Three-quarter inch diameter pipe refers to the outside diameter. Different pipe types of the same outside diameter usually have different inside diameters. ASTM SCH 40 pipe of 3/4 inch diameter has an inside diameter of 0.824 inches. ASTM CL 200 pipe of 3/4 inch diameter has an inside diameter of 0.930 inches because of the thinner wall.
8 "
Approx 10.3 US gallons.
The inside diameter (ID) is 8 inches. The nominal pipe size (NPS) and outside diameter (OD) depend on the thickness of the walls of the pipe.
The volume in the pipe is pi times diameter squared/4 times the length. Eight inch diameter = 2/3 ft so volume is 59.31 cubic feet. Since 27 cu ft = 1 yard then that is 59.31/27 = 2.2 yards of concrete
30-inch (inside diameter) RCP has a wall thickness of 2.75 inches. Therefore, the outside diameter of 30-inch RCP is 35.5 inches.
1/12th inside diameter plus 1 inch for 'B' wall (most common type), additionally, pipe sizes are normally in 1/4 or 1/2 foot increments, so the closest size would be a 24 inch diameter with 3 inch wall (24/12=2+1=3) having a outside barrel diameter thickness of 30 inches for 'A' wall 1/12th inside diameter, 'C' wall is 1/12th inside diameter plus 1 3/4 inch
It could be 65" (b wall - 5.5" wall thickness), or 66.5" (c wall - 6.25" wall thickness).
2 1/2"
Less than an inch.
Three-quarter inch diameter pipe refers to the outside diameter. Different pipe types of the same outside diameter usually have different inside diameters. ASTM SCH 40 pipe of 3/4 inch diameter has an inside diameter of 0.824 inches. ASTM CL 200 pipe of 3/4 inch diameter has an inside diameter of 0.930 inches because of the thinner wall.
Assuming that the 14 inch box is square, you could fit a circle inside with a 14 inch diameter.
This all depends on the class of Reinforced Concrete Pipe (RCP) it is. Typically the manufactorers of RCP recommend one foot of compacted fill over a pipe for construction traffic. As long as the material is not wet I would drive over it any day.
8 "
you are going to want at least a 6 inch base of packed stone, then at least six inches of concrete reinforced with either rebar or highway rated mesh.
The inside diameter of the inner bull is 1/2 inch. The inside diameter of the outer bull is 1 1/4 inches.
The answer depends on what the "36 inch" measures: inside circumference, radius, diameter?