Question

A bridge has an expected life of 50 years and is designed for a flood magnitude of return period 100 years. What is the risk associated with this hydrologic design?

• A. $1-(0.99{)}^{50}$
• B. $(0.5{)}^{50}$
• C. $(0.99{)}^{50}$
• D. $(0.99{)}^{100}$

Answer 1

The correct option is A $1-(0.99{)}^{50}$

Risk = Probability of flood being exceeded at least once over a period of n years.
$=1-{(1-\frac{1}{100})}^{50}=1-(0.99{)}^{50}$