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CC - Geotech Evaluation Ger'aTok,Inc. 3s c-yEu,-a,. ' _�I 1=`T,t«t_.. ti''4•ri .1 ->: .�I IP.d `_t'iv ., .ID 120bi WH N 10 n l 'iti !',4 January 28, 2016 Project No. 1780-ID3 J-U-B Engineers 250 S. Beachwood Ave, Suite 201 Boise, Idaho 83709 Attention: Mr. Scott Wonders Subject: Geotechnical Evaluation for "Locust Grove Apartments" "Locust Grove Apartments"-a 16±Acre Multi-Family Residential Development Located on the South East Corner of North Locust Grove Road and East Wilson Lane, Meridian, Idaho In accordance with your request, GeoTek, Inc. (GTI) has completed a geotechnical evaluation of the subject property for the construction of two- to three-story multi-family residential structures and associated improvements. The purpose of our study was to evaluate the soils underlying the site and to provide recommendations for project design and construction based on our findings. This report outlines the geologic and geotechnical conditions of the site based on current data, and provides earthwork and construction recommendations with respect to those conditions. SCOPE OF SERVICES The scope of our services has included the following: . Review of soils and geologic reports and maps for the site (Appendix A). 2. Site reconnaissance. 3. Review of aerial photographs. 4. Excavating and logging of six (6) exploratory test pits (Appendix B). 5. Obtaining samples of representative soils, as the exploratory test pits were advanced. 6. Performing laboratory testing on representative soil samples (Appendix D). 7. Assessment of potential geologic constraints. 8. Engineering analysis regarding foundation design/construction,foundation settlement,and site preparation. 9. Preparation of this report. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS LOCUST GROVE APARTMENTS JANUARY 28, 2016 J-U-B ENGINEERS PAGE 3 PROJECT NO. 1779-I133 topographic high extending generally from Boise to Emmett, Idaho. The Boise Front consists of Cretaceous aged granitic and metamorphic rocks cut by Tertiary aged rhyolite and overlain with Miocene aged lake sediments (Wood and Clemens, 2004). These units have been cut by northwest trending faults which down drop these units toward the southwest. The faults also provide conduits for Quaternary aged basalt intrusions and flows (Malde, 1991). The depositional environment for the valley floor is dominantly lake laid deposits of sand,silt and clay. These materials were deposited during two periods of lake activity, one during the Miocene and the other during the Pleistocene. This valley infilling process has been subsequently truncated by down faulting within the valley ranging in height from a few feet to over 50 feet. Younger alluvium has been, and continues to be,transported dominantly by water and deposited on the basins gently sloping valley floor and within low-level flood plains. Portions of the alluvial deposits are being down cut by intermittent streams to the flood plain, and as a result stream terraces are being formed. SITE SOILS Artificial Fill Based on our field studies,some spread fills were observed near the existing residence as well as along perimeter of the site. This fill is generally associated with the construction of the adjacent roadways and apartment complex as well as the onsite residence. This spread fill shall be considered artificial fill. Much of the property has been cultivated for agricultural use, the upper 12 to 24 inches of material has been disturbed and consists of a dark brown lean clay with a moderate amount of organics and roots, this shall be considered artificial fill. Deeper fills may be encountered onsite. The "Artificial Fills" are loose/soft and contain organics/roots and are not considered suitable for support of foundations. All artificial fill material should be removed as described in the"Removals"section of this report. Native Alluvial Soils Alluvial soils encountered generally consisted surficial layers of clays, silts, and sands underlain by partially cemented sands and sands with varying amounts of gravel and cobbles. The moisture content within the alluvial materials was generally slightly moist to moist near surface to wet to saturated at depth. The consistency of these soils was soft near surface and ranged from firm/medium dense to very dense at depth. We anticipate that the onsite soils can be excavated with conventional earthwork equipment. Partially cemented layers of material were encountered in the majority of our excavations; however, we anticipate that the onsite soils can be excavated with conventional earthwork equipment equivalent to CAT D9R dozers and CAT 235 excavators. Special excavation equipment and techniques may be necessary dependent upon