Q.: What is the pressure of concrete on the bottom 1-inch-high portion of an 8-inch-wide form 8 feet high? This form section is located in the corner of a wall forming system.

A.: The maximum initial pressure of a full 8 feet of liquid concrete can be calculated by multiplying the unit weight of concrete by the height, 150 pounds per cubic foot times 8 feet, or 1200 pounds per square foot. To convert to psi, divide by 144 (square inches per square foot). This gives a pressure of 8.33 psi.