The URL can be used to link to this page

Home My WebLink AboutBLD2008-00233 Geotechnical Report w • • • �r NTI ENGINEERING & SURVEYING, INC. 7 �`, . �.'^.° 717 SOUTH PEABODY STREET,PORT ANGELES,WA 98362 \ Engineers 1 I Land Surveyors 1 1 Geologists Construction Inspection!I Materials Testing Ni"! (360)452-8491 1-800-654-5545 FAX 452-8498 E-Mail info@nti4u.com www.nti4u.corn RCE-_ WED October 29, 2008 DEC - 1 200$ Seahome Services JEFFERSON END' QC0 Greg Barron 7425 Thorndyke Road Quilcene, WA 98376 Subject: Pin Pile Recommendations for House Foundation 1671 Camp Discovery Road Tax Parcel # 701224012, Jefferson County, WA. Dear Mr. Barron, NTI Engineering completed a geotechnical test pit inspection of the subject parcel on October 22, 2008. The purpose of the inspection was to verify foundation soil conditions for a new house being constructed on the site. A landslide hazard assessment was completed for the property by others. Our work is limited to providing foundation recommendations for the house. We recommend that the firm that completed the landslide study review this report for consistency with their recommendations. One test pit was excavated just east of the house location to a depth of approximately 10 feet. The upper 2 feet consisted of uncompacted sandy gravelly pit run fill. From 2 to 4 feet, the material was organic rich soil with wood debris. From 4 to 7 feet the material was sand with gravel, organic material and wood debris. The organic material had a strong rotting odor. At 7 feet there was a layer of saturated silt. At about 9.5 feet a large stump or log was encountered. Water was flowing into the test pit from about 5.5 feet on and the sides were caving in. The test pit excavation was terminated at about 10 feet, the limit of the mini-excavator. The test pit was backfilled with the excavated material. Based upon this information, we recommend that the house be founded on pin piles driven to refusal. Therefore, we have the following specific recommendations with respect to pin piles. • I14VCEJIVEL) DEC - 12008 Pin Pile Type JEFFERSON COUNTY OCO 3 inch schedule 80 iron pipe may be used for the pin piles. It is recommended that the upper 10 feet of each pile be galvanized for corrosion protection. The pile pipe should be coupled by all-around butt welds or by the use of a tight internal pipe sleeve. Provide bearing enhancing caps for the piles with a bearing area of at least 6 x 6 inches. Installing the Piles Piles should be driven into the soil using a minimum 650 pound hydraulic impact hammer until there is less than 1 inch of pile advance in 12 seconds of continuous driving (near-refusal). Due to the depth limitations of the subsurface exploration, it is difficult to predict the depth of embedment that is necessary to achieve the recommended near- refusal drive depth. Nevertheless, we suspect that the piles will come to near- refusal somewhere between 25 and 35 feet of pile length. If pile refusal is reached at a depth greater than 35 feet we need to be informed so that we can reevaluate the situation and modify our recommendations if necessary. Large woody debris was encountered at -10 feet in the test pit. No pile should be terminated in wood debris or other deleterious material. We suggest that piles be cast into a high-quality concrete plinth or tee-footing that is at least 12 inches thick so that it has adequate bearing and punching shear capacity and minimum concrete clear cover can be maintained. Capacity of Pin Piles Properly installed pin piles will have an allowable downward load capacity of 12 kips per pile. That allowable load may be increased by 1/3 for short duration loading under seismic or wind loads. This allowable load applies only to piles that are separated by 5 feet or more. We recommend a load test to confirm pile capacity. Piles that are properly installed will have an allowable lateral load capacity of 500 pounds per pile for piles that are tightly