Reinforced Concrete

I. Operation of Rational Numbers

Addition: 5 + 3 = 8 (The equation expressed in

English is five plus three equals eight, in which 5

is defined as addend, 3 as addend or augend, and

8 as sum or total.

Subtraction: 7

–

3 = 4 (The equation expressed in

English is seven minus three makes four, in

which 7 is defined as minuend, 3 as subtrahend,

and 4 as remainder or difference.)

Multiplication: 3 x 4 = 12 (The equation

expressed in English can be three times /by/

multiplied by four makes twelve, in which 3 is

defined as multiplicand, 4 as multiplier, and 12

as product.)

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Monday, November 25, 2013

Reinforced Concrete

I. Operation of Rational Numbers

4.

Division:

1)

8

÷

4 = 2 (The equation expressed in English can be

eight divided by four makes two, in which 8 is defined as

dividend, 4 as divisor, and 2 as quotient.)

2)

9

÷

4 = 2 … 1: (The equation expressed in English can

be nine divided by four makes two and one over, in

which 9 can be called partial dividend and 1 as

remainder.)

4.

Power

3

2

= 3 x 3 = 9 Three squared equals three times three

equals nine.

2

3

= 2 x 2 x 2 = 8 Two cubed equals two times two times

two equals eight.

2

4

= 2 x 2 x 2 x 2 = 16 The fourth power of two equals

two times two times two times two equals sixteen.

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Monday, November 25, 2013

Reinforced Concrete

I.

Disadvantages of plain concrete

Weak in tensile strength

II.

*The disability of plain concrete is overcome in two

ways:

reinforced concrete

(RC) and prestressed

concrete (PC).

1.

Reinforced concrete is plain

concrete

in which

steel

rods or bars ("

rebars

") have been incorporated to

reinforce the naturally brittle concrete.

III. *Function of Steel and concrete in RC

1.

Steel takes up a small quantity but a major part of

the cost (the cost of the formwork, the cost of the

concrete and the cost of the steel are approximately

the same)

2.

Concrete takes the compression, steel takes the

tension.

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Monday, November 25, 2013

Reinforced Concrete

III.

Function of Steel and concrete in RC

3.

Steel is the vital part of the structure due to the

deficient tensile strength of concrete;

4.

The coverage of concrete prevents steels from

rapid rusting;

5.

The proper adhesion between the steel and the

concrete is of the greatest importance, and bars

should be of a sufficiently small diameter;

6.

The bars should be limited so that they do not

obstruct the proper placing the concrete and so as

to provide adequate space for the reinforcement

to develop the stress by transmission from the

concrete;

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Monday, November 25, 2013

Reinforced Concrete

7.

Individual reinforcing bars generally do not

exceed 12 m (39ft) in length.

IV. *Advantages of RC

1.

Advantages of concrete: low cost, good weather

and fire resistance, good compressive strength,

excellent workability/formability

2.

Advantages of steel: high tensile strength, greater

ductility, toughness

3.

Advantages of combination of steel and concrete

1)

Relatively low cost

2)

Good weather and fire resistance

3)

Good compressive strength

4)

Excellent formability

5)

Considerably high tensile strength

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Monday, November 25, 2013

Reinforced Concrete

V. *Disadvantages of RC

1.

Cracking is inevitable which is induced by the

mere process of the reinforcing steel being

stressed under the normal working loads

2.

The higher steel stress increases the strain of the

concrete

3.

Stress v.s. Strain

1)

stress: the force per unit area

2)

Strain: the elongation per unit length

VI.

Homework

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Monday, November 25, 2013

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