Before builders can move in or roadways can be installed, contractors must use a technique known as site grading to adjust the slope of the area. This makes a foundation more even and sturdy. Before grading can begin, however, the level of moisture in the soil as well as its composition is considered. “Soil moisture information is valuable to a wide range of government agencies and private companies concerned with weather and climate, runoff potential and flood control, soil erosion and slope failure, reservoir management, geotechnical engineering, and water quality” (Arnold, Laymon, Samuelson, 1999).
Firms need a hard, flat surface on which to safely build or construct a roadway. It is still possible to build on wet sites, though special drainage under the structure is required. “The weaker the soil, the more difficult and expensive it is to build a suitable foundation” (Bliss, 2015). Issues such as erosion, damage to foundations, basement flooding, and much more can occur “when properties aren’t graded to facilitate proper drainage” (Nearsay, 2017).
How does site grading work?
Heavy machinery, such as bulldozers, excavators, and graders are used throughout the process. First, the surface is prepared for leveling, and then with the use of a grader, an even finish is achieved. Technology also plays a huge part in the grading process. We have several equipment outfitted with GPS for grading purposes and much more. It helps us discover the exact level and angle to set the blade on our grader or dozer, and gives us a more precise end result.
GPS not only helps get the job done more efficiently, but it also saves money. One contractor in Sarasota, Florida commented on how prior to the addition of GPS on his machines, three crew members would check the grade line. With GPS, however, he didn’t need those three people anymore, and they’re free to work on other areas of the project (Hudson, 2010).
Rough grading is typically handled by a dozer, and “may take more than one go-over to compact the pavement base if it is more than six inches thick” (Merlo Construction Company, n.d.). Once this is complete, it is time to fine grade using grading equipment. There are two goals in fine grading: (1) adjust the top couple of inches of aggregate, and (2) compress and level the aggregate. Once this is complete, the paving contractor can move in and focus on his work.
Currently, we are in the rough grading process at Six Mount Zion (Toano, VA), and the site is looking great.
View all progress photos on our Facebook page.
Arnold, J.E., Laymon, C., Samuelson, D. (1999). Soil Moisture. Retrieved from https://weather.msfc.nasa.gov/landprocess/
Bliss, S. (2015). Building on a Wet Site. Retrieved from https://buildingadvisor.com/building-on-wet-site/
Hudson, S. (2010). Grading with GPS. Retrieved from https://www.constructionequipment.com/grading-gps
Merlo Construction Company. (n.d.) Retrieved from https://www.merloconstructionmi.com/what-is-fine-grading-construction/
Nearsay. (2017). What is Site Grading & How is it Used in Construction? Retrieved from https://nearsay.com/c/362163/338839/what-is-site-grading-how-is-it-used-in-construction