A pin-jointed plane frame is unstable if (where m is number of members, r is reaction components and j is number of joints)

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

A. 2

B. 3

C. 6

D. 8

For heavily reinforced concrete member, the nominal maximum size of the aggregates should be restricted to

A. 5 mm less than the minimum clear distance between the main bars

B. 5 mm less than the minimum cover to the reinforcement

C. Smaller of A and B

D. Greater of A and B

The fixed support in a real beam becomes in the conjugate beam a

A. Roller support

B. Hinged support

C. Fixed support

D. Free end

When a series of wheel loads crosses a simply supported girder, the maximum bending moment under any given wheel load occurs when

A. The centre of gravity of the load system is midway between the centre of span and wheel load under consi-deration

B. The centre of span is midway between the centre of gravity of the load system and the wheel load under consideration

C. The wheel load under consideration is midway between the centre of span and the centre of gravity of the load system

D. None of the above