CHRISTIAN WHEELER E N G I N E E R I N G

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CHRISTIAN WHEELER E N G I N E E R I N G April 22, 2016 Robert and Michelle Soltys CWE 2150237.

1 CHRISTIAN WHEELER E N G I N E E R I N G April 22, 2016 Robert and Michelle Soltys CWE Cambridge Avenue Cardiff By-The-Sea, California Subject: Additional Recommendations, Proposed Soltys Residence 5261 La Glorieta, Rancho Santa Fe, San Diego County, California References: 1) Coffey Engineering, Inc., Grading Plan, Soltys Residence, undated 2) Coffey Engineering, Inc., Fire Turn Out-Soltys Residence, undated 3) Christian Wheeler Engineering, Report of Preliminary Geotechnical Investigation, Proposed Soltys Residence, CWE Report , dated August 31, 2015 Dear Mr. and Mrs. Soltys: In accordance with the request of EOS Architecture, Inc., we have prepared this addendum to our referenced report of geotechnical investigation to provide additional site grading and foundation recommendations for the subject project associated with the currently proposed grading. PROPOSED FILL SLOPE The referenced grading plans indicate that a portion of the proposed fill slope north of the proposed building pad will be reconstructed at a 1.5:1 (horizontal to vertical) or flatter inclination. The maximum anticipated slope height is approximately 50 feet. It is assumed that the slope will be constructed using onsite soils or similar imported fill materials. In order to allow for minimum factors-of-safety of 1.5 against global and surficial slope failures along those portions of the re-graded slope that are to be steeper than 2:1 (horizontal to vertical), it is recommended that geotextile reinforcing be placed during slope construction as described hereinafter H o m e A v e n u e San Diego, CA FAX

2 CWE April 22, 2016 Page No. 2 FILL SLOPE CONSTRUCTION Slope reconstruction should begin with the removal of existing artificial fill and potentially compressible native soils. The removals should extend to contact with the underlying dense formational soils. The bottom of the excavation should be approved by our project geologist or engineer prior to placing new fill or geotextile reinforcement. The soils removed should be moisture conditioned and may be replaced as compacted fill in accordance with the recommendations presented in the Compaction and Method of Filling section of the referenced geotechnical report. A minimum 12-foot wide keyway sloped back into the hillside at least 2 percent should be graded at the toe of the slope. Minimum recommended keyway dimensions are presented in Plate No. 1. A similar keyway is recommended for the proposed 2:1 (horizontal to vertical) inclination section of the reconstructed slope. As fill placement progresses up the portions of the slope that are to be steeper than 2:1 (H:V), geotextile reinforcing such as MiraGrid 5XT or approved equivalent should be installed every 5 feet vertically, with the first layer of reinforcing grid placed at toe of the lowest portion of the fill slope. Each grid should be placed such that it is within 6 inches of the finished face of the re-graded slope and extends horizontally back to the contact with competent formational materials or a distance of 20 feet, whichever is less. New fills should be benched at least 6 feet into undisturbed formational soils. The benching should remove all loose surficial soils and should create level to slightly into-slope inclined areas on which to place the fill material. FIRE TURN OUT It is our opinion that the general site preparation and grading recommendations provided in the referenced report are also applicable to the proposed fire turn out area. FOUNDATIONS As described above, constructing portions of the proposed fill slope along the north side of the residence at inclination steeper than 2:1 (H:V) will require the inclusion of geotextile reinforcement to provide for adequate global and surficial stability of said slope areas. Based on the proposed location of the residence and associated improvements along and in close proximity to the top of this slope and the presence of geotextile reinforcing within portions of the proposed fill slope, the use of conventional shallow foundations to support the proposed improvements along the northern portion of the proposed building pad is not recommended. As such, it will be recommended to support the proposed improvements within the northern portion of the building pad on drilled, cast-in-place concrete piers that are tied together with grade beams and which extend into the underlying formational materials. Furthermore, in order to reduce

