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Report Construction Inspection & Related Tests Testing, on Geotechnical Consulting P.O. Box 23814 - - �-- - Tigard, Oregon 97281 2, 1996 e • Phone (503) 684 -3460 Feburar Y d FAX (503) 684 -0954 CTI # 95 -4577 J.T. Roth Construction, Inc. 12540 SW 68th Pkwy, Ste. B Tigard, Oregon 97223 � Attn: Tim Roth lt "T 6/( Tk- FOUNDATION INVESTIGATION p J.T. ROTH OFFICE BUILDINGS (LOTS 2 - 4) TIGARD, OREGON This report presents the results of our shallow foundation investigation for the proposed office buildings in Tigard. The purpose of our investigation is to characterize the near - surface soils and provide geotechnical evaluations and recommendations for the proposed building foundations. Our work was performed per your verbal authorization. BACKGROUND Previous Reports Foundation Investigation for the J.T. Roth Office Building - Lot 1, Carlson Testing, Inc., December 5, 1995. Site Description The Lot 2 property (.55 acres) is located on the northwest corner of SW Gonzaga St. and SW 68th Ave. The site is thickly covered with small and large fir trees, brush, and berry bushes. Lot 3 (.55 acres) is located on the northeast corner of SW Gonzaga St. and SW 69th Ave. There is an existing abandoned house near the center of the site. We understand the house is planned for demolition. The property contains large amounts of garbage and debris. Lot 4 (.52 acres) is located on the southeast corner of SW Franklin St. and SW 69th Ave. The property is thickly covered with trees and brush. The above mentioned lots are relatively level and rectangular in shape. Proposed Construction The plan indicates that the proposed construction on Lot 2 will consist of a one - story, wood - framed structure with a raised wood flgor. The building is roughly rectangular in shape (53 x 85 feet). The construction also includes 100 feet of driveway and 22 parking spaces. We understand the proposed buildings on Lots 3 & 4 will be two - story, wood - framed structures with a concrete slab -on- grade. Also included in the projects are several feet of driveway and numerous parking spaces. CTI # 95 -4577 J.T. Roth Office Buildings Page 2 Project Data l..ocation - Lot 2; NW corns of SW r-: - S' �:.: c::' : �: . ' . . _ - L _ • of SW Gonzaga St. and SW 69th Ave. - Lot 4; SE corner of SW Franklin St and SW 69th Ave. (Thomas Bros. Map 655, Grid Column H:Row 4, 1996 ed). Client - J.T. Roth Construction, Inc. - Address on title page. Jurisdictional Agency - City of Tigard, Oregon. GEOLOGIC CONDITIONS Review of the Lake Oswego geologic map from Earthquake Hazard Geology Maps of the Portland Metropolitan Area (USGS Open -File .Report 0 -90 -2) indicates that the site is immediately underlain by about 30 feet of fine - grained catastrophic flood deposits (Off) over Boring Lava (QTb). Geological and seismological evidence suggests that the northwest coast has a "locked subduction zone" which is capable of generating very large (M8 to M9 Richter Scale) earthquakes with long durations of shaking over a vast region. Local faulting and seismicity are not as well understood, but are also believed to be capable of strong shaking. In response, Oregon State regulators upgraded the entire Western Region to a UBC Seismic Zone 3. An inferred fault has been mapped approximately 2000 feet north of the property. No evidence is currently available to determine definitively whether this inferred fault exists, and if so, whether it is still active. To our knowledge, the property is not in an area prone to inordinate seismic activity in the immediate vicinity. The adoption of Seismic Zone 3 as defined