Concrete
A concrete is a stone like material which is the careful combination of cement, sand, stone & water.
1. Concrete is strong in compression & weak in tension.
2. Tensile strength of concrete is about (1/10) of its Compressive strength.
Suppose, a concrete block has compressive strength of 3000 psi, then its tensile strength will be approximately 300 psi.
Design of reinforced concrete
Design of reinforced concrete is the combination of selection of dimension & selection of materials.
A reinforced concrete design should be:
I. Safe.
II. Economical.
III. Environmental friendly.
Types of concrete
Concrete is generally of three types:
I. Normal concrete.
II. Reinforced concrete.
III. Pre-stressed concrete.
Loads
Loads are generally of three types:
I. Dead Load.
II. Live Load And
III. Environmental load (wind, water, snow & earthquake etc).
Fundamental assumptions of reinforced concrete:-
a) Internal forces at any section are in equilibrium.
b) The strain in the embedded reinforcing bar is the same as that of the surrounding concrete.
c) Cross- section that was plain prior to loading will remain plain after loading.
d) Tensile strength of concrete is only a small portion of compressive strength concrete having tension is usually considered to be cracked.
e) The theory is based on the actual stress-strain relationship and strength properties of
the two constituent materials.
Basic Equation:-
Here,
WSD= Working Stress Design
USD= Ultimate Strength Design
Fundamental assumption on flexure and shear:-
a) A cross section that was plain before loading remain plain under loading.
b) The intensity of bending stress normal to the section increases directly with the distance from
the neutral axis and is maximum at the outer fiber.
c) The stress at any given point in the cross-section is represented by the equation݂ (f=MY/I)
d) Distribution of the shear stress will depend on the geometry of the section.
Crack:-
There are four type of crack:
a) Flexural crack.
b) Shear crack.
c) Flexural & shear.
d) Crushing crack.
A concrete is a stone like material which is the careful combination of cement, sand, stone & water.
1. Concrete is strong in compression & weak in tension.
2. Tensile strength of concrete is about (1/10) of its Compressive strength.
Suppose, a concrete block has compressive strength of 3000 psi, then its tensile strength will be approximately 300 psi.
Design of reinforced concrete
Design of reinforced concrete is the combination of selection of dimension & selection of materials.
A reinforced concrete design should be:
I. Safe.
II. Economical.
III. Environmental friendly.
Types of concrete
Concrete is generally of three types:
I. Normal concrete.
II. Reinforced concrete.
III. Pre-stressed concrete.
Loads
Loads are generally of three types:
I. Dead Load.
II. Live Load And
III. Environmental load (wind, water, snow & earthquake etc).
Fundamental assumptions of reinforced concrete:-
a) Internal forces at any section are in equilibrium.
b) The strain in the embedded reinforcing bar is the same as that of the surrounding concrete.
c) Cross- section that was plain prior to loading will remain plain after loading.
d) Tensile strength of concrete is only a small portion of compressive strength concrete having tension is usually considered to be cracked.
e) The theory is based on the actual stress-strain relationship and strength properties of
the two constituent materials.
Basic Equation:-
Here,
WSD= Working Stress Design
USD= Ultimate Strength Design
Fundamental assumption on flexure and shear:-
a) A cross section that was plain before loading remain plain under loading.
b) The intensity of bending stress normal to the section increases directly with the distance from
the neutral axis and is maximum at the outer fiber.
c) The stress at any given point in the cross-section is represented by the equation݂ (f=MY/I)
d) Distribution of the shear stress will depend on the geometry of the section.
Crack:-
There are four type of crack:
a) Flexural crack.
b) Shear crack.
c) Flexural & shear.
d) Crushing crack.
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