How to Calculate Sagging Pipe in a Wetland

Swamp land provides limited support for pipes.

When pipe rests on a wetland's surface, it will sink into the ground beneath it. Yet it will not sink fully, because the water below provides buoyancy. The flotation acting on the pipe, measured in newtons, is the difference between these two forces: weight and buoyancy. Flotation can let pipes support larger surfaces. It can also put unwanted pressure on pipes if the designers have not taken the flotation into account.

Instructions

1. Calculate the pipe's weight, which is the product of its mass and the gravitational force on each kilogram. For example, if you are determining the flotation on a 40-kilogram length of pipe, multiply 40 by 9.81, a constant factor, giving 392.4 newtons of weight.

2. Multiply the number of liters of water the pipe displaces, which is equivalent to the water's mass in kilograms, by the same specific gravity constant. For example, if the pipe displaces 15 liters, 15 multiplied by 9.81 gives 147.15 newtons.

3. Find the difference between the two values. The difference between 392.4 and 147.15 is 245.25. This is the sagging pipe's flotation, measured in newtons.

References

• North Carolina State University: Engineering Field Manual
• University of Rhode Island; Dredging Applications of High Density Polyethylene Pipe; Virginia R. Pankow

Resources

• University of Colorado: Buoyancy
• Oxford Plastics Inc.: Floating Pontoons Using Hdpe Pipe