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2009-184 SGCHRISTIAN WHEELER LNCIN[[_RINC FINAL REPORT OF OBSERVATIONS AND RELATIVE COMPACTION TESTING GRADING AND SITE PREPARATION BAUER DUPLEX 2271 & 2273 MONGOMERY AVENUE CARDIFF -BY- THE -SEA, CALIFORNIA PREPARED FOR: BAUER PACIFIC CONSTRUCTION, INC 449 SANTA FE DRIVE, #181 ENCINITAS, CALIFORNIA 92024 PREPARED BY: CHRISTIAN WHEELER ENGINEERING 3980 HOME AVENUE SAN DIEGO, CALIFORNIA 92105 1 004- 5G. C" 0� 5 cD F�01 6 tip10� 3980 Home Avenue ♦ San Diego, CA 92105 f 619 -550 -1700 ♦ FAX 619 -550 -1701 0 IRIS IAN WHEELER FNcitiFFizitic January 12, 2010 Bauer Pacific Construction, Inc. "— 449 Santa Fe Drive, #181 Encinitas, California 92024 CWE 2070383.05R SUBJECT: FINAL REPORT OF FIELD OBSERVATIONS AND RELATIVE T COMPACTION TESTS, GRADING AND SITE PREPARATION, BAUER DUPLEX, 2271 & 2273 MONTGOMERY AVENUE, CARDIFF -BY- THE -SEA, CALIFORNIA. Reference: Report of Preliminary Geotechnical Investigation, Proposed Duplex, 2271 Montgomery Avenue, Encinitas, California, prrparrd by Christian Wheeler Engineering, Report No. 2040221.01, dated October 27, 2004. Dear David Bauer, In accordance with your request, Christian Wheeler Engineering has prepared this report to summarize the results of tests conducted in the backfill behind the basement retaining walls, as well as the site improvements at the subject site. Our geotechnical services were coordinated by Bauer Pacific Construction, Inc., and were provided periodically from June 20, 2007 through December 9, 2009. PLAN REFERENCE: In order to augment our understanding of the designed configuration of the project, our firm was provided with a grading plan for the site prepared by NLS Design Services, Inc. Plate No. 1 of this report is a reproduction of the plan, modified to show the approximate locations of our field tests. SCOPE OF SERVICE Services provided by Christian Wheeler Engineering during the course of the earthwork operations consisted of the following elements: 3980 Home Avenue + San Diego, CA 92105 + 619 -550 -1700 + FAX 619 -550 -1701 CWE 2070383.05R January 12, 2010 Page 2 • Observation of the soil conditions exposed by the excavation for the lower building elevation; - • Observation of the subdrain system constructed behind the lower level retaining walls; • Provide field recommendations to remove the previously existing unsuitable backfill material; • Provide periodic observation of the work in progress; • Perform relative compaction tests in the backfills, subgrade, aggregate base, and asphaltic concrete placement; • Perform laboratory maximum density and optimum moisture determinations on the soil used for the backfill subgrade, and aggregate base; • Perform laboratory maximum density on the asphaltic concrete; and, • Prepare a written report presenting the results of tests conducted at the subject site. FOUNDATION AND EXCAVATION OBSERVATION: Prior to the construction of the building retaining walls, the excavation for the lower level was observed by a representative of our firm. The excavation was found to extend into competent bearing strata; however, our office was not contacted to observe the foundation excavations for the proposed structure and therefore cannot verify the dimensions of the excavations. SUBDRAIN: Preceding the backfilling of the building retaining walls, a subdrain system was - installed at the base of the walls. The subdrain system consisted of a `Miradrain' type drainage board system with a four -inch diameter perforated PVC pipe set in a matrix of crushed rock, wrapped with geotechnical filter fabric. The subdrain system was in accordance with our recommendations. The final connection of the subdrain system to its point of discharge was not observed by our personnel. WALL BACKFILL: The retaining walls were originally backfilled and tested between November 29, 2007 and February 11, 2008. In general, the original backfill material was placed below the required 90 percent of material's maximum dry density, with two of the three compaction tests taken on the south side showing a 86.3 and 87.5 percent compaction and one of the four compaction tests taken on the north side showing a 89.7 percent compaction. The backfill soils along the eastern wall were removed and replaced per our recommendations. The eastern retaining wall was backflled using native and imported sandy soils. This soil backfill was replaced in thin horizontal lifts which were watered to near optimum conditions and compacted in place by means of reciprocating compactors to attain at least 90 percent of maximum dry density. The locations of these tests are shown on Plate No. 1. The backfill for the north sand south retaining was not removed and recompacted. CWE 2070383.05R January 12, 2010 Page 3 The north and south retaining walls were backfilled using native and imported sandy soils. The soil backfills were placed in thin horizontal lifts which were watered to near optimum conditions and compacted in place by means of reciprocating compactors. It can be noted that backfill material with a compaction of less that 90 percent relative compaction still exists behind the north and south retaining walls. Our office cannot verify that these areas were reworked and /or recompacted to recommended values. The locations of these tests are shown on Plate No. 1. FIELD OBSERVATIONS SEWER TRENCH BACKFILL: The sewer trench backfill operations for the sewer laterals consisted of the excavated silty sands being placed in thin, uniform lifts, moisture conditioned and compacted by means of a manually operated reciprocating compactors to attain a minimum of 90 percent of the maximum dry density. SUBGRADE AND BASE PREPARATION: The subgrade preparations in the areas of the sewer laterals and within the driveway and alley areas generally consisted of making minor cuts and /or fills to the designed grades. The soils were scarified, moisture conditioned and compacted to at least 95 percent of the maximum dry density in the alley and roadway areas and at least 90 percent in the driveway area. Aggregate base course materials were placed in the roadway and alley areas in thin, uniform lifts, moisture conditioned and compacted by means of dual drum vibratory rollers to at least 95 percent of the maximum dry density. ASPHALTIC CONCRETE PLACEMENT: Asphaltic concrete placement was monitored for its laydown temperature during its construction. Mix temperatures were noted to be within the acceptable range of 270 °F to 320 °F, as specified in section 302 -5.5 of the Standard Specifications for Public Works Construction. Compactive efforts were made by a smooth drum vibratory roller to attain a minimum of at least 95 percent of the maximum density. SUMMARY OF TESTS FIELD TESTS: Field tests to measure the relative compaction of the backfill, subgrade and aggregate base course were conducted in accordance with ASTM Test Designation D 6938, "Standard Test Methods for Density of Soil and Soil- Aggregate in Place by Nuclear Methods." Field tests to measure the relative compaction of the asphaltic concrete were conducted in accordance with ASTM Test Designation D2950, "Standard Test Method for Density of Bituminous Concrete in CWE 2070383.05R January 12, 2010 Page 4 Place by Nuclear Method." The locations of the field tests were selected by our technician in areas discerned to exhibit a degree of relative compaction that was generally representative of that achieved in the backfill, subgrade, aggregate base course and asphaltic concrete. LABORATORY TESTS: The maximum dry density and optimum moisture content determinations of the predominate soils encountered in the backfill, subgrade and aggregate base were performed in our laboratory by ASTM Test Designation D 1557, "rest Method for Laboratory Compaction Characteristics of Soil Using Modified Effort." The tests were conducted in accordance with the methodology prescribed for the grain -size distribution of the soils tested. The maximum density of the asphaltic concrete was determined by ASTM Test Designation D1560, "Standard Test - Methods for Resistance to Deformation and Cohesion of Bituminous Mixtures by Means of Hveem Apparatus." The results of these tests are presented on the attached Plate Nos. 4 and 5. CONCLUSIONS Based upon the field and laboratory tests and except as noted below, it is our opinion that earthwork addressed by this report was performed substantially in accordance with our recommendations, the standard grading requirements of the City of Encinitas, and the California Building Code. It is further our opinion that the east retaining wall backfill, the paving area subgrade and aggregate base material, and the asphalt concrete pavement were placed and compacted in accordance with our recommendations and the City of Encinitas requirements. As previously stated, two of the three compaction tests taken in the retaining wall backfill on the south side retaining wall were less than 90 percent, with the relative compaction measured at 86.3 percent and 87.5 percent in the two low tests. Considering that the surface above the area of low compaction is a grass lawn, it is our opinion that the low compaction tests should not be a significant problem. The one low compaction test on the north side retaining wall was measured at 89.7 percent. This area is presently covered with an on -grade concrete slab. Considering the level of compaction measured and the fact that the other three compaction tests in this area were above the 90 percent level, it is also out opinion that this low compaction test will also not present a significant problem. CWE 2070383.05R January 12, 2010 Page 5 LIMITATIONS The descriptions, conclusions and opinions presented in this report pertain only to the work performed on the subject site during the period from June 20, 2007 through December 9, 2009. As limited by the scope of the services which we agreed to perform, the conclusions and opinions presented herein are based upon our observations of the work and the results of our laboratory and field tests. Our services were performed in accordance with the currently accepted standard of practice in the region in which the earthwork was performed, and in such a manner as to provide a reasonable measure of the compliance of the described work with applicable codes and specifications. With the submittal of this report, no warranty, express or implied, is given or intended with respect to the services performed by our firm, and our performance of those services should not be construed to relieve the grading contractor of his responsibility to perform his work to - the standards required by the applicable building codes and project specifications. Christian Wheeler Engineering sincerely appreciates the opportunity to provide professional service on this project. If you should have any questions after reviewing this report, please do not hesitate to contact our firm. Respectfully submitted, ENGINEERING I ). � 1� I oug ks, Field Supervisor C Charles H. Christian, R.G.E. 00215 CHC /DH:mah:dh cc: (6) Submitted cc> No. GE215 z Exp. 9 -30 -11 '� GlECHN�/ SUMMARY OF TESTS Project: Bauer Duplex RETAINING WALL ASTI4 03 Test No. Date Location Elev. Soil Moisture Dry Max. % Rel. (feet) Type N Density Density Comp. (pC0 East Side of Site 122.0 88.5 ................................................... ...................... E ............................................. ................ J ....... ........ I ........ �2 ....... ...... .................... ..... .... . 2/7/2008 i 125.5 j East Side of Site 1 7.6 127.3 132.5 96.1 ... I 120.5 .. - ..................... ..................... ..................... .................... RW9 'N" * 'ort'h - G- "a* 'r-a' e- ... F- o-o-t' i*n- g**,/ ... T, *r-e- ... . . . ..... ...... ................................................... ............................... g ................. . .......... nch ' 1 13.6 123.7 1 .......... .. ! 132.5 ..................................... ...................... 93.4 2/7/2008 South Garage Footing /Trench ............ ..................... .................... ............................... ............................... . ....... 120.5 121.0 132.5 91.3 14.1 : ............................... ...................... ..................... .................... 2/7/2008 East Side of Site 123.5 1 10.5 119.4 132.5 90.1 i .......................................................... ..................... .................................... .... ............................... .......... ..................... .................... RW1 2 :: ...... 2/7/2008 East Side of Site " ...... ............... 1 8.4 106.9 i 132.5 80.7 .................... ......................... 123.5 ......... ..................... ..................... ..................... .................... 2/7/2008 East Side of Site 11.5 ............................... ........................................................................... ...................... 7.8 122.2 132.5 92.2 ?1-111111 ...... 4 ....... ..................... .................... RW14 ............. ............................... 2 7/2008 North Side of Site : * ... * ........... : ..................... .................... .............................................................. 113.0 . 1 : 10.1 : 126.8 132.5 95.7 .......... I ........... : ........................................ ............................................. ..................... 2/7/2008 North Side of Site i 110.0 i 1 11.6 100.2 132.5 .. ......................................................................................................... !11-1*111111 ......... ................ ...................... 75.6 ..................... ..................... .... �.A./2.00.8 ..... ...................... East..Si.de..o.f.S.ite ................... ....... 120.0 13.4 117.4 132.5 88.6 I ... . .... .... . ...... . ... .... ................................ ...................... ...... .......... ................................................................................................. .................. RW17 : 2/11/2008 East Side of Site 121.5 14.2 113.6 ** .. . ...... ...... 132.5 ... '- .......... .................... ................... ; 85.7 i................ ..................... ......... 2/11/2008 East Side of Site ............ ..................... ..................... ............................... 121.5 :: ....... 11*9 115.9 132.5 87.5 ...................... RW1 9 2/12/2008 East Side of Site ..................... ..................... ...................... ................ .............................. 27.5 132.5 96.2 ................... ........................... ........................................................................ 118.0 9.0 ..................... ....... 2/12/2008 East Side of Site ............................... ........................................................................ 120.0 8.2 125.0 132.5 4. !- ... .. . . ...... ................ .................. RW21 2/12/2008 East Side of Site ................. ............ .............................. ................................................... ........................................................................... ...... I ....... ....... 132.5 : 94.2 2/12/2008 East Side of Site 119.0 1 11.7 125.3 132.5 94.6 ..................... ..................... ............................... ........................................... RW23 2/12/2008 's ; ................ ...................... ..................... ..................... ..................... East Side of Site s 121.0 ......................................................................... ..: ...................... ....... ....... ...... ...... 132.5 92.9 RW24 2/12/2008 East Side of Site i . ................ ..................... ................... ............................... ......................................................................... :: 123.0 8.7 :: 120.3 132.5 90.8 ..I ..................... ....................................... I ..................... . ... RW25 2/12/2008 East Side of Site : 123.5 1 10.2 1 0 ..................... ..................... .............................................. ................................................. 120.7 :: 132.5 91.1 :: 2/13/2008 :: East Side of Site : ....................................... ..................... • ..................... ..................... ...................... ................................ ........................................................................... ...... 125.0 3 9.9 119.5 126.0 94.8 ................................. ...................... ...................... ..................... ...................... 2/13/2008 East Side of Site ............................... ........................................................................... 125.0 3 8.9 119.4 126.0 .8 ...................... ................ ...................... ..................... ..................... i....... 94.......... RW28 2/14/2008 East Side of Site 127.0 3 .................................................... ...................................................................... ....................................... ....... ...... 116.6 126.0 : 92.5 : 116.0 126.0 92.1 ..................... ...................... 2/14/2008 East Side of Site RW30 2/14/2008 ............................... .......................................................................... 127.0 3 9.4 116.0 : 126.0 92.1 ................... ................ ...................... ................... : .......... ....... 6� .......... East Side of Site .................................................... 118.0 i 1 10.3 119.9 13 ..................... : .............. ............................... Y�--: .5 ..................... 31 1 2/14/2008 East Side of Site 120.1 132.5 90.6 ............................... .......................................................................... 9.8 .... 2/14/2008 East Side of Site ...................... ................ ...................... ..................... ..................... I ..................... 122.0 i 1 . ........................... ........................................................................... ............................. .............. ............ 120.8 i 132.5 i 91.2 J.1.3 ...................... ........ 2/15/2008 East Side of Site 124.0 ............. ..................... ...... ............................... .. ............... ................... 12.1 :: 121.4 :: 132.5 91.6 ...................... ..................... ..................... ...................... 2/15/2008 ...... * ....... E-s- t, ... S, i, d-e- , o**'f ... S-it-e- 126.0 1 132.5 90.2 ................................ .......................................................................... I ...................... ................ <............. .........;..................... ... RW35 ... ..... 2/15/2008 East Side of Site ..... . .......................... 128.0 3 1 11.5 117.9 ................... ................ I ..................... 1 6.0 93.6 .; ..................... ..................... ..................... 2/15/2008 East Side of Site ............................... ........................................................................... i 120.0 1 10.4 119.6 132.5 90.3 !, ..................... ................ .................... RW37 2/15/2008 East Side of Site .1 ...................... ..................... ..................... ................................... b ................ ...................... 122.0 1 ....................... 10.9 121.3 132.5 ................ ..................... 91.5 2/15/2008 East Side of Site i 124 0 9:4........;.....1.22:4.. ...;.....132..5.....;........`. 2.4 ............................... ........................................................................... ........... : 1 :I .................... !,**, ............ ........ ................... 39 2/15/2008 East Side of Site 127.0 : ............................... ........................................................................... ............. : ........ * 1 8.3 122.8 132.5 92.7 1 ....................................... ...... 2/15/2008 East Side of Site i ............. .... 29.0 i 3 11.8 : 114.0......126.0....;... * .................. ................. ............................... ......................................................... ....................... ............... 90.5 2/15/2008 East Side of Site 4 ...................... ..................... ..................... ..................... ..................................... ........... I ............................................................... 129.0 3 9.5 126.0 95.9 : ....................................... ...................... ...... ..................... ..................... ..RE42 2/15/2008 East Side of Site 129.5 : 3 12.0 ............................... ........................................................................... 116.3 126.0 92.3 ...................... R i ....... I .............. ..................... ..................... 2/15/2008 East Side of Site 129.5 '3"' * ...... : ...... ............. ...................... ................ 9.8 117.7 126.0 93.4 ............................... ..................................... I ........................ ..................... ..................... I ...................... ..................... ..... 2/27/2008 Fast Side of Site ....... 130.5 2 112.7 :: 120.2 ................................................... ......... . .......................... ........ I - 2. - 6 ....... R-\,V45 ! ........ I .............. ..................... ....... 93 2 / 2 �� '2- 0-0- .......... *"*'*Y*,,ast Side of Site ...... t 32.0 3 10.6 1 116.7 126.0 92.6 #2()70383.05 Nate 2 11/29/2007 East Side of Site 1 115.0 4 4.8 1 115.3 132.5 8 87.0 RW2 1 11/29/2007 N North Side of Sit'e*"**'* . ................ . ..................... 1 118.8 : : ............... ................... 89.7 ................................................... . 11/29/2007 S South Side of Site 1 ...................... ....................................... . 5.8 1 ..................... . ..................... .................... 86.3 RW4 1 11/29/2007 E East Side of Site 1 ................ . ..................... . .............. ..................... .................... 87.6 MV5 1 1/31/2008 1 East Side of Site i ...... ..................... • ..................... . ..................... ................... 86.4 RW6 :: 2 2/7/2008 S South Side of Site ..................... : ...................... . ............ .................... 87.5 RW7 2/7/2008 ................ . ...................... ..................... . ..................... .................... #2()70383.05 Nate 2 SUBGRADE eSL 0. Date Location Elev S_;1 AT ; to -Ivl_ BASE ts 00,&cr Optimum Moisture (0/6) 8.7 Maximum Dry Density (pco 132.5 S re 1K sot -/o Rel. Test No. Date Location Elev. Soil -M, Moisture Dry Max. % Rel. Elev. Soil Moisture (feet) Type N Density Density Comp. Type N Density Density Comp. (pco N/A 141.8 (pco 96.4 AC2 :: .............. SGl 3/24/2009 Lot 30 Lateral ............... ............................................................................................ SG 3 :: 10.2 :: .............................................................. 122.6 126.0 97.3 SG2 ........... 3/24/2009 ............................... .......................................................................... Lot 29 Lateral SG ....................................... 3 9.8 ................... 120.9 ............ ..................... 96.0 SG3 ................... 11/18/2009 ............................... ......................... Alley East f ............ 2 ... R�P!�� ................ SG ,...................... >. 3 ...................... 9.9 <...........................12 120.5 ..................... ...................... 126.0 95.6 SG4 11/18/2009 J Alley East of Duplex ................ 14.1 ...... 10.4 *"- 121.7: . ..................... ...................... 126.0 96.6 eSL 0. Date Location Elev S_;1 AT ; to -Ivl_ BASE USCS Class SM 00,&cr Optimum Moisture (0/6) 8.7 Maximum Dry Density (pco 132.5 S re L Max. -/o Rel. 1W 3 Medium brown, SILTY SAND (feet) Type (9/6) Density Test No. Date Location Elev. Soil Moisture AN N Dry Max. % Rel. (pco (feet) Type N Density Density Comp. ACI 1 12/9/2009 1 East Side of Alley-North ............................. ................ Alley ............................ WC ...................... N/A 141.8 (pco 96.4 AC2 :: .............. 12/9/2009 ............................... .......................................................................... East Side of Allev-Center WC ....................................... ...AC1 ........................ Acl N/A 140.4 . ................ 147.1 Bl :: 3/24/2009 ................... ............................... Lot 29 Lateral ........................................................................ Base ....................................... 4 11.1 118.6 123.8 95.8 ....... �? ....... Lot 30 Lateral ........................................................ ........ Base 4 . ..................... 10.7 ...................... % 119.4 ..................... 123.8 ..................... 96.4 B3 ............................ ...................... ia� 11 19/2009 on Gutter Alley East of Duplex .................... ........................................ I ........................ Duplex; ............ t"". Base 5 ... *: ... : ................ 14.1 ..................... b............ 112.1 .........1..................... 116.3 96.4 .................... :: 11/19/2009 1 Ribbon Gutter Alley East of ......................................... ......... .......................................... ............................................. Base 5 :: 13.9 ..................... . 113.7 ..................... 116.3 ...................... 97.8 B5 ...................... ................ 11/19/2009: Alley East of Duplex Base 5 ..................... 14.4 ..................... ..................... 111.5 116.3 ..................... 95.9 ..................... 147.1 ........ ...... ASPHALTIC CONCRETE 96.6 NT eSL 0. Date Location Elev S_;1 AT ; to -Ivl_ Soil Type 1 Description Reddish-brown, SILTY SAND USCS Class SM 00,&cr Optimum Moisture (0/6) 8.7 Maximum Dry Density (pco 132.5 S re L Max. -/o Rel. 120.0 3 Medium brown, SILTY SAND (feet) Type (9/6) Density Density Comp. 10.6 123.8 5 Recycled Base SM 13.7 (pco ACI 1 12/9/2009 1 East Side of Alley-North ............................. ................ Alley ............................ WC ...................... N/A 141.8 147.1 96.4 AC2 :: .............. 12/9/2009 ............................... .......................................................................... East Side of Allev-Center WC ....................................... ...AC1 ........................ Acl N/A 140.4 . ................ 147.1 ..................... 95.4 AC3 1 .................................. 12/9/2009 w ................ ............................................... East Side of Allev-South I ................................... :T� 143.6 ..................... 147.1 ..................... 97.6 ............................... 12/9/2009 ........... West Side of All ...... ........... ....... : WC ....................... ....... A!�j ..................... N/A 141.8 ..................... 147.1 ..................... 96.4 ACS 12/9/2009 ..................... t Side of Alley-Center ......................... ........................... W ........ .................. ............ ......... 140.7 %? ..................... : 147.1 ..................... :: 95.6 AC6 12/9/2009 West Side of Alley-South ............ ....... WC ... 6�2 ... AC1 ...................... N/A 142.1 ..................... 147.1 ........ ...... 96.6 Soil Type 1 Description Reddish-brown, SILTY SAND USCS Class SM 00,&cr Optimum Moisture (0/6) 8.7 Maximum Dry Density (pco 132.5 2 Light brown, SILTY SAND SM 11.0 120.0 3 Medium brown, SILTY SAND SM 9.6 126.0 4 Recycled Base SM 10.6 123.8 5 Recycled Base SM 13.7 116.3 CW1, #20710383.05 Plate 4 NLS Design Services, Inc. P.O. Box 210912, Chula Vista, CA 91921, Bus. Lic. No. 052415 -10 Fax No. (619) 869 -7797, Cell No. (619) 733 -0737, E -mail: nsellona @cox.net May 20, 2010 City of Encinitas Debbie Engineering Technician Engineering Services Permits 505 South Vulcan Avenue Encinitas, CA 92024 Subject: Engineer's Final Grading Certification for Project No. 184 -SG and Grading Permit No. 06- 635 -731, Plan File No. 04 -045 for 2271 & 2273 Montgomery Avenue, Cardiff -by -the -Sea, CA 92007 The grading under Permit No. 06- 635 -731 has been performed in substantial conformance with the approved grading plan or as shown on the attached "As- Built" plan. Final grading inspection has demonstrated that lot drainage conforms with the approved grading plan and that swales drain at a minimum of I% to the street and/or an appropriate drainage system. All the Low Impact Development, Source Control and Treatment Control Best Management Practices as shown on the drawing and required by the Best Management Practices Manual Part II were constructed and are operational, together with the required maintenance covenant(s). Engineer of Record: NELSON L. SELLONA, License No. C -62644 Expiration Date: 6/30/2010 Dated: 5/20/2010 Verification by the Engineering Inspector of this fa' i done by the Inspector's signature hereon and will take place only after the above is signed and stamped and will not relieve the Engineer of Record of the ultimate responsib' ity. p Engineering In ect `� Dated:rJ I 84 -SG NLS Design Services Inc. ° c' - U cl�s P.O. Bog 210912, Chula Vista, CA 91921, Bus. Lic. No. 052415 -09 Fax No. (619) 869 -7797, Cell No. (619) 733 -0737, E -mail: nsellona @cox.net August 4, 2009 City of Encinitas Steven Nowak Engineering Technician Engineering Services Permits 505 South Vulcan Avenue Encinitas, CA 92024 Subject: Letter of Certification - Retaining Wall for Grading Permit No. 06- 635 -731, Plan Check No. 09 -423 for 2271 & 2273 Montgomery Avenue, Cardiff -by- the -Sea, CA 92007 Pursuant to Section 23.24.3 10 of the Encinitas Municipal Code, this letter is hereby submitted as a Certification Letter for Lots 29 and 30, Block 23 of Cardiff According to Map No. 1298, as recorded in the City of Encinitas, County of San Diego, State of California. As the Engineer of Record for the subject project, I hereby certify that the retaining wall ( -15' long x 4' -8" high per Detail 14/C6) perpindicular to the garage on both sides of the property has been completed in conformance with the plans and requirements of the City of Encinitas, Codes and Standards. I further certify that the retaining wall is adequate and safe to carry the retained soil per the existing soil and grading condition. If you have any questions about this certification, please call me at (619) 733 -0737. 