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HomeMy WebLinkAboutS_S&EE_3-18-17_Geotechnical_Report_Gate_D-50_Modification_170425_v1 Rpt1707 S&EE S&EE SOIL & ENVIRONMENTAL ENGINEERS, INC. 16625 Redmond Way, Suite M 124, Redmond, Washington 98052, www.SoilEnvironmental.com (425) 868-5868 March 18, 2017 Ms. Cynthia Johnson The Boeing Company Cynthia.a.johnson4@boeing.com CC: Mr. Michael Sullivan Letter Report Geotechnical Engineering Services Proposed Gate D-50 Modification Boeing Renton Plant Dear Cynthia: INTRODUCTION Soil & Environmental Engineers, Inc. (S&EE) has been retained by you to perform a geotechnical evaluation for the above-referenced project. The project will involve re-configuration of the traffic flow through the existing D-50 gate. I understand that new underground electrical lines will be constructed, some minor re- grading will be performed, and new asphalt pavement will be installed. SURFACE AND SUBSURFACE CONDITIONS The project site is located in the southeastern portion of Renton Municipal Airport. Figure 1, which is included at the end of this report, shows the site location. The existing gate is surrounded by buildings, and the site surface is covered with asphalt pavement. The gate is accessed by East Perimeter Road which borders the west side of Cedar river and its levee. The site surface is relatively flat. S&EE performed a previous soil test boring, B-2, at the location shown in Figure 1. Based on our knowledge of soil conditions in the area, it is our opinion that the boring data are representative of the subsurface conditions at D-50 gate. The boring shows that the subsurface conditions at the site include fill over alluvial soils. The former is about 10 to 11 feet thick and consists of loose to medium dense silty sand, gravel and sand. The alluvial soils include a soft to medium dense silt and sand layer to a depth of about 30 feet, then dense to very dense sand and gravel below. This sand and gravel layer turns into a dense silty sand at a depth of 97.5 feet. Boring B-2 was terminated in this soil. Ms. Cynthia Johnson March 18, 2017 Page 2 Rpt1707 S&EE Groundwater was encountered at a depth of 7 feet during the drilling of Boring B-2. Based on our experience in the project area, the groundwater depth will vary with season and precipitation, and will fluctuate between depths of 5 to 10 feet. CONCLUSION AND RECOMENDATION General It is our opinion that the proposed project is feasible from a geotechnical standpoint. The areas disturbed by construction will be stabilized and should remain stable. It is our further opinion that the project will not incur any soil instability. Underground Utility Construction Subgrade preparation and trench backfill should be monitored by a site inspector from our office. All loose soil cuttings should be removed from the excavation subgrade prior to the placement of bedding materials. In the event that soft or loose soil is encountered at subgrade, the subgrade should be over-excavated for a minimum of 6 inches. A non-woven geotextile having a minimum grab tensile strength of 200 pounds should be installed at the bottom of the over-excavation and the over-excavation be backfilled with 1-1/4” minus crushed rock. The geotextile should be installed flat with all wrinkles removed and have 12 inches overlap. The rock should be compacted to a firm a non-yielding condition using a mechanical compactor approved by our site inspector. The onsite soils are suitable for use as backfill. The soils are slightly moisture sensitive. As such, the contractor should protect the excavated soils from rain. Pavement We recommend that all pavement subgrades be proof-rolled to identify areas of soft, wet, organic, or unstable soils. Proof-rolling should be accomplished with a heavy (12-ton) vibratory roller, front-end- loader, or loaded dump truck (or equivalent) making systematic passes over the subgrade while being observed by a site inspector from our office. In areas where unstable and/or unsuitable subgrade soils are observed, the subgrade should be over-excavated a minimum 6 inches. Woven geotextile having a minimum 200 pounds grab tensile strength may be necessary for additional subgrade stabilization. The geotextile, if used, should be placed with 12-inch overlaps with all wrinkles removed. LOGAN AVEEXIT 5 900 515 900 EXIT 4 EXIT 4A 405 405 167 EXIT 4B 405 169 167 D9 D40 D35 D30 EXIT 2B From Issaquah From Bellevue 4-04 Medical Clinic Safety LK WASHINGTON BLVD N From Seattle LAKE WASHINGTON Boeing Employees Flying Association RA I N I E R A V E N 4-41 4-20 4-21 4-69 4-402 4-78 4-77 4-79 4-71 4-42 4-45 Apron D 5-27 5-403 5-288 9 7 1 16 17 15 12 13A 14 10-18 GARDEN AVE N N EVA NEDRAGEVA KRAPN 8TH ST 11 10-16 10-13 4-89 4-88Badge Office 10-20 10-80 Hub 4-17 4-90 4-75 4-81 4-82 4-83 4-86 Renton Airport From I-5 From Longacres Park From Kent and Auburn From Enumclaw Apron A Apron BRAINIER AVE N AIRPORT WAY RE N T O N A V E S S 3RD ST S 2ND ST Renton Stadium 5-09 5-02 S U N S E T B L V D W BENSON RD S M. L . K I N G J R W A Y S SW 10TH S T OAKESDALE AVE SW SW 19TH ST SW 16TH ST DNOMYAR WS EVA WS EVA DNILTALBOT RD S EVA NIAM HOUSER WAY N LOGAN AVE N CEDAR RIVER N 1 S T S T BRONSON W AY N S 4TH ST N 3RD ST N 4TH ST N NEDRAG S EVA TTENRUBLOGAN AVE S SW 7TH ST GRADY WA Y S W N EVA YROTCAFMONSTER RD 5-50 5-51 N EVA SMAILLIW7-206 Triton Tower Two 7-207 Triton Tower Three From Seattle 5-08 Washington – Renton North 8th and Park Avenue North, Renton, WA 98055 N 5TH ST N 6TH ST N 8TH ST 5-45 Revised 03-09 Boeing North Bridge Boeing South Bridge 7-244 Rivertech Corporate Center HOUSER WAY BYPASS Copyright 2009© The Boeing Company. All rights reserved.PARK AVE N WELLS AVE N POWELL AVE SW NACHES AVE 4-95Shed 4-96GuardShack Employee gates AMS Turnstile gates Fence lines Boeing property General parking Restricted parking Bus stop Helistop 51 52 53 54 55 51 52 53 54 55 A B C D E F A B D E F C D44 D41 D4 D32