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Home My WebLink AboutCDP 16-26; TABATA RANCH; GRADING PLAN SHEET 2 (OF 4) REVIEW; 2018-07-17-------.. ... - 1111 - 1111 1111 ... ... .. ... ---- 1111 ------------- Construction Testing & Engineering, Inc. Inspection I Testing I Geotechnical I Environmental & Construction Engineering I Civil Engineering I Surveying July 17, 2018 Tabata Family Trust C/O: WNC General Contractors, Inc. Attention: Mr. Bruce Wiegand 760 Garden View Ct., Suite 200 Encinitas, California 92024 Telephone: (760)803-2427 CTE Project No. 10-132920 R.ECF~''f4 f.) JUL 2 3 20'18 Via Email: bruce@wncommunities.com Subject: Grading Plan Sheet 2 (of 4) Review Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017-0043) 6764 Strawberry Place Carlsbad, California At End of Document R_EC()R1) COPY References: Mr. Wiegand: Date At your request, Construction Testing & Engineering, Inc. (CTE) has reviewed the referenced and attached grading plan Sheet 2 (of 4) for the referenced project. The object of our review was to identify potential conflicts with the recommendations presented in our referenced geotechnical report. It is our conclusion that the reviewed grading plans are in general conformance with recommendations presented in our referenced soils reports. Portion of the plan sheet that are approved include, but are not limited to: • Pervious paver section detail. • Paver and cutoff wall detail (including perforated pipe sizing and cross-section detail). • Cross Section A gravity retaining wall (including distance to structure). • Cross Section B deepened column footing to obtain minimum distance to daylight. • Permeable Pavers adjacent to structure (pavers and sub grade sloped away from structure). Should you have any questions or need further information please do not hesitate to contact this office. Respectfully submitted, CONSTRUCTION TESTING & ENGINEERING, INC. Dan T. Math, GE #2665 Principal Engineer Rodney J. Jones, RCE# 84232 Project Engineer 1441 Montiel Road, Suite 115 I Escondido, CA 92026 I Ph (760) 746-4955 I Fax (760) 746-9806 www.cte-inc.net CJJ.j) /w-2lt' --... -----------------... ---------------- Grading Plan Sheet 2 (of 4) Review Page2 Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017-0043) 6764 Strawberry Place, Carlsbad, California July 17, 2018 References: Update Geotechnical Recommendations for Proposed Tabata Ranch Subdivision Lot-4 Lemon Leaf Drive, Carlsbad California CTE Job No. 10-132920 CTE Project No. 10-132920, dated August 26, 2016 (revised Mar 5, 2018) Interim As-Graded Geotechnical Report Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California CTE Project No. 10-12101G, dated August 2, 2015 Transfer of Geotechnical Responsibility Letter Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California CTE Project No. 10-12101G, dated July 1, 2014 Geotechnical and Update Report and Grading Plan Review Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California Vinje & Middleton Engineering Job# 01-364-P, dated August 2, 2006 Preliminary Geotechnical Investigation Proposed 4-Lot Subdivision, Tabata Ranch Off Camino De Las Ondas and Lonicera Street, Carlsbad, California Vinje & Middleton Engineering Job# 01-364-P, dated October 24, 2001 Minor Grading Plan For: Evelyn Tabata Residence Lot 4-Tabata Ranch Carlsbad, CA-Project No. CDP16-26 Sheet 2 of 4 DWG No. 471-9F Rancho Coastal Engineering & Surveying, dated 04/21/2016 (Attached) \\ESC_SERVER\Projects\10-13000 to 10-13999 Projects\10-13292G\Ltr_plan Review -Lot 4.doc --... --.... ... -------... ---... ---------------- -- Construction Testing & Engineering, Inc . Inspection I Testing I Geotechnical I Environmental & Construction Engineering I Civil Engineering I Surveying July 12, 2018 Tabata Family Trust C/0: WMC General Contractors, Inc. Attention: Mr. Bruce Wiegand 760 Garden View Ct., Suite 200 Encinitas, California 92024 Telephone: (760)803-2427 CTE Project No. 10-132920 Via Email: bruce@wncommunities.com Subject: Response to City of Carlsbad Comments (July 9, 2018) CDP16-26 Evelyn Tabata Residence-Lot 4, 2nd PC (DWG 471-9F) and 1st review of soils report Proposed Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017-0043) 6764 Strawberry Place Carlsbad California References: At End of Document Mr. Wiegand: Presented herein is our response to the City of Carlsbad's Comments based on review of the soils report. To facilitate review of this document, responses are presented in the order of the City comments: Issue No. 1: Review the project grading/foundation plans, provide any additional geotechnical recommendations considered necessary, and confirm that the plans have been prepared in accordance with the geotechnical recommendations. Response to Issue No. 1: As stated in the referenced and attached previously submitted "Grading and Foundation Plan Review -Lot 4" letter, project grading/foundations plans have been reviewed and approved. The object of our review was to identify potential conflicts with the recommendations presented in the referenced geotechnical documents. It is our conclusion that the reviewed plans are in general conformance with recommendations presented in the referenced soils documents. No additional geotechnical recommendations are considered necessary. 1441 Montiel Road, Suite 115 Escondido, CA 92026 Ph (760) 746-4955 Fax (760) 746-9806 I www.cte-inc.net -.. .. -.. -.. ----- """ ------------------------- Response to City of Carlsbad Comments (July 9, 2018) Page 2 CDP16-26 Evelyn Tabata Residence-Lot 4, 2nd PC (DWG 471-9F) and 1st review of soils report Propsed Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017-0043) 6764 Strawberry Place, Carlsbad California July 12, 2018 CTE Job No.: 10-132920 Issue No. 2: Provide seismic design category . Response to Issue No. 2: According to the table below presented by ASCE 7-10 in combination with the site specific seismic parameters of Sos (0.780g) and Sm (0.447g), the seismic design category is D. TABLE 11.1-1 SEISIIIC DESIGN CATEGORY BASED ON SHORT PEIIOD RESPONSE ACCB.ERATION PARAIIETER ,. -.. .... ·-· ■ .. Sos <0.167 A A A 0.167 :: Sas < 0.33 B B C 0.33 ~ Sos < 0.50 C C D 0.50 < Sos D D D TABLE 11.1-2 8EWIC DESIGN CATEGORY BASED ON 1-S PERIOD RESPONSE ACCB.ERATION PARAMETER OCCHMNCYCAl'EGORY ,... ..... ·-· • IV Sot< 0.067 A A A 0.067 < Soi < 0.133 B B C 0.133:: S01 < 0.20 C C D 0.20 < S01 D D D Issue No. 3: Provide a statement with respect to the feasibility of the proposed grading and construction. Response to Issue No. 3: CTE concludes that the proposed improvements at the site are feasible from a geotechnical standpoint, provided the recommendations in the referenced geotechnical documents are incorporated into the design and construction of the project Issue No. 4: Provide a statement with respect to the impact of the proposed grading and construction on adjacent properties. Response to Issue No. 4: CTE concludes that the proposed improvements will not impact adjacent properties from a geotechnical standpoint, provided the recommendations in the referenced geotechnical documents are incorporated into construction of the project. Surface drainage is not considered a geotechnical aspect and should be appropriately designed by the project civil engineer of record. \\ESC_SERVER\Projects\10-13000 to 10-13999 Projects\l0-13292G\Ltr_Response to Comments Lot 4.doc ---.... -... -... ----------------------- ------ Response to City of Carlsbad Comments (July 9, 2018) Page 3 CDP16-26 Evelyn Tabata Residence-Lot 4, 2nd PC (DWG 471-9F) and 1st review of soils report Propsed Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017-0043) 6764 Strawberry Place, Carlsbad California July 12, 2018 CTE Job No.: 10-13292G Issue No. 5: Provide recommendations for temporary excavations necessary to facilitate proposed grading and retaining wall construction . Response to Issue No. 5: Recommendations for temporary excavations necessary to facilitate proposed grading and retaining wall construction were included in the original geotechnical report (Vinje & Middleton Engineering, Inc. Job #01-364-P, Section VII-A-4, 2001 [attached for convenience]) approved by the referenced update recommendations letter (CTE, revised 2018). Recommendations as also presented below. • Construction slopes required during removal operations should not exceed ¼: 1 gradients maximum (This is considered appropriate for non-fractured, native soft-rock material). • Previously placed fill and disturbed or fractured native soils should be cut at a 1: 1 ratio for temporary construction excavations. In addition, actual field conditions and soil type designations must be verified by a "competent person" while excavations exist, according to Cal-OSHA regulations. In addition, the above sloping recommendations do not allow for surcharge loading at the top of slopes by vehicular traffic, equipment or materials. Appropriate surcharge setbacks must be maintained from the top of all unshored slopes. Issue No. 6: Provide foundation and slab recommendations for the proposed structure. Response to Issue No. 6: Recommendations for foundation and slab recommendations were included in the original geotechnical report (Vinje & Middleton Engineering, Inc. Job #01-364- P, Section VII-Band VII-D, 2001 [attached for convenience]) approved by the referenced update recommendations letter (CTE, revised 2018). Issue No. 7: Provide recommendations for proposed hardscape. Response to Issue No. 7: Recommendations for hardscape were included in the original geotechnical report (Vinje & Middleton Engineering, Inc. Job #01-364-P, Section VII-C, 2001 [attached]) approved by the referenced update recommendations letter (CTE, revised 2018). Issue No. 8: Provide a list of recommended geotechnical observations and testing during the proposed grading and construction. Response to Issue No. 8: • Bottom of excavations should be inspected by a CTE geotechnical representative prior to fill placement. • CTE should observe and test all backfill placement and compaction. • All temporary excavations should be observed and approved by a qualified competent person. \\ESC_SERVER\Projects\10-13000 to 10-13999 Projects\l0-l3292G\Ltr_Response to Comments Lot 4.doc .. .. -----... ------------------------- ---- Response to City of Carlsbad Comments (July 9, 2018) Page 4 CDP16-26 Evelyn Tabata Residence -Lot 4, 2nd PC (DWG 471-9F) and 1st review of soils report Propsed Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017-0043) 6764 Strawberry Place, Carlsbad California July 12, 2018 CTE Job No.: 10-132920 • A CTE representative should inspect all foundations excavations to ensure adequate embedment and confirm competent bearing . • All foundation and slab reinforcement should be inspected and approved by a CTE representative. We appreciate the opportunity to be of service on this project. Should you have questions, please contact the undersigned at your convenience. Respectfully submitted, CONSTRUCTION TESTING & ENGINEERING, INC. ~ Dan T. Math, GE# 2665 Principal Engineer Rodney J. Jones, RCE #84232 Project Engineer RJJ/DTM/JFL:nri 11.f-r-- Jay F. Lynch, CEG #1890 Principal Engineering Geologist \\ESC_SERVER\Projects\10-13000 to 10-13999 Projects\10-13292G\Ltr_Response to Comments Lot 4.doc --... -... --------------------------------- Response to City of Carlsbad Comments (July 9, 2018) Page 5 CDP16-26 Evelyn Tabata Residence-Lot 4, 2nd PC (DWG 471-9F) and 1st review of soils report Propsed Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017-0043) 6764 Strawberry Place, Carlsbad California July 12, 2018 CTE Job No.: 10-132920 Attachments: -Referenced Geotechnical Documents and Plans -City of Carlsbad Review Comments CDP16-26 Evelyn Tabata Residence -Lot 4, 2nd PC (DWG 4 71-9F) and 1st review of soils report -Foundation and Grading Plan Review Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017- 0043) 6764 Strawberry Place, Carlsbad, California, CTE Project No. 10-132920, dated March 26,2018 -Update Geotechnical Recommendations for Proposed Tabata Ranch Subdivision Lot-4, Lemon Leaf Drive, Carlsbad California, CTE Project No. 10-132920, dated August 26, 2016 (revised Mar 5, 2018) -Geotechnical and Update Report and Grading Plan Review, Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California, Vinje & Middleton Engineering Job# 01-364-P, dated August 2, 2006 -Preliminary Geotechnical Investigation, Proposed 4-Lot Subdivision, Tabata Ranch, Off Camino De Las Ondas and Lonicera Street, Carlsbad, California, Vinje & Middleton Engineering Job# 01-364-P, dated October 24, 2001 \\ESC_SERVER\Projects\10-13000 to 10-13999 Projects\l0-13292G\Ltr_Response to Comments Lot 4.doc -... -----... ------------------------------ REFERENCES Foundation and Grading Plan Review Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017-0043) 6764 Strawberry Place, Carlsbad, California CTE Project No. 10-132920, dated March 26, 2018 Update Geotechnical Recommendations for Proposed Tabata Ranch Subdivision Lot-4 Lemon Leaf Drive, Carlsbad California CTE Project No. 10-132920, dated August 26, 2016 (revised Mar 5, 2018) Interim As-Graded Geotechnical Report Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California CTE Project No. 10-121010, dated August 2, 2015 Transfer of Geotechnical Responsibility Letter Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California CTE Project No. 10-121010, dated July 1, 2014 Geotechnical and Update Report and Grading Plan Review Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California Vinje & Middleton Engineering Job# 01-364-P, dated August 2, 2006 Preliminary Geotechnical Investigation Proposed 4-Lot Subdivision, Tabata Ranch Off Camino De Las Ondas and Lonicera Street, Carlsbad, California Vinje & Middleton Engineering Job# 01-364-P, dated October 24, 2001 Minor Grading Plan For: Evelyn Tabata Residence Lot 4-Tabata Ranch Carlsbad, CA-Project No. CDP16-26 (Sheets 1-4) Rancho Coastal Engineering & Surveying, dated 04/21/2016 Structural Plans, Tabata Ranch -Lot 4 (Foundations) 6764 Strawberry Place, Carlsbad, California HTK Structural Engineers, LLP Job No 17-748 dated 2/9/2018 \\ESC _SERVER\Projects\l 0-13000 to 10-13999 Projects\l0-13292G\Ltr _ Response to Comments Lot 4.doc ----CITY OF CARLSBAD REVIEW COMMENTS -----.... ---------------------------\\ESC _ SERVER\Projects\10-13000 to 10-13999 Projects\l 0-13292O\Ltr _ Response to Comments Lot 4.doc - .. ... -.. -... -... ------------------------- --- «~ CITY OF ~ CARLSBAD Community & Economic Development July 9, 2018 Rancho Coastal Engineering and Surveying, Inc. Attn: Doug Logan 310 S. Twin Oaks Valley Rd, #107-297 San Marcos, CA 92078 Attn: Mr. Logan: FROM: Jennifer Horodyski, City of Carlsbad project engineer SUBJECT: CDP16-26 Evelyn Tabata Residence-Lot 4, 2nd PC (DWG 471-9F) and 1st review of the soils report In addition to the 2nd plan check comments already returned to you, please have the soils engineer address the following comments pertaining to the "Update Geotechnical Recommendations for Proposed Tabata Subdivision Lot 4, Lemon Leaf Drive, Carlsbad, California" by Construction Testing & Engineering, Inc., dated August 26, 2016 (revised March 5, 2018) and "Interim As-Graded Geotechnical Report, Proposed Tabata Ranch Subdivision, Lemon Leaf Drive, Carlsbad, California" by Construction Testing & Engineering, Inc., dated July 6, 2015 (modified August 2, 2015) with your next submittal for plan check: 1. Review the project grading/foundation plans, provide any additional geotechnical recommendations considered necessary, and confirm that the plans have been prepared in accordance with the geotechnical recommendations. 2. Provide the seismic design category. 3. Provide a statement with respect to the feasibility of the proposed grading and construction. 4. Provide a statement with respect to the impact of the proposed grading and construction on adjacent properties. 5. Provide recommendations for temporary excavations necessary to facilitate proposed grading and retaining wall construction. 6. Provide foundation and slab recommendations for the proposed structure. 7. Provide recommendations for proposed hardscape. 8. Provide a list of recommended geotechnical observation and testing during proposed grading and construction. --------------------------- -------- To facilitate review of the response to this geotechnical review, the Consultant should respond to each comment individually in a separate letter rather than updating the report. If you have any questions, you may contact me at 760-602-2747 or jennifer.horodyski@carlsbadca.gov Sincerely, Jennifer Horodyski Assistant Engineer ----FOUNDATION AND GRADING PLAN REVIEW {CTE 2018) --------------------------------\\ESC_SERVER\Projects\10-13000 to 10-13999 Projects\10-13292O\Ltr_Response to Comments Lot 4.doc .. -------------------------- - -... - .. - Construction Testing & Engineering, Inc. Inspection I Testing I Geotechnical I Environmental & Construction Engineering I Civil Engineering I Surveying March 26, 2018 Tabata Family Trust C/O: WNC General Contractors, Inc. Attention: Mr. Bruce Wiegand 760 Garden View Ct., Suite 200 Encinitas, California 92024 Telephone: (760)803-2427 CTE Project No. 10-132920 Via Email: bruce@wncommunities.com Subject: Foundation and Grading Plan Review Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017-0043) 6764 Strawberry Place Carlsbad, California References: At End of Document Mr. Wiegand: At your request, Construction Testing & Engineering, Inc. (CTE) has reviewed the foundation and grading plans for the referenced project. The object of our review was to identify potential conflicts with the recommendations presented in our referenced geotechnical report. It is our conclusion that the reviewed grading and foundation plans are in general conformance with recommendations presented in our referenced soils reports. Should you have any questions or need further information please do not hesitate to contact this office. Respectfully submitted, CONSTRUCTION TESTING & ENGINEERING, INC. Dan T. Math, GE #2665 Principal Engineer Rodney J. Jones, RCE# 84232 Project Engineer 1441 Montiel Road, Suite 115 Escondido, CA 92026 I Ph (760) 746-4955 I Fax (760) 746-9806 I www.cte-inc.net -... - 111111 - 111111 --------------------- --- .. • • • Foundation and Grading Plan Review Page2 Evelyn Tabata Residence Lot 4-Tabata Ranch (PC2017-0043) 6764 Strawberry Place, Carlsbad, California March 26. 2018 References: Update Geotechnical Recommendations for Proposed Tabata Ranch Subdivision Lot-4 Lemon Leaf Drive, Carlsbad California CTE Job No. 10-132920 CTE Project No. 10-132920, dated August 26, 2016 (revised Mar 5, 2018) Interim As-Graded Geotechnical Report Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California CTE Project No. 10-121010, dated August 2, 2015 Transfer of Geotechnical Responsibility Letter Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California CTE Project No. 10-121010, dated July 1, 2014 Geotechnical and Update Report and Grading Plan Review Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California Vinje & Middleton Engineering Job# 01-364-P, dated August 2, 2006 Preliminary Geotechnical Investigation Proposed 4-Lot Subdivision, Tabata Ranch Off Camino De Las Ondas and Lonicera Street, Carlsbad, California Vinje & Middleton Engineering Job# 01-364-P, dated October 24, 2001 Minor Grading Plan For: Evelyn Tabata Residence Lot 4-Tabata Ranch Carlsbad, CA-Project No. CDP16-26 (Sheets 1-4) Rancho Coastal Engineering & Surveying, dated 04/21/2016 Structural Plans, Tabata Ranch -Lot 4 (Foundations) 6764 Strawberry Place, Carlsbad, California HTK Structural Engineers, LLP Job No 17-748 dated 2/9/2018 \\ESC _SERVER\Projects\10-13000 to I 0-13999 Projects\I0-13292G\Ltr _ Grading and Foundation Plan Review -Lot 4.doc --.. -... --... ------------------- --- - • .. • .. UPDATE GEOTECHNICAL RECOMMENDATIONS FOR PROPOSED TABATA RANCH SUBDIVISION LOT-4 (CTE 2016, REVISED 2018) \ \ESC _ SERVER\Projects\10-13000 to I 0-13999 Projects\ I 0-13292G\Ltr _ Response to Comments Lot 4.doc -.... -... Construction Testing & Engineering, Inc . -Inspection I Testing I Geotechnical I Environmental & Construction Engineering I Civil Engineering I Surveying --August 26, 2016 (Revised March 5, 2018) CTE Project No. 10-13292G - -Tabata Family Trust ---------------------- .. .. .. .. C/O: WMC General Contractors, Inc. Attention: Mr. Bruce Wiegand 760 Garden View Ct., Suite 200 Encinitas, California 92024 Telephone: (760)803-2427 Via Email: bruce@wncommunities.com Subject: Update Geotechnical Recommendations for Proposed Tabata Ranch Subdivision Lot-4 Lemon Leaf Drive Carlsbad California References: At end of document Mr. Wiegand: In accordance with your request, Construction Testing & Engineering, Inc. (CTE) has completed a review of the previously prepared geotechnical reports and documentation for Lot 4 at the subject site, as referenced herein. We also visited the site on August 23, 2016 to confirm current conditions. Recommendations are based on prior site documentation referenced herein, new and/or updated regulatory requirements, review of current site conditions, and the scope of work we agreed to perform at this time. Based on the project improvement plans, the proposed construction is to consist of a two-story, light- framed, residential structure with conventional continuous and/or spread footings. Associated utilities, flatwork, paving, landscaping, and other minor improvements may also be constructed. CTE has found the recommendations in the referenced geotechnical documents to be in compliance with common geotechnical engineering practices and should be considered valid unless revised herein. However, CTE reserves the right to further modify recommendations and/or provide additional recommendations based on the actual conditions encountered at the site during earthwork and/or construction. Updated seismic loading parameters are also provided herein in accordance with the requirements of the current California Building Code. Updated standard grading recommendations (Appendix D) are also attached herewith, though additional grading is anticipated to be relatively mmor . 