by the Uniform Building Code (UBC) by the State of Oregon for the region west of the Cascades should be adequate for earthquake- resistant design at the site. Based on our literature research, it is our opinion that the UBC soil profile type "S," description best matches the site, however, because no deep subsurface explorations were performed, we recommend using the site factor for S3. FIELD EXPLORATIONS A total of 4 hand augers to a maximum depth of 6 feet were augered on January 22nd, 1996 located just outside of any anticipated building foundations. A description of the field exploration procedures and the hand auger logs are presented in Appendix A. The test pit locations are shown on the Site Plan, attached as Figure 1. Laboratory testing procedures and test results are presented in Appendix B. CTI # 95 -4577 J.T. Roth Office Buildings Page 3 SOIL CONDITIONS Near - surface soil conditions observed in the hand augers at the site were very consistent with those found in our previous investigation. The surface of the building sites are currently overlain by approximately 18 to 24 inches of topsoil and roots. Occasional deeper mounds (approx. 4 feet) were observed at the sites. Beneath the topsoil to the maximum depth explored, the native soils consisted of a tan and brown silt with some clay and ranged in consistency from stiff to very stiff between 4 and 6 feet. No groundwater was observed in any of the hand augers. CONCLUSIONS AND RECOMMENDATIONS General It is our opinion that the proposed buildings are geotechnically feasible given the soil • conditions encountered in this investigation. It is also our opinion that the native soils beneath the proposed building pads are suitable for support of spread footings. Building Pad Preparation /Slabs -On -Grade The upper 18 to 24 inches of the topsoil should be removed from within the building pad. The trees root systems and stumps should be excavated and backfilled with engineered fill. Occasional deeper topsoil removals should be anticipated. For winter construction, engineered fill should consist of a clean granular fill (3a " -0 or 1 1 " -0 crushed aggregate). The slabs should be underlain by a minimum of 6 inches of V4"-0 crushed aggregate base compacted to at least 95 percent of the standard Proctor (ASTM D698) maximum dry density. The building designer(s) should use their experience on deciding if a vapor barrier beneath the slab is necessary. No groundwater or other geotechnical reasons requiring extraordinary precautions against ground moisture were discovered at the site. Engineered Fill • If earthwork is to be performed during the wet weather season, then a wet weather construction plan should be discussed with the contractor and the Soil Engineer. All grading should be performed in accordance with Chapter 70 of the Uniform Building Code, with the exceptions and additions noted herein. Imported material should be approved by the Soil Engineer prior to arrival on site. Engineered fill should be compacted in horizontal lifts not exceeding 8 inches using standard compaction equipment. A minimum of 90 percent of the maximum dry density obtained from the modified Proctor, AASHTO T -180, or equivalent standard is recommended for engineered fill. Field density testing should conform to ASTM D 2922 and D 3017, or D 1556. All engineered fill should be observed and tested by the Soil Engineer's representative. Typically for a project CTI # 95 -4577 J.T. Roth Office Buildings Page 4 of this type, at least one density test is performed for foot of fill placed or every 200 yd of earthwork performed, whichever is greater. The earth