7e iy yours, 1,i SE L. REGIST O E TIO AT cc: David Bauer k, P.E. C -62644 6/30/2010 Owner/Project coordinator Bauer Pacific Construction, Inc. (Fax # 1- 858 -523 -9929) 243 N. Highway 101, Suite 12 Solana Beach, CA 92075 ^n 1 1 w CHRISTIAN WHEELER ENCINE.ERINC REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED DUPLEX 2271 MONTGOMERY AVENUE CARDIFF BY THE SEA, ENCINITAS, CALIFORNIA -- SUBMITTED TO: ANP ENGINEERING 2658 DEL MAR HEIGHTS ROAD #301 DEL MAR, CALIFORNIA 92014 J JR r 1 ENGINES! L CITY OF SUBMITTED BY: CHRISTIAN WHEELER ENGINEERING 4925 MERCURY STREET SAN DIEGO, CALIFORNIA 92111 4925 Mercury Street ♦ San Diego, CA 9211 1 ♦ 858 -496 -9760 ♦ FAX 858- 496 -9758 �i� CHRISTIAN WHIELEK E N G I N E l K I N G October 27, 2004 ANP Engineering 2658 Del TJar Heights Road #301 Del filar, California 92014 C\XE 2040221.01 SUBJECT: REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION, PROPOSED DUPLEX, 2271 MONTGOMERY AVENUE, ENCINITAS, CALIFORNIA. M Ladies and Gentlemen: In accordance with your request and our proposal dated March 4, 2004 we have completed a preliminarl geotechnical investigation for the subject property. We are presenting herewith a report of our findings and recommendations. In general, our findings indicate that the subject site is suitable to support the proposed duplex provided the recommendations presented herewith are followed. The subject site was determined to be underlain by Tertiary -age materials of the Delmar Formation that are overlain b}, a layer of fill and residual soil (subsoil) in the western portion and by a laver of residual soil (topsoil/ subsoil) in the remaining portions of the property. The existing fill and residual soil (topsoil /subsoil) are considered unsuitable to support the proposed duplex. Therefore, any fill and /or residual soil not removed by planned grading will need to be removed from areas to support settlement - sensitive improvements and, where necessary to achieve planned site grades, be replaced as structural fill. In addition, based on the expansion potential of the existing on -site soils, the proposed conventional foundations and on -grade floor slabs will need to be thickened and more heavily reinforced. No geologic hazards of sufficient magnitude to preclude development of the site as we presently- contemplate it are known to exist. In our professional opinion and to the best of our knowledge, the site is suitable from a geologic perspective for the proposed construction, provided the structure is designed in accordance with the requirements of the most recent edition of the Uniform Building Code and the local governmental agencies. - 4925 Mercury Street + San Diego, CA 92111 + 858- 496 -9760 + FAX 858- 496 -9758 C\N'-E 2040221.01 October 27, 2004 Page No. 2 If you have any questions after reviewing this report, please do not hesitate to contact our office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted, CHRISTIAN WHEELER ENGINEERING "- J Charles H. Christian, R.G.E. #00215 CHC:CRB:scc:wm cc: (G) Submitted 6 s' R. Burdett, C.E.G. #1090 H. C y 2Q Z U CERTIFIED UM U No. GE215 Z "' F- t'ia-&JE`ii'ING Exp. 9 -30 -05 ;;;40 0. * * t� Fes. 1404 4 �T 1' Cal.1F��\Q TABLE OF CONTENTS Page Introduction and Project Description ............................................................................................................................... 1 ProjectScope ........................................................................................................................................................................ z Findings......��3 Gu,I�op � 6vo-----------------------------------------------------3 General Geolog and Subsurface Conditions ............................................................................................................ J - Set600xoJSod Description --------------------------------------'J Fill 1,4ten'x-----------------------------------------------------4 TonsoJ----------------------------------------------------. 4 Subsoil...................................................................................................................................................................... 4 DelmarFormation .................................................................................................................................................. 4 Groundwater.--------------------------------------------------'5 TectonicSetting ........................................................................................................................................................... 5 GeologicHazards ............................................................................................................................................................. 5 Ground Shaking -------------------------------------------------'i Landslide Potential and Slope Sta6ilit� .--------------------------------------.6 Liquefaction................................................................................................................................................................. 6 Flooding____------------------------------------------------.6 Tsunamis...................................................................................................................................................................... 6 Scic6e* .......................................................................................................................................................................... / Conclusions--------------------------------------------------------7 Recommendations _______________-------------------------------------7 Gradingand Earthwork ................................................................................................................................................. 7 Gcoc,u-------------------------------------------------------7 Observation of -----------------------------------------------8 Clearing and � ----------------------------------------------8 SitePreparation ........................................................................................................................................................... 8 TemporaryCut Slopes ............................................................................................................................................... 8 Processingof Fill Areas .............................................................................................................................................. 9 Compactionand Method of Filling ........................................................................................................................... 9 Surface Drainage --------------------------------------------------.Y Foundations................................................................................................................................................................... l0 General....................................................................................................................................................................... lO CourcutiooxFnouJu6nus--------------------------------------------'1U � -------------------------------------------10 Footing� ---------------------------------------------'1V Late,uLnx6Dcuistaocc--------------------------------------------J0 SettlementCharacteristics ........................................................................................................................................ 1 ExpansiveCharacteristics ........................................................................................................................................ ll FoundationPlan Review ............................................................... .......................................................................... U Foundation Excavation Observation .................................................................................................................... D ScisoicI}c^iguPurumcter----- ----------------------------------------- U — On-Grade Slab ............................................................................................................................................................... 2 Gcu,zu----------------------------------------------------12 InteriorFloor Slabs ..................................................................................................................................... .............. 12 Moisture Protection for Interior Slabs .................................................................................................... .............. 12 ExteriorConcrete F6twock ...................................................................................................................... .............. 12 EarthRetaining � Walls ..................................................................................................................................... .............. 13 Foundations................................................................................................................................................. .............. l3 PassivePressure ........................................................................................................................................... .............. l3 EquivalentFluid Pressures ........................................................................................................................ .............. 13 \X��z�ono600xnJ8u6J�x��-------------------------------------------'l3 — CVE204O2l.0\ Propcosed Duplez 22 71 -Montgomery Avenue, Encinitas, California Backfill........................................................................................................................................... .............................13 Limitations............................................................................................................................................. .............................13 Review, Observation and Testing ................................................................................................... .............................13 Uniformity of Conditions ........................................ ............................... Changein Scope ................................................................................................................................ .............................14 TimeLimitations ................................................................................................................................ ............................1.1 ProfessionalStandard ....................................................................................................................... .............................15 Client's Responsibility ...................................................................................................................... .............................15 FieldExplorations ................................................................................................................................ .............................15 LaboratoryTesting ............................................................................................................................... .............................16 ATTACHMENTS TABLES Table I Maximum Ground Acceleration, Page 6 Table I1 Seismic Design Parameters, Page 11 FIGURES Figure 1 Site Vicinity Map, Follows Page 1 PLATES Plate 1 Site Plan Plates 2 -4 Boring Logs Plate 5 Retaining Wall Subdrain Detail Plate 6 Laboratory- Test Results APPENDICES .appendix A References Appendix B Recommended Grading Specifications — General Provisions C%XB 2040221.01 Proposed Duplex 2271 Nfontgomen- Avenue, Encinitas, California CHRISTIAN WHEELER F..NCINCf R I N C PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED DUPLEX 2271 MONTGOMERY AVENUE CARDIFF BY THE SEA, ENCINITAS. CALIFORNIA INTRODUCTION AND PROJECT DESCRIPTION _ This report presents the results of a preliminary geotechnical investigation for a new duplex to be constructed at 2271 Montgomery Avenue in the Cardiff by the Sea area of the city of Encinitas, California. Figure Number 1, presented on the following page, provides a vicinity map showing the location of the property. The subject site is a developed residential property located to the east of Montgomery Avenue. The lot is identified as assessor's Parcel Number 261- 073 -14. We understand that it is proposed to demolish the _ existing home and improvements on the lot and construct a new two and three -story duplex and an attached garage. The lower level of the duplex will be a basement. The center level will have a slightly larger footprint than the lower level, while the upper level will have a slightly smaller footprint than the center level. A garage and driveway are to be constructed within the eastern portion of the site to match the approximate elevation of the adjacent alleyway, and to be close to the elevation of the upper level of the duplex. The proposed structure will require retaining walls up to about 8 to 10 feet high. The on -grade portions of the duplex and garage are expected to have on -grade concrete floor slabs. Conventional shallow foundations are expected to be used to support both the home and the garage. Grading is expected to consist of cuts of up to 1.1 feet and fills of up to about 8 feet from existing grades. Temporary shoring will likely be needed along portions of the north and south property lines in order to make the necessary vertical cuts for the side retaining walls. To aid in the preparation of this report, we were provided with a grading plan for the proposed duple~ prepared by Design Decisions, dated Nlav 23, 2004. A copy of the grading plan \vas modified to show our geologic mapping and the locations of our exploratory borings, and this modified map is included herewith as Plate No. 1. 4925 Mercury Street ♦ San Diego, CA 92111 i 858- 496 -9760 ♦ FAX 858- 496 -9758 SITE VICINITY MAP (Adapted from Thomas Brothers Maps) PROPOSED DUPLEX 2271 MONTGOMERY AVENUE CARDIFF BY THE SEA, ENCINITAS, CALIFORNIA North CWE 2040221 October 2004 Figure 1 C\X'E 2040221.01 October 27, 2004 Page No. 2 This report has been prepared for the exclusive use of ANP Engineering and their design consultants for specific application to die project described herein. Should the project be changed in any way, the modified plans should be submitted to Christian Wheeler Engineering for review to determine their conformance with our recommendations and to determine if any additional subsurface investigation, laboratory testing and /or recommendations are necessary. Our professional services have been performed, our findings obtained and our recommendations prepared in accordance with generally accepted engineering principles and practices. This warranty is in lieu of all other warranties, express or implied. PROJECT SCOPE The scope of our preliminary investigation included: surface reconnaissance, subsurface exploration, obtaining representative soil samples, laboratory testing, analysis of the field and laboratory data and review of relevant geologic literature. Our scope of service did not include assessment of hazardous substance contamination, recommendations to prevent floor slab moisture intrusion or the formation of mold within the structure, or any other services not specifically described in the scope of services presented belo -,v. 'More specifically, the intent of this investigation was to: - a) Explore the subsurface conditions of the site to the depths influenced by the proposed construction; b) Evaluate, by laboratory tests, the engineering properties of the various strata that may influence the proposed development, including bearing capacities, expansive characteristics and settlement potential; C) Describe the general geology at the site including possible geologic hazards that could have an effect on the site development, and provide the seismic design parameters as required by the most recent edition of the Uniform Building Code; d) Address potential construction difficulties that may be encountered due to soil conditions, groundwater or geologic hazards, and provide recommendations concerning these problems; e) Develop soil engineering criteria for site preparation and grading including temporary slope construction and temporary- shoring; 0 Provide design parameters for unrestrained and restrained retaining %calls; C \X'E 2040221.01 October 27, 2004 Page No. 3 g) Recommend an appropriate foundation system for the type of structure anticipated and develop soil engineering design criteria for the recommended foundation design; h) Present our professional opinions in this report, which includes in addition to our conclusions and recommendations, a plot plan, exploration logs and a summary of the laboratory test results. It is not within the scope of our services to perform laboratory tests to evaluate the chemical characteristics of the on -site soils in regard to their potentially corrosive impact to on -grade concrete and below grade improvements. If desired, we can submit representative soil samples to a chemical laboratory for analysis. Further, it should be understood Christian \X'heeler Engineering does not practice corrosion engineering. If such an analysis is necessary, we recommend that the developer retain an engineering firm that specializes in this field to consult with them on this matter FINDINGS SITE DESCRIPTION The subject site is a developed, rectangular- shaped parcel of land located at the address of 2271 Montgomery Avenue in the Cardiff by the Sea area of the city of Encinitas, California. The lot is identified as :assessor's Parcel Number 261- 073 -14. The lot is bounded on the \vest by Montgomery-.avenue, on the east by an alleyway, and by developed residential lots on the two remaining sides. The property supports a relatively old, single- story, single - family home and associated improvements, including a wooden deck at the front, northwestern portion of the property, and a 5- foot -high retaining wall at the front of the property. The lot is a hillside lot that ascends about 8 feet from Montgomery Street to a relatively level pad, where the existing home is located. A relatively short site retaining wall exists behind the existing residence. From this wall the site continues to ascend approximately 9 to 10 feet to the alleyway that bounds the site to the east. Elevations on- site ranges from approximately 116 feet at the front northwestern corner to about 134 feet at the rear southeastern corner of the property. Vegetation on -site consists of typical residential landscaping with trees and bushes in the rear eastern portion of the property. GENERAL GEOLOGY AND SUBSURFACE CONDITIONS GEOLOGIC SETTING AND SOIL DESCRIPTION: The subject site is located in the Coastal Plains Physiographic Province of San Diego County. Based on the results of our subsurface explorations and review of CWE 2040321.01 October 27, 2004 Page No. 4 pertinent, readily available geologic literature, the lot is underlain by Tertiary -age materials of the Dehnar Formation that are overlain by a layer of fill and residual soil (subsoil) in the western portion and by a layer of residual soil (topsoil/ subsoil) in the remaining portions of the property. Each of the encountered soil units is discussed below. FILL MATERIAL (Qao: Man- placed fill material was encountered within our exploratory- test boring B -3, which was drilled at the front, western portion of the property. The fill layer had a thickness of approximately 4//2 feet. The fill material generally consisted of medium to dark brown, sandy clay (CL) that was typically damp to moist and loose to medium dense in consistency. Based on our experience with similar soils, the existing fill materials are expected to possess a "medium" Expansion Index and medium to high settlement potential. The existing fill material is considered unsuitable in its present condition to support setdement - sensitive improvements. TOPSOIL: A thin layer of topsoil was encountered within our exploratory test borings B -1 and B -2. The liver of topsoil ranged in thickness from G inches to about F/2 feet. The topsoil generally consisted of medium to dark brown, silty sand (Sh1) that was dump to moist and loose in consistency. The topsoil is expected to possess a "low" expansion ithdex and high settlement potential. The topsoil is considered unsuitable in its present condition to support settlement - sensitive improvements. SUBSOIL: A layer of subsoil was encountered below the topsoil or fill within each of our exploratory test borings. The layer of subsoil ranged in thickness from 2 to 2' /2 feet. The subsoil generally consisted of olive green, sandy clay (CL) that was moist and stiff to very stiff in consistency. The subsoil is expected to possess a "medium" expansion index and low to medium strength parameters. The subsoil is considered unsuitable in its present condition to support settlement - sensitive improvements. DELMAR FORMATION (Td): Tertiary-age materials of the Delmar Formation were encountered below the fill material and the residual soil (topsoil /subsoil) within each of our exploratory test borings. The materials of the Delmar Formation, which are expected to underlie the entire site, generally consisted of interbedded layers of olive green, silty clay (CL /CH), medium reddish - brown, clayey sand (SC), light to medium greenish- brown, silty sand (SN\ , and light reddish - brown, silty sand /poorly graded sand (SNI /SP). These materials were typically moist and medium dense to very dense in the sandy portions and stiff to hard in the clayey portions. Based on our laboratory test, the formational materials are anticipated to have a "low " to "medium" Expansion Index, low- settlement potential, and moderate strength parameters. The materials of the Delmar Formation are considered suitable in their present condition to support settlement- sensiti -ve improvements. CWE 2040221.01 October 27, 2004 Page No. 5 GROUNDWATER: No groundwater was encountered in our subsurface explorations and we do not expect any groundwater related conditions during or after the proposed construction. However, it should be recognized that minor groundwater seepage problems might occur after construction and landscaping at a site even where none were present before construction. These are usually minor phenomena and are often