Survey unit:-4

(: Hello guys I am Pranish. In this blog you will get info about civil engineering so please feel free to share my posts Construction Survey unit:-3

 Unit:-2

               Masonry Work

      

Introduction

Masonry can be define as elements of building conctruction unit bounded together with mortar. The defination of masonry is that trade or work for building with bricks or stone.

Stone Masonry

Stone is used in building construction is known as stone masonry. The stone used  for masonry should be hard, durable and free from weathering, defacts like cracks, holes(pouras) and sand etc.

Classification of stone masonry
1.rubble masonry
2.Ashar masonry

rubble masonry

The stone in which either dressed or roughly dressed stone are laid in the suitable mortar is called rubble masonry. It is classified uner four groups. They are:-
1.Coursed
2.Uncoursed
3.Square rubble masonry
4.Miscella heaus
5.Fine rubble masonry
6.Rolonal rubble masonry
7.Dry rubble masonry

Ashlar masonry

The stone masonry in which finely dressed stone are used with cement or lime mortar is known as ashlar masonry. These are classified into six tyoe. They are:-
1.Ashlar fine masonry
2.Ashlar rough masonry
3.Ashlar rock masonry
4.Ashlar rock incourse masonry
5.Ashlar chamfred masonry
6.Ashlar facing masonry

Terminology of bricks

Strecher

A strecher is the layer face of the brick that is 230*55mm as seen in elevation of wall.

Header

Header is the smaller face of the bricks that is 110*55mm as seen in elevation of wall

Lap

Lap is the horizontal distance between the vertical joints of sucessive brick force.

Prepend

Prepend is a imaganry vertical line which include the vertical joint seperating to adjoining brick.

Bed

A bed is the lower portion of brick having dimension of 230*110 of the brick when laid flated.

Queen closer

It is a portion of brick obtain by cutting to length wise into 2 portion it's dimensionis 230*55*55.

Bevelled closer

It is  brick which is so cut that the width of 1 end of alf that of full brick while the width of other end is equal to ful bricks.

King closer

The brick whose one corner is cuted away at the half of it's length and half of it's width is king closer.

bat/Half brick

It is the portion f brick cut from half of it length, it is smaller than full brick.

Arrise

Arrise is the edge of brick.

BullNose

It is special moulded brick with one edge round.

Quoi

It is a corner or enternal angle on the face of side of the wall, generally it is 90 degree.

Frog

A frog is an identity in the face of brick to form key for holding mortar.

Racking back

It is the termination of wall in stepped fashion.

Toothing

It is the termination of wall in such a fashion that is alternate force at the and protection in order to provide good apperence.

Defect in brick masonry

Brick masonry develop defect due to following reason:-
1.Sulphate attack
2.Crystallization of saltsfrom bricks
3.Corrision of embedded fixtures
4.Drying shrinkage

1)Sulphate attack

This is common defects specially deen in exposed brick works likely to come in contact of moisture. The sulphate salt present in bricks reacts with lime and alumina in case of cement mortar. Due to this reaction the increase in the volume of morter take place, as a result cracks are found in joints.

2)Crystallization of salts from bricks

If the bricks are manufactured from earth containing exessive salt, entry of moisture due to dampness or due to rain disolve the soluble salt. These apperas in the form of fine whitesh crystals on the exposed surface of bricks. This is known as efflorence.

3)Corrision of embedded fixtures

Iron or steel such as pipes or holes frames of door, window etc embedded in brick masonry gets carraded with times specially when lime mortar is used. The corrison results in the increase in volume resulting in cracks in bricks masonry joints.

4)Dry shrinkage

When moisture derietrakes in brick work it awells on evaporation of moisture during the drying due to atmospheric heat etc. The bricks shrinks in the development of cracks in the masonry joints.

Block works

Blocks are constructed by using cement aggregate, water, sand, and admixture in the appropriate propoion. The standered size of blocks is 440*100*215mm. In context of Nepal the size of blocks is 16 inch*8 inch*8 inch.

Properties of blocks

1.Light in weight
2.Easy to handle
3.Due to large size number of joints in masonry is less
4.Hallow block are structurally stronger than bricks
5.There id great saving of materials

Supervision of stone masonry.

The point should be mamorize are as follow:-
1.Stone used in construction should be well watered.
2.Stone used in construction should be tough, durable, hard and strong.
3.All stone should be laid on their natural bed.
4.Proper bond should be maintane.
5.Broken stone, small piece of stone should not be used for facing and backing.
6.Horixontaly and vertically should be regular check with construction.
7.Curing should be done for about 1 to 2 weeks.
8.Height of stone masonry should nt raise 1 meter in a day.

Supervision of brick masonry

The point should be memorize are as follow:-
1.Brick used in construction should be hard, strona and durable.
2.Bricks should be immerged in water for 24 hrs before its use .i.e if brick absorbe water more than 20% it should not be used in construction.
3.Brick should be laid in their natural bed.
4.Brick work should be horizontaly and vertically straight.
5.The height of brick wall should not raise more than 1 meter in a day.
6.Curing should be done about 1 to 2 weeks.

``Thank you for visiting website. Do not forget to share with your buddies. Have a good day.``

Related Posts