars, Cement hydration

formation is reduced due to flyash and silica fume substitution, therefore a lower compressive

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In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

Freeda Christy C, Tensing D, Mercy Shanthi R

International Journal of Civil and Structural Engineering

Volume 2 Issue 4 2012

1147

strength was obtained at the early ages when compared to Portland cement. During

subsequent days of hydration, flyash and silicafume having pozzolanic structure bind calcium

hydrate in time and turn it into new (pozzolanic) C-S-H gel and cause the strength values to

reach that of Portland cement. Rafat Siddique, partially replaced fine aggregate (sand) with

five percentages (10%, 20%, 30%, 40% and 50%) of class F flyash by weight and had no

delayed early strength development but rather enhanced its strength on long-term basis,

(Rafat Siddique, 2003). This study explored the possibility of replacing part of fine aggregate

with flyash as a means of incorporating significant amounts of flyash. Compressive strength,

split tensile strength, flexural strength and modulus of elasticity of cement mortar with fine

aggregate (sand) replaced with flyash mortar continued to increase with age for all flyash

percentages. The maximum compressive strength occurred with 50% flyash content at all

ages. It was 40.0 MPa at 28 days, 51.4 MPa at 91 days, and 54.8 MPa at 365 days. It was

suggested that class F flyash could be very conveniently used in structural mortar.

1.4 Behaviour of Shear Walls

Masonry is now generally classified into six categories, historic (or load) bearing,

unreinforced structural masonry, confined masonry, retrofitted masonry, reinforced masonry

and pre-stressed masonry. Unreinforced masonry has been widely used as a construction

material for housing, flats, and commercial premises across large areas of the world and has

been common in those parts of the world identified as intra plate zones which covers the

interior of the tectonic plates. A shear walls capacity derives from a high moment of inertia

about one axis, high compressive strength brickwork, and some tensile capacity, preferably

augmented with a compressive stress generated by dead load from higher storeys. In a

masonry building subjected to earthquake loads, horizontal seismic inertia forces develop in

the walls and the floor and roof slabs. The floor and roof slabs are called diaphragms where

they transfer lateral loads to the lateral load resisting system. These inertia forces are

proportional to the mass of these structural components and the acceleration at their level.

The lateral load resistance of masonry buildings is mainly due to in-plane shear resistance of

the masonry elements. Therefore detailed investigation on the in-plane shear behaviour of

masonry element thus becomes necessary. In general, brick unit - mortar combination

provides greater bond strength and also provides greater shear strength. Steel reinforcement

may be added to the masonry assemblage to increase the shear strength. Shear reinforcement

should be provided parallel to the direction of applied shear force. Two types of test were

characterized by the way the load is applied: the shear compression test, as well as the

diagonal compression test, was designed in order to evaluate the shear strength of the

masonry wall, (Van Vliet, 2004).

Pankaj Agarwal and Thakkar demonstrated the differences in the behaviour of brick masonry

model subjected to either shock table motion or quasi-static loading. The shock model

responds with a significantly higher initial strength and stiffness as compared to the quasi-

static model subjected to equivalent lateral displacements. Severity of damage was greater in

quasi-static test due to increased crack propagation. The shock test suggested that at low

levels of excitation at the base, acceleration gets amplified at the roof, with an almost elastic

behaviour of the model. Marked reduction in both strength and stiffness has been observed

when the model was loaded statically rather than dynamically. The crack patterns obtained

under both the test methods were nearly similar, (Pankaj Agarwal and Thakkar, 2001).

Essy Arijoeni Basoenondo concluded that the capacity of wall under cyclic loads is 50% less

than that under monotonic and repeated lateral in-plane loads. All walls collapsed in brittle

failure mechanism, without the presence of ductility. It was also recorded that the presence of

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In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

Freeda Christy C, Tensing D, Mercy Shanthi R

International Journal of Civil and Structural Engineering

Volume 2 Issue 4 2012

1148

surface mortar plaster as wall confinement system increased the stiffness of wall, but did not

affect the improvement of wall ductility, (Essy Arijoeni Basoenondo, 2008).