1441 Montiel Road, Suite 115 I Esoondido, CA92026 I Ph (760)746-4955 I Fax (760) 746-9806 I www.cte-inc.net ... .... -.... -... ----------------------- -.. • Update Geotechnical Recommendations Proposed Tabata Ranch Subdivision Lot-4 Lemon Leaf Drive, Carlsbad California August 26, 2016 (Revised March 5, 2018) Page2 CTE Job No. 10-132920 Based on our review, the existing building pad at the subject site was previously graded in accordance with the referenced reports. It appears that site conditions have remained generally consistent to those described in the original and as-graded reports. Significant changes, distress, and/or erosion in the building pad areas was not noted. Therefore, based on this information and on reference review, we provide the following update recommendations. 1.0 SITE PREPARATION Based on the limited preliminary plans and information provided, as well as our understanding of the proposed development, the following remedial recommendations are believed to be appropriate at this time. All proposed building footprints and other distress sensitive improvement areas should be cleared of existing vegetation, construction debris, stockpiled, deleterious, and other loose materials. Objectionable materials, such as construction debris and vegetation, not suitable for structural backfill should be properly disposed of offsite. Following removal of loose and unsuitable soils and approval from the geotechnical representative, exposed areas should be scarified a minimum of eight inches, moisture conditioned, and compacted to a minimum relative compaction of 90 percent, as evaluated by ASTM D 1557, at a minimum two percent above optimum. Fill and backfill should be compacted to a minimum relative compaction of 90 percent as evaluated by ASTM D 1557, at a minimum two percent above optimum. Minimum relative compaction of 95 percent (per ASTM D-1557) should be conducted for the minimum top 12 inches of subgrade beneath proposed pavement and drive areas, and for all/any aggregate base. The optimum lift thickness for backfill soil will depend on the type of compaction equipment used. Generally, fill soil should be placed in uniform lifts not exceeding eight inches in loose thickness. Fill placement and compaction should be performed in overall conformance with the geotechnical recommendations and project specifications in conformance with local ordinances. A CTE geotechnical representative should observe and test the bottom of overexcavation and compaction of soils within the proposed building footprints and other distress sensitive improvement areas. 2.0 SEISMIC LOADING PARAMETERS The seismic ground motion values listed in the table below were derived in accordance with the ASCE 7-10 Standard that is incorporated into the California Building Code, 2016. This was accomplished by establishing the Site Class based on the soil properties at the site, and then calculating the site coefficients and parameters using the United States Geological Survey Seismic Design Maps application. These values are intended for the design of structures to resist the effects of earthquake ground motions. \\ESC_SERVER\Projects\10-13000 to 10-13999 Projects\10-13292G\Ltr_Update Recommendations Lot 4 -10-13292G.doc .... -------------------------- - - - ... .. Update Geotechnical Recommendations Proposed Tabata Ranch Subdivision Lot-4 Lemon Leaf Drive, Carlsbad California August 26, 2016 (Revised March 5, 2018) TABLE2.0 SEISMIC GROUND MOTION V ALOES 2013 CBC AND ASCE 7-10 PARAMETER VALUE Site Class D Mapped Spectral Response 1.108g Acceleration Parameter, Ss Mapped Spectral Response 0.426g Acceleration Parameter, S1 Seismic Coefficient, Fa 1.057 Seismic Coefficient, Fv 1.574 MCE Spectral Response 1.171g Acceleration Parameter, SMs MCE Spectral Response 0.671g Acceleration Parameter, SM1 Design Spectral Response 0.780g Acceleration, Parameter Sos Design Spectral Response 0.447g Acceleration, Parameter S01 Peak Ground Acceleration PGAM 0.466g Page 3 CTE Job No. 10-13292G : CBC REFERENCE (2016) ASCE 7, Table 20.3-1 Figure 1613.3.1 (1) Figure 1613.3.1 (2) Table 1613.3.3 (1) Table 1613.3.3 (2) Section 1613.3.3 Section 1613.3.3 Section 1613.3.4 Section 1613.3.4 ASCE 7, Section 11.8.3 3.0 FOUNDATION WALL AND SLOPE SETBACK Footings for structures should be designed such that the horizontal distance from the face of adjacent descending slopes to the outer edge of the footing is a minimum of 10 feet. In addition, foundations should bear beneath an imaginary 1: 1 plane extended up from the nearest bottom edge of adjacent parallel trenches or excavations located within 10 feet. Deepening of affected footings should be a suitable means of attaining the prescribed setbacks. In addition, footings located adjacent to retaining walls should bear beneath an imaginary 1: 1 plane extending upward from the base of the wall retaining soil in order to minimize additional surcharge load to the wall itself. 4.0 WALLS BELOW GRADE If retaining walls are to be constructed in association with the proposed development, the following parameters are anticipated to be applicable. For the design of subterranean walls where the surface of the backfill is level, it may be assumed that the soils will exert a lateral pressure equal to that developed by a fluid with a density of 35 pcf. The active pressure should be used for walls free to yield at the top at least 0.2 percent of the wall height. For walls restrained so that such movement is not permitted, an equivalent fluid pressure of 60 pcf should be used, based on at-rest soil conditions. The recommended \\ESC_SERVER\Projects\10-13000 to 10-13999 Projects\10-13292G\Ltr_Update Recommendations Lot 4 -10-13292G.doc Update Geotechnical Recommendations Proposed Tabata Ranch Subdivision Lot-4 Lemon Leaf Drive, Carlsbad California August 26, 2016 (Revised March 5, 2018) Page4 CTE Job No. 10-132920 equivalent fluid pressures should be increased according to Table 4.0 below for walls retaining soils inclined at 2: 1 (horizontal: vertical). Walls below the water level are not anticipated for the subject site. In addition to the recommended earth pressure, subterranean structure walls adjacent to traffic loads should be designed to resist a uniform lateral pressure of 100 psf. This is the result of an assumed 3 00- psf surcharge behind the walls due to normal street traffic. If the traffic is kept back at least 10 feet or a distance equal to the retained soil height from the subject walls, whichever is less, the traffic surcharge may be neglected. The project architect or structural engineer should determine the necessity of waterproofing retaining walls to reduce moisture infiltration. Retaining wall backfill located within a 45-degree wedge extending up from the heel of the wall should consist of soil having an Expansion Index of 30 or less (ASTM D 4829) with less than 30 percent passing the No. 200 sieve. The upper 12 to 18 inches of wall backfill should consist of lower permeability soils, in order to reduce surface water infiltration behind walls. The project structural engineer and/or architect should detail proper wall backdrains, including gravel drain zones, fills, filter fabric and perforated drain pipes. TABLE4.0 EQUIVALENT FLUID UNIT WEIGHTS (pounds per cubic foot) SLOPE BACKFILL WALL TYPE LEVEL BACKFILL 2: 1 (HORIZONTAL: VERTICAL) CANTILEVER WALL 35 45 (YIELDING) RESTRAINED WALL 60 80 Lateral pressures on cantilever retaining walls (yielding walls) due to earthquake motions may be calculated based on work by Seed and Whitman (1970). The total lateral thrust against a properly drained and backfilled cantilever retaining wall above the groundwater level can be expressed as: For non-yielding ( or "restrained") walls, the total lateral thrust may be similarly calculated based on work by Wood (1973): Where PA= Static Active Thrust (given previously Table 4.0) PK= Static Restrained Wall Thrust (given previously Table 4.0) ~p AE = Dynamic Active Thrust Increment= (3 /8) kh yH2 ~PKE = Dynamic Restrained Thrust Increment= kh yH2 \\ESC _SERVER\Projects\ I 0-1 3000 to I 0-13999 Projects\! 0-1 3292O\Ltr _ Update Recommendations Lot 4 - I 0-1 32920 .doc -----.. -.. -.. -.. --------------.. ---- --.. .. Page 5 Update Geotechnical Recommendations Proposed Tabata Ranch Subdivision Lot-4 Lemon Leaf Drive, Carlsbad California August 26. 2016 (Revised March 5. 2018) CTE Job No. 10-13292G kh = 2/3 Peak Ground Acceleration= 2/3 (PG.AM) H = Total Height of the Wall y = Total Unit Weight of Soil::::: 135 pounds per cubic foot The increment of dynamic thrust in both cases should be distributed triangularly with a line of action located at H/3 above the bottom of the wall (SEAOC, 2013). These values assume non-expansive backfill and free-draining conditions. Measures should be taken to prevent moisture buildup behind all retaining walls. Drainage measures should include free-draining backfill materials and sloped, perforated drains, as designed and detailed by the wall engineer or architect of record. These drains should discharge to an appropriate off-site location. Any necessary waterproofing should be as specified by the project architect. 5.0 LIMITATIONS As indicated, the updated recommendations herein are based on our evaluation performed to date and could require modification as project improvement plans further progress and/or based on conditions encountered during construction. The field evaluation and geotechnical analysis referenced in our geotechnical documents was conducted according to current engineering practice and the standard of care exercised by reputable Geotechnical Consultants performing similar tasks in this area. No other warranty, expressed or implied, is made regarding the conclusions, recommendations and opinions expressed. Variations may exist and conditions not observed or described may be encountered during construction. Our conclusions and recommendations are based on an analysis of the observed conditions. If conditions different from those described are encountered, our office should be notified and additional recommendations, if required, will be provided upon request. We appreciate the opportunity to be of service on this project. Should you have questions, please contact the undersigned at your convenience. Respectfully submitted, CONSTRUCTION TESTING & ENGINEERING, INC. ~ Dan T. Math, GE #2665 Principal Engineer Rodney J. Jones, RCE #84232 Project Engineer RJJ/JFL/DTM:nri Appendix D Standard Grading Recommendations \\ESC_SERVER\Projects\10-13000 to 10-13999 Projects\10-13292O\Ltr_Update Recommendations Lot 4-10-13292O.doc -... .. .. .. ... ... ... ... ... .... --------------------.. - .. -.. Update Geotechnical Recommendations Proposed Tabata Ranch Subdivision Lot-4 Lemon Leaf Drive, Carlsbad California August 26, 2016 (Revised March 5, 2018) Page 6 CTE Job No. 10-132920 References: Interim As-Greaded Geotechnical Report Proposed Tabata Ranch Subdivision Lemon Leaf Drive Carlsbad, California CTE Project No. 10-12101G, dated August 2, 2015 Lot 3 Subdrain Recommendations and Elimination of Retaining Wall Proposed Tabata Ranch Subdivision Lemon Leaf Drive Carlsbad California CTE Project No. 10-12101G, dated July 14, 2014 Transfer of Geotechnical Responsibility Letter Proposed Tabata Ranch Subdivision Lemon Leaf Drive Carlsbad, California CTE Project No. 10-12101G, dated July 1, 2014 Geotechnical and Update Report and Grading Plan Review Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California Vinje & Middleton Engineering Job# 01-364-P, dated August 2, 2006 Preliminary Geotechnical Investigation Proposed 4-Lot Subdivision, Tabata Ranch Off Camino De Las Ondas and Lonicera Street, Carlsbad, California Vinje & Middleton Engineering Job# 01-364-P, dated October 24, 2001 \\ESC_SERVER\Projects\10-13000 to 10-13999 Projects\10-13292O\Ltr_Update Recommendations Lot 4 -10-13292O.doc ... ... - 1111 - --... -... -... ---------------------- -- APPENDIXD STANDARD SPECIFICATIONS FOR GRADING -... -.. -----... ----------- ------------... -- Appendix D Page D-1 Standard Specifications for Grading Section 1 -General Construction Testing & Engineering, Inc. presents the following standard recommendations for grading and other associated operations on construction projects. These guidelines should be considered a portion of the project specifications. Recommendations contained in the body of the previously presented soils report shall supersede the recommendations and or requirements as specified herein. The project geotechnical consultant shall interpret disputes arising out of interpretation of the recommendations contained in the soils report or specifications contained herein. Section 2 -Responsibilities of Project Personnel The geotechnical consultant should provide observation and testing services sufficient to general conformance with project specifications and standard grading practices. The geotechnical consultant should report any deviations to the client or his authorized representative. The Client should be chiefly responsible for all aspects of the project. He or his authorized representative has the responsibility of reviewing the findings and recommendations of the geotechnical consultant. He shall authorize or cause to have authorized the Contractor and/or other consultants to perform work and/or provide services. During grading the Client or his authorized representative should remain on-site or should remain reasonably accessible to all concerned parties in order to make decisions necessary to maintain the flow of the project. The Contractor is responsible for the safety of the project and satisfactory completion of all grading and other associated operations on construction projects, including, but not limited to, earth work in accordance with the project plans, specifications and controlling agency requirements. Section 3 -Preconstruction Meeting A preconstruction site meeting should be arranged by the owner and/or client and should include the grading contractor, design engineer, geotechnical consultant, owner's representative and representatives of the appropriate governing authorities. Section 4 -Site Preparation The client or contractor should obtain the required approvals from the controlling authorities for the project prior, during and/or after demolition, site preparation and removals, etc. The appropriate approvals should be obtained prior to proceeding with grading operations. STANDARD SPECIFICATIONS OF GRADING Page 1 of 26 -.... .... -... -.... -.... ---.... --------------------.. .. -- Appendix D Page D-2 Standard Specifications for Grading Clearing and grubbing should consist of the removal of vegetation such as brush, grass, woods, stumps, trees, root of trees and otherwise deleterious natural materials from the areas to be graded. Clearing and grubbing should extend to the outside of all proposed excavation and fill areas . Demolition should include removal of buildings, structures, foundations, reservoirs, utilities (including underground pipelines, septic tanks, leach fields, seepage pits, cisterns, mining shafts, tunnels, etc.) and other man-made surface and subsurface improvements from the areas to be graded. Demolition of utilities should include proper capping and/or rerouting pipelines at the project perimeter and cutoff and capping of wells in accordance with the requirements of the governing authorities and the recommendations of the geotechnical consultant at the time of demolition . Trees, plants or man-made improvements not planned to be removed or demolished should be protected by the contractor from damage or injury. Debris generated during clearing, grubbing and/or demolition operations should be wasted from areas to be graded and disposed off-site. Clearing, grubbing and demolition operations should be performed under the observation of the geotechnical consultant. Section 5 -Site Protection Protection of the site during the period of grading should be the responsibility of the contractor. Unless other provisions are made in writing and agreed upon among the concerned parties, completion of a portion of the project should not be considered to preclude that portion or adjacent areas from the requirements for site protection until such time as the entire project is complete as identified by the geotechnical consultant, the client and the regulating agencies. Precautions should be taken during the performance of site clearing, excavations and grading to protect the work site from flooding, ponding or inundation by poor or improper surface drainage. Temporary provisions should be made during the rainy season to adequately direct surface drainage away from and off the work site. Where low areas cannot be avoided, pumps should be kept on hand to continually remove water during periods of rainfall. Rain related damage should be considered to include, but may not be limited to, erosion, silting, saturation, swelling, structural distress and other adverse conditions as determined by the geotechnical consultant. Soil adversely affected should be classified as unsuitable materials and should be subject to overexcavation and replacement with compacted fill or other remedial grading as recommended by the geotechnical consultant. STANDARD SPECIFICATIONS OF GRADING Page 2 of 26 -.... -.... - Ill,., -------------------------------- Appendix D Page D-3 Standard Specifications for Grading The contractor should be responsible for the stability of all temporary excavations. Recommendations by the geotechnical consultant pertaining to temporary excavations (e.g., backcuts) are made in consideration of stability of the completed project and, therefore, should not be considered to preclude the responsibilities of the contractor. Recommendations by the geotechnical consultant should not be considered to preclude requirements that are more restrictive by the regulating agencies. The contractor should provide during periods of extensive rainfall plastic sheeting to prevent unprotected slopes from becoming saturated and unstable. When deemed appropriate by the geotechnical consultant or governing agencies the contractor shall install checkdams, desilting basins, sand bags or other drainage control measures. In relatively level areas and/or slope areas, where saturated soil and/or erosion gullies exist to depths of greater than 1.0 foot; they should be overexcavated and replaced as compacted fill in accordance with the applicable specifications. Where affected materials exist to depths of 1.0 foot or less below proposed finished grade, remedial grading by moisture conditioning in-place, followed by thorough recompaction in accordance with the applicable grading guidelines herein may be attempted. If the desired results are not achieved, all affected materials should be overexcavated and replaced as compacted fill in accordance with the slope repair recommendations herein. If field conditions dictate, the geotechnical consultant may recommend other slope repair procedures. Section 6 -Excavations 6.1 Unsuitable Materials Materials that are unsuitable should be excavated under observation and recommendations of the geotechnical consultant. Unsuitable materials include, but may not be limited to, dry, loose, soft, wet, organic compressible natural soils and fractured, weathered, soft bedrock and nonengineered or otherwise deleterious fill materials. Material identified by the geotechnical consultant as unsatisfactory due to its moisture conditions should be overexcavated; moisture conditioned as needed, to a uniform at or above optimum moisture condition before placement as compacted fill. If during the course of grading adverse geotechnical conditions are exposed which were not anticipated in the preliminary soil report as determined by the geotechnical consultant additional exploration, analysis, and treatment of these problems may be recommended. STANDARD SPECIFICATIONS OF GRADING Page 3 of 26 .. .. .. ... .. .... -----... --------------------.. -.. --- Appendix D PageD-4 Standard Specifications for Grading 6.2 Cut Slopes Unless otherwise recommended by the geotechnical consultant and approved by the regulating agencies, permanent cut slopes should not be steeper than 2: 1 (horizontal: vertical). The geotechnical consultant should observe cut slope excavation and if these excavations expose loose cohesionless, significantly fractured or otherwise unsuitable material, the materials should be overexcavated and replaced with a compacted stabilization fill. If encountered specific cross section details should be obtained from the Geotechnical Consultant. When extensive cut slopes are excavated or these cut slopes are made in the direction of the prevailing drainage, a non-erodible diversion swale (brow ditch) should be provided at the top of the slope. 