10-23-23-R - Laserfiche WebLink

Home Browse Search

Attachment A GEOPHYSICS AND NDE FOR INFRASTRUCTURE ASSESSMENT — BEYOND VISUAL - October 6th, 2023 Arden Hills Department of Public Works 1425 Paul Kirkwold Drive Arden Hills, MN 55112 Attn: David Swearingen, P.E. Phone: 651-788-0269 Email: DSwearingen@cityofardenhills.org RE: Proposed Geophysical Subsurface Investigation Ground Penetrating Radar (GPR) Surveys at Hazelnut Park Mapping of Ground Tire Fill in Parking Lot Subgrade 3245 New Brighton Rd, Arden Hills MN 55112 Olson Proposal No. P2023149. I GP Mr. Swearingen: I24014i. 4qe, 00 Avenue wne�i aid��.ca �ao33 W 1SOrI Rhone:303.423.1217 E"ERING fax; 303.423.6011 Olson Engineering is pleased to submit this proposal for GPR surveys across an approximately 250'x250' parking lot at Hazelnut Park in Arden Hills, Minnesota to attempt to locate an area of tire fill beneath the pavement. This proposal outlines our understanding of the project scope, our proposed investigation and our proposed lump sum costs. PROJECT BACKGROUND Olson understands that the Public Works Department of the City of Arden Hills is interested in geophysical mapping of subsurface conditions below the asphalt pavement of a parking lot at Hazelnut Park in Arden Hills, Minnesota. We understand that a pavement section of the existing parking lot (see Figure 1) requires pavement rehabilitation. The objective of the investigation is to determine where a ground rubber tire fill layer exists and where it is present within the aforementioned pavement section in plan view, and if possible, the thickness of the layer which is anticipated to be on the order of 2 to 3 ft. Olson proposes to perform the survey in a grid across the parking lot utilizing a PinPointR GPR unit seen in Figure 2. Grid spacing will depend on obstructions in the parking lot, acquisition rates and other factors determined in the field. Olson plans to take approximately 25 scans in each longitudinal direction (—N to S and —E to W) across the parking lot to delineate the presence of the ground rubber tire layer. As time allows, Olson will tighten the grid and obtain more lines throughout the survey area. Occasionally during data acquisition, the layer of interest can be seen without processing in the office. If the layer is seen in the raw data, the field engineer/geophysicist will take more lines in order to accurately determine the lateral extent of the tire layer. If possible, the thickness of the layer will also be determined, but this depends on the dielectric contrast between the near -surface soils (likely somewhat conductive) over any tire fill (insulating — nonconductive) and the deeper underlying soils below any tire fill. www.OlsonEngineering.com Rockville MD Wheat Ridge CO