Max Spacing Between Anchors in Tension
Maximum spacing between anchors within the group of all tension
anchors. The group of anchors here are anchors inside redline area
as shown below.

This input is used to calculate the reduced hef when anchors are
located less than 1.5hef from three or more edges as per
ACI 318-14 17.4.2.3.

This input is calculated by the program based on user's other inputs.