Last updated on September 7th, 2023 at 11:34 pm
What do you understand by Frog in brick? Why is it provided?
(a) The depression provided in the face of a brick during its manufacturing is called a brick frog.
The size of a frog in a brick is 100 X 40 X 10 to 20 mm deep. A hand moulded brick has one frog; a pressed brick has two frogs, whereas a wire cut brick has no frog.
Frog is provided in bricks to achieve the following objects:
a) To form a key of mortar in between any two adjacent courses or layers of brickwork so as to increase the lateral strength of the structure.
To reduce the weight of bricks so that they can be laid with convenience.
To provide a place for putting impression of trade-mark or the year of manufacture of the bricks.
(b) Bricks are laid in any structure according to the required bond. In general, bricks are laid on their bed in English bond unless otherwise specified. All the necessary principles and precautions should be considered while laying bricks in any structure.
The method of laying bricks in various structures such as walls, pillars and their footings is practically of same nature but in each case some special considerations are made.
(c) The portions made by cutting standard bricks across their length or in such a manner that their one stretcher face remains uncut or half cut are known as closers.
These are used for forming a proper bond in brick masonry.
These are usually placed next to the quoin brick of a course to close up the bond.
The cut surfaces of closers are usually concealed when properly arranged in the brickwork.
The following are the circumstances where these closers are used:
a) Queen closer: This closer is half wide as a full brick. This type of closer is placed next to the quoin header for forming a proper bond in brick-work of walls and pillars.
b) King closer: Its one end width is half of that of the standard brick. It is used for forming a proper bond in brickwork of oblique junctions.
What is reinforced brick masonry? List out the working stresses considered to design any reinforced brick masonry along with the precautions needed? Also give it’s advantages and disadvantages?
The brick masonry done by embedding reinforcement in rich cement mortar is known as reinforced brick masonry.
The plain brick masonry is weak in tension and, therefore, cannot be used for members subjected to tensile and shear stresses.
Hence, the plain brick masonry is reinforced for such members to enable them to bear tensile and shear stresses and also increase their load carrying capacity.
why frog provided in bricks? what is frogs in a bricks?
This type of brick masonry is used for members subjected to light loads such as partition walls, lintels over doors and windows, openings, slabs, etc. the design of a reinforced brick member is based on same principles which are considered for designing reinforced cement concrete (R.C.C) members.
For designing any reinforced brick member, the following working stresses of brick masonry are considered:
1. Compressive Stress = 2.5 N/mm² To 3.5 N/mm²
2. Shear Stress = 0.1 M/M
3. Bond Stress = 0.6 KN/MM2
4. Tensile Stress For Steel = 140 N/MN2
5. Modular Ratio (M) = 40
The following precautions should be taken while constructing any member in reinforced brick masonry.
1. The centering and shuttering should be properly designed and constructed.
2. All the bricks must be well burnt, uniform in shape and size and structurally sound.
3. All the bricks should be thoroughly soaked in water and properly laid before concreting.
4. The rich cement mortar (1:3) should be used for filling up the joints.
5. The reinforcement should be effectively bedded in the joints and surrounded with mortar to provide full strength to the member,
6. The reinforced brickwork should be cured for at least 10 days.
The advantages and disadvantages of reinforced brick masonry are discussed below:
a) Reinforced brick masonry is cheaper in initial cost.
b) It is simple in construction,
c) It requires little or no side shuttering,
d) it provides better bond appearance,
e) It requires less quantity of concrete and thus heavy machinery is not required for mixing and preparing concrete.
f) it provides more fire-proof construction.
g) The work can be carried out rapidly in its case.
a) Reinforced brick masonry has short life as compared to R.C.C construction.
b) It is less strong as compared to R.C.C construction.
c) The reinforcement is liable to corrosion under the effect of sulphates present in the bricks.
d) the member and spacing of bars is essentially kept conforming to The thickness the size of bricks to be used in the masonry.
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