coupled with internal sleeves or welded at joints. Lateral loading cannot be increased for short duration loads. Piles in groups will have less lateral capacity per pile. Lateral Bearing Capacity of Soil Next to Footings and Plynths Grade beams and tee footings should have an allowable lateral bearing capacity of 275 pounds per square foot per foot of depth at this site provided that clean • • • soil similar to the imported pit run material is used for backfill and the soil is compacted as it is replaced. Inspection of Pile Work It is recommended that the pile layout and initial pile drive be reviewed on site by NTI to confirm the capacities and to establish good communication with the pile installer in case problems arise. Periodic pile installation inspection should also be conducted by NTI. Sincerely yours, NTI ENGINEERING & SURVEYING, INC. '„�fi' is s _r 1--. •i L:r .. ter' �. 9honlnq NOG* �w i • �jt—A 191 ti / 23i>57 :, ,"JONAL William C. Payton Jr. 6 EXPIRES:3#23 is 1 4.,4e..- • 1-1.4.-->i,7.;-__ Bill Payton, LEG Steve S. Luxton, MSc. PE Engineering Geologist Civil Engineer Cc: David Bradley, PE B'\Reports\SEAH0802.22(27-1).revised test pit for pile foundation David Project.Coyle Peninsula.otOcECb�• `' D DEC - 12118 JE BS" t"1 1Y 41 i • ce-04, NTI ENGINEERING & SURVEYING, INC. ' 717 SOUTH PEABODY STREET,PORT ANGELES,WA 98362 Engineers 'Land Surveyors' Geologists Construction Inspection Materials Testing NTI (360)452-8491 1-800-654-5545 FAX 452.8498 E-Mail:infoOnti4u.com u'%rfr.nli4u.com December 3, 2008 Seahome Services Greg Barron 7425 Thorndyke Road Quilcene, WA 98376 RE: Observation of pipe pile installation at 1671 Camp Discovery Road, Tax Parcel # 701224012, Jefferson County, WA. Dear Mr. Barron, NTI Engineering & Surveying, Inc. (NTI) made two trips to the above referenced property in order to periodically observe the installation of pipe piles for foundation support of a proposed residence. Site visits were made on November 25th and 26th of 2008. On the 26th, a load test was also performed on one pile. Based upon our periodic observations of the pile installation process and load test, it is our opinion that the piles were installed in substantial accordance with the recommendations of our October 29, 2008 letter. If you have any questions regarding this inspection or need further assistance, please contact us. f ® : as + Sincerely, rp c t114�r } Nil ENGINEERING & SURVEYING, INC. ;, ,f'''•:', .• Bill Payton, L.E.G. �_ Engineering Geologist William C. Payton Jr, Cc: Frank Benskin, Jefferson County B:1Reports\SEAH0802.22(27-1).pipe pile observation.doc c �30 VOZ L + • NTI ENGINEERING & SURVEYING, INC. T 717 SOUTH PEABODY STREET,PORT ANGELES,WA 98362 Engineers Land Surveyors Geologists Construction Inspection Materials Testing NTI (360)452-8491 1-800-654-5545 FAX 452-8498 E-Mail:infoOnti4u.com um'ur.nl,l u.con, December 3, 2008 Seahome Services Greg Barron 7425 Thorndyke Road Quilcene, WA 98376 RE: Observation of pipe pile installation at 1671 Camp Discovery Road, Tax Parcel # 701224012, Jefferson County, WA. Dear Mr. Barron, NTI Engineering & Surveying, Inc. (NTI) made two trips to the above referenced property in order to periodically observe the installation of pipe piles for foundation support of a proposed residence. Site visits were made on November 25th and 26th of 2008. On the 26th, a load test was also performed on one pile. Based upon our periodic observations of the pile installation process and load test, it is our opinion that the piles were installed in substantial accordance with the recommendations of our October 29, 2008 letter. If you have any questions regarding this inspection or need further assistance, please contact us. Sincerely, ' Q�' ' C p` NTI ENGINEERING & SURVEYING, INC. . � �Asn 191 • • re". Bill Payton, L.E.G. _ Engineering Geologist William C. Payton Jr. Cc: Frank Benskin, Jefferson County B:1Reporls\SEAH0802.22(27-1).pipe pile observation.doc g04Z t