work contractor should be contractually hold tt) t iil_t1l)thhil111J .110 treAlluellcv. Foundations The proposed structure, of the type anticipated, can be founded on shallow spread footings bearing on the native soil. Spread footing construction and setback requirements should conform to the Uniform Building Code (UBC). For uniform bearing conditions, the spread footings should bear at a depth of 24 inches below original grade and a minimum of 18 inches below finish grade. The minimum recommended widths for a continuous wall footing and a square pad footing is 18 and 24 inches, respectively. We anticipate that the allowable bearing capacity can be taken as 2,000 Ib /ft for footings bearing on the native soils, with a one -third increase for short duration loads such as wind and seismic. The coefficient of friction between on -site soil and poured -in -place concrete may be taken as 0.40. The maximum anticipated total and differential footing movements (generally from settlement) are 1 inch and Y2 inch over a span of 20 feet, respectively. Drainage Surface water drainage should be directed away the proposed structure. Roofdrain water should be carried to the closest possible catch basin in the parking lot. Perimeter footing drains should be used in areas adjacent the building that are not paved. The on -site soils are not conducive to in- ground storm water disposal. CTI # 95 -4577 J.T. Roth Office Buildings Page 5 GENERAL NOTES This report was prepared solely for the Owner and Engineer for the design of the project. We encourage its review by bidders and /or the Contractor as it relates to factual data only (test pits and laboratory data). The opinions and recommendations contained within the report are not intended to be nor should they be construed to represent a warranty of subsurface conditions but are forwarded to assist in the planning and design process. Our reports pertain to the material tested /inspected only. Information contained herein is not to be reproduced, except in full, without prior authorization from this office. We would be pleased to provide additional input, as necessary, during the design process and to provide on -site observation and testing during construction. Please feel free to contact us for this work as well as for any questions you might have regarding this report. Sincerely, CARLSON TESTING, INC. rv‘c �Ep OFFS GIN f Sa 4743 r &i4 ()1/. OR EGON 0 7 � 23 • 1g ���, £ D. taVo C /. 30 -- `' 7 B / By Brian D. Leach, E.I. James D. Imbrie, P.E. Engineering Associate Geotechnical Engineer • CTI # 95 -4577 J.T. Roth Office Buildings Page 6 APPENDIX A FIELD INVESTIGATION A total of 4 hand augers to approximately 6 feet were excavated on January 22nd, 1996 at site locations shown on Figure 1. The augering was performed using a 3 -inch diameter bucket -type auger attached to 1 -inch diameter threaded rods and turned using a T- handle by hand. The hand augers were logged as to changes in soil type, moisture, relative strength, and ground water occurrence. Representative soil samples were taken from selected depths in the test pits and retained in airtight jars for moisture testing. Field testing consisted of pocket penetrometer testing on the exposed walls of the hand augers. Logs of the test pits showing changes in soil type, groundwater seepage, sampling details, and results of field and laboratory testing of moisture testing are presented on Figures A -1 and A -4. • -A -1- APPENDIX B LABORATORY TESTING Classification, Water Contents and Unit Weights Soil conditions were evaluated, described, and classified in accordance with the classification format