Question

According to the concept of Limit State Design as per IS 456-2000, the probability of failure of a structure is ________.

• A. 0.0975

Answer 1

The correct option is A 0.0975
The structure is assumed to fail in LSM if :

1. The load exceeds the design load.
2. The strength is less than the characteristic strength.
3. The load exceeds the design load and strength is less than the characteristic strength.

As per probability of load exceeding design load =5% and the probability of strength less than characteristics strength = 5%.

Thus, the probability of failure

$=0.05\times 0.95+0.05\times 0.95+0.05\times 0.05$
= 0.0975