6.3 Pad Areas All lot pad areas, including side yard terrace containing both cut and fill materials, transitions, located less than 3 feet deep should be overexcavated to a depth of 3 feet and replaced with a uniform compacted fill blanket of 3 feet. Actual depth of overexcavation may vary and should be delineated by the geotechnical consultant during grading, especially where deep or drastic transitions are present. For pad areas created above cut or natural slopes, positive drainage should be established away from the top-of-slope. This may be accomplished utilizing a berm drainage swale and/or an appropriate pad gradient. A gradient in soil areas away from the top-of-slopes of 2 percent or greater is recommended. Section 7 -Compacted Fill All fill materials should have fill quality, placement, conditioning and compaction as specified below or as approved by the geotechnical consultant. 7.1 Fill Material Quality Excavated on-site or import materials which are acceptable to the geotechnical consultant may be utilized as compacted fill, provided trash, vegetation and other deleterious materials are removed prior to placement. All import materials anticipated for use on-site should be sampled tested and approved prior to and placement is in conformance with the requirements outlined. STANDARD SPECIFICATIONS OF GRADING Page 4 of 26 .. .. .. .. ... ... -... -... ... ... ... - ... ... -... ----------------- Appendix D Page D-5 Standard Specifications for Grading Rocks 12 inches in maximum and smaller may be utilized within compacted fill provided sufficient fill material is placed and thoroughly compacted over and around all rock to effectively fill rock voids. The amount of rock should not exceed 40 percent by dry weight passing the 3/4-inch sieve. The geotechnical consultant may vary those requirements as field conditions dictate . Where rocks greater than 12 inches but less than four feet of maximum dimension are generated during grading, or otherwise desired to be placed within an engineered fill, special handling in accordance with the recommendations below. Rocks greater than four feet should be broken down or disposed off-site . 7 .2 Placement of Fill Prior to placement of fill material, the geotechnical consultant should observe and approve the area to receive fill. After observation and approval, the exposed ground surface should be scarified to a depth of 6 to 8 inches. The scarified material should be conditioned (i.e. moisture added or air dried by continued discing) to achieve a moisture content at or slightly above optimum moisture conditions and compacted to a minimum of 90 percent of the maximum density or as otherwise recommended in the soils report or by appropriate government agencies . Compacted fill should then be placed in thin horizontal lifts not exceeding eight inches in loose thickness prior to compaction. Each lift should be moisture conditioned as needed, thoroughly blended to achieve a consistent moisture content at or slightly above optimum and thoroughly compacted by mechanical methods to a minimum of 90 percent of laboratory maximum dry density. Each lift should be treated in a like manner until the desired finished grades are achieved. The contractor should have suitable and sufficient mechanical compaction equipment and watering apparatus on the job site to handle the amount of fill being placed in consideration of moisture retention properties of the materials and weather conditions. When placing fill in horizontal lifts adjacent to areas sloping steeper than 5:1 (horizontal: vertical), horizontal keys and vertical benches should be excavated into the adjacent slope area. Keying and benching should be sufficient to provide at least six-foot wide benches and a minimum of four feet of vertical bench height within the firm natural ground, firm bedrock or engineered compacted fill. No compacted fill should be placed in an area after keying and benching until the geotechnical consultant has reviewed the area. Material generated by the benching operation should be moved sufficiently away from STANDARD SPECIFICATIONS OF GRADING Page 5 of 26 -------.. -.... ------------------------- -- Appendix D Page D-6 Standard Specifications for Grading the bench area to allow for the recommended review of the horizontal bench prior to placement of fill. Within a single fill area where grading procedures dictate two or more separate fills, temporary slopes (false slopes) may be created. When placing fill adjacent to a false slope, benching should be conducted in the same manner as above described. At least a 3-foot vertical bench should be established within the firm core of adjacent approved compacted fill prior to placement of additional fill. Benching should proceed in at least 3-foot vertical increments until the desired finished grades are achieved. Prior to placement of additional compacted fill following an overnight or other grading delay, the exposed surface or previously compacted fill should be processed by scarification, moisture conditioning as needed to at or slightly above optimum moisture content, thoroughly blended and recompacted to a minimum of 90 percent of laboratory maximum dry density. Where unsuitable materials exist to depths of greater than one foot, the unsuitable materials should be over-excavated. Following a period of flooding, rainfall or overwatering by other means, no additional fill should be placed until damage assessments have been made and remedial grading performed as described herein. Rocks 12 inch in maximum dimension and smaller may be utilized in the compacted fill provided the fill is placed and thoroughly compacted over and around all rock. No oversize material should be used within 3 feet of finished pad grade and within 1 foot of other compacted fill areas. Rocks 12 inches up to four feet maximum dimension should be placed below the upper 10 feet of any fill and should not be closer than 15 feet to any slope face. These recommendations could vary as locations of improvements dictate. Where practical, oversized material should not be placed below areas where structures or deep utilities are proposed. Oversized material should be placed in windrows on a clean, overexcavated or unyielding compacted fill or firm natural ground surface. Select native or imported granular soil (S.E. 30 or higher) should be placed and thoroughly flooded over and around all windrowed rock, such that voids are filled. Windrows of oversized material should be staggered so those successive strata of oversized material are not in the same vertical plane. It may be possible to dispose of individual larger rock as field conditions dictate and as recommended by the geotechnical consultant at the time of placement. STANDARD SPECIFICATIONS OF GRADING Page 6 of 26 ---... ------------------------------.. --- Appendix D Page D-7 Standard Specifications for Grading The contractor should assist the geotechnical consultant and/or his representative by digging test pits for removal determinations and/or for testing compacted fill. The contractor should provide this work at no additional cost to the owner or contractor's client. Fill should be tested by the geotechnical consultant for compliance with the recommended relative compaction and moisture conditions. Field density testing should conform to ASTM Method of Test D 1556-00, D 2922-04. Tests should be conducted at a minimum of approximately two vertical feet or approximately 1,000 to 2,000 cubic yards of fill placed. Actual test intervals may vary as field conditions dictate. Fill found not to be in conformance with the grading recommendations should be removed or otherwise handled as recommended by the geotechnical consultant. 7.3 Fill Slopes Unless otherwise recommended by the geotechnical consultant and approved by the regulating agencies, permanent fill slopes should not be steeper than 2: 1 (horizontal: vertical). Except as specifically recommended in these grading guidelines compacted fill slopes should be over-built two to five feet and cut back to grade, exposing the firm, compacted fill inner core. The actual amount of overbuilding may vary as field conditions dictate. If the desired results are not achieved, the existing slopes should be overexcavated and reconstructed under the guidelines of the geotechnical consultant. The degree of overbuilding shall be increased until the desired compacted slope surface condition is achieved. Care should be taken by the contractor to provide thorough mechanical compaction to the outer edge of the overbuilt slope surface. At the discretion of the geotechnical consultant, slope face compaction may be attempted by conventional construction procedures including backrolling. The procedure must create a firmly compacted material throughout the entire depth of the slope face to the surface of the previously compacted firm fill intercore. During grading operations, care should be taken to extend compactive effort to the outer edge of the slope. Each lift should extend horizontally to the desired finished slope surface or more as needed to ultimately established desired grades. Grade during construction should not be allowed to roll off at the edge of the slope. It may be helpful to elevate slightly the outer edge of the slope. Slough resulting from the placement of individual lifts should not be allowed to drift down over previous lifts. At intervals not STANDARD SPECIFICATIONS OF GRADING Page 7 of 26 ---... -... --------------- -------------... -- Appendix D Page D-8 Standard Specifications for Grading exceeding four feet in vertical slope height or the capability of available equipment, whichever is less, fill slopes should be thoroughly dozer trackrolled. For pad areas above fill slopes, positive drainage should be established away from the top-of-slope. This may be accomplished using a berm and pad gradient of at least two percent. Section 8 -Trench Backfill Utility and/or other excavation of trench backfill should, unless otherwise recommended, be compacted by mechanical means. Unless otherwise recommended, the degree of compaction should be a minimum of90 percent of the laboratory maximum density. Within slab areas, but outside the influence of foundations, trenches up to one foot wide and two feet deep may be backfilled with sand and consolidated by jetting, flooding or by mechanical means. If on-site materials are utilized, they should be wheel-rolled, tamped or otherwise compacted to a firm condition. For minor interior trenches, density testing may be deleted or spot testing may be elected if deemed necessary, based on review of backfill operations during construction. If utility contractors indicate that it is undesirable to use compaction equipment in close proximity to a buried conduit, the contractor may elect the utilization of light weight mechanical compaction equipment and/or shading of the conduit with clean, granular material, which should be thoroughly jetted in-place above the conduit, prior to initiating mechanical compaction procedures. Other methods of utility trench compaction may also be appropriate, upon review of the geotechnical consultant at the time of construction. In cases where clean granular materials are proposed for use in lieu of native materials or where flooding or jetting is proposed, the procedures should be considered subject to review by the geotechnical consultant. Clean granular backfill and/or bedding are not recommended in slope areas. Section 9 -Drainage Where deemed appropriate by the geotechnical consultant, canyon subdrain systems should be installed in accordance with CTE's recommendations during grading. Typical subdrains for compacted fill buttresses, slope stabilization or sidehill masses, should be installed in accordance with the specifications. STANDARD SPECIFICATIONS OF GRADING Page 8 of 26 .. -.. --------.... --------------- ---------- Appendix D Page D-9 Standard Specifications for Grading Roof, pad and slope drainage should be directed away from slopes and areas of structures to suitable disposal areas via non-erodible devices (i.e., gutters, downspouts, and concrete swales). For drainage in extensively landscaped areas near structures, (i.e., within four feet) a minimum of 5 percent gradient away from the structure should be maintained. Pad drainage of at least 2 percent should be maintained over the remainder of the site. Drainage patterns established at the time of fine grading should be maintained throughout the life of the project. Property owners should be made aware that altering drainage patterns could be detrimental to slope stability and foundation performance. Section 10 -Slope Maintenance 10.1 -Landscape Plants To enhance surficial slope stability, slope planting should be accomplished at the completion of grading. Slope planting should consist of deep-rooting vegetation requiring little watering. Plants native to the southern California area and plants relative to native plants are generally desirable. Plants native to other semi-arid and arid areas may also be appropriate. A Landscape Architect should be the best party to consult regarding actual types of plants and planting configuration. 10.2 -Irrigation Irrigation pipes should be anchored to slope faces, not placed in trenches excavated into slope faces. Slope irrigation should be minimized. If automatic timing devices are utilized on irrigation systems, provisions should be made for interrupting normal irrigation during periods of rainfall. 10.3 -Repair As a precautionary measure, plastic sheeting should be readily available, or kept on hand, to protect all slope areas from saturation by periods of heavy or prolonged rainfall. This measure is strongly recommended, beginning with the period prior to landscape planting. If slope failures occur, the geotechnical consultant should be contacted for a field review of site conditions and development of recommendations for evaluation and repair. If slope failures occur as a result of exposure to period of heavy rainfall, the failure areas and currently unaffected areas should be covered with plastic sheeting to protect against additional saturation. STANDARD SPECIFICATIONS OF GRADING Page 9 of 26 ---.. -------.. ----------------------- -- Appendix D Page D-10 Standard Specifications for Grading In the accompanying Standard Details, appropriate repair procedures are illustrated for superficial slope failures (i.e., occurring typically within the outer one foot to three feet of a slope face). STANDARD SPECIFICATIONS OF GRADING Page 10 of 26 ... .. ... .. ... .. ... ------------------------------- FINISH CUT SLOPE ------------ BENCHING FILL OVER NATURAL FILL SLOPE 10' TYPICAL SURFACE OF FIRM EARTH MATERIAL 15' MIN. (INCLINED 2% MIN. INTO SLOPE) BENCHING FILL OVER CUT FINISH FILL SLOPE SURFACE OF FIRM EARTH MATERIAL 10' TYPICAL 15' MIN OR STABILITY EQUIVALENT PER SOIL ENGINEERING (INCLINED 2% MIN. INTO SLOPE) NOT TO SCALE BENCHING FOR COMPACTED FILL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 11 of 26 -- -- - ---... ----------- ------ --- ------- -- -- - MINIMUM DOWNSLOPE KEY DEPTH TOE OF SLOPE SHOWN ON GRADING PLAN FILL ___ _ -------------..,._;;;;..,.--~ ----~~~~\~ --- --i'<'~ -- --x:.~~~ -----~~~~ ---~'2;u' ~...---------------1 ---\) ----1 O' TYPICAL BENCH // ---WIDTH VARIES ~1 ---/ 1 ----COMPETENT EARTH / --MATERIAL - 2% MIN --- 15' MINIMUM BASE KEY WIDTH TYPICAL BENCH HEIGHT PROVIDE BACKDRAIN AS REQUIRED PER RECOMMENDATIONS OF SOILS ENGINEER DURING GRADING WHERE NATURAL SLOPE GRADIENT IS 5:1 OR LESS, BENCHING IS NOT NECESSARY. FILL IS NOT TO BE PLACED ON COMPRESSIBLE OR UNSUITABLE MATERIAL. NOTTO SCALE 4' FILL SLOPE ABOVE NATURAL GROUND DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 12 of 26 111111 II II II II II II 11 II II fl fl 1111 fl fl fl U> ~ z Cl )> :D Cl U> ""C ""Cm Ill C') (C - CD !! ..... C') c,J )> 0 :::! -+, 0 1\)2 O') U) "Tl 0 :D Ci) :D )> Cl z Ci) REMOVE ALL TOPSOIL, COLLUVIUM, AND CREEP MATERIAL FROM TRANSITION CUT/FILL CONTACT SHOWN ON GRADING PLAN CUT/FILL CONTACT SHOWN ON "AS-BUILT" NATURAL~ --TOPOGRAPHY __ -------------CUT SLOPE* FILL -----------t".: --- -E.Wio....i~ ----E.~~-~ ----~oC~ --- - -D'-J\\.)Wi ~ --I --:s~\., co\.:,_ - - ----1 74' TYPICA~ ,of" --- -------2% MIN _ I " 1 0' TYPICAL 15' MINIMUM NOT TO SCALE BEDROCK OR APPROVED FOUNDATION MATERIAL *NOTE: CUT SLOPE PORTION SHOULD BE MADE PRIOR TO PLACEMENT OF FILL FILL SLOPE ABOVE CUT SLOPE DETAIL -... ... ... -----... ---... -----... ------------------ :-~-------------~ -..... ' ,,,,,,.,,,,,,,. ,'\ COMPACTED FILL /'/ \\ // \ / [ SURFACE OF COMPETENT MATERIAL TYPICAL BENCHING \ \ / '' / / .._____.... ' -/ A--"' SEE DETAIL BELOW MINIMUM 9 FP PER LINEAR FOOT OF APPROVED FILTER MATERIAL CAL TRANS CLASS 2 PERMEABLE MATERIAL FILTER MATERIAL TO MEET FOLLOWING SPECIFICATION OR APPROVED EQUAL: '.._ _ __. / REMOVE UNSUITABLE DETAIL 14" MINIMUM MATERIAL INCLINE TOWARD DRAIN AT 2% GRADIENT MINIMUM MINIMUM 4" DIAMETER APPROVED PERFORATED PIPE (PERFORATIONS DOWN) 6" FILTER MATERIAL BEDDING SIEVE SIZE PERCENTAGE PASSING APPROVED PIPE TO BE SCHEDULE 40 POLY-VINYL-CHLORIDE (P.V.C.) OR APPROVED EQUAL. MINIMUM CRUSH STRENGTH 1000 psi 1" NO.4 NO.8 NO. 30 NO. 50 NO. 200 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 PIPE DIAMETER TO MEET THE FOLLOWING CRITERIA, SUBJECT TO FIELD REVIEW BASED ON ACTUAL GEOTECHNICAL CONDITIONS ENCOUNTERED DURING GRADING LENGTH OF RUN NOTTO SCALE INITIAL 500' 500' TO 1500' > 1500' PIPE DIAMETER 4" 6" 8" TYPICAL CANYON SUBDRAIN DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 14 of 26 -.... - ... ----------------------------- --- CANYON SUBDRAIN DETAILS __ ...... .,.,.. ..... ' ,,,,,,., ,', COMPACTED FILL /~ '' /I ' / [ SURFACEOF COMPETENT MATERIAL TYPICAL BENCHING \' / '' / / --,_,,,,,, __ ...._ ' / SEE DETAILS BELOW TRENCH DETAILS 6" MINIMUM OVERLAP REMOVE UNSUITABLE MATERIAL INCLINE TOWARD DRAIN AT 2% GRADIENT MINIMUM OPTIONAL V-DITCH DETAIL MINIMUM 9 FT3 PER LINEAR FOOT OF APPROVED DRAIN MATERIAL MIRAFI 140N FABRIC OR APPROVED EQUAL 1 DRAIN MATERIAL TO MEET FOLLOWING SPECIFICATION OR APPROVED EQUAL: SIEVE SIZE PERCENTAGE PASSING 1 ½" 88-100 1" 5-40 ¾" 0-17 ¾" 0-7 NO. 200 0-3 0 24" MIRAFI 140N FABRIC OR APPROVED EQUAL MINIMUM APPROVED PIPE TO BE SCHEDULE 40 POLY- VINYLCHLORIDE (P.V.C.) OR APPROVED EQUAL. MINIMUM CRUSH STRENGTH 1000 PSI. PIPE DIAMETER TO MEET THE FOLLOWING CRITERIA, SUBJECT TO FIELD REVIEW BASED ON ACTUAL GEOTECHNICAL CONDITIONS ENCOUNTERED DURING GRADING LENGTH OF RUN INITIAL 500' 500' TO 1500' > 1500' PIPE DIAMETER 4" 6" 8" NOTTO SCALE GEOFABRIC SUBDRAIN STANDARD SPECIFICATIONS FOR GRADING Page 15 of 26 -.... -... ---... -... -... ------------------------.. FRONT VIEW 24"Min. - 6"Min. SIDE VIEW ~ 12" Min.~ 6" Min. CONCRETE 7 CUT-OFF WALL ----•:,..