Monday, January 16, 2012

TYPES OF BRICKS USED IN CIVIL STRUCTURAL ENGINEERING CONSTRUCTION BASICS

BRICKS USED IN CIVIL STRUCTURAL CONSTRUCTION BASIC INFORMATION
What Are The Different Type of Bricks Used In Construction?


Brick is obtained by moulding good clay into a block, which is dried and then burnt. This is the oldest building block to replace stone.

Manufacture of brick started with hand moulding, sun drying and burning in clamps. A considerable amount of technological development has taken place with better knowledge about to properties of raw materials, better machinaries and improved techniques of moulding drying and burning.

The size of the bricks are of 90 mm × 90 mm × 90 mm and 190 mm × 90 mm × 40 mm. With mortar joints, the size of these bricks are taken as 200 mm × 100 mm × 100 mm and 200 mm × 100 mm × 50 mm.


Types of Bricks
Bricks may be broadly classified as:
(i) Building bricks
(ii) Paving bricks
(iii) Fire bricks

(iv) Special bricks.
(i) Building Bricks: These bricks are used for the construction of walls.
(ii) Paving Bricks: These are vitrified bricks and are used as pavers.
(iii) Fire Bricks: These bricks are specially made to withstand furnace temperature. Silica bricks belong to this category.
(iv) Special Bricks: These bricks are different from the commonly used building bricks with respect to their shape and the purpose for which they are made. Some of such bricks are listed below:
(a) Specially shaped bricks
(b) Facing bricks
(c) Perforated building bricks
(d) Burnt clay hollow bricks
(e) Sewer bricks
( f ) Acid resistant bricks.

(a) Specially Shaped Bricks: Bricks of special shapes are manufactured to meet the requirements of different situations. Some of them are shown in Fig. 1.3.
(b) Facing Bricks: These bricks are used in the outer face of masonry. Once these bricks are provided, plastering is not required. The standard size of these bricks are 190 × 90 × 90 mm or 190 × 90 × 40 mm.

(c) Perforated Building Bricks: These bricks are manufactured with area of perforation of 30 to 45 per cent. The area of each perforation should not exceed 500 mm2. The perforation should be uniformly distributed over the surface. They are manufactured in the size 190 × 190 × 90 mm and 290 × 90 × 90 mm.

(d) Burn’t Clay Hollow Bricks: Figure 1.4 shows a burnt clay hollow brick. They are light in weight. They are used for the construction of partition walls. They provide good thermal insulation to buildings. They are manufactured in the sizes 190 × 190 × 90 mm, 290 × 90 × 90 mm and 290 × 140 × 90 mm. The thickness of any shell should not be less than 11 mm and that of any web not less than 8 mm.

e) Sewer Bricks: These bricks are used for the construction of sewage lines. They are manufactured from surface clay, fire clay shale or with the combination of these. They are manufactured in the sizes 190 × 90 × 90 mm and 190 × 90 × 40 mm. The average strength of these bricks should be a minimum of 17.5 N/mm2 . The water absorption should not be more than 10 per cent.

( f ) Acid Resistant Bricks: These bricks are used for floorings likely to be subjected to acid attacks, lining of chambers in chemical plants, lining of sewers carrying industrial wastes etc. These bricks are made of clay or shale of suitable composition with low lime and iron content, flint or sand and vitrified at high temperature in a ceramic kiln.

STEEL PLATES MECHANICAL PROPERTIES AND MANUFACTURING PROCESS BASICS AND TUTORIALS

STEEL PLATES BASIC INFORMATION - MECHANICAL PROPERTIES AND MANUFACTURING
What Are Steel Plates? What Are The Mechanical Properties Of Steel Plates?


This article covers hot-rolled uncoated steel plates with a minimum thickness of 3 mm, supplied flat or precurved
in any shape as required. Steel for cold forming is not within the scope of this article.


Manufacturing process
Rimming steel shall not be allowed and the steel shall be at least semi-killed in the deoxidation process. The plates may be produced directly on reversing mill, by cutting from parent plates rolled on reversing mill or hot rolled wide strips.

The plate edges may be as rolled or sheared, flame cut or chamfered. The products may be supplied in as rolled, normalized or quenched and tempered condition, or with controlled rolling (normalized rolling or thermo-mechanical rolling).


Strength
The nominal yield strength shall be in the range of 235 N/mm2 to 690 N/mm2. The nominal tensile strength shall be in the range of 300 N/mm2 to 1000 N/mm2.

Ductility
The elongation after fracture on proportional gauge length shall be at least 15 %, for nominal yield strength not greater than 460 N/mm2; and shall be at least 10 % for nominal yield strength greater than 460 N/mm2. The tensile strength to yield strength ratio shall be at least 1.2 based on nominal values, or at least 1.1 based on actual values, for nominal yield strength not greater than 460 N/mm2.

NOTE Conversion of elongation values measured not based on proportional gauge length is necessary and shall be performed according to BS EN ISO 2566-1.

Impact toughness
As a minimum, the product shall be able to absorb at least 27 J of impact energy at 20 °C. NOTE Depending on other factors including the thickness and minimum service temperature, the impact toughness should also conform to the appropriate requirements as given in BS 5950-1.

Through thickness deformation properties
Where appropriate, through thickness deformation properties shall be specified to guarantee adequate deformation capacity perpendicular to the surface to provide ductility and toughness against lamellar tearing.


Chemical composition
In general, based on ladle analysis, carbon content shall not exceed 0.26 %; maximum CEV and content of impurities shall be in accordance with the requirements given in Table 1.

NOTE 1 Interpolation for maximum content shall be allowed for design strength not given in Table 1.
NOTE 2 Depending on the product thickness or variation in metallurgical process and intended use, the requirements for chemical composition might vary and shall be referred to BS EN 10025-1, BS EN 10025 2, BS EN 10025-3, BS EN 10025-4, BS EN 10025-5 and BS EN 10025-6.

Table 1 — Chemical composition requirements for steel plates based on ladle analysis

Dimensional and mass tolerances
Dimensions
In general, the deviation in actual thickness from nominal plate thickness shall not exceed the larger of ± 2 mm and ± 10 %.

Mass
In general, the deviation in actual mass from mass computed using a density of 7850 kg/m3 shall be limited by the dimensional tolerances.

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