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DocuSign Envelope ID:AD41 E8C7-FC41-4249-A9C6-849589FOC156 <br /> Draper Aden Associates <br /> V Engineering • Srrn•el•ing • Environmental Ser%ices <br /> 1030 Wilmer Avenue, Suite 100 <br /> Richmond,Virginia 23227 <br /> 804.264,2228 <br /> www.daa.com November 10, 2020 <br /> Mr. Bruce Woody <br /> Assistant Solid Waste Director <br /> Orange County Solid Waste <br /> 1514 Eubanks Rd. <br /> Chapel Hill, NC, 27516 <br /> RE: GPR Study for Rebar Location <br /> Orange County Regional Landfill <br /> Chapel Hill, NC <br /> DAA Project No.: R00592-204G <br /> Dear Mr. Woody, <br /> Draper Aden Associates (DAA) has completed the ground penetrating radar (GPR) study for the <br /> Metal &White Goods Retaining Wall Repair located at the Orange County Regional Landfill facility <br /> on Eubanks Road in Chapel Hill, North Carolina (Figure 1). The objective of this study was to locate <br /> rebar within the east and west sides of the retaining wall. <br /> GPR data were collected on November 3, 2020 in two grids, one located along the east side of the <br /> retaining wall and the other located along the west side of the retaining wall (Figures 1 and 2). <br /> The GPR grid on the east side of the retaining wall measured a maximum of approximately 21 feet <br /> horizontally by six (6) feet vertically. The GPR grid on the west side of the retaining wall measured <br /> a maximum of approximately 12 feet horizontally by seven (7) feet vertically. Individual grid <br /> traverses were spaced one (1) foot apart in both orientations of each grid. The GPR instrument <br /> used for this study operated at 1000 MHz, which provided subsurface imagery to a depth of <br /> approximately three (3) feet. <br /> The GPR data were visually reviewed real-time and interpreted for evidence of rebar. Strong <br /> repeating reflectors indicative of rebar reinforcements were observed in the traverses from both <br /> orientations, the locations of which were marked real-time using blue spray paint. Figure 3 depicts <br /> the observed rebar locations as interpreted in the GPR data. <br /> Blacksburg•Charlottesville •Manassas •Newport News •Richmond• Virginia Beach <br /> Fayetteville •Raleigh <br />