Corradi et al performed tests on the walls in the laboratory and in-situ under compression,

diagonal compression and shear–compression. These tests involved the use of panels of two

different dimensions: 120x120 cm2 for the diagonal compression tests and 90x180 cm

2 for

the compression and shear–compression tests. All panels were cut using the diamond-wire

technique and isolated from the remaining masonry walls in order to leave the panels

undisturbed. Regarding the solid brick panel, it was significant to note that the particular

brick texture caused a nominal shear strength τk of 0.069 MPa, (Corradi et al, 1999).

Choubey found that the behavior was almost similar for all panel specimens irrespective of

the type of mortar (1:3, 1:4.5, and 1:6) and size of panel. But the specimens made of richer

mortar mixes showed lesser deflections, (Choubey, 1993).

2. Retrofitted masonry wall

Mustafa Taghdi et al retrofitted to strengthen the un-reinforced walls and partially reinforced

walls using a steel strip system consisting of diagonal and vertical strips that were attached

using through-thick bolts. All walls were tested under combined constant gravity load and

incrementally increasing in-plane lateral deformation reversals showed that the complete steel

strip system was effective in significantly increasing the in-plane strength and ductility of

low-rise un-reinforced and partially reinforced masonry walls and lightly reinforced concrete

walls. The capability of un-reinforced masonry walls to resist lateral loads was limited by the

strength of both masonry brick units and bed joint mortar. (Mustafa Taghdi et al, 2000).

Shambu Sinha retrofitted by applying a layer of reinforced shotcrete to one surface

strengthened to provide earthquake resistance by applying a 76mm thick layer of shotcrete to

either the outside or inside surface of the walls. The shotcrete greatly increased the strength

of the un-reinforced brick panels. Panels reinforced with the welded wire fabric showed a

significant increase in strength after first cracking and large inelastic deflection capacity. The

shotcrete along with reinforcement permitted the panels to deflect in-elastically and to remain

intact even after the full reversed cycle loading. Bond strength between the shotcrete and

bricks directly influenced the strengthening of the structural panels, including its stiffness

properties, (Shambu Sinha, 2006)

Gabor et al strengthened the unreinforced masonry panels by fibre reinforced polymer (FRP)

composite strips and tested in diagonal compression. Three types of FRP composites are

employed: a unidirectional glass fiber (noted RFV), a unidirectional carbon fiber (noted RFC)

and a bidirectional glass fiber (noted RFW). The global behaviour was described by the

applied load vs. strain along the compressed diagonal curve, is quasi elastic with a very weak

yield plateau. Indeed, the failure strength was conditioned by the shear strength induced by

the interaction of the mortar notches with the internal wallettes at the brick/joint interface.

The load corresponding to the elastic limit and the ultimate load of the reinforced panels are

much higher than the one of the unreinforced panels. The gain in strength was quite

remarkable: 42% for the RFV reinforcement and over 65% for the RFW. The deformations

corresponding to the maximum loads of the reinforced walls are three times higher than those

of the unreinforced walls. Therefore, the seismic behaviour was enhanced, (Gabor et al,

2006). Maria Rosa Valluzzi proposed a strengthening technique based on the insertion of

steel bars in the bed joints. It is particularly suitable for regular brick masonry showing a

critical crack pattern due to high compressive loads. Experimental tests and numerical

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In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

Freeda Christy C, Tensing D, Mercy Shanthi R

International Journal of Civil and Structural Engineering

Volume 2 Issue 4 2012

1149

analyses showed that the presence of the bars allows control of the cracking phenomena,

keeping the structure in the desired safety conditions. Both experimental and numerical

analyses showed that the most significant result concerns the reduction of the tensile stresses

in the bricks and of the dilatancy of the wall, (Maria Rosa Valluzzi, 2005).

