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HomeMy WebLinkAboutBLDR-2-11-15345 Engr Report 8-5-11.tif -� ECS Carolinas, LLP 4811 Koger Boulevard Greensboro, NC 27407 (336) 856 -7150 LETTER OF TRANSMITTAL (336) 856 -7160 August 8, 2011 RE: 1013 14th Ave. Drive NW -GPR Paramount Automotive Group ECS Job # 09:20100 1205 S. Center Street Permits: Hickory, NC 28602 Location: Hickory, NC ATTN: Mr. Danny C Jordan We are enclosing: X Materials Engineering Division Reports X For your use X As requested ENCL: Field Report # 1 08/05/2011 GPR Testing ECS Carolinas, LLP 4811 Koger Boulevard Eno Greensboro, 36)8W- 7 150 27407 (3 FIELD REPORT 36)856 -150 (336) 856 -7160 Project No. 09:20100 NC Registered Engineering Firm # F -1078 Report No. 1 Project 1013 14th Ave. Drive NW -GPR Day & Date Friday 08/05/2011 Location Hickory, NC Weather 85 Cloudy Client Paramount Automotive Group - Danny C. Jordan On -Site Time 0.75 Lab Time 0.25 Travel Time* 0.50 Total 1.50 Remarks GPR Testing Re Obs.Time 0.00 Trip Charges* Tolls /Parking* Mileage* 25 Time of Arrival Departure Chargeable Items 1 - GPR Equipment Rental 03:OOP 03:45P * Travel time and mileage will be billed in accordance with the contract. Summary of Services Performed (field test data, locations, elevations & depths are estimates) & Individuals Contacted. The undersigned arrived on -site, as requested, to perform a Ground Penetrating Radar (GPR) structural survey on a slab on grade. The purpose of this survey was to determine the placement and spacing of reinforcing steel and to determine slab thickness. Utilizing the GPR unit to observe the 11 ft. x 24 ft. slab, three areas were scanned across the slab to determine thickness and placement of reinforcement. Two other areas were scanned across the slab edge to observe if there was a turn down with reinforcement. The slab average 7 inches with welded wire reinforcement and a 12 inch turn down section was observed along the perimeter with two additional bars in the turn down footing. This was pointed out to the site representative Danny Jordan. As explained in the note below, many factors can influence the quality and the value of the GPR imagery. For this project, the observed results appeared to be good. Engineer's Note on GPR Limitations: Successful use of GPR is dependent upon site conditions that may not be determined until actual testing begins. The presence of highly- conductive materials within the concrete may adversely affect GPR results. Green concrete ( <28 days old) is relatively damp; the conductive nature of wet concrete can limit the depth that the GPR signal can penetrate. GPR can detect steel members within concrete; however, GPR cannot determine the specific nature of the detected steel members (i.e., GPR does not differentiate between rebar, post- tension cables, metal conduit, etc.). GPR cannot determine reinforcing st eel b s ize. By Alan L. Raulston, — CMT Project Manager 1510 271405 ECS Carolinas, LLP 4811 Koger Boulevard Ei!a Greensboro, 36)8 7150 27407 FIELD REPORT (336) 856 -7150 (336) 856 -7160 Project No. 09:20100 NC Registered Engineering Firm # F -1078 Report No. 1 Project 1013 14th Ave. Drive NW -GPR Day & Dat Friday 08/05/2011 Closely- spaced reinforcing steel may produce results that "mask" the presence of other reinforcing steel bars or metal conduit within the concrete. Metal conduit can be detected using GPR; however, PVC or plastic conduit may only be faintly observable. Water can interfere with GPR technology, and the testing surface should be dry when performing GPR testing. L - C AR David M. Cutter, P.E. AV6i Z_ Alan L. Raulston Principal Eng9r. 22089 CMT Project Manager . 4, By Alan L. Raulston, — CMT Project Manager 1510 Page 2 271405