·_-'t .. _-6" Min. . -. -----~•-~t-.. ;-.f ... ; • .I I ... ·'·'· .1-1 ""' NOT TO SCALE RECOMMENDED SUBDRAIN CUT-OFF WALL STANDARD SPECIFICATIONS FOR GRADING Page 16 of 26 ... ... ------... -... --------------------------- FRONT VIEW SUBDRAIN OUTLET PIPE (MINIMUM 4" DIAMETER) SIDE VIEW ALL BACKFILL SHOULD BE COMPACTED IN CONFORMANCE WITH PROJECT SPECIFICATIONS. COMPACTION EFFORT SHOULD NOT DAMAGE STRUCTURE -► . .!►. -'►. _ .... 'b.''b.''b.' ~-'~.,A.., . ' -'l(J' ' I ► -'► -'►-, ,·b.. ,'r::.,. ,·b.. ~., .... ,~., ► -,. -'►-, ,, • b. • ' • b. ' ' • b. • .6. ,~ ,.6,, -·· -··-... ► -, ► - , ►-, 1, • b. • • .... b. ' ' • b. • 6,,.o..,~ .... 1----24" Min. 1----24" Min. NOTE: HEADWALL SHOULD OUTLET AT TOE OF SLOPE OR INTO CONTROLLED SURFACE DRAINAGE DEVICE ALL DISCHARGE SHOULD BE CONTROLLED THIS DETAIL IS A MINIMUM DESIGN AND MAY BE MODIFIED DEPENDING UPON ENCOUNTERED CONDITIONS AND LOCAL REQUIREMENTS NOT TO SCALE 24" Min. 12" TYPICAL SUBDRAIN OUTLET HEADWALL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 17 of 26 ---... -... -.... ---.... ------1' -2'MI ------------------- ------.-'," - 4" DIAMETER PERFORATED PIPE BACKDRAIN 4" DIAMETER NON-PERFORATED PIPE LATERAL DRAIN SLOPE PER PLAN FILTER MATERIAL 1-i : -: : i I I BENCHING AN ADDITIONAL BACKDRAIN AT MID-SLOPE WILL BE REQUIRED FOR SLOPE IN EXCESS OF 40 FEET HIGH. KEY-DIMENSION PER SOILS ENGINEER (GENERALLY 1/2 SLOPE HEIGHT, 15' MINIMUM) DIMENSIONS ARE MINIMUM RECOMMENDED NOT TO SCALE TYPICAL SLOPE STABILIZATION FILL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 18 of 26 --- -----------.... ---------------------- 4" DIAMETER PERFORATED PIPE BACKDRAIN 4" DIAMETER NON-PERFORATED PIPE LATERAL DRAIN SLOPE PER PLAN FILTER MATERIAL I .. I ! I BENCHING H/2 ; ! I . I ' ADDITIONAL BACKDRAIN AT MID-SLOPE WILL BE REQUIRED FOR SLOPE IN EXCESS OF 40 FEET HIGH. KEY-DIMENSION PER SOILS ENGINEER DIMENSIONS ARE MINIMUM RECOMMENDED NOT TO SCALE TYPICAL BUTTRESS FILL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 19 of 26 -----.... -------------------------------- 20' MAXIMUM FINAL LIMIT OF EXCAVATION OVEREXCAVATE OVERBURDEN (CREEP-PRONE) DAYLIGHT LINE OVEREXCAVATE 3' AND REPLACE WITH COMPACTED FILL COMPETENT BEDROCK TYPICAL BENCHING LOCATION OF BACKDRAIN AND OUTLETS PER SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST DURING GRADING. MINIMUM 2% FLOW GRADIENT TO DISCHARGE LOCATION. EQUIPMENT WIDTH (MINIMUM 15') NOT TO SCALE DAYLIGHT SHEAR KEY DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 20 of 26 NATURAL GROUND PROPOSED GRADING ----- --------------------COMPACTED FILL ----------------------------------------------------- PROVIDE BACKDRAIN, PER BACKDRAIN DETAIL. AN ADDITIONAL BACKDRAIN AT MID-SLOPE WILL BE REQUIRED FOR BACK SLOPES IN EXCESS OF BASE WIDTH "W" DETERMINED BY SOILS ENGINEER NOT TO SCALE 40 FEET HIGH. LOCATIONS OF BACKDRAINS AND OUTLETS PER SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST DURING GRADING. MINIMUM 2% FLOW GRADIENT TO DISCHARGE LOCATION. TYPICAL SHEAR KEY DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 21 of 26 -.... ... .... .... ... .... ... ... ... ... ... --... -... -------------------- FINISH SURFACE SLOPE 3 FT3 MINIMUM PER LINEAR FOOT APPROVED FILTER ROCK* CONCRETE COLLAR PLACED NEAT A COMPACTED FILL 2.0% MINIMUM GRADIENT A 4" MINIMUM DIAMETER SOLID OUTLET PIPE SPACED PER SOIL ENGINEER REQUIREMENTS 4" MINIMUM APPROVED PERFORATED PIPE** (PERFORATIONS DOWN) MINIMUM 2% GRADIENT TO OUTLET DURING GRADING TYPICAL BENCH INCLINED TOWARD DRAIN **APPROVED PIPE TYPE: MINIMUM 12" COVER SCHEDULE 40 POLYVINYL CHLORIDE (P.V.C.) OR APPROVED EQUAL. MINIMUM CRUSH STRENGTH 1000 PSI BENCHING DETAIL A-A OMPACTE BACKFILL 12" MINIMUM TEMPORARY FILL LEVEL MINIMUM 4" DIAMETER APPROVED SOLID OUTLET PIPE *FILTER ROCK TO MEET FOLLOWING SPECIFICATIONS OR APPROVED EQUAL: SIEVE SIZE 1" ¾" ¾" NO.4 NO. 30 NO. 50 NO. 200 PERCENTAGE PASSING 100 90-100 40-100 25-40 5-15 0-7 0-3 NOTTO SCALE TYPICAL BACKDRAIN DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 22 of 26 ---... -.... -------... -------------------- -- FINISH SURFACE SLOPE MINIMUM 3 FP PER LINEAR FOOT OPEN GRADED AGGREGATE* TAPE AND SEAL AT COVER CONCRETE COLLAR PLACED NEAT COMPACTED FILL A 2.0% MINIMUM GRADIENT A MINIMUM 4" DIAMETER SOLID OUTLET PIPE SPACED PER SOIL ENGINEER REQUIREMENTS MINIMUM 12" COVER *NOTE: AGGREGATE TO MEET FOLLOWING SPECIFICATIONS OR APPROVED EQUAL: SIEVE SIZE PERCENTAGE PASSING 1 ½" 100 1" 5-40 ¾" 0-17 ¾" 0-7 NO. 200 0-3 TYPICAL BENCHING DETAIL A-A NOT TO SCALE MIRAFI 140N FABRIC OR APPROVED EQUAL 4" MINIMUM APPROVED PERFORATED PIPE (PERFORATIONS DOWN) MINIMUM 2% GRADIENT TO OUTLET BENCH INCLINED TOWARD DRAIN TEMPORARY FILL LEVEL MINIMUM 4" DIAMETER APPROVED SOLID OUTLET PIPE BACKDRAIN DETAIL (GEOFRABIC) STANDARD SPECIFICATIONS FOR GRADING Page 23 of 26 ... ... ... .... ... ... ... ... ... ... ... ... ------------------------.. .. SOIL SHALL BE PUSHED OVER ROCKS AND FLOODED INTO VOIDS. COMPACT AROUND AND OVER EACH WINDROW . 10' 1 FILL SLOPE 1 CLEAR ZONE __/ rEOUIPMENT WIDTH__/ STACK BOULDERS END TO END. DO NOT PILE UPON EACH OTHER. 0 0 0 ~ /~~~~~~~~ / I I ,' / / ••• / .• ~OMPET~NT MAT£R1AL ' ·, I/ / ~ , NOTTO SCALE I / ROCK DISPOSAL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 24 of 26 STAGGER ROWS ... ... ... ... ... -- ---.... -.. ------------------------ STREET 10' 5' MINIMUM OR BELOW DEPTH OF DEEPEST UTILITY TRENCH (WHICHEVER GREATER) FINISHED GRADE BUILDING NO OVERSIZE, AREA FOUR FOUNDATION, UTILITIES, AND SWIMMING POOLS ~ 0 0 0 ~ 4•L-. WINDROW~ 0 TYPICAL WINDROW DETAIL (EDGE VIEW) GRANULAR SOIL FLOODED TO FILL VOIDS HORIZONTALLY PLACED COMPACTION FILL PROFILE VIEW NOT TO SCALE ROCK DISPOSAL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 25 of 26 -... ---.... -... - -----.... -----.... ---------------- GENERAL GRADING RECOMMENDATIONS --- ------ CUT LOT ----- TOPSOIL, COLLUVIUM AND _ --- WEATHERED BEDROCK --------- - ----ORIGINAL GROUND ----- 3'MIN , --UNWEATHERED BEDROCK OVEREXCAVATE AND REGRADE CUT/FILL LOT (TRANSITION) ----------COMPACTED FILL ----------.,,,...,,,...,,,..' .,,,..,-' TOPSOl~UVIUM -.,,,.. .,,,.. .,,,.. .,,,.. --AND WEATHERED -- BEDROCK .,,,.. ~ -------UNWEATHERED BEDROCK NOT TO SCALE TRANSITION LOT DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 26 of 26 _....--:: ORIGINAL .,,,..,,,,GROUND 'MIN 3'MIN OVEREXCAVATE AND REGRADE .. --... ---... -------------- 11111 ------ -------- GEOTECHNICAL AND UPDATE REPORT AND GRADING PLAN REVIEW (VINJE & MIDDLETON ENGINEERING 2006) \\ESC _SERVER\Projects\l 0-13000 to 10-13999 Projects\10-13292G\Ltr _ Response to Comments Lot 4.doc ---.... -... ... .... ----- --------------------- Geotechnical Update Report and Grading Plan Review Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad, California August 2, 2006 Prepared For: MR. GREG HARRINGTON P.O. Box 679 Carlsbad, California 92018 Prepared By: VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Suite 102 Escondido, California 92029 Job #01-364-P {/ ' 1111" ' .. .... ... ... --... ... -... ... ... ------------------------ Job #01-364-P August2,2006 Mr. Greg Harrington P.O. Box679 Carlsbad, California 92018 GE~TECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW, PROPOSED TABATA RANCH SUBDIVISION, LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA Pursuant to your request, Vinje and Middleton Engineering, Inc., has· completed the enclosed Geotechnical Update Report and Grading Plan Review for the above-referenced project site. The following report summarizes the results of our research and review of previous pertinent geotechnical reports and maps, current field inspections, additional laboratory testing and engineering analyses and provides update conclusions and recommendations for the proposed development as understood. From a geotechnical engineering standpoint, it is our opinion that the site is suitable for the planned residential subdivision provided the recommendations presented in this report are incorporated into the design and construction of the project. The conclusions and recommendations provided in this study are consistent with the indicated site geotechnical conditions and are intended to aid in preparation of final development plans and allow more accurate estimates of development costs. If you have any questions or need clarification, please do not hesitate to contact this office. Reference to our Job #01-364-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERING, INC. ~=~,.._ ___ _ CEG#980 DM~t f • -. • f .... 4 -.... -----.... ---... ------------------------ . TABLE OF CONTENTS PAGE NO. I. INTRODUC1"1ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 11. SITE DESCRIPTION / PROPOSED DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . 1 111. GEOTECHNICAL CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 A. Earth Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 B. Slope Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 C. Seismicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 D. Added Laboratory Tests .. ~-............................. _. . . . . . . . . 3 IV. SITE CORROSION ASSESSMENT ..................................... 4 V. CONCLUSIONS AND RECOMMENDATIONS ........................... 5 VI. LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 REFERENCES TABLE NO. Site Specific Seismic Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 pH and Resistivity Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . 2 Sulfate Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Chloride Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Years to Perforation of Steel Culverts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 PLATE NO. Grading Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Geologic Cross-Sections ............................................. 2-3 Key and Benching Details ............................................ 4-5 APPENDIX A Preliminary Geotechnical Investigation ................................... . Dated October 24, 2001 -, . ' . ' lat -.... ---------------------------------- GEOTECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW PROPOSED TABATA RANCH SUBDIVISION LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA I. INTRODUCTION Precise Grading Plans for the planned residential subdivision at the above-referenced property have recently been completed by Pasco Engineering. A copy of the plan is enclosed with this report as Plate 1. A previous study of the property by this office resulted in the following report of site geotechnical conditions: "Preliminary Geotechnical Investigation, Proposed 4-Lot Subdivision Tabata Ranch off Camino De Las Ondas And Lonicera Street, Carlsbad,• Job #01-364-P, dated October 24, 2001 A copy of the above-referenced report is included with this report as Appendix A. The purpose of this work was to update the enclosed report to current codes and standards and to provide additional recommendations that are compatible to the enclosed plan. Our efforts also included a recent site inspection, and additional surface ··soil sampling and laboratory testing as required by the current building industry standards. 11. SITE DESCRIPTION / PROPOSED DEVELOPMENT The scope of the planned new development is delineated on the enclosed Plate 1. The lower west portion of the property has been partially graded in connection with the recent development of the adjacent property to the west. The graded areas include much of an entrance roadway that will provide access to three of the proposed lots from Lonicera Street. The following technical reports relate to the west perimeter grading and improvements completed at the project site: 1. "Final Report of Testing and Observation Services During Site Grading, Tabata Property Driveway on Lot 35, City of Carlsbad Tract No. 98-14, Carlsbad, California", report prepared by GeoCon, dated February 8, 2006. 2. "Final Report of Testing and Observation Services During Site Grading, Thompson I Tabata Property, Phase 2, Lot No's 16 through 54, and 177 through 197, City of Carlsbad Tract No. 98.-14, Carlsbad, California", report prepared by GeoCon, dated September 30, 2004. .... -.... ---.... -.... -... ---------... -------------- .. GEOTECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW PAGE 2 LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA AUGUST 2, 2006 The above-referenced reports were reviewed in connection with this effort and copies are available at this office. Resulting elevations in the graded areas of the property are as shown on the enclosed Plate 1 and geotechnical Cross-Sections enclosed herein as Plates 2 and 3 . Other areas of the property remain the same as reported in the referenced Preliminary Geotechnical Investigation report, dated October 24, 2001. These include upper, nearly level terrain much of which presently supports a dwelling and associated structures planned for demolition. The Grading Plan (Plate 1) depicts the creation of 5 residential lots by minor to modest cut- fill grading. Slopes are programmed at 2:1 gradients and reach a maximum height of 16 feet. Access to the elevated Lots 1 and 2 will be provided from the Lemon Leaf Drive. The entrance cul-de-sac roadway will provide access to the proposed lots 3, 4 and 5 from Lonicera Street. A temporary slope is proposed at the end of the driveway on Lot 3 which will be redesigned /removed based on site adaptive architecture (see Plate 1). Building and foundation plans are not available. However, the use of conventional wood- frame with exterior stucco buildings supported on shallow foundations with stem walls and slab-on-grade floors or slab-on-ground with turned-down footings are assumed for the purpose of this update study. Ill. GEOTECHNICAL CONDITIONS Detailed site and geotechnical conditions at the project site were outlined in the referenced Preliminary Geotechnical Investigation Report. Except for the recently graded entrance roadway, surface and geotechnical conditions at the site remain the same as previously reported. A. Earth Materials The project site is underlain by Eocene age sedimentary bedrock units consisting of massive sandstone in a cemented condition. Surface terrain is mantled by a modest cover of topsoil I colluvium and old fill soils cover much of the south portion as shown on Plate 1. Much of the site surface soils will be removed by cut grading and exported from the property. Remaining surface soils will also be removed to underlying bedrock units prior to placing new fill as recommended in the referenced report. Details of site earth materials are given on the exploratory Test Trench Logs included in Appendix A (Plates 3-5). Trench locations are shown on the enclosed Plate 1. ) .. • f \. GEOTECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW PAGE 3 LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA AUGUST 2, 2006 B. Slope Stability Slope instability is not indicated in site exposures. A large graded cut slope below the south margin of the property (above nearby Poinsettia Lane) has performed well since its creation. Site bedrock units are massive sandstone deposits that characteristically perform well in graded slope conditions and provide a good support for planned new fills, structures and improvements. Existing graded slopes below the west margin of the property have recently been constructed (see Plates 1 and 2) and were inspected by others . Details of exposed conditions are outlined in the referenced reports, prepared by GeoCon, Inc. C. Sejsmicity The seismic environment at the project site is outlined in the referenced Preliminary Report enclosed with this report as Appendix A. The following supplemental evaluations were also performed based on the indicated project seismic environment, and our experience with similar earth deposits in the vicinity of the project.site; and will supersede those previously provided where appropriate and applicable: TABLE1 A site specific probabilistic estimation of peak ground acceleration was performed using the FRISKSP (T. Blake, 2000) computer program. Based upon Boore et al (1997) attenuation relationship, a 10 percent probability of exceedance in 50 years was estimated to produce a site specific peak ground acceleration of 0.30g (Design-Basis Earthquake, DBE). The results were obtained from the corresponding probability of exceedance versus acceleration curve. D. Added Laboratory Tests Added laboratory tests were conducted on representative site soil samples recently collected at the site. The following tests were completed: .. GEOTECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW PAGE 4 LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA AUGUST 2, 2006 1. pH and Resistivity Test: pH and resistivity of a representative sample of surface soils was determined using "Method for Estimating the Service Life of Steel Culverts," in accordance with the California Test Method (CTM) 643. The test result is presented in Table 2. TABLE2 2. Sulfate Test: A sulfate test was performed on a representative sample of surface soils in accordance with the California Test Method (CTM)'417. The test result is presented in Table 3. TABLE3 3. Chloride Test: A chloride test was performed on a representative sample of surface soils in accordance with the California Test Method (CTM) 422. The test result is presented in Table 4. TABLE4 IV. SITE CORROSION ASSESSMENT A site is considered to be corrosive to foundation elements, walls and drainage structures if one or more of the following conditions exist: * Sulfate concentration is greater than or equal to 2000 ppm (0.2% by weight). * Chloride concentration is greater than or equal to 500 ppm (0.05 % by weight). * pH is less than 5.5. GEOTECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW PAGE 5 LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA AUGUST 2, 2006 For structural elements, the minimum resistivity of soil (or water) indicate the relative quantity of soluble salts present in the soil (or water). In general, a minimum resistivity value for soil (or water) less than 1000 ohm-cm indicates the presence of high quantities of soluble salts and a higher propensity for corrosion. Appropriate corrosion mitigation measures for corrosive conditions should be selected depending on the service environment, amount of aggressive ion salts (chloride or sulfate), pH levels and the desired service life of the structure. Limited laboratory testing performed on selected representative site samples indicated that the minimum resistivity is less than 1000 ohm-cm suggesting presence of high quantities of soluble salts. Test results further indicated pH is greater than 5.5 and sulfate concentration is less than 2000 ppm. However, chloride concentration was found to be greater than 500 ppm. Based on the available limited corrosion analyses performed on selected samples, the project site is considered corrosive. Corrosion mitigation should be implemented and incorporated into the design of new structures and associated improvements. A corrosion engineer should be consulted in this regard and additional corrosion conformation testing may be considered at the completion of remedial grading and earthwork operations. The project site is not located within 1000 feet qf sea or brackish water. The amount of water soluble sulfate (SO4) was found to be 0.015 percent by weight which is considered negligible according to the California Building Code Table No. 19-A-4. Portland cement Type II may be considered. However, due to the site corrosiveness, Portland cement Type V (minimum f c = 4500 psi, maximum water cement ratio= 0.45) and steel reinforcement covering greater than 3 inches or as determined appropriate by the project corrosion / structural engineer should be considered. Table 5 is appropriate based on the pH-Resistivity test results: TABLES V. CONCLUSIONS AND RECOMMENDATIONS Site geotechnical conditions remain the same as reported in the referenced Preliminary Geotechnical Report (Appendix A). The Project Grading Plan (Figure 1) also represents a feasible design from a geotechnical engineering viewpoint. All conclusions and recommendations provided in the referenced report remain valid and should be considered in final designs and implemented during the construction phase except where specifically superseded below: - --------.. ----... ---------------------- .. GEOTECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW PAGE 6 LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA AUGUST 2, 2006 1. Existing graded slopes to the western portions of project property are engineered embankments constructed under engineering observations of testing provided by others. The existing cut slopes below the project south margin are also underlain by competent sandstone units with no evidence of geologic instability. New graded slopes are also programmed for 2:1 gradients and will be constructed as recommended as specified. Slope stability is not considered a major geotechnical concern at the project site. Other adverse geologic conditions including faults or significant shear zone which could preclude site development were also not indicated at the property. 