Civil Engineering - Soil Mechanics and Foundation Engineering - Discussion

Discussion Forum : Soil Mechanics and Foundation Engineering - Section 2 (Q.No. 14)
14.
If L and B are the length and breadth of a footing, e the eccentricity along the length and P and Q are the axial force and bearing capacity of the soil, then, to avoid tension,
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
12 comments Page 1 of 2.

Kiran said:   4 years ago
Bearing capacity of soil= Axial stress + Bending Stress.
Q = P/A + M/Z.
Where, M= Moment = P * e.
Z= Section Modulus = BL^2/6 [For rectangular footing].
Therefore, Q = P/(BL) + Pe/(BL^2/6),
Q = P/(BL) + 6Pe/(BL^2),
Q = P/(BL)* [1+6e/L],
BL = P/Q*[1+6e/L].
(5)

Sandeep mourya said:   6 years ago
All of the above given options are wrong.

The answer should be
BL = P/Q(1-6e/L)
(1)

KRISHNA said:   6 years ago
I agree @Sarang.

In option C, If e is too large tension will develop on the footing. Therefore A is the answer. No chance of tension development.

We get two equations when we write stress balancing equation under the footing. One is A and the other is C.

So, the answer is A.
(1)

Vivek said:   10 years ago
How to avoid tension P/BL = 6Pe/BL^2?

Garry said:   8 years ago
I think the answer should be C.

KRISHAN said:   8 years ago
Maximum option A and Minimum eccentricity option C.

Bhagwat said:   7 years ago
I think the Answer should be C.

Rahul said:   7 years ago
How this is possible? Please explain.

Uttu said:   7 years ago
Yes, right. I agree @Krishan.

Sarang said:   6 years ago
To avoid tension reaction should be compressive all along with the structure so options A becomes rational.


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