Column Form Calculator

Both, through the same mechanism. Max Pressure at Base equals Concrete Unit Weight × Column Height, so a taller column produces proportionally more pressure at its base. That higher pressure forces Minimum Clamp Spacing tighter, which in turn raises Total Clamps needed across the full column height -- height affects clamp count twice, once through pressure and once through the physical distance being clamped.

Neither -- they're mathematically tied. Max Pressure at Base is their direct product, so a 10% increase in Column Height and a 10% increase in Concrete Unit Weight raise pressure by the exact same amount. Treat them as equally influential rather than assuming the taller-sounding input matters more.

No. Max Pressure at Base depends only on Concrete Unit Weight and Column Height -- full hydrostatic head, per ACI's formwork guide (PRC-347-14(21), published by the American Concrete Institute), which treats columns as filling too quickly for the concrete to gain any stiffening benefit partway up. Column Width and Column Depth instead drive Plywood Contact Area and, through whichever one is larger (the wider face), Minimum Clamp Spacing and Total Clamps.

A stronger clamp can resist more lateral force before failing, so it can be spaced farther apart while still holding the same pressure -- Minimum Clamp Spacing increases. Wider spacing across the same column height means fewer clamps are needed in total, so Total Clamps falls as Clamp/Yoke Capacity rises.

It means the pressure at the column base requires clamps closer together than a real clamp/yoke can physically be installed -- about 3 in is the practical floor for standard hardware. When that flag reads "Yes," this clamp isn't strong enough for this column at full hydrostatic head: Total Clamps is still calculated from the true required spacing (not rounded up to 3 in) so the number reflects how far short the design falls, but the fix is a higher-capacity clamp/yoke or additional bracing -- not more clamps at 3 in spacing.