if harder materials are encountered during construction. After artificial fill is removed, the upper 12 inches of the alluvium will require, at a minimum, some jremoval and/or processing efforts to be considered suitable for the support of the proposed site improvements. Locally deeper processing/removals may be necessary. Refer to the "Recommendations Earthwork Construction" section of this report for specific site preparation recommendations. GeoTek, Inc. LOCUST GROVE APARTMENTS JANUARY 28, 2016 J-U-B ENGINEERS PAGE 5 PROJECT NO. 1779-I133 potential for these phenomenon to occur and adversely affect surface improvements. These potential risks are no greater at this site than they are for other structures and improvements developed on the alluvial materials in this vicinity. RESULTS OF LABORATORY TESTING Laboratory tests were performed on representative samples of the onsite earth materials in order to evaluate their physical and chemical characteristics. The tests performed and the results obtained are presented in Appendix D. CONCLUSIONS Based on our field exploration, laboratory testing and engineering analyses, it is our opinion that the subject site is suited for development from a geotechnical engineering viewpoint. The recommendations presented herein should be incorporated into the final design, grading, and construction phases of development.The engineering analyses performed concerning site preparation and the recommendations presented below, have been completed using the information provided to us regarding site development. In the event that the information concerning proposed development is not correct, the conclusion and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of this report are modified or approved in writing by this office. RECOMMENDATIONS - EARTHWORK CONSTRUCTION General All grading should conform to the International Building Code (IBC)and the requirements of the City of Meridian except where specifically superseded in the text of this report. During earthwork construction all removals, drain systems, slopes, and the general grading procedures of the contractor should be observed and the fill selectively tested. If unusual or unexpected conditions are exposed in the field, they should be reviewed by this office and if warranted, modified and/or additional recommendations will be offered. It is recommended that the earthwork contractor(s) perform their own independent reconnaissance of the site to observe field conditions first hand. If the contractor(s)should have any questions regarding site conditions,site preparation, or the remedial recommendations provided,they should contact an engineer at GeoTek for any necessary clarifications prior to submitting earthwork bids.All applicable requirements of local and national construction and general industry safety orders,the Occupational Safety and Health Act, and the Construction Safety Act should be met. Demolition The following recommendations are provided as guidelines in the event a structure is encountered that are not intended to remain. GeoTek, Inc. LOCUST GROVE APARTMENTS JANUARY 28, 2016 J-U-B ENGINEERS PAGE 7 PROJECT NO. 1779-I133 If existing improvements or property line restrictions limit removals, condition specific recommendations would be provided on a case-by-case basis. During earthwork construction, care should be taken by the contractor so that adverse ground movements or settlements are not generated affecting existing improvements. Transitional Pads Transitional pads are defined in this report as pads which are partially cut and partially fill. To mitigate some of the differential settlement which will occur on transitional pads,the cut side should be over- excavated/processed to a minimum depth equal to 2 feet below the bottom of the footings or to the depth of the fill, which ever is less. On transitional pads with more than 7.5 feet of fill, plans need to be reviewed by GTI and site-specific recommendations will be provided. Excavation Difficulty We anticipate that the onsite soils can be excavated with conventional earthwork. Seasonal conditions could cause wet soil conditions to occur onsite. Depending on the depth of cuts, it should be expected that special excavation and fill placement measures may be necessary. Wet materials should be spread out and air-dried or mixed with drier soils to reduce their moisture content to the appropriate level for fill placement. Frozen soils, if encountered, should be removed and allowed to thaw prior to any fill placement or construction. Removal bottoms should be checked by a representative of GTI to see if deeper removals are necessary. Fill Placement Subsequent to completing removals/processing and ground preparation,the excavated onsite