described in the Oregon Department of Transportation Soil and Rock Classification Manual (ODOT Highway Division, 1987), based on the Unified Soil Classification System. Natural moisture contents were taken in plastic baggies; all samples were tested in accordance with ASTM D 2216. The moisture contents are expressed as a percentage of free water lost by evaporation compared to the dry weight of soil. These are presented numerically on the hand auger logs. - B -1 - Ft; 27 18 27 18 II. T T T I I 1 1 I I '° 4300 4500 1 N . AC. /7 AC. • 23 24 25 26 19 201 21 22 23 24 25 26 19 20121 2.2 1 P 1 0 r . 1 I 1 1 _ 1 1 t , 1 1 1 FRANKLIN • ---^ 5 25 - . __25 • / - — — — 8300 8200 ' 8 t.00- - - - .52Ac. .29 AC. 1 .23 AC. 5 6 7 8 • 1 2 3 4 5 6 7 9 1 1 2 3 4 e � : 1 1 1 ' 1 1 1 .. 36 ' I 36 . 1 = 7700 1 34 AC. 35 35 1 J 34 C.4 1 Q 1 it 1 I I I 33 i I2 / AC . - l W I2 . 32 8700 t68; Y 1 13 2 i ./2 AC. .i 4 31 N 7600 1- • 30 V • .34 AC. - 8800 r — . /2 AC. 1 6 4- -I - 5o ' UUS b' 8 9 00 � , .06 Ac. 28 17 4- T T T .� M G 27 ' 18 9000 Q 9001 1 1c 23 24 25 26 19 1 22 23 it 26 19 20 21 22 125' 60 ' 25' 1.., 1 25 ' 25' 0 25 6 (.6 0' 25' 25' Q) VACATED A IS.W. GON — — — 0 7 - 00900 •5" ." VACATED — — — — — — — SEE MAP- 1 - — — - 2S 1 IAD ti e CTI # 95 -4577 J.T. Roth Office Buildings Page 5 APPENDIX A FIELD INVESTIGATION A total of 5 hand augers to approximately 6 feet were excavated on January 22nd, 1996 at site locations shown on Figure 1. The augering was performed using a 3 -inch diameter bucket -type auger attached to 1 -inch diameter threaded rods and turned using a T- handle by hand. The hand augers were logged as to changes in soil type, moisture, relative strength, and ground water occurrence. Representative soil samples were taken from selected depths in the test pits and retained in airtight jars for moisture testing. Field testing consisted of pocket penetrometer testing on the exposed walls of the hand augers. Logs of the test pits showing changes in soil type, groundwater seepage, sampling details, and results of field and laboratory testing of moisture testing are presented on Figures A -1 and A -5. -A -1- Hand Auger No. HA -1 Logged by: Brian Leach Date Excavated: 1 -22 -96 Location: See site plan Surface Elevation: ? e - a) a - a 1) > o • `= ° °' a) a °' Material Description v c E a 0 da_ v) O SILT with some clay (ML); roots, dark brown, med. stiff, wet 1- 2 (24" Topsoil Layer) _ SILT with some clay (ML); tan /light brown, stiff, moist 3- 4 - Transitions to very stiff. 5- 6 (Native) Bottom of hand auger © 6 ft. 7 - No groundwater encountered. 8- 9- 10- 11- 12- 13- 14- 15- 16- 17- ( Job No. 95 -4577 Log of Hand Auger Hole Figure: A -1 GP a LSO + ',OA?: Carlson Testing, Inc. - P.O. Box 23814 - Tigard, Oregon 97281 - 684 -3460 - Fax 684 -0954 • [ -. Hand Auger No. HA- 2 L ogged by: Brian Leach Date Excavated: 1 -22 -96 Location: See site plan Surface Elevation: J e Zi5 m • a) o EE m E j E o r ; a Material Description a V c E •"—' c 0 a a. c a n 2 U 0 v SILT with some clay (ML); roots, dark brown, med. stiff, wet 1- (24" Topsoil Layer) 2 -- SILT with some clay (ML); tan /light brown, stiff, moist 3 - Transitions to very stiff. 4- 5- (Native) 6 Bottom of hand auger © 6 ft. 7 - No groundwater encountered. 8- 9- 10- 11- 12- 13- 14- 15- 16- 17- ‘ J C Job No. 95 -4577 Log of Hand Auger Hole Figure: A-2 ) O T al Carlson Testing, Inc. - P.O. Box 23814 - Tigard, Oregon 97281 - 684 -3460 - Fax 684 -0954 resnN� •iNC. • Logged by: Brian Lea ch Hand Auger No. HA- 3 Date Excavated: 1 -22 -96 Location: See site map Surface Elevation: ? / - - - a) 1 4- o E a c s Y a a o= Material Description ID eL O o o crs O O �, z- o a a. to 2 U 0 SILT with some clay (ML); roots, dark brown, med. stiff, wet 1 - (18" Topsoil Layer) 2 - SILT with some clay (ML); brown, med. stiff, moist 3- 4- 5- 6 - Transitions to very stiff. (Native) 7 Bottom of hand auger @ 7 ft. 8 - No groundwater encountered. 