Navaratnarajah Sathiparan et al retrofitted wallettes by polypropylene (PP) band meshes. The

retrofitted wallettes achieved 2.5 times larger strengths and 45 times larger deformations than

the non-retrofitted wallettes. In out-of plane tests, the mesh effect was not observed before

the wall cracked. After cracking, the mesh presence positively influenced the wallettes

behaviour. In the retrofitted case, although the initial cracking was followed by a sharp drop,

atleast 45% of the peak strength remained. After this, the strength was regained by

readjusting and packing by PP band mesh. The final strength of the specimen was equal to

1.2 kN much higher than initial strength of 0.6kN. The retrofitted wallettes achieved 2 times

larger strengths and 60 times larger deformations than the non-retrofitted wallettes,

(Navaratnarajah Sathiparan et al, 2005).

Mohamed Elgawady etal presented preliminary comparisons between the test results of the

dynamic and static cyclic tests. The test specimens are half-scale specimens built using half-

scale hollow clay masonry units and weak mortar. The specimens, before and after

retrofitting, are subjected to a series of either synthetic earthquakes or static cyclic test runs.

The tests showed that the composites improve the cracking and ultimate load of the retrofitted

specimen by a factor of 3 and 2.6, respectively. The lateral resistance of the reference

specimen measured in the static cyclic tests is 1.2 times the lateral resistance of the similar

reference specimen measured in the dynamic test. In spite of relatively poor mortar, the

specimen friction coefficient exceeded 1.0, (Mohamed Elgawady etal, 2004).

Haroun etal evaluated the in-plane shear behavior of masonry walls externally reinforced

with fiber reinforced polymer (FRP) composite laminates. The wall specimens were built

with a height-to-length aspect ratio of 1:1 to promote a shear dominated behavior under in-

plane loading. The control as-built wall was cyclically tested to failure and demonstrated a

pure shear mode. The failure of the specimen was initiated by diagonal shear cracks and

developed a diagonal strut action resulting in the crushing of the wall edge boundaries. When

the performance of the repaired wall is compared with that of the as-built wall, it becomes

clear that the repair technique has improved the strength and energy dissipation of the wall. It

not only succeeded in restoring the capacity of the original wall, but also increased to a level

of 120 % that of the original wall capacity. The energy dissipation observed for repaired

specimen was also increased to 167 % that of the control wall. The ductility of the

carbon/epoxy repaired specimen was 1.7 times that of the as built specimen. For the

retrofitted specimens, the enhancement in the ductility ranged from 3.4 times that of the as-

built in case of double-side carbon/epoxy retrofit to 6 folds in the case of pre-cured

carbon/epoxy strips. Despite the premature failure caused by localized compression failure of

the masonry at the wall toes, notable gains in strength, stiffness and ductility were achieved

by applying the FRP laminates to either one or two sides of the walls, (Haroun etal, 2005).

Steel bracing is a highly efficient and economical method of resisting horizontal forces in a

frame structure. Bracing has been used to stabilize laterally the majority of the world’s tallest

building structures as well as one of the major retrofit measures. A bracing system improves

the seismic performance of the frame by increasing its lateral stiffness and capacity. Steel

bracings can be used as an alternative to the other strengthening or retrofitting techniques

available as the total weight on the existing building will not change significantly. Steel

bracings reduce flexure and shear demands on beams and columns and transfer the lateral

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In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

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International Journal of Civil and Structural Engineering

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loads through axial load mechanism. Displacement due to seismic load is decreased by 72%

with the X bracings compared to the unbraced frames, (Viswanath etal, 2010)

From the literature, it has been found that the load-deformation response and failure patterns

of the shear walls are affected by various factors. Reinforcement, vertical compression,

aspect ratio and material properties are some of the main parameters that significantly affect

the behaviour of the shear walls.