and/or imported soils may be placed in relatively thin lifts (less than 8 inches thick), cleaned of vegetation and debris, brought to at least optimum moisture content, and compacted to a minimum relative compaction of 95 percent of the laboratory standard (ASTM D 1557). Import Material Potentially, soils will be imported to the site for earthwork construction purposes. A sample of any intended import material should first be submitted to GTI so that, if necessary, additional laboratory or chemical testing can be performed to verify that the intended import material is compatible with onsite soils. In general, import material should be within the following minimum guidelines: * Free of organic matter and debris. * Maintain less than 0.2 percent sulfate content. * Maintain less than 3.0 percent soluble material. * Maintain less than 0.02 percent soluble chlorides. * Maintain less than 0.2 percent sodium sulfate content. * Maintain a Plasticity Index less than 12 (i.e., low expansive). * One hundred percent passing the six-inch screen. * At least seventy-five percent passing a three-inch screen. Observation and Testing During earthwork construction all removal/processing and the general grading procedures should be observed and the fill selectively tested by a representative(s) of GTI. If unusual or unexpected conditions are exposed in the field,they should be reviewed by GTI and if warranted, modified and/or additional recommendations will be offered. GeoTek, Inc. LOCUST GROVE APARTMENTS JANUARY 28, 2016 J-U-B ENGINEERS PAGE 9 PROJECT NO. 1779-ID3 RECOMMENDATIONS — FOUNDATIONS General Foundation design and construction recommendations are based on preliminary laboratory testing and engineering analysis performed on near surface soils. The proposed foundation systems should be designed and constructed in accordance with the guidelines contained herein and in the International Building Code. Based on our experience in the area, the soils onsite should have a negligible corrosive potential to concrete and metal, materials selected for construction purposes should be resistant to corrosion. Where permitted by building code, PVC pipe should be utilized. All concrete should be designed, mixed, placed, finished, and cured in accordance with the guidelines presented by the Portland Cement Association (PCA) and the American Concrete Institute (ACI). Based on our grading recommendations,the soils beneath the foundations are anticipated to have low expansion potential. Therefore, foundation recommendations for low expansive soil conditions are provided below. If more expansive soils are encountered, the pad(s) will either need to be regraded and the more expansive soils removed by the contractor or increased foundation recommendations will need to be provided. Conventional Foundation Recommendations Column loads are anticipated to be 50 kips or less while wall loads are expected to be 3 kips per lineal foot or less. The conventional recommendations provided are from a geotechnical engineering perspective (i.e.,for expansive conditions) and are not meant to supersede the design by the project's structural engineer. Preliminary recommendations for foundation design and construction are presented below. The specific criteria to be used should be verified on evaluation of the proposed buildings,structural loads, and expansion and chemical testing performed after grading is complete. The bearing values indicated are for the total dead plus frequently applied live loads and may be increased by one third for short duration loading which includes the effects of wind or seismic forces. When combining passive pressure and friction for lateral resistance,the passive component should be reduced by one third. A grade beam, reinforced as below and at least 12 inches wide, should be utilized across all large entrances. The base of the grade beam should be at the same elevation as the bottom of the adjacent footings. Footings should be founded at a minimum depth of 24 inches below lowest adjacent ground surface as required by local codes to extend below the frost line. Reinforcement for spread footings should be designed by the project's structural engineer. For foundations systems including a crawl space, it is recommended that it be designed so that water is not allowed to penetrate the crawl space. Proper grading and backfill for the foundations is critical and should adhere to the"fill placement"and"drainage"recommendations of this evaluation as well as local building codes. GeoTek, Inc. LOCUST GROVE APARTMENTS JANUARY 28, 2016 J-U-B ENGINEERS PAGE I I PROJECT NO. 1779-I133 Positive site drainage should be maintained at all times. Water should not be allowed to pond or seep into the ground. If planters