Question

If the degrees of redundancy for a structure is \( r \), the number of plastic hinges required to convert a stable structure into an unstable mechanism is

• A. \( r + 1 \)
• B. \( r + 2 \)
• C. \( r - 1 \)
• D. \( r - 2 \)

Hint:

For structures with redundancy \( r \), the number of plastic hinges required to form a mechanism is \( r + 1 \).

Answer 1

The Correct Option is A

The number of plastic hinges required to convert a stable structure into an unstable mechanism is \( r + 1 \), where \( r \) is the degree of redundancy. This accounts for the fact that one additional plastic hinge makes the structure unstable. Hence, the correct answer is (1).