2. New graded slopes to be constructed as specified in the referenced report and as directed in the field in general accordance with the enclosed Typical Key Benching Details, Plates 4 and 5. All graded slopes greater. than 30 feet in maximum vertical height should be provided with adequate drainage terraces per applicable codes and standards, unless otherwise approved or specified. 3. Excavations, trenching and temporary backcut slopes adjacent to the existing structures/foundations and improvements shall be performed under inspeot1ons of the project geotechnical engineer. Undermining existing structures/improvements and underground utilities to remain shall not be allowed by the project earthwork operations and constructions. Top of temporary construction slopes and site excavations should maintain adequate set-backs (1-foot minimum) from the existing structures and improvements as directed in the field. Project temporary construction slopes and trench excavations less than 3 feet high may constructed at near vertical gradients. Construction slopes greater than 3 feet and less than 10 feet maximum exposing dense sandstone units may be constructed at near vertical gradient within the lower 3 feet and laid back at ½:1 gradients maximum within the upper portions. The backfill soils should then be properly benched and tightly keyed into the temporary side slopes as the backfilling progresses, and as directed in the field by the project geotechnical consultant. The construction slope should be protected from rain and irrigation water. Stockpiling the removed soils atop the construction slope should also not be allowed. Periodic inspections of the temporary slopes, trench excavations and backcut embankments shall be required and should be performed by the project geotechnical consultant. The need for flatter slope gradients or shoring shall be determined at that time based on actual field exposures and should anticipated. - .. l ---.... ... ---... -----... --------------------- .. GEOTECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW PAGE 7 LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA AUGUST 2, 2006 The project contractor shall also obtain appropriate permits, as necessary, and conform to Cal-OSHA and local governing agencies for a safe construction site and protection of the workmen. Permits to perform off-site grading and earthworks, if applicable, should be obtained as appropriate and necessary. 4. Site remedial grading and proposed reconstructions is not expected to impact the adjacent properties provided our recommendations are incorporated into the field procedures and implemented during the construction phase. Added field recommendations, however, may also be necessary and should be given by the project geotechnical consultant for the protection of adjacent properties and should be anticipated. 5. Remedial grading and bearing/subgrade soils preparations will be required in all areas of the property to receive new fills, structures and improvements plus 10 feet outside the perimeter as specified in the referenced report. Approximate removal depths are also provided in the referenced report. However, specific removal depths should be given by the project geotechnical consultant in the field at the time of grading operations based on actual exposures. Locally deeper removals may be necessary and should be anticipated. Bottom of all removals should be additionally prepared and recompacted to a minimum depth of 6 inches as directed in the field. All grounds steeper than 5:1 receiving fills/backfills should be properly benched and keyed prior to fill/backfill placement. 6. Compaction procedures and fill materials specification remain the same as specified. A minimum 90% compaction levels will be required for all fills, and wall and trench backfills uhless otherwise specified. Subgrade soils beneath the asphalt paving surfaces should be compacted to a minimum 95% of the corresponding maximum dry density within the upper 12 inches. 7. Expansive soils are not expected to be a factor in the site development. Project earth materials at final pad grades are anticipated to predominantly consist of silty sandy (SM) deposits with very low expansion potential (expansion index less than 21) according to the California Building Code classification (Table 18A-I-B). 8. Soil design parameters and foundation/slab recommendations will remain the same as specified. -' ------... -.... -----.... -.... -.... -------.... ---------- .. GEOTECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW PAGE 8 LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA AUGUST 2, 2006 Open or backfilled trenches parallel with a footing shall not be below a projected plane having a downward slope of 1-unit vertical to 2 units horizontal (50%) from a line 9 inches above the bottom edge of the footing, and not closer than 18 inches form the face of such footing. Where pipes cross under-footings, the footings shall be specially designed. Pipe sleeves shall be provided where pipes cross through footings or footing walls, and sleeve clearances shall provide for possible footing settlement, but not less than 1-inch all around the pipe. Foundations for all buildings, walls and structures, where the surface of the ground slopes more than 1-unit vertical in 10 units horizontal (10% slope) shall be level or shall be stepped so that both top and bottom of such foundation are ~evel. Individual steps in continuous footings shall not exceed 18 inches in height and the slope of a series of such steps shall not exceed 1-unit vertical to 2 units horizontal (50%) unless otherwise specified. The steps shall be detailed on the structural drawings. The local effects due to the discontinuity of the steps shall also be considered in the design of foundations as appropriate and applicable . 9. Minimum pavement structural section design as specified in the referenced report or the minimum structural section required by the City of Carlsbad, whichever is more, may be. considered for initial planning phase cost estimating purposes only for the on-site asphalt paving surfaces outside the public and private right-of-way. New pavement sections and street improvements within the public right-of-way shall conform to the minimum requirements established by the City of Carlsbad standards and improvement plans. Actual design will also depend on the design traffic index (Tl) and approval of the City of Carlsbad. Revised structural sections may be necessary and should be anticipated. In the areas where the longitudinal grades exceed 10%, ½-inch asphalt should be added to the design asphalt thickness·for each 2% increase in grade or portions thereof. PCC paving surfaces are recommended for longitudinal grades over 15% . In the areas where PCC paving longitudinal grades exceed 20%, provide minimum 8 inches wide by 12 inches deep pavement shear anchors dug perpendicular to the driveway longitudinal profile into the approved subgrade at each 25 feet intervals maximum. The pavement shear anchors should be poured monolithically with the concrete paving surfaces. - ---.. ----------------- --------.. -.. -- .. GEOTECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW PAGE 9 LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA AUGUST 2, 2006 VI. LIMITATIONS The conclusions and recommendations provided herein have been based on all available data obtained from the review of pertinent geotechnical documents, current site observations, soil sampling, laboratory testing, as well as our experience with the soils and formational materials located in the general area. The materials encountered on the project site and utilized in laboratory testing are believed representative of the total area; however, earth materials may vary in characteristics between exposures. Of necessity we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is necessary, therefore, that all observations, conclusions, and recommendations be verified during the grading operation. In the event discrepancies are noted, we should be contacted immediately so that an inspection-can be made and additional recommendations issued if required. The recommendations made in this report are ·applicable to the site at the time this report was prepared. It is the responsibility of the owner/developer to ensure that these recommendations are carried out in the field. It is almost impossible to predict with certainty the future performance of a property. The future behavior of the site is also dependent on,t1umerous unpredictable variables, such as earthquakes, rainfall, and on-site drainage patterns. The firm of VINJE & MIDDLETON ENGINEERING, INC., shall not be held responsible for changes to the physical conditions of the property such as addition of fill soils, added cut slopes, or changing drainage patterns which occur without our inspection or control. The property owner{s) should be aware that the development of cracks in all concrete surfaces such as floor slabs and exterior stucco are associated with normal concrete shrinkage during the curing process. These features depend chiefly upon the condition of concrete and weather conditions at the time of construction and do not reflect detrimental ground movement. Hairline stucco cracks will often develop at window/door comers, and floor surface cracks up to ¼-inch wide in 20 feet may develop as a result of normal concrete shrinkage {according to the American Concrete Institute). This report should be considered valid for a period of one year and is subject to review by our firm following that time. If significant modifications are made to your tentative development plan, especially with respect to the height and location of cut and fill slopes, this report must be presented to us for review and possible revision. This report is issued with the understanding that the owner or his representative is responsible to ensure that the information and recommendations are provided to the project architect/structural engineer so that they can be incorporated into the plans . ... . . --... -... -.... -.... -.... -------... --------------.. --- GEOTECHNICAL UPDATE REPORT AND GRADING PLAN REVIEW PAGE 10 LEMON LEAF DRIVE, CARLSBAD, CALIFORNIA AUGUST 2, 2006 Necessary steps shall be taken to ensure that the project general contractor and subcontractors carry out such recommendations during construction . The project soils engineer should be provided the opportunity for a general review of the project final design plans and specifications in order to ensure that the recommendations provided in this report are properly interpreted and implemented. The project soils engineer should also be provided the opportunity to field verify the foundations prior the placing concrete. If the project soils engineer is not provided the opportunity of making these reviews, he can assume no responsibility for misinterpretation of his recommendations. Vinje & Middleton Engineering, Inc., warrants that this report has been prepared within the limits prescribed by our client with the usual-thoroughness and competence of.-the engineering profession. No other warranty or representation, either expressed or implied, is included or intended. Once again, should any questions arise concerning this report, please do not hesitate to contact this office. Reference to our Job #01-364-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you . VINJE & MIDDLETON ENGINEERING, INC. ~~ ~ CEG#980 DM/SMSS/SJM/jt Enclosures Distribution: Addressee (1) Pasco Engineering; Attn: Mr. Jim Beeker (5) c:/jt/myfiles/06-updates/O 1-364-P ... ... , -... -----... -------... -... ------------- -.. -- REFERENCES Annual Book of ASTM Standards, Section 4 -Construction, Volume 04.08: Soil And Rock (I); D 420-D 5611, 2005. Annual Book of ASTM Standards, Section 4 -Construction, Volume 04.09: Soil And Rock (II); D 5714-Latest, 2005. Highway Design Manual, Caltrans. Fifth Edition. Corrosion Guidelines, Caltrans, Version 1.0, September 2003. California Building Code, Volumes 1 & 2, International Conference of Building Officials, 2001 . "Green Book" Standard Specifications For Public Works Construction, Public Works Standards, Inc., BNi Building News, 2003 Edition. California Department of Conservation, Division of Mines and Geology (California Geological Survey), 1997, Guidelines for Evaluating and Mitigating Seismic Hazards in California, DMG Special Publication 117, 71p. California Department of Conservation, Division of Mines and Geology (California Geological Survey), 1986 (revised), Guidelines for Preparing Engineering Geology Reports: DMG Note 44. ·-. - California Department of Conservation, Division of Mines and Geology (California Geological Survey), 1986 (revised), Guidelines to Geologic and Seismic Reports: DMG Note 42. EQFAUL T, Ver. 3.00, 1997, Deterministic Estimation of Peak Acceleration from Digitized Faults, Computer Program, T. Blake Computer Services And Software. EQSEARCH, Ver 3.00, 1997, Estimation of Peak Acceleration from California Earthquake Catalogs, Computer Program, T. Blake Computer Services And Software . Tan S.S. and Kennedy, M.P., 1996, Geologic Maps of the Northwestern Part of San Diego County, California, Plate(s) 1 and 2, Open File-Report 96-02, California Division of Mines and Geology, 1 :24,000 . UBCSEIS, Ver. 1.03, 1997, Computation of 1997 Uniform Building Code Seismic Design Parameters, Computer Program, T. Blake Computer Services And Software. "Proceeding of The NCEER Workshop on Evaluation of Liquefaction Resistance Soils,• Edited by T. Leslie Youd And lzzat M. Idriss, Technical Report NCEER-97-0022, Dated December 31, 1997. "Recommended Procedures For Implementation of DMG Special Publication 117 Guidelines For Analyzing And Mitigation Liquefaction In California," Southern California Earthquake center; USC, March 1999. "Soil Mechanics,• Naval Facilities Engineering Command, DM 7.01. "Foundations & Earth Structures,• Naval Facilities Engineering Command, DM 7.02. "Introduction to Geotechnical Engineering, Robert D. Holtz, William D. Kovacs. "Introductory Soil Mechanics And Foundations: Geotechnical Engineering,• George F. Sowers, Fourth Edition. "Foundation Analysis And Design,• Joseph E. Bowels. Caterpillar Performance Handbook, Edition 29, 1998. Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas, California Division of Mines and Geology, Geologic Data Map Series, No. 6. Kennedy, M.P., 1977, Recency and Character of Faulting Along the Elsinore Fault Zone in Southern Riverside County, California, Special Report 131, California Division of Mines and Geology, Plate 1 (East/West), 12p. Kennedy, M.P. and Peterson, G.L., 1975, Geology of the San Diego Metropolitan Area, California: California Division of Mines and Geology Bulletin 200, 56p. -... .. ... .. ... --... ... ----... ------------------... .. --- Kennedy, M.P. and Tan, S.S., 1977, Geology of National City, Imperial Beach and Otay Mesa Quadrangles, Southern San Diego Metropolitan Area, California, Map Sheet 24, California Division of Mines and Geology, 1:24,000. Kennedy, M.P., Tan, S.S., Chapman, R.H., and Chase, G.W., 1975, Character and Recency of Faulting, San Diego Metropolitan Areas, California: Special Report 123, 33p. Caterpillar Performance Handbook, Edition 29, 1998. Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas, California Division of Mines and Geology, Geologic Data Map Series, No. 6. Kennedy, M.P., 1977, Recency and Character of Faulting Along the Elsinore Fault Zone in Southern Riverside County, California, Special Report 131, California Division of Mines and Geology, Plate 1 (East/West), 12p. Kennedy, M.P. and Peterson, G.L., 1975, Geology of the San Diego Metropolitan Area, California: California Division of Mines and Geology Bulletin 200, 56p. Kennedy, M.P. and Tan, S.S., 1977, Geology of National City, Imperial Beach and Otay Mesa Quadrangles, Southern San Diego Metropolitan Area, California, Map Sheet 24, California Division of Mines and Geology, 1 :24,000. Kennedy, M.P., Tan, S.S., Chapman, R.H., and Chase, G.W., 1975, Character and Recency of Faulting, San Diego Metropolitan Areas, California: Special Report 123, 33p. "An Engineering Manual For Slope Stability Studies," J.M. Duncan, A.L. Buchignani And Marius De Wf3t, Virginia Polytechnic Institute And State University, March 1987. "Procedure To Evaluate Earthquake-Induced Settlements In Dry Sandy Soils," Daniel Pradel, ASCE Journal Of Geotechnical & Geoenvironmental Engineering, Volume 124, #4, 1998. ... -... ----... -----------------------------.... project 1: 1 line from top_ of slope to outside edge of key 1 materi min. key key depth· 2' min. key depth KEY AND BENCHING DETAILS (Typical -no scale) existing ground surfac~ ~ slope_...,/ finish·cut pad I ~m (pad overexcavation and recompaction per project geotechnical engineer competent bedrock or. fir) ~ native ground per project f geotechnical engineer Side Hill Stability Fill Slope finish pad finish slope ~ project l: l line from toe of slope to competent materials 15 1 min.' f key width one equipment· width minimum -- ~ competent bedrock or firm \ native ground per project geotechnical engineer Fill Slope Note: Key and benching details shown herein are subject to rev1s1ons by the project geotechnical engineer based upon actual site conditions. Back drains may also be necessary as determined by the project geotechnical consultant. PLATE 4 ---... -..... -... -.... -------.... -------------------- existing surface KEY AND BENCHING DETAILS (Typical -No Scale) finish slope finish pad 15 1 min. key width .. cut slope (to be excavated prior to fill placement) r-· Fill-Over-Cut Slope existing ground surface remove unsuitable cted fil competent bedrock or I firm native ground per_./. project geotecbnical consultant finish pad project 1:1 line materials from toe of slope to competent materials cut slope (to be excavated prior to fiil placement) Note: 15' min. key width ~--'bench per project geotechnical engineer in the field -also, see geotechnical report ___ competent bedrock or firm I' native ground per project geotechnical consultant Cut-Over-Fill Slope _) Key and benching details shown herein are subject to revision by the project geotechnical engineer based upon actual site conditions. Back drains may also be necessary as determined by the project geotechnlcal consultant. PLATE 5 I • . -r ·, . .. I I f' I I • .. i : ! ' f 1. I I ·i•·; l .i I .. ' I I I i ·1·-; ! •· :., -:-i • I i i ' ' ··-, -;··· .... ··: ·. -; 'i ~-1-·, ••• • -; •• 1 ·r I .t • ' .... -... -· i·-·-' !_ -- .. ·--: - I L.l.·_. -i ___ ---L~.L ~ t j __ :._j__..:_'' i i-_:i_,.J· __ J~ _ _._ __ ......._~_ .... _,.,. ___ _ ~IE(Q)IJ!E C~ 1M I C#\l C~(Q)~%~=~1ECIJ!(Q)!M ~ I ' ' ! I • I --~-... ·--,· ... --.... ' .. ' I . . ··! i.; ! I • ' : ·-' •. , ! • I i ·,--. H I i ' i ! j·· ; I • ' :~ . .-L •-••' I ' • -: • roposed grade;; : .. ORK 1·-:-1 , : ·'· • ' ' I ' I ! ' : .. I .. -r·; ... ·•-·"7··i t ;. ::1- : : . , > :•· .... ;4 •-i l • • -'· _.