or landscaping are adjacent to paved areas, measures should be taken to minimize the potential for water to enter the pavement section. MINIMUM MINIMUM AGGREGATE ASSUMED TRAFFIC SUBGRADE ASPHALT THICKNESS (in.) RIGHT-OF-AWAY R-VALUE CONCRETE Aggregate THICKNESS Base (3/4" Subbase (in.) minus) (Pitrun) Parking and Drives No Truck Access 12 2.5 4.0 8.0 TI = 5.0 Truck Access 12 3.0 6.0 15.0 TI = 8.0 OTHER RECOMMENDATIONS Site Imlrovements As is commonly known, expansive soils are problematic with respect to the design, construction and long term performance of concrete flatwork. Due to the nature of concrete flatwork, it is essentially impossible to totally mitigate the effects of soil expansion. Typical measures to control soil expansion for structures include; low expansive soil caps, deepened foundation system, increased structural design, and soil presaturation. As they are generally not cost effective, these measures are very seldom utilized for flatwork because it's less costly to simply replace any damaged or distressed sections than to "structurally" design them. Even if "structural" design parameters are applied to flatwork construction,there would still be relative movements between adjoining types of structures and other improvements (e.g., curb and sidewalk). This is particularly true as the level of care during construction of flatwork. is often not as meticulous as that for structures. Unfortunately, it is fairly common practice for flatwork to be poured on subgrade soils, which have been allowed to dry out since site grading. Generally after flatwork construction is completed, landscape irrigation begins, utility lines are pressurized, and drainage systems are utilized; presenting the potential for water to enter the dry subgrade soils, causing the soil to expand. Recommendations for exterior concrete flatwork design and construction can be provided upon request. If, in the future, any additional improvements are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. This office should be notified in advance of any fill placement, grading, or trench backfilling after rough grading has been completed. This includes any grading, utility trench and retaining wall back.fiills. GeoTek, Inc. LOCUST GROVE APARTMENTS JANUARY 28, 2016 J-U-B ENGINEERS PAGE 13 PROJECT NO. 1779-I133 minimum of 90 relative compaction. Compaction testing and observation, along with probing should be performed to verify the desired results. Drainage Positive site drainage should be maintained at all times in accordance with the IBC. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond and/or seep into the ground. Pad drainage should be directed toward the street or other approved area. The ground immediately adjacent to the foundation shall be sloped away from the building at a minimum of 5-percent for a minimum distance of 10 feet measured perpendicularly to the face of the wall. If physical obstructions prohibit 10 feet of horizontal distance, a 5-percent slope shall be provided to an approved alternate method of diverting water away from the foundation. Swales used for this purpose shall be sloped a minimum of 2-percent where located within 10 feet of the building foundation. Impervious surfaces within 10 feet of the building foundation shall be sloped a minimum of 2-percent away from the building. Roof gutters and down spouts should be utilized to control roof drainage. Down spouts should outlet onto paved areas or a minimum of five feet from proposed structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall. Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. PLAN REVIEW Final grading, foundation, and improvement plans should be submitted to this office for review and comment as they become available, to minimize any misunderstandings between the plans and recommendations presented herein. In addition,foundation excavations and earthwork construction performed on the site should be observed and tested by this office. If conditions are found to differ substantially from those stated, appropriate recommendations would be offered at that time. LIMITATIONS The materials encountered on the project site and utilized in our laboratory study are believed representative of the area; however, soil materials vary in character between excavations and conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. GeoTek, Inc. assumes no responsibility or liability for work, testing, or recommendations performed or provided by others. Since our study is based upon the site materials observed,selective laboratory testing and engineering analysis, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice and no warranty is expressed or implied. Standards of practice are subject to change with time. GeoTek, Inc. 