3 CWE April 22, 2016 Page No. 3 the potential for differential performance of dissimilar foundation bearing strata across the footprint of the proposed residence, we recommend that all conventional shallow foundations used to support the southern portions of the proposed home be extended into firm and unyielding formational materials (Torrey Sandstone). Revised foundation recommendations for deep foundations and shallow foundations embedded into the Torrey Sandstone are presented below. Exterior improvements, including site retaining walls, within the southern portion of the proposed building pad may be supported by either conventional, shallow foundations embedded into properly compacted structural fill in accordance with the recommendations contained in our referenced geotechnical report, or shallow foundations embedded into formational materials per the recommendations presented below. DRILLED CAST-IN-PLACE CONCRETE PIERS MINIMUM PIER DIMENSIONS: Cast-in-place concrete pier foundations should have a minimum diameter of 24 inches. The piers should extend to a minimum depth of 10 feet below finish grade and 10 feet into the Torey Sandstone materials, whichever is more. At this depth, a bearing capacity of 5,000 pounds per square foot (psf) may be assumed for said piers. This bearing pressure may be increased by 1,000 psf for each additional foot of depth, and 800 psf for each additional foot of width, up to a maximum bearing pressure of 20,000 psf. This value may be increased by one-third when considering wind and/or seismic loads. PIER REINFORCING: The reinforcing steel for the piers should be specified by the project structural engineer. As a minimum, we recommend that the pier reinforcing extend the full depth of the pier excavation. LATERAL BEARING CAPACITY: The allowable lateral bearing resistance to lateral loads for the portion of the piers embedded into existing fill soils may be assumed to be 300 pounds per square foot per foot of depth up to a maximum of 3,000 pounds per square foot. Lateral bearing resistance may be assumed staring at a depth such that a minimum horizontal setback of 10 feet exists between the pier and the face of the slope. The allowable lateral bearing resistance to lateral loads for the portion of the piers embedded into Torrey Sandstone deposits may be assumed to be 400 pounds per square foot per foot of depth up to a maximum of 4,000 pounds per square foot. This value may be assumed to act on an area equal to twice the pier diameter.

4 CWE April 22, 2016 Page No. 4 EXCAVATION CHARACTERISTICS: It is anticipated that the proposed piers may be drilled utilizing conventional drilling equipment in good working condition. Moderately to highly cemented soils may be encountered within the Torrey Sandstone. PIER EXCAVATION OBSERVATION AND CLEANING: All pier excavations should be observed by Christian Wheeler Engineering during drilling to determine whether the minimum pier depth recommended has been achieved and that the foundation soils are as anticipated in the preparation of this report. Prior to placing the steel reinforcing cages, all loose or disturbed soils at the bottom of the pier excavations should be removed. The cleanout of the pier excavations should be approved by the geotechnical engineer. SHALLOW FOUNDATIONS EMBEDDED INTO FORMATIONAL MATERIALS DIMENSIONS: Spread footings supporting the proposed structure and associated improvements should be embedded at least 12 inches or 18 inches below finished pad grade for one-story or two-story construction, respectively. In addition, the footings should extend at least 6 inches into Torrey Sandstone materials. Continuous spread footings should have a minimum width of 12 inches. Isolated spread footings should have a minimum width of 24 inches. Retaining wall footings should be embedded at least 18 inches below lowest adjacent finish pad grade, and should have a minimum width of 24 inches. FOOTING SETBACKS: Footings proposed adjacent to the top of the slopes will need a minimum horizontal setback of 10 feet between the outer lower edge of the footing to the adjacent slope face. The setback distance may be achieved by using deepened footings. Footings planned under the specified setbacks should be provided specific review by the Geotechnical Consultant prior to construction. BEARING CAPACITY: Spread footings with a minimum embedment of 12 inches and a minimum width of 12 inches may be designed for an allowable soil bearing pressure of 3,000 pounds per square foot (psf). This value may be increased by 700 pounds per square foot for each additional foot of embedment and 500 pounds per square foot for each additional foot of width up to a maximum of 6,000 pounds per square foot. The bearing value may also be increased by one-third for combinations of temporary loads such as those due to wind or seismic loads. FOOTING REINFORCING: Reinforcement requirements for foundations should be provided by a structural engineer. However, based on the existing soil conditions, we recommend that the minimum

5 CWE April 22, 2016 Page No. 5 reinforcing for continuous footings consist of at least 2 No. 5 bar positioned three inches above the bottom of the footing and 2 No. 5 bar positioned two inches below the top of the footing. LATERAL LOAD RESISTANCE: Lateral loads against foundations may be resisted by friction between the bottom of the footing and the supporting soil, and by the passive pressure against the footing. The coefficient of friction between concrete and soil may be considered to be The passive resistance may be considered to be equal to an equivalent fluid weight of 300 pounds per cubic foot. This assumes the footings are poured tight against undisturbed soil. If a combination of the passive pressure and friction is used, the friction value should be reduced by one-third. TRANSITION PAD UNDERCUT It is anticipated that the building pad will have a cut and fill transition, where a portion of the pad will be underlain by the Torrey Sandstone while the remaining portion of the lot will be underlain by newly compacted fill material. We previously recommended that the cut portion of the pad be undercut at least 5 feet below finish grade or one foot below the bottom of the proposed footings, whichever is more. The intent of this previous recommendation was to provide for a uniformity of bearing strata below the proposed residence. However, based on the currently proposed grading concept, including the geotextile reinforcement of those portions of the proposed fill slope along the north side of the building pad that are to be steeper than 2:1 (H:V) and the resulting foundation recommendations presented herein, we no longer recommend that the cut portions of the building pad be undercut. The intent of this revised recommendation is to allow for the use of conventional shallow foundations that extend into competent formational materials within the southern portion of the proposed home s footprint. INTERIOR FLOOR SLABS The minimum floor slab thickness should be 5 inches (actual) and all floor slabs should be reinforced with at least No. 4 reinforcing bars placed at 12 inches on center each way. Slab reinforcement should be supported on chairs such that the reinforcing bars are positioned at mid-height in the floor slab. Slab reinforcement should be supported on chairs such that the reinforcing bars are positioned at mid-height in the floor slab. The slab reinforcement should extend into the perimeter foundations at least six inches.