9- 10- 11- 12- 13- 14- 15- 16- 17- ( Job No. 95 -4577 Log of Hand Auger Hole Figure: A- 3 ) pa1-S0 C. ' : <41 ? Carlson Testing, Inc. - P.O. Box 23814 - Tigard, Oregon 97281 - 684 -3460 - Fax 684 -0954 TE 6TING INC Ha nd Auger No. HA- 4 Logged by: Brian Leach Date Excavated: 1 -22 -96 Location: See site map Surface Elevation:? e (1) T a H E - M Material Description p a a a U 0 SILT with some clay (ML); roots, dark brown, med. stiff, wet 1 - (20" Topsoil Layer) 2 - SILT with some clay (ML); brown, soft to med. stiff, moist to wet 3 - Transitions to light brown, med.stiff. 4 - 5 - Transitions to stiff. (Native) 6 Bottom of hand auger @ approx. 6 ft. 7 - No groundwater encountered. 8- 9- 10- 11- 12- 13- 14- 15- 16- 17- C Job No. 95 -4577 I Log of Hand Auger Hole Figure: A- 4 P aLSO G <etts Carlson Testing, Inc. - P.O. Box 23814 - Tigard, Oregon 97281 - 684 -3460 - Fax 684 -0954 TESTING INC APPENDIX B LABORATORY TESTING Classification, Water Contents and Unit Weights Soil conditions were evaluated, described, and classified in accordance with the classification format described in the Oregon Department of Transportation Soil and Rock Classification Manual (ODOT Highway Division, 1987), based on the Unified Soil Classification System. Natural moisture contents were taken in plastic baggies; all samples were tested in accordance with ASTM D 2216. The moisture contents are expressed as a percentage of free water lost by evaporation compared to the dry weight of soil. These are presented numerically on the hand auger logs. - B -1 - PDW DESIGN * 22 SE 134th PL * PORTLAND, OR. 97233 • DECEMBER II, 1996 ** *SITE PLAN REVIEW * ** CITY OF TIGARD Attn: Jim Funk 13125 SW HALL BLVD. TIGARD, OR. 97223 RE: 2 -STORY OFFICE BUILDING PC #: 10 -71 C AND PC #: 10 -76 C DEAR SIRS IN RESPONSE TO YOUR BUILDING PLAN REVIEW CHECK LIST WE HAVE CORRECTED ALL OF YOUR ITEMS AS NOTED IN REVISED BLUE PRINTS DATED AND WET STAMPED 12/10/96 AND IDENTIFIED BY REVISION SYMBOL Q . PLEASE NOTE THE ONLY EXCEPTION TO YOUR CHECK LIST IS THAT THE DUMPSTER ENCLOSURE IS CHANGE TO A CHAIN LINK FENCE TO ELIMINATE THE PROPERTY LINE AND STRUCTURAL DESIGN ISSUES. PLEASE CALL ME AT 252 -8015, PAYTON ROWELL AT 254 -6292 OR TIM ROTH AT 639 -2639 IF YOU HAVE ANY QUESTION REGARDING ANY OF THE CORRECTED ITEMS. SIN RELY, PETER WASCH RECEIVED DEC 13 1996 COMMUNITY DEVELOPM /, � Cons ion Inspection & Related Tests C arlson Testing, Inc. /.? 7 90 six 6 9 Geotechnical Consulting P.O. Box 23814 Tigard, Oregon 97281 MOISTURE — DENSITY RELATIONSHIP CURVE Phone (503) 684 -3460 FAX (503) 684 -0954 Client: JT ROTH CONSTRUCTION COMPANY 04 -03 -97 Project: R & W BUILDING 97 -7430 Location: ON —SITE (TRENCH) Sample: 3/4 " -0 ROCK FROM EATON Test Method: AASHTO T -99 METHOD "D" T -27, T -265 Sample Methods: AASHTO T -2 Preparation Method: MOIST Type of Comp. Hammer: CIRCULAR Compactive Effort: MANUAL Percent Passing 3/4" Sieve: 97.0% Oversized Material: REMOVED Date Received: 03 -28 -97 Date Tested: 04 -01 -97 OPTIMUM MOISTURE: 153 % MAX. DRY DENSITY: 1262 lb/ft3 128 - 127 126 k 125 as H124 p+123 a 122 121 120 - 12 13 14 15 16 17 18 19 MOISTURE CONTENT ( %) Zero Air Voids Line Based on Assumed Specific Gravity = 2.90 cc: CITY OF TIGARD PDW DESIGN S & N EXCAVATIION OTAK INC. Information contained herein is not to be reproduced, except in full, without prior authorization.