If P is the allowable bending stress in a slab, whose greater and lesser projections from the column faces, are A and B, the thickness (t) of the slab base, is (where w is the intensity of earth pressure.)

• A. The minimum width of lacing bar connected with rivets of nominal diameter 16 mm, is kept 50 mm
• B. The minimum thickness of a flat lacing bar is kept equal to one-fortieth of its length between inner end rivets
• C. The angle of inclination of lacing bars and the axis of the members should be between 40¬∞ and 70¬∞
• D. All the above.