The degree of static indeterminacy of a pin-jointed space frame is given by (where m is number of unknown member forces, r is unknown reaction components and j is number of joints)
A. m + r - 2j
B. m + r - 3j
C. 3m + r - 3j
D. m + r + 3j
Answer: Option B

For rigid jointed frame. 3m+r-3j
For pin jointed frame. m+r-3j
For space frame m=1 hence m+r-3j is correct
3m+r-3j. Is right