# Civil Engineering - Theory of Structures - Discussion

Discussion Forum : Theory of Structures - Section 3 (Q.No. 1)

1.

If a concrete column 200 x 200 mm in cross-section is reinforced with four steel bars of 1200 mm

^{2}total cross-sectional area. Calculate the safe load for the column if permissible stress in concrete is 5 N/mm^{2}and*E*is 15_{s}*E*_{c}Discussion:

16 comments Page 1 of 2.
Nazeer said:
9 years ago

How is it done?

Bapan Halder said:
8 years ago

P = 5 * {(40000 - 1200) + (1200 * 15)}.

MRINAL KANTI BISWAS said:
8 years ago

P = 5*(200*200-1200) + (1200*15) = 212000 N

So the answer is E.

So the answer is E.

Abhishek.kumar said:
8 years ago

Sir. Plese tell me the correct answer with explanation.

Nishant Jain said:
8 years ago

Ans is C.

Find permissible stress[$] in steel first as:

Permissible stress in steel/permissible stress in concrete = Es/Ec.

Permissible stress in steel = 5 * 15Ec/Ec = 75.

Now solve:

P = 5 * (200 * 200 - 1200) + (1200 * 75) = 284000N = 284.

Find permissible stress[$] in steel first as:

Permissible stress in steel/permissible stress in concrete = Es/Ec.

Permissible stress in steel = 5 * 15Ec/Ec = 75.

Now solve:

P = 5 * (200 * 200 - 1200) + (1200 * 75) = 284000N = 284.

Shiva said:
7 years ago

Explain this with formula.

Chulbul said:
7 years ago

As the elongations are equal, use the formula.

Strain= stress/Young's modulus.

Strain= stress/Young's modulus.

Maniesh said:
6 years ago

Stress= load/ area,

Stress in steel = load / area of steel and likewise same for concrete,

Es= permissible stress in steel/ strain in steel and likewise same for concrete,

strain in concrete and steel are same = permissible stress in steel/ Es= permissible stress in concrete/ Ec.

Es= 15Ec.

=permissible stress in steel= permissible stress in concrete/ Ec xEs =( 5 /Ec)x 15Ec= 75Mpa for steel.

Load = permissible Stress in steel x area of steel +permissible stress in concrete x area of concrete.

= 75 x 1200+ 5 x (200X200 -1200)= 284kN.

Stress in steel = load / area of steel and likewise same for concrete,

Es= permissible stress in steel/ strain in steel and likewise same for concrete,

strain in concrete and steel are same = permissible stress in steel/ Es= permissible stress in concrete/ Ec.

Es= 15Ec.

=permissible stress in steel= permissible stress in concrete/ Ec xEs =( 5 /Ec)x 15Ec= 75Mpa for steel.

Load = permissible Stress in steel x area of steel +permissible stress in concrete x area of concrete.

= 75 x 1200+ 5 x (200X200 -1200)= 284kN.

(1)

Kisan prasad gaire said:
5 years ago

Excellent explanation, Thanks @Maniesh.

Abhishek said:
5 years ago

Thank you for explaining.

Post your comments here:

Your comments will be displayed after verification.

Quick links

Quantitative Aptitude

Verbal (English)

Reasoning

Programming

Interview

Placement Papers

© IndiaBIX™ Technologies