the result of an alteration in drainage patterns and /or an increase in irrigation water. Based on the anticipated construction and landscaping, it is our opinion that any seepage problems that may occur aYll be minor in extent. It is further our opinion that these problems can be most effectively corrected on an individual basis if and when they occur. TECTONIC SETTING: It should be noted that much of Southern California, including the San Diego County area, is characterized by a series of Quaternary -age fault zones that consist of several individual, en echelon faults that generally strike in a northerly to northwesterly direction. Some of these fault zones (and the individual faults within the zone) are classified as "active" according to the criteria of the California Division of Mines and Geology. Active fault zones are those that have shown conclusive evidence of faulting during the Holocene Epoch (the most recent 11,000 years). The Division of Mines and Geology used the term "potentially active" on Earthquake Fault Zone maps until 1988 to refer to all Quaternary -age (last 1.6 million years) faults for the purpose of evaluation for possible zonation in accordance with the Alquist -Priolo Earthquake Fault Zoning Act and identified all Quaternary -age faults as "potentially active" except for certain faults that were presumed to be inactive based on direct geologic evidence of inactivity during all of Holocene time or longer. Some faults considered to be "potentially- active" would be considered to be "active" but lack specific criteria used by the State Geologist, such as srrfciently actire and u)ell- defined! Faults older than Quateman- -age are not specifically defined in Special Publication 42, Fault Rupture Hazard Zones in California, published by the California Division of Mines and Geology. However, it is generally accepted that faults showing no movement during the Quaternary- period may be considered to be "inactive ". A review of available geologic maps indicates that the active Rose Canyon Fault Zone is located approximately 3.9 kilometers west of the subject site. Other active fault zones in the region that could possibly affect the site include the Newport- Inglewood and Palos Verdes Fault Zones to the northwest and the Coronado Bank and San Clemente Fault Zones to the southwest and the Elsinore, Earthquake Valley, San Jacinto, and San Andreas Fault Zones to the northeast. GEOLOGIC HAZARDS GROUND SHAHING: A likely geologic hazard to affect the site is ground shaking as a result of movement along one of the major active fault zones mentioned above. The maximum ground accelerations that would be C%N`E 2040221.01 October 27, 2004 Page No. 6 attributed to a maxunum probable earthquake occurring along the nearest fault segments of selected fault zones that could affect the site are summarized in Table I presented below. TABLE I: MAXIMUM GROUND ACCELERATIONS Fault Zone Distance Max. Magnitude Earthquake Maximum Ground Acceleration Rose Canyon 3.9 km 6.9 magnitude 0.38 g Newport- Inglewood 21 km 6.9 magnitude 0.16 g Coronado Bank 28 km 7.4 magnitude 0.17 g Elsinore —Julian 47 km 7.1 magnitude 0.09 g Earthquake Valley 67 km 6.5 magnitude 0.05 g San Jacinto - Anza 83 km 7.2 magnitude 0.06 g Probable ground shaking levels at the site could range from slight to moderate, depending on such factors as the magnitude of the seismic event and the distance to the epicenter. It is likely that the site will experience the effects of at least one moderate to large earthquake during the life of the proposed improvements. LANDSLIDE POTENTIAL AND SLOPE STABILITY: As part of this im-estigation we reviewed the publication, "Landslide Hazards in the Northern Part of the San Diego Metropolitan Area" by Tan, 1995. This reference is a comprehensive study that classifies San Diego County into areas of relative landslide susceptibility. According to this publication, the site is located in Relative Landslide Susceptibility Area 3 -1, which is considered to be "generally susceptible" to landsliding and includes gentle to moderate slopes. Based on the relatively gentle existing and proposed topographies of the site, the absence of significant slopes adjacent to the site, and the competent nature of the formational materials observed within subsurface explorations, it is our professional opinion that the potential for slope failures on or adjacent to the site is low. LIQUEFACTION: The near - surface soils encountered at the site possess a low risk potential for liquefaction due to such factors as soil density, soil plasticity and grain -size distribution and the absence of shallow groundwater conditions. FLOODING: The site is located outside the boundaries of both the 100 -year and the 500 -year floodplains according to the maps prepared by the Federal Emergency Management Agency. TSUNAMIS: Tsunamis are great sea waves produced by submarine earthquakes or volcanic eruptions. Due to the site's setback from the ocean and elevation, it a --ill not be affected by a tsunami. CAT 2040221.01 October 27, 2004 Page No. 7 SEICHES: Seiches are periodic oscillations in large bodies of water such as lakes, harbors, bays or reservoirs. Due to the site's location, it will not be affected by seiches. CONCLUSIONS In general, no geotechnical conditions were encountered which would preclude the construction of the proposed duplex provided the recommendations presented herein are followed. The project site was determined to be underlain by Tertiary -age materials of the Delmar Fortation that are overlain by a layer of fill and residual soil (subsoil) in the western portion and by a layer of residual soil (topsoil /subsoil) in the remaining portions of the property. The existing fill and residual soil (topsoil /subsoil) are considered unsuitable to support the proposed duplex. Therefore, any fill and /or residual soil not removed by planned grading will need to be removed from areas to support settlement- sensitive improvements and, where necessary to achieve planned site grades, be replaced as structural fill. In addition, based on the expansion potential of the existing soils, the proposed conventional foundations and on -grade floor slabs will need to be thickened and more heavily reinforced, and footings for the perimeter retaining walls «ill need to be deepened and be embedded into the underlying Delmar Formation. Furthermore, temporary shoring of die excavation sides will be necessary due to the proximity of the adjacent residences. No geologic hazards of sufficient magnitude to preclude development of the site as we presently contemplate it are known to exist. In our professional opinion and to the best of our knowledge, the site is suitable from a geologic perspective for the proposed construction, provided the structure is designed in accordance With the requirements of the most recent edition of the Uniform Building Code and the local governmental agencies. RECOMMENDATIONS GRADING AND EARTHWORK GENERAL: All grading should conform to the guidelines presented in Appendix Chapter 133 of the Uniform Building Code, the minimum requirements of the city of Encinitas, and the recommended Grading Specifications and Special Provisions attached hereto, except where specifically superseded in the text of this report. Prior to grading, a representative of Christian \Xlleeler Engineering should be present at the pre - construction meeting to provide additional grading guidelines, if necessary, and to review the earthwork schedule. Cy \B 2040221.01 October 27, 2004 Page No. 8 OBSERVATION OF GRADING: Continuous observation by the Geotechnical Consultant is essential during the site preparation and grading operations to confirm conditions anticipated by our investigation, to allow adjustments in design criteria to reflect actual field conditions exposed, and to determine that the grading proceeds in general accordance with the recommendations contained herein. CLEARING AND GRUBBING: Site preparation should begin with the demolition of the existing structure and associated improvements, and the removal of all foundations, slabs, existing utilities, vegetation and construction debris from the portions of the lot that will receive improvements. This should include all root balls from the trees to be removed and all significant root material. The resulting materials should be disposed of off -site in a legal dumpsite. SITE PREPARATION: Site grading is expected to consist of cuts of approximately 14 feet from existing grade and fills of approximately 8 feet, as xvell as backfilling behind the proposed retaining walls. The proposed cuts are expected to expose competent formational soils for the support of the proposed home. However, any fill and /or residual soil not removed by planned grading will need to be removed from areas to support settlement- sensitive improvements, such as in the proposed garage and driveway areas, and be replaced as structural fill. Based on our subsurface explorations, the layer of fill and residual soil (topsoil /subsoil) had a thickness of up to about 7 feet in the area of the garage, but may be thicker in localized areas. Horizontally, removals should extend at least 5 feet outside the proposed duplex or to the property lines, which ever is greater. It should be noted that some heaving and distress of the exterior flat-,vork can be expected if placed on expansive materials. Therefore, it may be desirable to place a mat of properly compacted, non- detrimental1v expansive fill below the proposed exterior flatwork to minimize the potential for heaving (see "Exterior Concrete Flat,.vork "). The bottom of the excavation should be approved by our project geologist, engineer, or technician supervisor prior to placing fills or constructing improvements. TEMPORARY CUT SLOPES: Temporary- cut slopes of less than 20 feet in height are anticipated to be required during the proposed construction. Temporary cut slopes of up to 20 feet in height can be excavated vertical for the lower 4 feet and at an inclination of 0.75 to 1.0 (horizontal to vertical) or flatter above -I feet. All temporary cut slopes should be observed by the engineering geologist during grading to ascertain that no unforeseen adverse conditions exist. No surcharge loads such as soil or equipment stockpiles, vehicles, etc. should be allowed %11ritlun a distance from the top of temporary slopes equal to half the slope height. Temporary shoring of the excavation sides may be necessar- due to the proximity of the adjacent residences. Shoring may be designed using the following soil parameters: C \X'E 2040221.01 October 27, 2004 Page No. 9 Angle of internal friction