this report, please do not hesitate to contact our

This opportunity to be of professional service is

Respectfully submitted, CHRISTIAN WHEELER

6 CWE April 22, 2016 Page No. 6 CLOSURE If you have questions after reviewing this report, please do not hesitate to contact our office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted, CHRISTIAN WHEELER ENGINEERING Daniel B. Adler, RCE # David R. Russell, C.E.G. #2215 DBA:drr ec: torrey@eosarc.com; jen@eosarc.com; john@coffeyengineering.com

8 APPENDIX A Global Stability Analysis 1.5:1 (H:V) Fill Slope

9 # FS a 1.5 b 1.5 c 1.5 d 1.6 e 1.6 f 1.6 g 1.6 h 1.6 i 1.6 j 1.6 Soil Desc. Qdaf Tt Soil Type No. 1 2 Soltys Residence - CWE D-D' Reconstructed 1.5:1 Fill Slope c:\users\dave russell\desktop\d'd'\d1.5slope.pl2 Run By: DRR 4/22/ :58PM Total Unit Wt. (pcf) Saturated Unit Wt. (pcf) Cohesion Intercept (psf) Aniso Friction Angle (deg) 30.0 Aniso Piez. Surface No. 0 0 R R i h j a e f g cd b R R R R R R R R R Lb/ft GSTABL7 v.2 FSmin=1.5 Safety Factors Are Calculated By The Modified Bishop Method

10 c:\users\dave Russell\Desktop\D D \d1.5slope.out Page 1 *** GSTABL7 *** ** GSTABL7 by Garry H. Gregory, P.E. ** ** Original Version 1.0, January 1996; Current Version 2.003, June 2002 ** (All Rights Reserved-Unauthorized Use Prohibited) ********************************************************************************* SLOPE STABILITY ANALYSIS SYSTEM Modified Bishop, Simplified Janbu, or GLE Method of Slices. (Includes Spencer & Morgenstern-Price Type Analysis) Including Pier/Pile, Reinforcement, Soil Nail, Tieback, Nonlinear Undrained Shear Strength, Curved Phi Envelope, Anisotropic Soil, Fiber-Reinforced Soil, Boundary Loads, Water Surfaces, Pseudo-Static & Newmark Earthquake, and Applied Forces. ********************************************************************************* Analysis Run Date: 4/22/2016 Time of Run: 02:58PM Run By: DRR Input Data Filename: c:\users\dave Russell\Desktop\D D \d1.5slope.in Output Filename: c:\users\dave Russell\Desktop\D D \d1.5slope.out Unit System: English Plotted Output Filename: c:\users\dave Russell\Desktop\D 1.5slope.PLT PROBLEM DESCRIPTION: Soltys Residence - CWE D-D Reconstructed 1.5:1 Fill Slope BOUNDARY COORDINATES 3 Top Boundaries 7 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type (ft) (ft) Below Bnd User Specified Y-Origin = (ft) Default X-Plus Value = 0.00(ft) Default Y-Plus Value = 0.00(ft) ISOTROPIC SOIL PARAMETERS 2 Type(s) of Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No ANISOTROPIC STRENGTH PARAMETERS 1 soil type(s) Soil Type 2 Is Anisotropic Number Of Direction Ranges Specified = 4 Direction Counterclockwise Cohesion Friction Range Direction Limit Intercept Angle No. (deg) (psf) (deg) ANISOTROPIC SOIL NOTES: (1) An input value of 0.01 for C and/or Phi will cause Aniso C and/or Phi to be ignored in that range. (2) An input value of 0.02 for Phi will set both Phi and C equal to zero, with no water weight in the tension crack. (3) An input value of 0.03 for Phi will set both Phi and C equal to zero, with water weight in the tension crack. REINFORCING LAYER(S) 11 REINFORCING LAYER(S) SPECIFIED REINFORCING LAYER 1

