Brick Masonry Work, Technical Terms, Types

A masonry structure is one made by joining (bonding) multiple numbers of building blocks ( like brick, stone, block, etc) usually with cohesive material called mortar. These activities are known as brick masonry work.

The masonry may be mud mortar, cement mortar, etc. Sometimes based on requirements dry masonry is also built without any mortar.

Brick masonry work, technical terms, Types | Full detail

Different types of masonry structure

Burnt clay bricks
Sand lime bricks
Laterite stone
Granite stone
Concrete block: Hollow (25% – 50% cavity)
lightweight Autoclaved Cellular
Burnt clay hollow bricks
Gypsum Partition Blocks
Stone rubble

Advantages of Masonry Structure

Strength: Masonry structures are strong in compression
Heat Absorber: It resists temperature fluctuation
Maintenance-free: Most of the walls do not require painting
Fire Resistant: Fire protection due to the formation of non-combustible material
Masonry structures are environmentally friendly
It is used for great soundproofing
Masonry units can be prepared by the use of locally available material
It is Economical

Disadvantage of Masonry Structure

Moisture Absorber: Absorbs moisture when raining
Color Deteoration: Extreme weather causes masonry to degrade material such as wall surface decolorize due to frost damage
Strength: Masonry structures have a low tensile strength
Opening: Become weak while creating a large opening
Education: Lack of education in masonry
Need heavy foundation: A large foundation is required due to its heavy weight. Cracking and settlement may occur due to heavy load.

Construction Technology of Bricks

Size And Weight Of Brick

(a) Bricks that are not standardized are called traditional bricks. If the bricks are large it is difficult to burn them properly and they become too heavy to be placed.

(b) On the other hand, If bricks are small, more quantity of mortar is required.

(c) Hence, BIS ( Bureau of Indian Standards) has recommended bricks of uniform size, called modular bricks and the actual size is 190mm*90mm*90mm. If the thickness of mortar is included then it is called the nominal size of a modular brick and the size is 200mm*100mm*100mm.

(d) It is found that the weight of 1m³ of brick earth is about 1800kg. Hence, the average weight of a brick will be about 3 to 3.5kg.

(e) NBC (Nepal Building Code) has recommended the standard size of brick as 240mm*115mm*57mm with 10mm mortar in length side.

Basic terms in Masonry:

Course: Horizontal layer of bricks/ stones
Bed: Lower surface of bricks/ stones in each course which is perpendicular to line of pressure
Backing : Unexposed wall
Facing : Exposed to weather
Hearing : Between backing and facing.
Header : Face of brick when the length is perpendicular to the face of the wall
Stretcher : Face of brick when the length is parallel to the face of the wall
Bond: Individual brick units are tied together with mortar is called a bond.
Closer : A piece of brick obtained after cutting a brick across its width.
Soldier: Laid vertically with the long narrow side of the brick exposed.
Soilor: Laid vertically with the broad face of the brick exposed.
Rowlack: Laid on the long narrow side with the short end of the brick exposed.

Bonding in Brickworks:
Bonding is the method of arranging the bricks in courses so that individual units are tied together and vertical joints arranging the bricks in courses so that individual units are tied together and vertical joints of successive courses do not lie in the same vertical line.
The unbounded wall has less strength and durability.

Consideration in Brick Masonry

The lap should be minimum 1/4^th brick along the length of the wall and ½ brick across the thickness of the wall.
Bricks bats should be discouraged, except in special locations.
The vertical joint in the alternate courses should be along the same perpend.
The brick should be of uniform size.
All the finished masonry walls should be cured for at least 7 days.
The thickness of the mortar joint should be uniform and not more than 13mm in any case.
The height of brick masonry in one day should not exceed 1.5m.

Types Of Brick Bond:

Stretcher Bond: This bond is formed when a stretcher of bricks is laid along the face of the wall, used in the partition wall.

1) Header Bond

This bond is formed when the head of bricks is laid along the face of wall. ¾ bat is provided in each alternative course in corners. Unsuitable for load-bearing structures.

2) English Bond

It consists of alternative courses of header and stretchers. Queen closer after header in each heading course.

3) Flemish Bond

In this type of bond, each course is compressed of alternative headers and stretchers. Every alternate course starts with the header at the corner. Quron closer is placed next to the queen header in alternate courses to develop face lap.

4) Facing Bond

This bond is used where bricks of different thicknesses are to be used in facing and baking of walls.

5) Dutch Bond

Alternative courses of header and stretched bond as in English bond but every stretcher course starts at the corner with a three-quarter bat and header placed after the three-quarter bat.

6) Raking Bond

The bond is formed when bricks are laid in an inclination to the direction of walls.

Diagonal bond (Brick in the same direction)

Herring bond (opposite direction)

7) Zigzag Bond

Bricks are laid in a zigzag fashion, Used in brick flooring

8) Garden wall Bond

In the garden wall English bond, the header course is provided only after three t five stretcher courses. In the garden wall Flemish bond, each course contains one header after three to five stretchers.