-·__;.. I ··--··•' I ..... [,. . . ---•-( .... I -------... ------------------------------ PRELIMINARY GEOTECHINCAL INVESTIGATION (VINJE & MIDDLETON ENGINEERING 2001) \\ESC _ SERVER\Projects\10-13000 to I 0-13999 Projects\10-13292G\Ltr _ Response to Comments Lot 4.doc - -------... ----------------------- -.. -- Preliminary Geotechnical Investigation Proposed 4-Lot Subdivision, Tabata Ranch off Camino De Las Ondas and Lonicera Street Carlsbad, California (Parcel Map #2147054 and 72) October 24, 2001 Prepared For: MR. GREG HARRINGTON P.O. Box 679 Carlsbad, Callfornla 92018 Prepared By: VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Suite 102 Escondido, California 92029 Job #01-364-P --. ---------------------------------... .. Job #01-364-P October 24, 2001 Mr. Greg Harrington P.O. Box679 Carlsbad, California 92018 PRELIMINARY GEOTECHNICAL INVESTIGATION, PROPOSED 4-LOT SUBDIVISION, TABATA RANCH, OFF CAMINO DE LAS ONDAS AND LONICERA STREET, CARLSBAD, CALIFORNIA (PARCEL MAP #2147064 AND 72) Pursuant to your request, Vinje and Middleton Engineering, Inc., has completed the attached Preliminary Geotechnical Investigation Report for the above-referenced project site. The following report summarizes the results of our research and review of pertinent geotechnical maps and reports, subsurface field investigation and soil sampling, laboratory testing, engineering analyses and provides conclusions and construction recommendations for the proposed development as understood. From a geotechnical engineering standpoint, it is our opinion that the site is suitable for the proposed 4-lot residential subdMsion and the associated improvements, provided the recommendations presented in this report are incorporated into the design and reconstruction of the project. The conclusions and recommendations provided in this study are consistent with the site geotechnical conditions and are intended to aid in preparation of final development plans and allow more accurate estimates of the construction costs. If you have any questions or need clarification, please do not hesitate to contact this office. Reference to our Job #01-364-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERING, INC. CEG#980 DM/jt - ------------------------------------ TABLE OF CONTENTS PAGE NO. I. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 II. SITE DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Ill. PROPOSED DEVELOPMENT .. . . .. . .. .. .. .. . . .. .. .. . . . . . .. . .. . .. . . . 1 IV. SITE INVESTIGATION ............................................. 2 V. GEOTECHNICAL CONDITIONS ...................................... 2 A. Earth Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 B. Groundwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 C. Slope Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 3 D. Faults / Seismicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 E. Geologic Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 F. Laboratory Testing/ Results . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 VI. CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 VII. RECOMMENDATIONS . . . . .. . .. .. . . . . . . .. .. . . .. . . . . .. . . . . . . . . . . . .. . 9 A. Grading and Earthworks ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 B. Foundations and Interior Floor Slabs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 C. Exterior Concrete Slabs/ Flatworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 D. Soil Design Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 E. Asphalt and PCC Pavement Design .............................. 17 F. General Recommendations ..................................... 19 VIII. LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 TABLE NO. Fault Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Site Specific Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Soil Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Maximum Dry Density and Optimum Moisture Content . . . . . . . . . . . . . . . . . . . . . 4 In-Place Dry Density and Moisture Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Expansion Index Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Direct Shear Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Removals and Ground Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - -----.... -... ---... ---.... -----------------.. .. .. PLATE NO. Regional Index Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Site Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Test Trench Logs (with key) .......................................... 3-5 Fault -Epicenter Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 lsolatlon Joints and Re-Entrant Corner Reinforcement . . . . . . . . . . . . . . . . . . . . . 7 Retaining Wall Drain Detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 --·. -------.... ---------------------------..... PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED 4-LOT SUBDIVISION, TABATA RANCH OFF CAMINO DE LAS ONDAS AND LONICERA STREET CARLSBAD, CALIFORNIA I. INTRODUCTION The property investigated in this work includes a 2½-acre hillside parcel located between Camino De Las Ondas and Poinsettia Lane, in the La Costa area of the City of Carlsbad. The site location is shown on a Regional Index Map attached to this report as Plate 1. We understand that the property is planned for a subdivision into 4 individual lots upon which single-family dwellings will be supported. Consequently, the purpose of this study was to determine geologic and soil conditions beneath the property and their influence upon the planned construction. Test hole digging, soil sampling, and laboratory testing were among the activities conducted in connection with this study which has resulted in construction and development recommendations provided herein. II. SITE DESCRIPTION The subject property is a rectangular shaped parcel with the longer axi~_running north- south. Site access is via a driveway located on the south side of Camino De Las Ondas across from Lonicera Street. The northern half of the site presently supports a single- family dwelling on a level graded cut pad with a fenced yard. Two trailer type storage facilities occupy the southeast portion of the site. The southern half of the site presently is used for agricultural purposes and has recently been plowed over. Below the upper cut pad, site topography consists of gently sloping southwesterly draining terrain with grades approaching 6 (horizontal) to 1 (vertical). The southeast comer of the property is marked by a large 2 (horizontal) to 1 (vertical) cut slope which descends onto Poinsettia Lane below. Details of site topography are shown on a Site Plan attached to this report as Plate 2. Ill. PROPOSED DEVELOPMENT The planned site development is depicted on the attached Plate 2. As shown, 4 residential lots created by cut-fill grading will occupy the slope areas of the property. An entrance roadway and cul-de-sac will provide access along the upper portion. Lower graded slopes will reach a maximum height of 25 feet at gradients of 2:1. Building plans are not available at this time. However, the use of a conventional wood- frame buildings with exterior stucco supported on shallow still concrete continuous strip and spread pad footings with slab-on-grade floor foundation is assumed for the purpose of this study. -..... -... -.... -.... -.... ---------------------------- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD IV. SITE INVESTIGATION PAGE 2 OCTOBER 24, 2001 Site geotechnical conditions were determined from geologic mapping of existing exposures and the excavation of 6 test trenches dug with a tractor-mounted backhoe. All excavations were logged by our project geologist. Representative soil/bedrock samples were retained from trench excavations at selected depths and intervals for subsequent laboratory testing. Exploratory trench locations are shown on Plate 2. Logs of the excavations are included with this report as Plates 3 through 5. Laboratory test results are summarized in a following section: V. GEOTECHNICAL CONDITIONS The project site is a natural hillside parcel underlain by sedimentary formational rocks mantled by a thin soil cover and artificial fill. No evidence of instability is apparent at the property. A. Earth Materlals The following earth materials are recognized at the project location: Bedrock -Site terrain is underlain by sedimentary bedrock units of Eocene Age. The exposed rocks typically consist of fine to medium grained massive off-white to yellowish sandstone found in a friable and cemented condition. Site sandstone are stable units which should perform well in graded slopes and will generate good quality fill soils. Topsoil/Colluvium -Topsoil/colluvium overlie bedrock units throughout the site and represent a thin weathered reflection of the underlying sandstone. The soils consist chiefly of silty to clayey sands in a loose condition and range in thickness from 1½ to 3½ feet. Fill -In the southern portion of the site artificial fills mantle site topsoil. Some site fill soil was likely generated during the original grading of the existing cut pad. Additional site fill was imported from grading operations from the residential neighborhood directly north of the subject site. Site fill soil is typically light colored silty sands found in an overall loose condition. A small amount of trash and debris was encountered in fill soil exposed in test trench 3. Other local trashy deposits may also exist in site fill soils. As shown in our test trenches, site fill soil ranges from 5½ feet in thickness. - -.... -------.... ---.... ---------------------- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 3 OCTOBER 24, 2001 Details of project earth materials are given on the attached Test Trench Logs, Plates 3 through 5. B. Groundwater Groundwater conditions were not encountered in our test excavations to the depths explored and are not expected to impact the planned development. However, like all hillside properties, the proper control of surface drainage is a critical factor in the continued stability of the graded lots . C. Slope Stability Landslides or other forms of geologic slope instability are not in evidence at the project site. Local bedrock units are characteristically stable materials which are expected to perform well in natural and graded slopes . The nearby areas, large-scale landslides are known within Eocene aged sediments with bedding structure inclined in an unsupported manner. Project sediments are for the most part massive units, or characterized by poorly developed bedding structure which is flat-lying. Under these conditions, translational failures are not anticipated, and graded cut slopes are expected to be stable. Geologic inspections of cut embankments at the site should be inspected and approved by the project engineering geologist. D. Faults / Selsmiclty Faults or significant shear zones are not indicated on or near proximity to the project site. As with most areas of California, the San Diego region lies within a seismically active zone; however, coastal areas of the county are characterized by low levels of seismic activity relative to inland areas to the east. During a 40-year period (1934-1974), 37 earthquakes were recorded in San Diego coastal areas by the California Institute of Technology. None of the recorded events exceeded a Richter magnitude of 3.7, nor did any of the earthquakes generate more than modest ground shaking or significant damages. Most of the recorded events occurred along various offshore faults which characteristically generate modest earthquakes. PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 4 OCTOBER 241 2001 Historically, the most significant earthquake events which affect local areas originate along well known, distant fault zones to the east and the Coronado Bank Fault to the west. Based upon available seismic data, compiled from California Earthquake Catalogs, the most significant historical event in the area of the study site occurred in 1800 at an estimated distance of 7 miles from the project area. This event, which is thought to have occurred along an off-shore fault, reached an estimated magnitude of 6.5 with estimated bedrock acceleration values of 0.342g at the project site. The following list represents the most significant faults which commonly impact the region. Estimated ground acceleration data compiled from Digitized California Faults (Computer Program EQ Fault Ver. 2:01) typically associated with the fault is also tabulated. TABLE 1 Elsinore fault 25 miles 0.111g San Jacinto fault 48 miles 0.057g Coronado Bank fault 21 miles 0.154g 10 miles 0.138 The location of significant faults and earthquake events relative to the study site are depicted on a Fault-Epicenter Map attached to this report as Plate 6. More recently, the number of seismic events which affect the region appears to have heightened somewhat. Nearly 40 earthquakes of magnitude 3.5 or higher have been reCQrded in coastal regions between January, 1984 and August, 1986. Most of the earthquakes are thought to have been generated along offshore faults. For the most part, the recorded events remain moderate shocks which typically resulted in low levels of ground shaking to local areas. A notable exception to this pattern was recorded on July 13, 1986. An earthquake of magnitude 5.3 shook County coastal areas with moderate to locally heavy ground shaking resulting in $700,000 in damages, one death, and injuries to 30 people. The quake occurred along an offshore fault located nearly 30 miles southwest of Oceanside. A series of notable events shook County areas with a (maximum) magnitude 7.4 shock in the early morning of June 28, 1992. These quakes originated along PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 5 OCTOBER 24, 2001 related segments of the San Andreas Fault approximately 90 miles to the north. Locally high levels of ground shaking over an extended period of time resulted; however, significant damages to local structures were not reported. The increase in earthquake frequency in the region remains a subject of speculation among geologists; however, based upon empirical information and the recorded seismic history of County areas, the 1986 and 1992 events are thought to represent the highest levels of ground shaking which can be expected at the study site as a result of seismic activity. In recent years, the Rose Canyon Fault has received added attention from geologists. The fault is a significant structural feature in metropolitan San Diego which includes a series of parallel breaks trending southward from La Jolla Cove .. through San Diego Bay toward the Mexican border. Recent trenching along the fault in Rose Canyon indicated that at that location the fault was last active 6,000 to 9,000 years ago. Thus, the fault is classified as "active" by the State of California which defines faults that evidence displacement in the previous 11,000 years as active. More active faults (listed on the preceding page) are considered most likely to impact the region during the lifetime of the project. The faults are periodically active and capable of generating moderate to locally high levels of ground shaking at the site. Ground separation as a result of seismic activity is not expected at the property. For design purposes, site specific seismic parameters were determined as part of this investigation in accordance with the Uniform Building Code. The following parameters are consistent with the indicated project seismic environment and may be utilized for project design work: TABLE2 According to Cha ter 16, Division IV of the 1997 Uniform Building Code. PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD E. Geologic Hazards PAGE 6 OCTOBER 24, 2001 Geologic hazards are not presently indicated at the project site. Project slope terrain are stable, and proposed cut embankments are expected to expose stable units. The most significant geologic hazards at the property will be those associated with ground shaking in the event of a major seismic event. Liquefaction or related ground rupture failures are not anticipated. F. Laboratory Jesting / Results Earth deposits encountered in our exploratory test excavations were closely examined and sampled for laboratory testing. Based upon our test trench data and field exposures, site soils have been grouped into the following soil types: TABLE3 tan to red brown silty to clayey sand {fill-topsoil/colluvium) ·-· 2 . off white to ellow/rust color fine to meclium sand sandstone The following tests were conducted in support of this investigation: 1. Maximum Dry Density and Optimum Moisture Content: The maximum dry density and optimum moisture content of Soil Types 1 and 2 were determined in accordance with the A$TM D-1557. The test results are presented in Table 4. TABLE4 T-2@2' 125.9 11.7 T-2 4' 2 117.9 14.7 2. In-Place Dry Density and Moisture Content: In-place dry density and moisture contents of representative soil deposits beneath the site were determined from relatively undisturbed chunk samples using the water displacement test method. The test results are presented in Table 5 and tabulated on the attached Test Trench Logs. PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD TABLE5 T-2@2' 1 18.5 102.1 T-2@4' 2 12.2 112.2 T-3@4' 1 12.8 104.9 T-3@6' 1 5.7 111.2 T-3@8' 2 9.0 114.5 T-4@2' 1 2.5 111.0 T-5@2' 1 2.5 109.7 T-5@4' 2 1.3 • Designated as relative compaction for structural fills. Re uired relative com action for structural fill is 90% or 125.9 117.9 125.9 125.9 117.9 125.9 125.9 125.9 reater. PAGE 7 OCTOBER 24, 2001 81.1 95.2 83.3 88.3 97.1 88.1 87.1 sample disturbed 3. Expansion Index Test: Two expansion index tests were performed on repre_sentative samples of Soil Types 1 and 2 in accordance with the Uniform Building Code Standard 18-2. The test results are presented in Table 6. TABLES T-2@2' 1 10.6 49.4 20.0 14 very low T-2@4' 2 11.9 51.0 16.6 0 very low I (w) = moisture content in percent 4. Direct Shear Test Two direct shear tests were performed on representative samples of Soil Types 1 and 2. The prepared specimens were soaked overnight, loaded with normal loads of 1, 2, and 4 kips per square foot respectively, and sheared to failure in an undrained condition. The test results are presented in Table 7. PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD TABLE7 T-2@2' 1 90% remoldecl 125.6 T-2 4' 2 90% remoldecl 121.5 VI. CONCLUSIONS PAGE 8 OCTOBER 24, 2001 28 230 30 150 Based upon the foregoing investigation, development of the project site substantially as proposed, is feasible from a geotechnical viewpoint. The following conditions are unique to the project site and will influence grading procedures and development costs from a geotechnical viewpoint: * The project site is mantled by a cover of natural topsoil/colluvium, as well as old fill soil which occur in a loose condition. Below, sandstone bedrock units are stable, competent deposits which will adequately support planned improvements and graded fills. * Cut-fill grading is proposed at the site for the creation of project building pads. However, uniform soil conditions are recommended beneath finish grade pads and can best be accomplished by added removals of the cut portion of each pad. * Excavation difficulties or unusual grading problems are not expected at the project site. * Site soils are granular, non-expansive to very low expansive sandy deposits which work well in compacted fills. Based upon the anticipated grading scheme, finish grade soils are expected to consist of silty sand deposits (SM) with very low expansion potential (El less than 21). Actual classification and expansion characteristic of finished grade soil mix can only be provided in the final as-graded compaction report based on appropriate testing. * On-site natural terrain and bedrock units are expected to be geologically stable. * The overall stability of graded building surfaces developed over sloping terrain is most dependent upon adequate keying and benching of fill into the undisturbed bedrock during the grading operations. At the project site, added care should be given to proper construction of keyways and benching during regrading. - ----- ---.... -.... ---------------... -------- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 9 OCTOBER 24, 2001 * Natural groundwater is not expected to impact the project development or the long term stability of the developed site. * Adequate site surface drainage control is a critical factor in the future stability of the developed property. * Liquefaction and seismically induced settlements will not be factors in the development of the proposed structures and improvements, provided our soil treatment recommendations are implemented during the grading operations . * Post construction total and differential settlements after building construction are not expected to be factors in the development of the project site, provided our site improvement and foundation recommendations are implemented during the construction phase of the project. * Soil collapse will not be a factor in development of the study site, provided our recommendations for site development are followed. VII. RECOMMENDATIONS The following recommendations are consistent with the indicated geotechnical conditions at the project site and should be reflected in the final plans and implemented during the construction phase. Added or modified recommendations may be appropriate and can be provided at the plan review phase when final grading and building plans are available and actual building locations are established: A. Grading and Earthworks The planned construction areas are directly underlain by loose fills and topsoiVcolluvium. Treatment of these deposits will be required as specified below. All grading and earthworks should be completed in accordance with the Appendix Chapter 33 of the Uniform Building Code, City of Carlsbad Grading Ordinances, the Standard Specifications for Public Works Construction, and the requirements of the following sections: 1. Clearing and Grubbing: Existing vegetation, deleterious materials and debris should be removed from areas to receive fills, structures, and improvements plus 10 feet. All trash and construction debris generated from the demolitions of the existing structures/improvements should be properly disposed of from the site. Removals should be inspected and approved by the project geotechnical engineer or his designated field representative prior to grading. PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 10 OCTOBER 24, 2001 All existing underground facilities and utility improvements should be potholed, identified and marked prior to the initiation of the actual grading works. In the event there is a conflict between depths/locations of existing underground improvements/utilities and the recommended depths of over-excavations, this office should be notified to provide further recommendations. 