The Chadds Ford Senior Living project, located in Glen Mills, PA, was the beginning phases of a construction project on building a large senior living home. Master Locators provided mid construction services to confirm the location and depth of utilities running along the shoulder and in the middle lanes of a busy highway. Because all the utilities were on a highway, traffic control was needed and was provided by the client. The purpose of this utility designation was to prepare for the client to perform horizontal drilling across the highway.

Master Locators used GPR and EM scanning to attempt to locate several different utilities running through the scope of work. Utilities included communication, water, fiber optic, and gas lines. The only utility that was unlocatable was the gas line, which was a plastic line. It was not locatable with GPR, and our technician was not able to access the valve in the road to check for a tracer. Despite performing a two man sweep with a drop box and GPR, the gas line was not locatable. The water line was verified with a drop box, and the communication lines were located by accessing the line from a manhole and sending a current to locate the line with EM.

Prior to Master Locators arriving on site, PA OneCall marked the public utility lines with EM. As part of our standard routine, Master Locators verified the One Call markout using GPR and EM prior to beginning the vacuum excavation work. Because One Call does not always use GPR to locate utilities, Master Locators confirms the location of the lines with GPR. In this situation, One Calls markings were about 3 feet off from Master Locators markings.

After completing the mark outs, Master Locators dug with vacuum excavation on each both our technicians mark out and the One Call mark out, and found the lines to be right where our technician marked them. Verifying utilities using more than one method is always a better way to ensure the location of the utility. Master Locators performed test pits along the shoulder and in the right lanes of the highway. This was done to confirm the location and depths of all utilities.

Master Locators used a jackhammer and a core drill to break up the concrete, then used air vacuum excavation to do the test pits. Five test pits were done along the shoulder and five in the right lanes of the highway. After the depth and location of the lines were confirmed, the roadway was restored by hot mix asphalt.

Deliverables: Electronic Sketch / PMU; Test Hole Data Sheets


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