In a singly reinforced concrete beam section, maximum compressive stress in concrete and tensile stress reach their permissible stressess simultaneously. What is such a section called?a)Under-reinforced sectionb)Economic sectionc)Balanced sectiond)Over-reinforced sectionCorrect answer is option 'C'. Can you explain this answer?

Question

Answer

Explanation:

A balanced section is a section of a singly reinforced concrete beam in which the maximum compressive stress in concrete and the maximum tensile stress in steel occur simultaneously, at the point of failure. The balanced section is the most efficient section of a singly reinforced concrete beam because it makes the best use of the strength of both concrete and steel. At the point of failure, the steel has reached its maximum stress, and the concrete has reached its maximum compressive stress.

Types of Reinforced Concrete Beam Sections:

There are three types of reinforced concrete beam sections based on the position of the neutral axis and the amount of steel reinforcement used. They are:

Under-reinforced section: In this section, the steel reinforcement is not enough to resist the maximum tensile stress. The concrete reaches its maximum compressive stress before the steel reaches its maximum tensile stress. This results in a sudden failure of the beam without any warning. It is an inefficient use of steel reinforcement.

Over-reinforced section: In this section, the steel reinforcement is more than required to resist the maximum tensile stress. The steel reaches its maximum tensile stress before the concrete reaches its maximum compressive stress. This results in a sudden failure of the beam without any warning. It is an inefficient use of concrete and results in a brittle failure.

Balanced section: In this section, the steel reinforcement is balanced with the concrete compression zone. The maximum compressive stress in concrete and tensile stress in steel occur simultaneously at the point of failure. This results in a ductile failure with warning signs like cracking and deflection, allowing for repairs and maintenance before complete failure.

Advantages of Balanced Section:

The balanced section is the most efficient section of a singly reinforced concrete beam because it makes the best use of the strength of both concrete and steel. The advantages of a balanced section are:

It is the most efficient use of both concrete and steel.

The failure is ductile with warning signs like cracking and deflection.

It allows for repairs and maintenance before complete failure.

It is economical in terms of material and construction costs.

Answer

C

Similar Civil Engineering (CE) Doubts

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