Geotechnical_report_Addendum.pdf

Terracon Consultants, Inc. 9522 East 47 th Place, Unit D Tulsa, Oklahoma 74145

P [918] 250 0461 F [918] 250 4570 terracon.com

November 16, 2016

Professional Engineering Consultants, P.A. (PEC)

303 South Topeka

Wichita, KS 67202

Attn: Mr. Michael D. Kelsey, P.E.

E: mike.kelsey@pec1.com

Re: Addendum No. 1 to Geotechnical Engineering Report

Existing Parking Lot Repair and New Parking Lot

Tulsa Air National Guard

Tulsa, Oklahoma

Terracon Project No. 04165255

Dear Mr. Kelsey:

Per PEC’s request, this addendum supplements our geotechnical engineering report dated

November 04, 2016 and presents a gravel pavement section for the proposed new parking lot.

Gravel Drive and Parking Areas

I. Gravel-Surfaced Drive and Parking Design Recommendations

Based on the results of our borings and minor cut and fill depths to reach the final subgrade within the site, we anticipate the subgrade will generally consist of native lean clay, sandy lean clay, lean to fat clay, existing fill or new engineered fill.

We understand that the parking area will be utilized by passenger vehicles only. A recommended minimum gravel section for the parking area and driveway is presented in the following table. The gravel section will be subject to disturbance and deterioration due to exposure to the environment.

Ruts, potholes, and other distress will develop in the gravel-surfaced drive and parking areas.

Regular maintenance will be required to maintain the function of the gravel section.

Minimum Gravel Drive and Parking Section

Aggregate Base Over

Non-Woven Geotextile Separation Fabric Over

Compacted Subgrade

8” ODOT Type “A” Aggregate Base1

Non-Woven Geotextile Separation Fabric2

9’’ Compacted Subgrade3

1. Oklahoma Department of Transportation Standard Specifications

2. Mirafi 160N or equivalent

3. Subgrade preparation and fill construction should be done as per section 4.2 Earthwork of our report.