7 � r E . Fairview Ave . L r Z r O M C rf NA I , A �� o - M ' t t w. It r r Y 41 APPROXIMATE SITE LOCATION Source : Google Maps 2016 , GeoTelc Field Observations , 2016 . Not to Scale FIGURE I SITE VICINITY MAP f5*1 Locust Grove Apartments Meridian , Idaho G E O T E K Prepared for : J - U - B Engineers , Inc . GEOTECNNICAL j ENVIRONMENTAL MATERIALS Project No.: Report Date: Drawn By: 320 E . Corporate Dr, Suite 300 , Meridian , ID 83642 1779 - ID3 January 2016 DCW (203 ) 888 =7010 ( phone ) / (208 ) 888 -7924 ( FAX) APPENDIX A eoTek, Inc. APPENDIX B eoTek, Inc® LOG LEGEND MATERIAL DESCRIPTION Soil Pattern USCS Symbol USCS Classification FILL Artificial Fill GP or GW Poorly/Well graded GRAVEL GM Silty GRAVEL GC Clayey GRAVEL GP-GM or GW-GM Poorly/Well graded GRAVEL with Silt GP-GC or GW-GC Poorly/Well graded GRAVEL with Clay SP or SW Poorly/Well graded SAND SM Silty SAND Sc Clayey SAND SP-SM or SW-SM Poorly/Well graded SAND with Silt SP-SC or SW-SC Poorly/Well graded SAND with Clay ay SC-SM Silty Clayey SAND ML SILT MH Elastic SILT CL-ML Silty CLAY CL Lean CLAY CH Fat CLAY PCEM PARTIALLY CEMENTED CEM CEMENTED BDR BEDROCK SAMPLING SPT Ring Sample NR No Recovery Bulk Sample Water Table CONSISTENCY rDDense ss Soils Cohesive Soils Cementation Loose So Soft MH Moderately Hard ose F Firm H Hard Dense S Stiff VH Very Hard VS Very Stiff Dense TEST PIT LOG LOGGED BY: DCW PROJECT#: 1779-ID3 METHOD: Backhoe PROJECT: Locust Grove Apartments EXCAVATOR: Just Dig It CLIENT: JUB Engineers DATE: 1/14/15 G E 0 T E K LOCATION: ELEVATION: SAMPLES Q = .Q QEa TEST PIT NUMBER: TP-2 REMARKS oca E c o C o v) m m MATERIAL DESCRIPTION AND COMMENTS v FILL Brown to Dk Brown Sandy SILT w/organics; moist So 1 ML Lt Brown to Brown Sandy SILT; slightly moist S 2 3 CH Lt Brown to Brown Sandy Fat CLAY; moist F 4 SP Lt Brown Partially CEMENTED SANDS w/silt and gravel; VD- 5 slightly moist H 6 SP Tan to Lt Brown SAND w/gravel &some cobbles; slightly MD moist 7 8 9 moist to wet 10 saturated Water encountered at 10.5' 11 Bottom of Test Pit @ I V-0" 12 13 14 15 16 17 18 19 20 320 E. Corporate Drive, Suite 300, Meridian, Idaho 83642 (208)888-7010 Fax: (208)888-7924 , TEST PIT LOG LOGGED BY: DCW PROJECT#: 1779-ID3 METHOD: Backhoe PROJECT: Locust Grove Apartments EXCAVATOR: Just Dig It CLIENT: JUB Engineers DATE: 1/14/15 G E © T E K LOCATION: ELEVATION: SAMPLES E Q a TEST PIT NUMBER: TP-4 REMARKS o E c o o v CO) m MATERIAL DESCRIPTION AND COMMENTS FILL Brown to Dk Brown Sandy SILT w organics; moist So 1 CL Lt Brown to Brown Sandy Lean CLAY; moist F 2 SP Lt Brown Partially CEMENTED SANDS w/silt and gravel; D- 3 slightly moist VD 4 5 SP Tan to Lt Brown SAND w/gravel &some cobbles; slightly MD moist -D 6 7 8 9 moist to wet 10 wet to saturated Water encountered at 11 11.0' 12 Bottom of Test Pit @ 11'-6" 13 14 15 16 17 18 19 20 ammomd 320 E. Corporate Drive, Suite 300, Meridian, Idaho 83642 (208)888-7010 Fax: (208)888-7924 TEST PIT LOG LOGGED BY: DCW PROJECT#: 1779-ID3 METHOD: Backhoe PROJECT: Locust Grove Apartments EXCAVATOR: Just Dig It CLIENT: JUB Engineers DATE: 1/14/15 G E O T E K LOCATION: ELEVATION: SAMPLES Q N aE TEST PIT NUMBER: TP-6 REMARKS o E 3 "o v o co m � � MATERIAL DESCRIPTION AND COMMENTS v FILL Brown to Dk Brown Sandy CLAY w/organics; moist So 1 2 CL Tan Sandy Lean CLAY; moist F 3 SM Lt Tan to Tan Silty SAND; slightly moist MD 4 5 SIP Tan to Lt Brown SAND w/gravel &some cobbles; slightly MD 6 moist -D 7 8 9 moist to wet 10 wet to saturated Water encountered at 11 — 11.0' 12 Bottom of Test Pit @ 11'-6" 13 14 15 16 17 18 19 20 320 E. Corporate Drive, Suite 300, Meridian, Idaho 83642 (208)888-7010 Fax: (208)888-7924 FIELD TESTS AND OBSERVATIONS ( I 779-ID3) PERCOLATION TESTS The infiltration rate was determined by conducting percolation tests for onsite earth materials. The infiltration rate was determined in inches per hour in general accordance with the City of Eagle requirements. Infiltration rate results are presented below. LOCATION INFILTRATION RATE (Inches/Hour) P-I (TP-2) @ 2'-6" 24.0+ P-2 (TP-4) @ 1'-8" 24.0+ GROUND WATER MONITORING RESULTS Ground water monitoring results are presented below. Ground water elevation results are recorded in feet below existing grade. LOCATION GROUNDWATER ELEVATION GW-I (TP-1) 9'-6" GW-2 (TP-5) 9'-9"+ GW-3 (TP-6) 1 1'-0"+ + Indicates a dry reading to the bottom of piezometer GeoTek, Inc. LABORATORY TESTS RESULTS ( I 779-ID3) ATTERBERG LIMITS Atterberg limits were performed on representative samples in general accordance with ASTM D 4318. The results are shown in the following plates. PARTICLE SIZE ANALYSIS Sieve analyses were performed in general accordance with ASTM test method C 136 and ASTM C 117. Test results are presented in the following plates. eoTel,q Inc.