Construction Knowledge Series: What is a Bank Cubic Yard (BCY) vs. a Truck Cubic Yard (TCY)?

A cubic yard is volumetric measurement of something that is 3’ x 3’ x 3’ = 27 cubic feet.  A cubic yard of native soil in place would be called a bank cubic yard.  Native soils have been compacted over long time spans, so these soils are usually pretty dense.

If you were to excavate the native soil and dump it into a truck or pile, it would take up more volume in its uncompacted state.  In the Pacific Northwest, 1 bank cubic yard typically swells to approximately 1.3 yards when uncompacted.  This uncompacted volume is known as a truck cubic yard as excavated dirt is frequently loaded into trucks.  It is important to know how many yards are being loaded into a truck to ensure that the truck is not overloaded.

It is also important to understand the BCY to TCY when scheduling.  For example, if you have a project with 100,000 BCY export and the earthwork contractor tells you they can export 2,500 yards per day it will take them 52 days of export (100,000 x 1.3 @ 2500 TCY/day).  If you do not account for BCY to TCY conversions, you might accidently plug 40 days export into your schedule.