C5 Masonry Structures

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Masonry structures

Course 5March 2010


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Damages to brick walls


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Factors to consider when rehabilitating amasonry structure

the age of the building; the masonry type;

stone

brick

the type of the join(t)ing material between themasonry stone dry masonry

loam or lime mortar

cement mortar

the structural system: plain masonry

masonry with metallic elements

masonry with reinforced concrete columns and belts

the foundation type


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Masonry damage due to local soil degradation

DECREASED BEARING CAPACITY

OF SOIL AT PRESENT


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Local failures


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Typical failure of masonry structureduring earthquakes


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Evidence marks to monitor the developing

of further cracks


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Damages to brick walls


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Masonry rehabilitation must include:

the removal of the possible causes of materialdegradation,

improving the load transmission to foundations,

joining the contiguous vertical elements,

achieving co-working between vertical structural

elements

avoiding changes in the structural system,


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Local protection when working to reveal

the foundations


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Preservation of the front walls


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Principles of masonry rehabilitation

displaced masonry recovery;

partial concreting with concrete denticulations;

crack and craze injection and caulking;

crack fastening with steel dogs;

wall jacketing; opening planking;

corner area binding;

cross-tie implementation;

the use of metallic cover plates;

horizontal and vertical reinforced concrete element placement;

composite material jacketing.


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Masonry preparations

the existing plastering removal;

joint deepening for 15-20 mm;

the inadherent material removal by wire brush

rubbing till the opening of the masonry stone pores;

the air blast of the cleaned areas to remove the

dust.


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displaced masonry recovery


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Repointing

masonry

1 perete din zidrie de crmid;

2 fisur;

3 gol creat prin scoatereacrmizilor;

4 suprafa curat cu peria desrm;

5 gol tratat pentru a fi rezidit;

6 zidrie nou executat;

7 scrie (plase) amplasate n

mortar de ciment;

8 zone tratate prin pensulare cuamors


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Incorrect repointing of masonry walls


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Masonry injection - performance

removing the dust from the crack by means of a compressed-airjet;

washing the crack with a water jet if injection is done withgrouting or cement mortar;

introducing some fittings in the walls, 5 cm deep and 1 m fromone another along the crack to facilitate injection;

applying coating with a cement mortar layer on both sides of thecracked areas (crack caulking);

a bottom to top injection with a pressure of maximum 3 atm.When the injection material reaches this level, vertical injection is

performed through the next fitting;

fitting removal after the injection material has hardened and theareas have been repaired.


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Using steel dogs

CRACK CONCRETING ZONE FLAT STRIP


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Wall jacketing/coating/strengthening

20cm

20 cm

STEEL

DOGS

10-15

The thickness of the covering will be of:

4 cm in case of using mortar

10 cm when using concrete


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Opening planking

A A

A - A

A A

A - A

10 3-5

DOGS

BOUNDING

MEMBER

RAMA DINBETON ARMATREINFORCED

CONCRETE FRAMEMETALLICFRAMING


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Corner area binding

10


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Cross-tie system

CROSSING

MEMBER

CROSSING

MEMBER

CRAMP

CROSS-TIE

FRONT

PLATE

CONNECTING

NUT

1

1 1- 1

CROSS-TIE


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Introducing reinforced concrete belts/girdles

EXISTING MASONRY80 - 100 cm

REINFORCED CONCRETE

BELT

CONNECTOR


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Case studyBanffy Castle, Botinda


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Masonry ofstones &

bricks


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Mortar samples


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Restoration of the wall cornice at the main entrance


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Restoration and

strengthening

works


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Mosque of

Mopti - Mali


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Block of flats

1960 - Canada


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Damages of brick masonry walls cracks, local failures


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Repointing the brick works


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Block of flats

1973 - Ontario


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EXTERIOR INSULATION FINISHING SYSTEM - EIFS


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Conclusive remarks

Rehabilitation of masonry structures have the

particularity that:

It is difficult to assess the structural improvement interms of material properties after repairments are

made;

All operations require a special skill of workers andless technological newness.

Documents

C5 Masonry Structures