11 c:\users\dave Russell\Desktop\D D \d1.5slope.out Page REINFORCING LAYER REINFORCING LAYER REINFORCING LAYER REINFORCING LAYER REINFORCING LAYER REINFORCING LAYER REINFORCING LAYER REINFORCING LAYER REINFORCING LAYER REINFORCING LAYER A Critical Failure Surface Searching Method, Using A Random Technique For Generating Circular Surfaces, Has Been Specified Trial Surfaces Have Been Generated. 200 Surface(s) Initiate(s) From Each Of 10 Points Equally Spaced Along The Ground Surface Between X = 35.00(ft) and X = 45.00(ft) Each Surface Terminates Between X = (ft)

12 c:\users\dave Russell\Desktop\D D \d1.5slope.out Page 3 and X = (ft) Unless Further Limitations Were Imposed, The Minimum Elevation At Which A Surface Extends Is Y = 0.00(ft) 10.00(ft) Line Segments Define Each Trial Failure Surface. Following Are Displayed The Ten Most Critical Of The Trial Failure Surfaces Evaluated. They Are Ordered - Most Critical First. * * Safety Factors Are Calculated By The Modified Bishop Method * * Total Number of Trial Surfaces Evaluated = 2000 Statistical Data On All Valid FS Values: FS Max = FS Min = FS Ave = Standard Deviation = Coefficient of Variation = % Failure Surface Specified By 13 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Individual data on the 13 slices Water Water Tie Tie Earthquake Force Force Force Force Force Surcharge Slice Width Weight Top Bot Norm Tan Hor Ver Load No. (ft) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) Failure Surface Specified By 13 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 12 Coordinate Points

13 c:\users\dave Russell\Desktop\D D \d1.5slope.out Page Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 12 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 12 Coordinate Points Circle Center At X = 2.79 ; Y = ; and Radius = *** *** Failure Surface Specified By 12 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** ***

14 c:\users\dave Russell\Desktop\D D \d1.5slope.out Page 5 Failure Surface Specified By 12 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 13 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 11 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 11 Coordinate Points Circle Center At X = 3.74 ; Y = ; and Radius =

15 *** *** **** END OF GSTABL7 OUTPUT **** c:\users\dave Russell\Desktop\D D \d1.5slope.out Page 6

16 APPENDIX B Surficial Stability Analysis 1.5:1 (H:V) Fill Slope

17 SURFICIAL SLOPE STABILITY - 1.5:1 Slope ASSUMED PARAMETERS z Depth of Saturation (ft) 4 a Slope Ratio (H:1) 1.5 β Slope Angle (radians) 0.59 γ W Unit Weight of Water (pcf) 62.4 γ sat Saturated Unit Weight of Soil (pcf) φ Angle of Internal Friction Along Plane of Failure (degrees) 30 c Cohesion Along Plane of Failure (psf) 100 C i Coefficient of Interaction for Pullout 0.8 L Embedment Length (ft) 5 σ n Normal Stress acting over Geogrid Embedment Length (psf) 1250 T Max. Available Pullout Resistance (lb/ft); T = 2C i σ n tanφ 1155 T all Long Term Design Strenght (lb/ft); T all T 2575 OK H Reinforced Slope Height (ft) 50 S Vertical Geogrid Spacing (ft) 5 N Number of Geogrid Layers; N = H/S 10 F g Total Tensile Geogrid Reinforcement (lb/ft); F g = TN OF SAFETY Unreinforced FS c + (γ sat - γ W )(z)(cos β) 2 (tan φ) FS u = (γ sat )(z)(sin β)(cos β) 0.9 Reinforced FS F g (cosβsinβ+sinβtanφ) + c(h) + (γ sat - γ W )(H)(z)(cos a) 2 (tan φ) FS r = (γ sat )(H)(z)(sin β)(cos β) 1.6 References: 1. FHWA, 2001, Mechanically Stabilized Earth Walls and Reinforced Soil Slopes Design and Construction Guidelines. 2. Strata Systems, Inc., 2008, Reinforced Soil Slopes and Embankments (Version ). SOLTYS RESIDENCE 5261 La Glorieta, Rancho Santa Fe, CA BY: DRR DATE: Apr-16 CHRISTIAN WHEELER JOB : APPENDIX B: B-1

( KLEINFEL DER. November 17,2008 File No MARINA COAST WATER DISTRICT th Avenue Marina, California ATTENTION: Mr.

( KLEINFEL DER. November 17,2008 File No MARINA COAST WATER DISTRICT th Avenue Marina, California ATTENTION: Mr. ( KLEINFEL DER L Bright People. Right Solutions. November 17,2008 File No. 82142 40 Clark Street, Suite J Salinas, CA 93901 p1 831.755.7900 f 1831.755.7909 kleinfelder.com MARINA COAST WATER DISTRICT 2840