2. Removals and Ground Treatment: The most effective soil improvement method to mitigate loose and compressible upper fills and topsoil/colluvial deposits, will utilize removal and recompaction grading techniques. Site existing loose soils should be removed to the specified depths as recommended herein and placed back as properly compacted fill. Removals should extend a minimum of 10 feet beyond the building perimeter, while extending· the removals at a minimum of 3 feet from outside perimeter of the planned improvements, may be adequate unless otherwise specified in the field. T-4 T-5 T-6 Typical-removal depths in the vicinity of individual exploratory test sites are shown in Table 8. The tabulated values are subject to changes by the project geotechnical consultant in the field, also depending on the location of the planned buildings and improvements. Locally deeper removals may be , necessary based on the actual field exposures and should be anticipated. TABLES 4½' n/e 2½' fill slope, keyway/benching depth may govern 8½' n/e G.:_J pad areas, existing fill contains trash 5' n/e 3½' pad areas 4½' n/e 3½' fill slope, keyway/benching depth may govern 4½' n/e 3' - --- ... -------------- -· ---------------- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD Notes: 1. All depths are measured from the existing ground levels. PAGE 11 OCTOBER 24, 2001 2 Actual depths may vary at the time of construction based on seasonal conditions and actual subsurface exposures. 3. Bottom of all removals should be prepared and recompacted as directed In the field. 4. In the parking, roadway and drive lane areas removals will consist of depths to firm native ground or 1-foot below the deepest utility or 3 feet but not less one foot minimum as directed in the field. 5 .Exploratory trenches excavated in connection with our study at the indicated locations 1Nere backfilled with loose and uncompacted deposits. The loose/uncompacted backfill soils within these trenches shall also be rErexcavated and placed back as properly compacted fills as a part of the project grading operations. 6 n/e = not encountered. 3. Cut-fill Transition: Ground transition from excavated cut to placed fill should not be permitted underneath the proposed structures and improvements. Transition areas will require special treatment. The cut portion of the cut-fill pads plus 10 feet should be undercut to a sufficient depth to provide for a minimum of 3 feet of compacted fill mat below rough finish grades, or at least 12 inches of compacted fill beneath the deepest footing whichever is more. In the roadways, driveway, parking and on-grade slabs/improvement transition areas, there should be a minimum of 1 foot of compacted soil below rough finish subgrades. 4. Temporary Construction Slopes: Construction slopes required during removal operations should not exceed ¼:1 gradients maximum. Minor sloughing and caving of the temporary slopes may occur and can be anticipated which will not impact the overall gross stability of the temporary cut banks. ·Temporary slopes created by the removal operations should not impact the adjacent structures/improvements and existing underground utilities. All underground utilities should be marked and identified prior to grading. Temporary support and shoring may be required for the protection of nearby underground utilities and structures/improvements, and should be anticipated. Appropriate recommendations should be given by the project geotechnical engineer during the grading operations. Safety requirements enforced by the governing agencies for open excavations apply. 5. Fill Materials and Compaction: Soils generated from on-site removals are sandy materials suitable for reuse as new compacted site fills. Trash and construction debris shall not be allowed in compacted fills. Trash contaminated soils may be exported from the site. -..... ---... -.... -... -.... -.... -.... -... -------------------- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 12 OCTOBER 24, 2001 Uniform bearing soil conditions should be constructed at the site by the grading operations. Site soils should be adequately processed, thoroughly mixed, moisture conditioned to near optimum moisture levels, placed in thin uniform horizontal lifts and mechanically compacted to a minimum of 90% of the corresponding laboratory maximum dry density, per the ASTM D71557, unless otherwise specified . 6. Soil Shrinkage-Bulking and Import Soils: Based upon our analyses, on-site existing fills and topsoil/colluvium may be expected to shrink approximately 5% to 10%, and the soils generated from the excavations of the on-site bedrock may be anticipated to bulk nearly the same amount on a volume basis when compacted to at least 90% of the corresponding maximum density . Import soils, if required to complete grading/backfilling, should be non- expansive sandy granular deposits (expansion index less than 21 unless otherwise specified), tested and approved by the project geotechnical engineer prior to delivery to the site. 7. Permanent Graded Slopes: Graded cut-fill slopes should be programmed for 2:1 gradients maximum. Graded slopes constructed as recommended herein, will be grossly stable with respect to deep seated and surficial failures for the anticipated design maximum vertical heights. All fill slopes shall be provided with a lower keyway. The keyway should maintain a minimum depth of 2 feet into the competent bedrock with a minimum width of 12 feet as approved by the project geotechnical engineer or his designated representative. The keyway should expose competent bedrock or firm ground throughout with the bottom heeled back a minimum of 2% into the natural hillside. Additional level benches should be constructed into the natural hillside as the fill slope construction progresses. Fill slopes should also be compacted to 90% (minimum) of the laboratory standard out to the slope face. Over-building and cutting back to the compacted core, or backrolling at a minimum of 3-foot vertical increments and "track-walking" at the completion of grading, is recommended for site fill slope construction. Geotechnical engineering inspections and testing will be necessary to confirm adequate compaction levels within the fill slope face. Cut slopes should be inspected and approved by the project geotechnical consultant during the grading to confirm stability. Additional recommendations will be provided at that time based upon the actual field exposures if necessary. - --- -.... -.... -... ---.... -------------.... --- --- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 13 OCTOBER 24, 2001 8. Drainage and Erosion Control: A critical element to the continued stability of the building pads and slopes is an adequate surface drainage system and protection of the slope face. This can most effectively be achieved by appropriate vegetation cover and the installation of the following systems: * Drainage swales should be provided at the top and toe of the graded slopes per the project civil engineer design. * Building pad surface run--off should be collected and directed away from the planned buildings and improvements to a selected location in a controlled manner. Area drains should be installed. * The finished slope should be planted soon after completion of grading: Unprotected slope faces will be subject to severe erosion and should not be allowed. Over-watering of the slope faces should also not be allowed. Only the amount of water to sustain vegetation should be provided. 9. Engineering Inspections: All grading operations including removals, suitability of earth deposits used as compacted fill, and compaction procedures should be continuously inspected and tested by the project geotechnical consultant and presented in the final as-graded compaction report. The nature of finished subgrade soils should also be confirmed in the final compaction report at the completion of grading. Geotechnical engineering inspections shall include, but not limited to the following: * Initial Inspection -After the grading/brushing limits have been staked, but before grading/brushing starts. * Keyway/bottom of over-excavation inspection -After the natural ground or bedrock is exposed and prepared to receive fill, but before fill is placed. * Cut slope/excavation inspection -After the excavation is started, but before the vertical depth of excavation is more than 5 feet. Local and CAL-OSHA safety requirements for open excavations apply . * Fill/wall backfill inspection -After the fill/wall backfill placement is started, but before the vertical height of fill/backfill exceeds 2 feet. A minimum of one test shall be required for each 100 lineal feet maximum, with the exception ---------------------------------.. ---- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 14 OCTOBER 24, 2001 of wall backfills where a minimum of one test shall be required for each 25 lineal feet maximum. Finished rough and final pad grade tests shall be required regardless of fill thickness. * Foundation trench inspection -After the foundation trench excavations, but before steel placement. * Foundation bearing/slab subgrade soils inspection -Within 72 hours prior to the placement of concrete for proper moisture and specified compaction levels. * Geotechnical foundation/slab steel inspection -After the steel placement is -· completed, but 24 hours before the scheduled concrete pour. * Subdrain/wall back drain inspection -After the trench excavations, but during the actual placement. All material shall conform to the project material specifications and approved by the project geotechnical engineer. * Underground/utility trench inspection -After the trench excavations, but before installation of the underground-,facilities. Local and CAL-OSHA safety requirements for open excavations apply. Inspection of the pipe bedding may also be required by the project geotechnical engineer. * Underground/utility trench backfill inspection -After the backfill placement is started above the pipe zone, but before the vertical height of backfill exceeds 2 feet. Testing of the backfill within the pipe zone may also be required by the governing agencies. Pipe bedding and backfill materials shall conform to the governing agencies' requirements and project soils report if applicable. All trench backfills shall be compacted to a minimum 90% compaction levels unless otherwise specified. * Pavement/improvements subgrade and basegrade inspections -Within 72 hours prior to the placement of concrete or asphalt for proper moisture and specified compaction levels. B. Foundations and Interior Floor Slabs The following preliminary recommendations are consistent with very low expansive (El less than 21) silty sand (SM) foundation bearing soil. Final foundation and slab design will depend on expansion characteristics of finish grade soils and the actual - -----------.. ------------------------ PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 15 OCTOBER 24, 2001 fill differential thickness underneath the proposed buildings. All recommendations should be confirmed and/or revised as necessary in the rough grading compaction report based on-site as-graded geotechnical conditions and actual testing of the foundation bearing earth materials. Individual building sites may require specific foundation/slab design and may be anticipated. Additional specific recommendations may also be necessary and should be given at the time of the plan review phase when detailed grading and structural/architectural drawings are available. 1. Continuous wood stud bearing wall foundations should be sized 15 inches wide and 18 inches deep for single and two-story structures. Isolated pad footings should be at least 24 inches square and 12 inches deep. Footing depths are measured from the lowest adjacent ground surface, not including the- sand/gravel beneath floor slabs. Exterior continuous footings should enclose the entire building perimeter. 2. Continuous interior and exterior foundations should be reinforced by at least 4- #4 reinforcing bars. Place a minimum of 2-#4 bars 3 inches above the bottom of the footing, and a minimum of 2-#4 bars 3 inches below the top of the footing. Reinforcement details for spread pad footings should be provided by the project architect/structural engineer. 3. All interior slabs should be a minimum of 4 inches in thickness, reinforced with #3 reinforcing bars spaced 16 inches on center each way, placed mid-height in the slab. Slabs should be underlain by 4 inches of clean sand (SE 30 or greater) which is provided with a 6-mil plastic moisture barrier placed mid-height in the sand. In the case of good quality sandy subgrade soils, as approved by the project geotechnical engineer, the 6-mil plastic moisture barrier may be laid directly over the slab subgrade and covered with a minimum of 2 inches of clean sand (SE 30 or greater). 4. Provide "soft-cut" contraction/control joints consisting of sawcuts spaced 10 feet on center maximum each way for all interior slabs. Cut as soon as the siab will support the weight of the saw and operate without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. The sawcuts should be a minimum of 1-inch in depth but not to exceed 1 ¼-inches. Anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. - ------- ---------------------------- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 16 OCTOBER 24, 2001 5. Provide re-entrant corner reinforcement for all interior slabs. Re-entrant corners will depend on slab geometry and/or interior column locations. The attached Plate 7 may be used as a general guideline. 6. Foundation trenches and slab subgrade soils should be inspected and tested for proper moisture and specified compaction levels, and approved by the project geotechnical consultant within 72 hours prior to the placement of concrete. c. Exterior Concrete Slabs / Flatworks 1. All exterior slabs (walkways, and patios) should be a minimum of 4 inches in thickne~s. reinforced with 6x6/10x10 welded wire mesh carefully placed mid-···-· height in the slab. 2. Provide "soft-cuf contraction/control joints consisting of sawcuts spaced 1 0 feet on center (not to exceed 12 feet maximum) each way for all exterior slabs. Cut as soon as the slab will support the weight of the saw and operate without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to .SO0 psi. The sawcuts should be a minimum of 1-inch in depth but not to exceed 1¼-inches. Anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. 3. All exterior slab designs should be confirmed in the final as-graded compaction report. 4. Subgrade soils should be tested for proper moisture and specified compaction levels, and approved by the project geotechnical consultant within 72 hours prior to the placement of concrete. D. Soil Design Parameters The following preliminary soil design parameters are based on the tested representative samples of on-site earth deposits. All parameters should be re- evaluated when the characteristics of the final as-graded soils have been specifically determined: * Design wet density of soil = 121.5 pcf. * Design angle of internal friction of soil = 30 degrees. - .... ---- 1111111 ----------------------------- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 17 OCTOBER 24, 2001 * Design active soil pressure for retaining structures = 40 pcf (EFP), level backfill, cantilever, unrestrained walls. * Design at-rest soil pressure for retaining structures = 60 pcf (EFP), non- yielding, restrained walls. * Design passive soil pressure for retaining structures = 365 pcf (EFP), level surface at the toe. * Design coefficient of friction for concrete on soils = 0.36. * Net allowable foundation pressure for on-site compacted fills (minimum 15 inches wide by 18 inches deep footings) = 1750 psf. * Allowable lateral bearing pressure (all structures except retaining walls) for on- site compacted fill = 150 psf/ft. Notes: * Use a. minimum safety factor of 1.5 for wall overturning and sliding stability. However, because large movements must take place before maximum passive resistance can be developed, a safety factor of 2 may be considered for sliding stability where sensitive structures and improvements are planned near or on top of retaining walls. * When combining passive pressure and frictional resistance, the passive component should be reduced by one-third. * The net allowable foundation pressures provided herein were determined for footings having a minimum width of 15 inches, and a minimum depth of 18 inches. The indicated value may be increased by 20% for each additional foot of depth, and 20% for each additional foot of width to a maximum of 3500 psf if needed. The allowable foundation pressures provided herein also applies to dead plus live loads and may be increased by one-third for wind and seismic loading. * The allowable lateral bearing earth pressures may be increased by the amount of the designated value for each additional foot of depth to a maximum of 1500 pounds per square foot. E. Asphalt and PCC Pavement Design Specific pavement design can best be provided at the completion of rough grading based upon R-value tests of the actual finish subgrade soils; however, the following structural sections may be considered for cost estimating purposes only (not for construction): --.. ---... -.... ------------------------------ PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 18 OCTOBER 24, 2001 1. A minimum section of 3 inches asphalt on 6 inches Caltrans Class 2 aggregate base may be considered for on-site asphalt paving surfaces. Actual design will also depend on the design Tl and approval of the City of Carlsbad. Base materials should be compacted to a minimum of 95% of the corresponding maximum dry density (ASTM D-1557). Subgrade soils beneath the asphalt paving surfaces should also be compacted to a minimum of 95% of the corresponding maximum dry density within the upper 12 inches. 2. Residential PCC driveways and parking supported on non-expansive to very low expansive (El less than 21) granular subgrade soils should be a minimum of 5 inches in thickness, reinforced with #3 reinforcing bars at 18 inches on center-each way, placed mid-height in the slab. Subgrade soils beneath the· •• -- PCC driveways and parking should be compacted to a minimum of 90% of the corresponding maximum dry density. Provide "soft-cur contraction/control joints consisting of sawcuts spaced 1 0 feet on center (not to exceed 15 feet maximum) each way. Cut as soon as the slab will support the weight of the saw, and operate without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. The softcuts should be a minimum of 1-inch in depth but not to exceed 1 %-inches. Anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. 3. Subgrade and basegrade soils should be tested for proper moisture and the specified compaction levels, and approved by the project geotechnical consultant within 72 hours prior to the placement of the base or asphalt/PCC finish surface. 