3. Conclusions

In some cases, the diagonal compression test and the shear–compression test were carried out

for the in-plane behaviour of masonry wall. Based on the brief review of literature, it is noted

that unreinforced masonry walls showed sudden brittle failure and were unable to maintain

further load. It is this brittle failure that poses significant danger to building occupants during

earthquakes. Retrofitted masonry walls allowed specimens to maintain load after initial

failure of the masonry and prevented the loss of debris, even after the failure of several straps.

The effect of horizontal reinforcement in bed joints on shear behaviour was not investigated.

Reinforced masonry with low cost, high availability, relative simplicity and improved

properties of strength of brick, mortar and reinforcement could be of important, especially for

masonry structures in seismic areas. There are several reinforcement materials (FRP

laminates or bars) and different types of mortars (synthetic materials) can be used. The main

objective of the reinforcement is to enhance the earthquake resistance of masonry structural

elements, in order to avoid failure modes that manifest in brittle and unforeseen manner, as

suggested by Carrodi, (Carrodi, 2003). Therefore, the knowledge of the parameters which

govern the shear behavior needs to be investigated. It is proposed to investigate the structural

shear behaviour of clay brick masonry walls and flyash brick masonry walls in 1:6 cement

mortar with partial replacement of fine aggregate with flyash and also reinforced with

hexagonal woven wire mesh along the horizontal bed joint in alternate bed course. The

experimental tests are to be conducted to determine the effectiveness of the reinforcement

scheme in terms of strength and behaviour to the failure modes at the low cost. The wire

meshing technique along the bed joint may potentially be used to prevent/delay brittle

collapse of masonry structures under seismic loading.

4. References

1. Choubey, Gupta U and Gangrade S D, (1993), An Experimental study of Flexural

Tensile Strength of Brick Masonry, Journal of Institutions of Engineers (India), 74,

pp 135 – 140.

2. Corradi M, Borri A and Vignolib A, (2003), Experimental study on the determination

of strength of masonry walls” Construction and Building Materials, 17, pp 325–337.

3. Corradi M, (1999), Stress-strain characteristics of brick masonry under uniaxial cyclic

loading, Journal of structural engineers, 125(6), pp 600-604.

4. Dayal U, (1995), Flyash – A Construction material, Journal of Institution of

Engineers, 76, pp 174 -177.

5. Emeritus A W Hendry, (2001), Masonry walls: materials and construction,

“Construction and Building Materials, 15, pp 323 – 330.

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In-plane shear behaviour of Brick Masonry – A Literature Review on experimental study

Freeda Christy C, Tensing D, Mercy Shanthi R

International Journal of Civil and Structural Engineering

Volume 2 Issue 4 2012

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6. Essy Arijoeni Basoenondo, (2008), Lateral load response of Cikarang Brick wall

structures – an experimental study, Doctoral thesis, Queensland University of

Technology.

7. Gabor A, Ferrier E, Jacquelin E and Hamelin P, (2006), Analysis and modeling of the

in-plane shear behavior of hollow brick masonry panel. Construction and Building

materials, 20, pp 308 – 321.

8. Haroun M A, Mosallam A S, and Allam K H, (2005), Cyclic In-Plane Shear of

Concrete Masonry Walls Strengthened by FRP Lamina, Proceeding of the Seventh

International Symposium on Fiber Reinforced Polymers for Reinforced Concrete

Structures, FRPRCS7, Kansas City, pp 327-339.

9. Henry Liu, Shankha K Banerji, William J Burkett and Jesse Van Engelenhoven,

(2009), Environmental properties of Flyash bricks, World of Coal Ash Conference, 2-

7 May 2009 in Lexington, USA, pp 1-18.

10. Krishnamoorthy N R, Mastanaiah G, Gopalakrishnayya A, (1994), Characteristics of

Flyash Treated Black cotton Soil Bricks, Journal of Institutions of Engineers (India),

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Freeda Christy C, Tensing D, Mercy Shanthi R

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