Pi… I did not forget the “e”, I am referring to the mathematical constant, π, for the value 3.141592…, *a* *ratio of the circumference of a circle to its diameter*. For some it was junior high and others it was high school, but almost everyone is taught the concept of Pi in geometry class in America. The staggering question asked by so many students over the years is “how do we use this in ‘real’ life?” Well we have answered that question for all of you as it relates to engineering:

When designing bridges many of the structures utilize reinforced concrete to provide the strength necessary to support its daily use by vehicles. For many of our bridge projects, the circle is most often representing the area of reinforcing steel used in the reinforced concrete beam. We determine the total amount of the (steel) reinforcing to determine the capacity of a structural member such as a beam, deck or slab.

In associated roadway design, Pi is used in a slightly different manner, to calculate curvature. A maximum curvature (minimum radius) is used to ensure adequate sight distance at differing speed limits. This promotes safe vehicular travel by providing a level of comfort and expectation to the driver.

Another application for the mathematical constant is in airfield markings. Their purpose is simple – to safely guide pilots during aircraft take-offs and landings, and while taxiing around the airfield. To create these markings, Pi is utilized when calculating the amount of airfield paint required for runway designation markers, taxiway centerlines and edge lines.

Pi is also used extensively in the calculation of areas of gravity sewers, wastewater force mains, water main pipes, storm drains, drainage culverts and other types of utility pipes. These calculations are used to establish the area of the pipe for the purpose of determining flow velocities and flow volumes as well as other types of hydraulics calculations.

Now that we have proved your mathematics teacher correct, and that someday you may need to know the value of Pi, the obvious question remaining is “what does pi and pie have in common?” My answer is Pi is focused on circles, radius and diameters… and so does pie! If you want a great Chocolate Cream Pie recipe check this out!