4. Base section and subgrade preparations per structural section design, will be required for all surfaces subject to traffic including roadways, travelways, drive lanes, driveway approaches and ribbon (cross) gutters. Driveway approaches within the public right-of-way should have 12 inches subgrade compacted to a minimum 95% compaction levels and provided with a 95% compacted Class 2 base section per the structural section design. Base section may not be required under curb and gutters, and sidewalks in the case of non-expansive subgrade soils (expansion index less than 21). Appropriate recommendations should be given in the final as-graded compaction report. - ------------------------------------ PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD F. General Recommendations PAGE 19 OCTOBER 24, 2001 1. The minimum foundation designs and steel reinforcement provided herein are based on soil characteristics and are not intended to be in lieu of reinforcement necessary for structural considerations. All recommendations should be further evaluated in the site specific study for each individual lot and confirmed by the project architect/structural engineer. 2. Adequate staking and grading control is a critical factor in properly completing the recommended remedial and site grading operations. Grading control and staking should be provided by the project grading contractor or surveyor/civil engineer and is beyond the geotechnical engineering services. Inadequate staking-and/or lack of grading control may result in unnecessary or additional grading· which will increase construction costs. 3. Footings located on or adjacent to the top of slopes should be extended to a sufficient depth to provide a minimum horizontal distance of 7 feet or one-third of the slope height, whichever is greater (need not exceed 40 feet maximum) between the bC>ttom edge of the footing and face of slope. This requirement applies toall improvements and structures including fences, posts, pools, spas, .c • etc. Concrete and AC improvements should be provided with a thickened edge to satisfy this requirement. 4. Expansive clayey soils should not be used for backfilling of any retaining structure. All retaining walls should be provided with a 1:1 wedge of granular, compacted backfill measured from the base of the wall footing to the finished surface. Retaining walls should be provided with a back drainage in general accordance with the attached Plate 8. 5. All underground utility trenches should be compacted to a minimum of 90% of the maximum dry density of the soil unless otherwise specified. Care should be taken not to crush the utilities or pipes during the compaction of the soil. Non-expansive, granular backfill soils should be used. 6. Site drainage over the finished pad surfaces should flow away from structures onto the street in a positive manner. Care should be taken during the construction, improvements, and fine grading phases not to disrupt the designed drainage patterns. Roof lines of the buildings should be provided with roof gutters. Roof water should be collected and directed away from the buildings and structures to a suitable location. Consideration should be given to adequately damp-proof/waterproof the basement walls/foundations and -... , -------... -----.. ---------------------- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 20 OCTOBER 24, 2001 provide the planter areas adjacent to the foundations with an impermeable liner and a subdrainage system. 7. Final plans should reflect preliminary recommendations given in this report. Final foundations and grading plans may also be reviewed by the project geotechnical consultant for conformance with the requirements of the geotechnical investigation report ouUined herein. More specific recommendations may be necessary and should be given when final grading and architectural/structural drawings are available. 8. All foundation trenches should be inspected to ensure adequate footing embedment and confirm competent bearing soils. Foundation and slab reinforcements should also be inspected and approved by the project geotechnical consultant. 9. The amount of shrinkage and related cracks that occur in the concrete slab-on- grades, flatworks and driveways depend on many factors, the most important of which is the amount of water in the concrete mix. The purpose of the slab reinforcement is to keep normal concrete shrinkage cracks closed tightly. The amount of concrete shrinkage can be minimized by reducing the amount of water in the mix. To keep shrinkage to a minimum, the following should be considered: * Use the stiffest mix that can be handled and consolidated satisfactorily. * Use the largest maximum size of aggregate that is practical. For example, concrete made with % inch maximum size aggregate usually requires about 40 ibs more (nearly 5 gal.) water per cubic yard than concrete with 1-inch aggregate. * Cure the concrete as long as practical. The amount of slab reinforcement provided for conventional slab-on-grade construction considers that good quality concrete materials, proportioning, craftsmanship, and control tests where appropriate and applicable are provided. 10. A preconstruction meeting between representatives of this office, the property owner or planner, the grading contractor/builder, and the city inspector is recommended in order to discuss grading/construction details associated with site development. - ------------------------------------ PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD VIII. LIMITATIONS PAGE 21 OCTOBER 24, 2001 The conclusions and recommendations provided herein have been based on available data obtained from pertinent reports and plans, subsurface exploratory excavations as well as our experience with the soils and formational materials located in the general area. The materials encountered on the project site and utilized in our laboratory testing are believed representative of the total area; however, earth materials may vary in characteristics between excavations. Of necessity we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is necessary, therefore, that all observations, conclusions, and recommendations be verified during the grading operation. In the event discrepancies are noted, we should be contacted immediately so that an inspection can be made and additional recommendations issued if required. The recommendations made in this report are applicable to the site at the time this report was prepared. It is the responsibility of the owner/developer to ensure that these recommendations are carried out in the field. It is almost impossible to predict with certainty the future performance of a property. The future behavior of the site is also dependent on numerous unpredictable variables, such as earthquakes, rainfall, and on-site drainage patterns. The firm of VINJE & MIDDLETON ENGINEERING, INC., shall not be held responsible for changes to the physical conditions of the property such as addition of fill soils, added cut slopes, or changing drainage patterns which occur without our inspection or control. The property owner(s) should be aware that the development of cracks in all concrete surfaces such as floor slabs and exterior stucco are associated with normal concrete shrinkage during the curing process. These features depend chiefly upon the condition of concrete and weather conditions at the time of construction and do not reflect detrimental ground movement Hairline stucco cracks will often develop at window/door corners, and floor surface cracks up to 1/e-inch wide in 20 feet may develop as a result of normal concrete shrinkage (according to the American Concrete Institute). This report should be considered valid for a period of one year and is subject to review by our firm following that time. If significant modifications are made to your tentative development plan, especially with respect to the height and location of cut and fill slopes, this report must be presented to us for review and possible revision. -.... -----------.. ---- -------- -· -------.... --- PRELIMINARY GEOTECHNICAL INVESTIGATION 4-LOT SUBDIVISION, TABATA RANCH, CARLSBAD PAGE 22 OCTOBER 24, 2001 Vinje & Middleton Engineering, Inc., warrants that this report has been prepared within the limits prescribed by our client with the usual thoroughness and competence of the engineering profession. No other warranty or representation, either expressed or implied, is included or intended. Once again, should any questions arise concerning this report, please do not hesitate to contact this office. Reference to our Job #01-337-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERING, INC . ~ dennis Middleton CEG#980 DM/SMSS/SM~t Distribution: Addressee (5) c:\jt\preHms.01 \01-364-P 0 z ~ " 0 0 g.. ti) □- 0. 0 z D 0 0 ] 117°19'00" w 117°19'00" w JODOrl[T FW NW 117°18'00" w L+ -ii wlf'" +Mi Pmdedfiom TOPOI C>lll!J9 Wlldllo,nr Ploclwtm (...,.,Jopo....-.) HU ,ooo .. I z g ;.:,..,4;;~--.""-':!-----fS WGS84 117°17'00" W 0 1'I 1'I D 0 L D D J D J J J J J SITE PLAN* LEGEND APPOXIMATE LOCATION OF TEST TRENCH APPROXIMATE LIMITS OF EXISTING FILL --- Vicinity Map N PLATE 2 f ·. . ~:· ! "' . ~:I • i •. ·: .. : ,•:· / *Showing existing site conditions and tentati!~ imp~gv~'!'~~fs_: ~'. NOTE: Site Plan copied from Tentative Parcel Map by Pasco Engineering and is for geotechnical purposes only. VME JOB #01-364-P ··o· ' I D 0 0 D 0 D D J J ] PRIMARY DIVISIONS GROUP SECONDARY DIVISIONS SYMBOL ...J GRAVELS GLEAN GW Well graded gravels, gravel-sand mixtures, little or no fines. < GRAVELS (J) 0C 0 MORE THAN HALF (LESS THAN GP Poorly graded gravels or gravel-sand mixtures, little or no fines. ...J WO 0 ~N OF COARSE 5% FINES) (J) ::E 0 FRACTION IS GRAVEL GM SIity gravels, gravel-sand-Silt mixtures, non-plastic fines. C LI. z w LARGER THAN WITH w Oz~ GC Clayey gravels, gravel-sand-clay mixtures, plastic fines. z u.. < (J) NO. 4 SIEVE FINES < ...Ji!:w CLEAN a: < > SANDS SW Wei graded sands, graveUy sands, little or no fines. C!l I a: W SANDS w ~ ~ ii5 MORE THAN HALF (LESS THAN SP Poorly graded sands or gravelly sands, little or no fines. (J) a: I a: OF COARSE 5% FINES) < r-:'.5 0 FRACTION IS SANDS SM SIity sands, sand-snt mixtures, non-plastic !Ines. 0 M:! !fl SMALLER THAN WITH 0 NO. 4 SIEVE FINES SC Clayey sands, sand-clay mixtures, plasHc fines. ~ w ML Inorganic silts and very ffne sands, rock flour, silty or clayey ffne (J) LI. a:~ SILTS AND CLAYS sands or clayey sills with slight plasttcity. ...J 0 ~ (J) CL 0 ~ ....1W LIQUID LIMIT IS Inorganic clays of low to medium plasHcity, gravelly clays, sandy rn <~~ LESS THAN 50% clays, sllty clays, lean clays. C :z: mm w z rn o OL Organic sots and organic sllty clays of low plasllclty. z < -0 < :z:·....IN MH Inorganic silts, mlcaceous or dlatomaceous flne sandy or silty a: r-< . SILTS AND CLAYS soils, elastic sifts. C, w oc 0 UJ a: w z LIQUID LIMIT IS CH Inorganic clays of high plasticity, fat clays. z o~z u: ~~< GREATER THAN 50% i!: OH Organic clays of medium to high plasticity, organic slits. HIGHLY ORGANIC SOILS PT Peat and other highly organic soils. GRAIN'SIZES U.S. STANDARD SERIES SIEVE CLEAR SQUARE SIEVE OPENINGS 200 40 10 4 3/4" 3" 12" SAND GRAVEL SILTS AND CLAYS COBBLES BOULDERS FINE I MEDIUM I COARSE FINE I COARSE RELATIVE DENSITY CONSISTENCY ISANDS, GRAVELS AND BLOWS/FOOT CLAYS AND STRENGTH BLOWS/FOOT NON-PLASTIC SIL TS PLASTIC SIL TS VERY LOOSE 0-4 VERY SOFT 0-¼ 0-2 LOOSE 4 • 10 SOFT ¼·½ 2-4 MEDIUM DENSE 10 • 30 FIRM ½ -1 4-8 DENSE 30 -50 STIFF 1 • 2 8 • 16 VERY DENSE OVER 50 VERY STIFF 2-4 16 • 32 HARD OVER 4 OVER 32 1. Blow count, 140 pound hammer fall!ng 30 inches on 2 inch 0 .D. split spoon sampler (ASTM D-1586) 2. Unconfined compressive strength per SOILTEST pocket penetrometer CL-700 6 = undisturbed chunk sample I 246 = Standard Penetration Test (SPll (ASTM D-1586) □ with blow counts per 6 inches = disturbed sample II 246 = California Sampler with blow counts per 6 inches 0 = sand cone test ' VINJE & MlQ,D,LETON KEY TO EXPLORATORY BORING LOGS Unified Soil Classification System (ASTM 0~2487) ENGlNEERiNG, INC. 24'50 Vineyard -Ave., #102 Escortdh:io, CA 92029--122'9 ·-·· ·-··---~--, .. ··-PROJECT NO. KEY l J 0 D D ;. I 0 D Date: DEPTH (ft) -0 - - - --.. - - 5 - -- -- -- -10 - -- .-- ·- 10-17-2001 SAMPLE T-1 uses DESCRIPTION SYMBOL FILL: Silty sand. Red brown. Loose. ST-1 SM TOPSOIL: Silty to clayey sand. Brown. Moist. Stiff. ST-1 SM/SC BEDROCK: Sandstone. Off-white color. Medium grained. Cemented friable. SP At 5' thin rust colored seam. Nearly horizontal. ST-2 End Test Trench at 7'. No Caving. No Groundwater. Date: 10-17-2001 0 DEPTH (ft) -0 - 0 - 0 - 0 - 5 - -10 -0 - SAMPLE T2 .uses 1-------------------------1 SYMBOL DESCRIPTION .EI.LI...;, Sil sand. Tan. Loose. ST-1 TOPSOIL: Silty to clayey sand. Fine grained. Moist. Stiff. ST-1 BEDROCK: Sandstone. Medium grained. Off-white to yellowish color. Friable. d. Rust colored stains. No a arent structure. ST-2 End Test Trench at 4½'. No Caving. No Groundwater. SM Logged by: OM DRY RELATIVE MOISTURE DENSITY COMPACTION ("k) (pcf) (%) Logged by: SM MOISTURE (".4) 18.5 12.2 DRY DENSITY (pcf) 102.1 112.2 RELATIVE COMPACTION (%) 81.1 95.2 D : VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 TABATA RANCH, CARLSBAD J 1--o_m_,c_e_1_s_o_-7_43_-_1_2_14 __ F_a_x_1_s_o-_1_39_-0_34_3_.......___P_R_O_J_E_C_T_N_0_._0_1_-3_64_-P _____ P_L_A_TE __ 3_-II J ] T Sand Cone Test ■ Bulk Sample □ Chunk Sample 0 • Driven Rings D Date: 10-17-2001 D T-3 DEPTli SAMPLE (ft) DESCRIPTION D -0 -~ Silty sand. Tan color. Ory. Loose. From 2½' grades to brown -:--color. Moist. Loose. At 5' mulch and pieces of plastic and metal --rebar. ST-1 D -- --0 - 5 - D --0 TOPSOIL: Siltv to clavev sand. Fine arained. Moist. Soft. ST-1 --n BEDROCK: 0 --~ Sandstone. Medium grained. Rust to yellowish color. Friable. -10 -Weaklv cemented. Moist. ST-2 D --- --End Test Trench at 8½'. --No Caving. No Groundwater. .,. - Date: 10-17-2001 DEPTH SAMPLE .(ft) -0 - 0 0-.5_ 0 - 01 -10 - T-4 DESCRIPTION COLLUVIUM: Silty sand. Light brown color. Dry. Blocky. Dense. Small rootlets throughout. ST-1 BEDROCK: Sandstone. Fine to medium grained. Off-white color. Cemented. End Test Trench at 5'. No Caving. No Groundwater. ST-2 Logged by: SM uses DRY RELATIVE SYMBOL MOISTURE DENSITY COMPACTION (%) (pcf) (04) , SM IJ$ 101/.J 83.3 SM/SC 5.7 111.2 88.3 SP 9.0 11.il. ~ ~7 1 / Logged by: SM uses DRY RELATIVE SYMBOL MOISTURE DENSITY COMPACTION (%) (pcf) (•.4) SM 2-> lll .O 88-\ SP VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 TABATA RANCH, CARLSBAD PROJECT NO. 01-364-P PLATE 4 ~J1====•=s=a=n=d=C=o=n=e=Te=s=t===•=s=u=lk=S=a=m=p=le===O=C=h=u=n=k=S=a=m==pl=e===O=D=riv=e=n=R=i=n=g=s====:::=.1 ]' [ [ [ 0 _o, Date: DEPTH (ft) -0 - -- -- -- -- -5 - -- -- -- -- -10 - -- 10-17-2001 T-5 SAMPLE DESCRIPTION COLL!.!Vl!JM: Silty sand. Light tan to light brown color. Dry. Locally dense from 2½' to 3½'. Very loose. a. ST-1 ~ BEDROCK: Sandstone. Fine to medium grained. Off-white color. Cemented. Locally friable. ST-2 End Test Trench at 4½'. No Caving. No Groundwater. 0 Date: 10-17-2001 uses SYMBOL MOISTURE (%) SM 2.5 SP 1.3 / 0 DEPTH (ft) SAMPLE T-6 uses 1----------------------SYMBOL MOISTURE (%) _,. - 0 -o- O u--~--....... -5 - DESCRi°PTtON COLLUVlUM: Silty sand. Fine grained. Light tan color. Locally dense. ST-1 BEDROCK; Sandstone. Fine to medium grained. "Dirty" color with rust colored stainin . Cemented. No a arent structure. ST-2 End Test Trench at 4½'. No Caving. No Groundwater. SM SP J VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 TABATA RANCH, CARLSBAD PROJECT NO. 01-364-P Logged by: SM DRY RELATIVE DENSITY COMPACTION {pct) (¾) 109.7 87.1 -- Logged by: SM DRY DENSITY (pcf) RELATIVE COMPACTION 1·,1 PLATE 5 11---------------,-------........ -----------------------i J L!:===T=S=a=n=d=C=o=n=e=T=e=s=t===•=B=u=lk=S=a=m==p=le===□=C=h=u=n=-k=S=a=m=p=l=e===O=D=r=iv=e=n=R=i=ng=s======J ] J ., . • •. ~ ·-~ -., •·· ... L ':- ! lJ J _] " " 30 20 FAULT -EPICENTER MAP SAN DIEGO COUNTY REGION JO 0 I INDICATED EARTHQUAKE EVENTS THROUGH 75 YEAR. PERIOD (1900-1974) 30 MILES Map data is compiled from various sources including California Division of Mines and Geology, California Institude of.Technology and the National Oceanic and Atmospheric Administration. Map is reproduced from California Division of Mines and Geology, "Earthquake Epicenter Map of California; Map Sheet 39.11 Earthquake Magnitude e ............. 4.0 TO 4.9 • (!) ··········-5.0 TO 5.9 J C) ............ 6.0 TO 6.9 -C) .......... 7.0 TO 7.9 PROJECT: -~01:.._-~36~4-....:.P ____ _ TABATA RANCH, LA COST8 J -----···· Fault. PLATE NO. ____;6::<.,._ _____ _ •, I \ . . ~ J. !] [] 0 D o· D D 0 D O D 0 0 0 '") J t NOTES: ISOLATION JOINTS AND RE-ENTRANT CORNER REINFORCEMENT Typical -no scale (a) (b) ISOLATION JOINTS CONTRACTION JOINTS RE-ENTRANT CORNER--. REINFO.RCEMENT NO. 4 BAR_S PLACED 1.5" BELOW TOP OF SLAB (c) ----RE-ENTRANT CORNER CRACK 1. Isolation joints around the columns should be either circular as shown in (a) or diamond shaped as shown in (b). If no isolation joints are used around columns, or if the comers of the isolation joints do not meet the contraction joints, radial cracking as shown in {c)may occur (reference ACI). 2. In order to control cracking at the re-entrant comers (±270° corners), provide· reinforcement as shown in (c). 3. Re-entrant comer reinforcement shown herein is provided as a general guideline only and is subject to verification and changes by the project architect and/or structural engineer based upon slab geometry, location, and other engineerin:g and construction factors. VINJ.E & MIDDLETON ENGINEERING, INC. PLATE 7 ,. . . . D □ 0 0 0 J J J Waterproofing RETAINING WALL DRAIN DETAIL Typical -no scale Perforated drain Filter Material. Crushed rock (wrapped in filter fabric) or Class 2 Permeable Material (see specifications below) Competent, approved soils or bedrock CONSTRUCTION SPECIFICATIONS: 1. Provide granular-, non-expansive backfil sol! In 1:1 gradient wedge behind wall. Compact backfill to minimum 90% of laboratory standard. 2. Provide back drainage for wall to prevent build-up of hydrostatic pressures. Use drainage openings along base of waU or back drain system as outlined below. 3. Backdrain should consist of 4" diameter PVC pipe (Schedule 40 or equivalent) with perforations down. Drain to suitable.outlet at minimum 1 %. Provide¾"• 1 ½" crushed gravel filter wrapped in filter fabric (Mirafi 140N or equivalent). Delete filter fabric wrap if Caltrans Class 2 permeable material Is used. Compact Class 2 material to minimum 90% of laboratory standard. 4. Seal back of waN with waterproofing in accordance with architect's specifications. 5. Provide positive drainage to disallow ponding of water above wall. Lined drainage ditch to minimum 2% flow 'clNa.Y from wall is recommended. • Use 1½ cubic foot per foot with granular backfiR soil and 4 cubic foot per foot if expansive backfiR soH is used. VINJE & MIDDLETON ENGINEERING, INC. PLATE 8 ,. I I I I CT/ CDP/ HDPI za GPA/ LCPA Scale: 1 ·=40· --------0 20 Ml 60 LBCJBND _,,.,_ 141' I.X -Llil EICIIII.-----25!t---- 141'-LOT..f I.IJl'MD-1,a!J -·-_,_ .. ,,,._ ----Ulll'llfl'- ~ -11!1'-KI. lllllrN-- .-n,,rrCfflll- '91:1'18 1W 1H -- --11111 I I ----1Vllf lS1& TEST IBENCH (FROM 10-17-2001) - GEOLOGIC CROSS-SECTION I ~ ID) I I I I : I I I ----- - ---.. ----., ---------- : • : l l \ ~ I I 1 1 ~ : 'I '' t \ I ; I l I ' I I Ii ' I • 'I I I : 1 I ! ; 1 ; \\I I ~ i I j ' ·, ! t I 1 ~ ' : \ 1 \ : 1 l I ~ 1 \\~~\~~~\~~ ~ ltubt!II-. • I, flt-All!Lf '. \~~•rM-' -----------, '.; '.; :\ '. !\\\ ! te ' 1 1 \ l ~ \ \I t : n;; ~ ~ ~ \ I \ . '. : I l i ; \ ', .'. \ '. '. ', ; ! '. I ' ' I • I i I I I ! I • I I I : I ·,1 ~ ; .:; -:. r --r_• ' . .~.:::-i :::1--V' ~ \. .,,.,,,,,. I •. > / ,,,.,,, ·. _,, /. {{(::.-~1-~ ... I i; I t i I I t . "· 8 , pj " ~ i I i I SHEET I I 2 I I OF 3 SHEETS !.. I I . i I .. 1 IA~ J •• J _!300 -\-:. ., . j RQ.!mh _gr?.9ing __ CQffiP.!et~~ .::. , (TESTED AND INSPECTED BY OTHERS)_ ·, -, .. __ ,. : I r ·-:-·· i -- · '· - -; ... ··-,. ~ • i ••. -··-:· -·"';·:_\. ~--r;,_--·_ ----.t • -·-····----··-•·•· . ' ., ... --~:....:========~ • ..: ProPOsed grade ,-· -· -• {WORK TO BE DONE);··· - T i .L .... ~-J... J Rough grading completed ----· -·•--v• • -·-----~· •• -(TESTED AND INSPECTED BY OTHERS)----~ -,-,·-,-•. ,_, -------r: -·----····-·--• f .._' : l • '· I ... ------•---. -~~~~f ~•: I~-;~ T' -.-• . I --·· ·--; --. - ·'· .. L --···'-·--..\... --- -·,-· .. --·-·-t -----;---··-···.····· -r· -,··-·--- ' i I I -.:r.-::. ~~_. -=--• Scale: 1 "=40' I' -·•·· 1 . ... ' ., ..... ,._ .... ,., .. -.--· ~-1- __ 1 __ :-.,- .1 -•• • I , . --· I )_. t--•-:•-; -~---~-· --:--: .. , ,-. . t·-···--•··:··-- l -----' •. - ·-•·••, -: .•• i• I _; ______ ---. -- • I, t .-- -~---·· ---··-' _·· "i,_ •• ..._ --·-----¥f" -... ' ' •,-----------,... _____ , -·-. ! l --:---..!--\ l • -•••••. ····r ·T . -·· ······-.. -___ , ____ ...... '