Apparent cohesion Total Unit weight: Topsoil /Subsoil 26 degrees 150 psf 120 pcf Delmar Formation 36 degrees 200 psf 125 pcf The contractor is solely responsible for designing and constructing stable, temporary excavations and will need to shore, slope, or bench the sides of trench excavations as required to maintain the stability of the excavation sides. The contractor's "responsible person ", as defined in the OSHA Construction Standards for Excavations, 29 CFR, Part 1926, should evaluate the soil exposed in the excavations as part of the contractor's safety process. Temporary- cut slopes should be constructed in accordance with the recommendations presented in this section. In no other case should slope height, slope inclination, or excavation depth, including utility trench excavation depth, exceed those specified in local, state, and federal safety regulations. PROCESSING OF FILL AREAS: Prior to placing any new fill in areas that have been cleaned out to receive fill and have been approved by the Geotechnical Consultant or his representative, the exposed soils should be scarified to a depth of 12 inches, moisture conditioned, and compacted to at least 90 percent relative compaction. No other special ground preparation is anticipated at this time. COMPACTION AND METHOD OF FILLING: All structural fill placed at the site should be compacted to a relative compaction of at least 90 percent of its maximum laboratory dry density as determined by ASTIv1 Laboratory Test D1557 -91. Fills should be placed at or slightly above optimum moisture content, in lifts six to eight inches thick, w --ith each lift compacted by mechanical means. Fills should consist of approved earth material, free of trash or debris, roots, vegetation, or other materials determined to be unsuitable by the Geotechnical Consultant. Fill material should be free of rocks or lumps of soil in excess of twelve inches in maximum dimension. However, in the upper two feet of pad grade, no rocks or lumps of soil in excess of six inches should be alloNved. Utility trench backfill within five feet of the proposed structure and beneath all concrete flatwork should be compacted to a minimum of 90 percent of its maximum dry- density. SURFACE DRAINAGE: The ground around the proposed structure should be graded so that surface water flows rapidly away from the structure without ponding. In general, we recommend that the ground adjacent to structures slope away at a gradient of at least two percent. Densely vegetated areas «•here runoff can be impaired should have a minimum gradient of at least five percent within the first three feet from the structure. CWE 2040221.01 October 27, 2004 Page No. 10 FOUNDATIONS w GENERAL: Based on our findings and engineering judgment, the proposed duplex and associated retaining walls may be supported by conventional continuous and isolated spread footings. The following recommendations are considered the minimum based on soil conditions and are not intended to be lieu of structural considerations. All foundations should be designed by a qualified structural engineer. CONVENTIONAL FOUNDATIONS: Based on the soil conditions, we recommend that spread footings supporting the proposed duplex should have a minimum overall embedment depth of 24 inches below building pad grade. Continuous footings should have a minimum width of 15 inches for two- story and 18 inches for three - story. Isolated footings should have a minimum width of 24 inches. Retaining wall footings should have a minimum embedment of 24 inches below the lowest adjacent grade, and should have a minimum «7dth of 24 niches. Perimeter retaining walls should be embedded at least 6 inches into the underlying Delmar Formation or have an overall embedment depth of 18 inches whichever is greater, and should have a minimum width of 24 inches. BEARING CAPACITY: Footings Wid7 the above minimum dimensions may be designed for an allou-able soil bearing pressure of 2,500 pounds per square foot (pso. This value may be increased by 800 pounds per square foot for each additional foot of embedment depth and 350 pounds per square foot for each additional foot of width, up to a maximum of 4,000 psf. Tlus bearing capacity may be increased by one - third, when considering temporary- loads such as wind and /or seismic loading. FOOTING REINFORCING: Reinforcement requirements for new foundations should be provided by a structural engineer. However, based on the existing soil conditions, we recommend that the minimum reinforcing for new continuous footings consist of at least two No. 5 bars positioned three inches above the bottom of the footing and two No. 5 bars positioned two inches below the top of the footing. LATERAL LOAD RESISTANCE: Lateral loads against foundations may be resisted by friction between the bottom of the footing and the supporting soil, and by the passive pressure against the footing. The coefficient of friction between concrete and soil may be considered to be 0.35. The passive resistance may be considered to be equal to an equivalent fluid weight of 350 pounds per cubic foot. This assumes the footings are poured tight against unclisturbed soil. If a combination of the passive pressure and friction is used, the friction value should be reduced by one - third. CV E 2040221.01 October 27, 2004 Page No. 11 SETTLEMENT CHARACTERISTICS: The anticipated total and differential settlement is expected to be about one inch and one inch in forty feet, respectively, provided the recommendations presented in this report are followed. It should be recognized that minor cracks normally occur in concrete slabs and foundations due to shrinkage during curing or redistribution of stresses, therefore some cracks should be anticipated. Such cracks are not necessarily an indication of excessive vertical movements. EXPANSIVE CHARACTERISTICS: The foundation soils are expected to have a "low" to "medium" expansive potential. The recommendations presented in this report reflect this condition. FOUNDATION PLAN REVIEW: The foundation plans should be submitted to this office for review in order to ascertain that the recommendations of this report have been implemented, and that no additional recommendations are needed due to changes in the anticipated construction. FOUNDATION EXCAVATION OBSERVATION: All foundation excavations should be observed by a representative of this office prior to the placement of forms or reinforcement in order to verify- that the footings have the proper dimensions and that the soil conditions are as anticipated during the formation of our foundation recommendations. SEISMIC DESIGN PARAMETERS Based on our Deterministic Seismic Hazard Analysis, the 1\Iaximum Ground Acceleration at the site is estimated to be 0.38 g (based upon a Maximum Magnitude Seismic Event of 6.9 Magnitude along the Rose Canyon Fault). For structural design purposes, a damping ratio not greater than 5 percent of critical dampening, and Soil Profile Type Sc; are recommended (UBC Table 16-J). Based upon the location of the site at approximately 3.9 kilometers of the Rose Canyon Fault (Type B Fault), Near Source Factors N, equal to 1.11 and N,- equal to 1.347 are also applicable. These values, along with other seismically related design parameters from the Uniform Building Code (UBC) 1997 edition, Volume II, Chapter 16, utilizing a Seismic Zone =4 are presented in tabular form on the following page. CWE 2040221.01 October 27, 2004 Page No. 12 TABLE II: SEISMIC DESIGN PARAMETERS UBC — Chapter 16 Table Number Seismic Design Parameter Recommended Value 16 -I Seismic Zone Factor Z 0.40 16-J Soil Profile Type Sc 16 -Q Seismic Coefficient C, 0.40 N, 16 -R Seismic Coefficient C, 0.56N, 16 -S Near Source Factor N, 1.11 16 -T Near Source Factor N, 1.347 16 -U Seismic Source Type B ON -GRADE SLABS GENERAL: It is our understanding that the floor system of the proposed duplex and garage will consist of concrete slab -on -grade floors. The following recommendations are considered the minimum slab requirements based on the soil conditions and are not intended to be in lieu of structural considerations. INTERIOR FLOOR SLABS: The minimum floor slab thickness should be five inches (actual) and all floor slabs should be reinforced with at least No. 3 reinforcing bars placed at 12 inches on center each way. Slab reinforcement should be supported on chairs such that the reinforcing bars are positioned at mid - height in the floor slab. The slab reinforcement should extend into the perimeter foundations at least six inches. MOISTURE PROTECTION FOR INTERIOR SLABS: It should be noted that it is the industry- standard that interior on -grade concrete slabs be underlain by a moisture retarder. \'i:'e suggest that the subslab moisture retarder consist of at least a two -inch -thick blanket of one - quarter -inch pea gravel or clean coarse sand overlain b5 a layer of 10 -mil visqueen. The visqueen should be overlain by a to -o- inch -thick layer of coarse, clean sand that has less than ten percent and five percent passing the No. 100 and No. 200 sieves. Our experience indicates that this moisture barrier should allow the transmission of from about six to twelve pounds of moisture per 1000 square feet per day through the on -grade slab. This may be an excess amount of moisture for some types of floor covering. If additional protection is considered necessary•, the concrete mix can be designed to help reduce the permeability of the concrete and thus moisture emission upwards through the floor slab. EXTERIOR CONCRETE FLATWORK: Exterior slabs should have a minunum thickness of four inches. Reinforcement and control joints should be constructed in exterior concrete flat,�vork to reduce the potential for cracking and movement. joints should be placed in exterior concrete flatwork to help control the location of shrinkage cracks. Spacing of control joints should be in accordance with the .American Concrete Institute specifications. It should be noted that some heaving and distress of the exterior flatwork can be expected if C\X7E 2040221.01 October 27, 2004 Page No. 13 placed on expansive material. In order to nunimize this distress, the exterior concrete flatwork can be underlain by a minimum of two feet of non - expansive soil (E.I less than 50). EARTH RETAINING WALLS FOUNDATIONS: Foundations for proposed retaining walls should be constructed in accordance with the recommendations for shallow foundations presented previously in this report. PASSIVE PRESSURE: The passive pressure for the design of sliding resistance of spread footings may be considered to be 350 pounds per square foot per foot of embedment. These pressures may be increased one - third for seismic loading. The coefficient of friction for concrete to soil may be assumed to be 0.35 for the resistance to lateral movement. EQUIVALENT FLUID PRESSURES: The active soil pressure for the design of "unrestrained" and "restrained" earth retaining structures «rith level backfnll may be assumed to be equivalent to the pressure of a fluid weighing 40 and 55 pounds per cubic foot, respectively. These pressures do not consider any surcharge. If any are anticipated, this office should be contacted for the necessary increase in soil pressure. These values assume a drained, moderately expansive (E.1 between 50 and 90) backfill condition. WATERPROOFING AND SUBDRAIN: Waterproofing details should be provided by the project architect. A suggested wall subdrain detail is provided in Plate Number 5. We recommend that the Geotechnical Consultant observe all retaining -,,.