Difference Between English and Flemish bond:

S.N	English Bond	Flemish Bond
1	Headers and stretchers are laid in alternate courses.	Header and stretchers are laid alternatively in each course.
2	Stronger	Less Strong
3	Provide a rough appearance.	Provide good appearance
4	Absence of vertical joints.	Partly continuous vertical joints.
5	Special attention is not required for this joint.	Special attention is required for this joint.
6	Progress of work-fast	Progress of work-slow
7	Costly	Economic.
8	Skill labor id not required.	Skill labor is required
9	Less mortar is used	More mortar is used.

Rat trap Bond

Bricks are placed in a vertical position which creates a cavity in the wall while maintaining the same wall thickness as that of conventional brick masonry walls. Also known as Chinese brick bond.

Advantage

Reduce the number of brick
Thermal insulation
Decrease a dead load of building
For structural safety, a reinforcement bar can be inserted.
A cavity can be used for plumbing, sanitary, wire, cable, etc.

Load Bearing And Non-Load Bearing Masonry:

1) Non-Load Bearing Masonry

Such masonry walls are used for partition or similar purposes only. They have to support self-weight and wind pressure or seismic force if any.

A Panell wall is a non-bearing wall supported by beams and columns in a framed structure. Also known as curtain wall. They are built lighter to reduce the dead load of the structure.

One can remove any non-load-bearing walls without endangering the safety of the building.

Types of non-load-bearing wall

Hallow concrete block wall
Focade Bricks Wall
Hollow Bricks Wall
Bricks wall

2) Load Bearing Masonry

These are the masonry walls that have to support considerable vertical loads and lateral loads other than their self-weight. Normally, loads are applied on the top of the wall from floors or roofs in building structures.

Load-bearing walls transfer loads to the foundation or other suitable frame members. It may interior or exterior wall.

Types of load-bearing masonry

Pre-cost concrete wall
Retaining wall
Masonry wall
Pre-panelized load-bearing metal stud walls
Engineering Brick wall
Stonewall

Reinforced And Un-reinforced Masonry

These are a special types of masonry structures that are strengthened by suitably embedding strong and continuous material within the masonry. Such strong materials include steel bars, reinforced concrete bonds, bamboo, timber, and other new materials.

These reinforcements are capable of maintaining the integrity of masonry units even in large lateral loads and resist a part of forces like tension and shear. In other words, it increases the ductility and strength of the structure.

Classification of reinforced and un-reinforced Masonry

Reinforced Hollow Unit Masonry
Reinforced Grauted Cavity Masonry
Reinforced Packet Type Walls.

Reinforced Hollow Unit Masonry: Vertical Reinforcement is inserted inside brick/block and filled with infill concrete or grout.

Reinforced Grauted Cavity Masonry: It consists of two leaves of masonry units separated by a cavity into which the vertical and horizontal reinforcement is placed and graduated with either concrete infill or grout.

Reinforced pocket-type walls: Vertical reinforcement is placed in the wall by a special bonding arrangement.

In reinforced hollow unit masonry, Vertical reinforcing bars are placed into a moving position before laying of the masonry unit but in reinforced pocket-type walls, the reinforcing bars are placed in mortar joints as the construction of the wall progresses.

Unreinforced Masonry

The reinforcing bar is not placed in such type of masonry. Likely to be damaged during the earthquake. The mortar holding the masonry together is generally not strong enough to resist earthquake forces.

A charge of walls to the floor and roof is critical. These houses are weak and can be broken apart. Walls may fall away or buckle, resulting in damage.

Properties and strength of cement mortar

For good masonry work, good mortar is required. The properties of good mortar are:

1) Good Workability

A good mortar shall be sufficiently workable such that it can be laid to the right thickness with sufficient easiness by a mason. The addition of a small quantity of lime in cement mortar improves workability without compromising strength.

2) Sufficient Strength

In general, mortar shall have sufficient strength to resist the load in a structure, but shall not be greater than that of masonry units.

It shall be confirmed that the failure of masonry shall be initiated from mortar, not the masonry units in order to make the failure ductile. NBC 109:1934 recommendation in the selection of mortar is as follows:

Masonry unit strength (N/mm²)	Recommend Mortar Type
24 and above 15-24.9 5-14.9 Less than 5	H1 H2 M1 M2

3) Water Retaintivity

A good mortar shall be able to retain the mixed water for a longer time so as to maintain workability during its use.

Also after use, it shall be able to retain the water (prevent high loss) so as to facilitate the hydration process, otherwise, proper hydration may not occur resulting in a greater loss in strength.

4) Low Drying Shrinkage

Generally, the volume of mortar reduces slightly on drying or setting. Such shrinkage may cause cracks in stiffened masonry, especially around the edges.

In some cases due to shrinkage, the whole masonry wall settles slightly creating debonding from the frame at the top and sides. Hence, mortar shall have low drying shrinkage.

Good mix proportion, use of properly graded sand, optimum use of water, and good quality of cement reduce the shrinkage. For special case, shrinkage-resistant cement (or mortar) are also available, especially for grouting.

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