Degree of static indeterminacy of a rigid-jointed plane frame having 15 members, 3 reaction components and 14 joints is

Answer: Option C

To determine the degree of static indeterminacy (Ds) for a rigid-jointed plane frame, use the formula: Ds = (3m + R) - (3j + A)

where:

m = number of members,
R = number of reaction components,
j = number of joints,
A = number of internal hinges (A = 0 in this case).

Given:

m = 15 (members),
R = 3 (reaction components),
j = 14 (joints),
A = 0 (no internal hinges).

Substitute these values into the formula:

Ds = (3 * 15 + 3) - (3 * 14 + 0)

Ds = (45 + 3) - (42)

Ds = 48 - 42 = 6

Thus, the degree of static indeterminacy is 6.