Estimating Concrete Volume

We do need to present some math so that you can estimate concrete volume.  Use the following formula to calculate concrete volume:

(L x W x H) divided by 27 equals the number of cubic yards of concrete.

Where: L = length (feet) of area.

W = width (feet) of area.

H = Thickness of the slab (0.33 for a four inch slab).  .33 is 1/3 of a foot (4” divided by 12”)

Drawing a Radius

A radius in a skatepark is the length of a straight line that could be drawn from the center of an arced object (an object with a single curve) to the outside edge.  A radius is defined as the length of a straight line from the center of a circle to the outside edge of a circle.  Laying out a radius is simple.  Take a nail or pushpin and place it into a board.  Tie string to the nail and measure out a length of string equal to the desired radius.  Make a loop in the string at the end opposite the nail and insert a pencil or other writing instrument into the loop.  Pull the string taut and draw the circle (radius) upon the desired material. 

In most instances, the radius of transitions in skateparks is 8 feet from the center to the outside edge of a circle.  Do not confuse this with the running length of the curve from top to bottom.  However, nothing is written in stone and other radius lengths can be used as desired.  However, your selection of radius length should be based upon an understanding of how this will influence the ride.  For example, the Upland Combi-Pool, if we remember correctly, had a 7-feet radius on some transitions.  This resulted in an 11-feet wall that felt more like 14-feet.  Likewise, the broader the arc (the larger the radius), the mellower the ride.

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