-all subdrains to verify proper construction. BACKFILL: All backfill soils should be compacted to at least 90 percent relative compaction. Expansive or clayey soils should not be used for backfill material. The wall should not be backfilled until the masonry has reached an adequate strength. LIMITATIONS REVIEW, OBSERVATION AND TESTING The recommendations presented in this report are contingent upon our review of final plans and specifications. Such plans and specifications should be made available to the Geotechnical Engineer and Engineering Geologist so that they may review and verify their compliance with this report and v6th the Uniform Building Code. CkXTE 2040321.01 October 27, 2004 Page No. 14 It is recommended that Christian �X` heeler Engineering be retained to provide continuous soil engineering services during the earthwork operations. This is to verify compliance «7th the design concepts, specifications or recommendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to start of construction. UNIFORMITY OF CONDITIONS The recommendations and opinions expressed in this report reflect our best estimate of the project requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface exploration locations and on the assumption that the soil conditions do not deviate appreciably- from those encountered. It should be recognized that the performance of the foundations and /or cut and fill slopes may be influenced by undisclosed or unforeseen variations in the soil conditions that may occur in the intermediate and unexplored areas. Any unusual conditions not covered in this report that may be encountered during site development should be brought to the attention of the Geotechnical Engineer so that he may make modifications if necessary. CHANGE IN SCOPE This office should be advised of any changes in the project scope or proposed site grading so that we may determine if the recommendations contained herein are appropriate. It should be verified in writing if the recommendations are found to be appropriate for the proposed changes or our recommendations should be modified by a written addendum. TIME LIMITATIONS The findings of this report are valid as of this date. Changes in the condition of a property can, however, occur with the passage of time, whether die), are due to natural processes or the work of man on this or adjacent properties. In addition, changes in the Standards -of- Practice and /or Government Codes may occur. Due to such changes, the findings of this report may be invalidated wholly or in part by changes beyond our control. Therefore, this report should not be relied upon after a period of two years without a review by us verifying the suitability- of the conclusions and recommendations. CAE 2040221.01 October 27, 2004 Page No. 15 PROFESSIONAL STANDARD In the performance of our professional services, we comply with that level of care and skill orduiarily exercised by members of our profession currently practicing under similar conditions and in the same locality. The client recognizes that subsurface conditions may vary, from those encountered at the locations where our borings, surveys, and explorations are made, and that our data, interpretations, and recommendations are based solely on the information obtained by us. We will be responsible for those data, interpretations, and recommendations, but shall not be responsible for the interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, express or implied, is made or intended in connection with the work performed or to be performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written reports or findings. CLIENT'S RESPONSIBILITY It is the responsibility of the Client, or their representatives, to ensure that the information and recommendations contained herein are brought to the attention of the structural engineer and arclitect for the project and incorporated into the project's plans and specifications. It is further their responsibility- to take the necessary measures to insure that the contractor and his subcontractors carry- out such recommendations during construction. FIELD EXPLORATIONS Three subsurface explorations were made at the locations indicated on the attached Plate Number 1 on September 15, 2004. These explorations consisted of borings drilled using a CNIE -55 rig. The fieldwork was conducted under the observation of our engineering geology personnel. The explorations were carefully logged when made. The boring logs are presented on the following Plate Numbers 2 through 4. The soils are described in accordance with the Unified Soils Classification System. In addition, a verbal textural description, die wet color, the apparent moisture and the density or consistency are provided. The density' of granular soils is given as ven' loose, loose, medium dense, dense or very dense. The consistency of silts or clays is given as either venti soft, soft, medium stiff, stiff, very- stiff, or hard. Relatively undisturbed drive samples were collected using a modified California sampler. The sampler, with an external diameter of 3.0 inches, is lined with 1 -inch long, thin, brass rings with inside diameters of approximately 2.4 inches. The sample barrel was driven into die ground with the weight of a 140 -pound hammer falling 30 niches in general accordance with ASTINI D 3550 -84. The driving weight is permitted to fall freely. The number CWE 204022 1.01 October 27, 2004 Page No. 16 of blows per foot of driving, or as indicated, are presented on the boring logs as an index to the relative resistance of the sampled materials. The samples were removed from the sample barrel in the brass rings, and sealed. Bulk samples of the encountered earth materials were also collected. Samples were transported to our laboratory for testing. LABORATORY TESTING Laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTI\I test methods or suggested procedures. A brief description of the tests performed is presented below: a) CLASSIFICATION: Field classifications were verified in the laboratory by visual examination. The final soil classifications are in accordance with the Unified Soil Classification Svstem. b) MOISTURE - DENSITY: In -place moisture contents and dry densities were determined for representative soil samples. This information was an aid to classification and permitted recognition of variations in material consistency with depth. The dry unit weight is determined in pounds per cubic foot, and the in -place moisture content is determined as a percentage of the soil's dry weight. The results are summarized in the boring logs attached herein as Plate Nos. 2 through 4. c) COMPACTION TEST: The maximum dry- density and optimum moisture content of apical soils were determined in the laboratory in accordance with ASThi Standard Test D -1557, Nlethod A. The results of tlus test are presented on the Plate No. 6. d) GRAIN SIZE DISTRIBUTION: The grain size distributions were determined from representative soil samples in accordance with ASTNI C136. The results of these tests are presented on Plate No. 6. e) DIRECT SHEAR TEST: Direct shear tests were performed on representative samples of the on -site soils to determine the failure envelope based on geld shear strength. The shear box was designed to accommodate a sample having a diameter of 2.375 inches or 2.50 inches and a height of 1.0 inch. The samples were saturated and tested at different vertical loads. The shear stress was applied at a constant rate of strain of approximately 0.05 inch per minute. The results of this test are presented on Plate No.6. CNVE 2040221.01 October 27, 2004 Page No. 17 f) EXPANSION INDEX TEST: Expansion Index tests were performed on remolded samples of representative samples. The test was performed on the portion of the sample passing the #4 standard sieve. The sample was brought to optimum moisture content and then dried back to a constant moisture content for 12 hours at 230 + 9 degrees Fahrenheit. The specimen was then compacted in a 4- inch - diameter mold in two equal layers by means of a tamper, then trimmed to a Final height of 1 inch, and brought to a saturation of approximately 50 percent. The specimen was placed in a consolidometer with porous stones at die top and bottom, a total normal load of 12.63 pounds was placed (144.7 pso, and the samples were allowed to consolidate for a period of 10 minutes. The sample was saturated, and the change in vertical movement was recorded until the rate of expansion became nominal. The expansion index is reported on Plate No. 6 as the total vertical displacement times 1000. Topsoil- Aledium to dark brown, damp to moist, loose, SILTY 2 SAND (SA . Subsoil: Olive green to medium grayish- brown, moist, stiff to very Cal 25 13.2 112.8 4 stiff, SANDY CLAY (CL). _Delmar Formation (Td): Olive green and fight to medium Cal 19 6 reddish - brown, moist, stiff, SILTY CLAY (CL /CH). E.I Expansion Index= 76 (Medium) 19.2 87.0 DS 8 <::::: <: Light to medium greenish- brown, moist, dense to very dense, SILTY Cal 7 10 SAND (SN ), fine to medium - grained. o /�" 11.8 104.7 At 9 feet near vertical precipitate stained fractures observed. 12 At 12 feet becomes very dense. From 12 to 13 feet becomes slightly 14 cemented with shell fragments. Cal 80/9" 16.8 109.6 Boring terminated at 14 feet. 16 M 20 MILY CUSTOM HOME t, Del Mar, California CHRISTIAN WHEELER L7M ATE: F N c i N 1_ I_ R i N C October 2004 LATE NO.: 2 LOG OF TEST BORING NUMBER B -1 Date Excavated: 9/15/2004 Equipment: Logged by: TSW Beaver Existing Elevation: Project Manager: CHC N/A Finish Elevation: Depth to Water: N/A N/A Drive Weight: 1401bs. Topsoil- Aledium to dark brown, damp to moist, loose, SILTY 2 SAND (SA . Subsoil: Olive green to medium grayish- brown, moist, stiff to very Cal 25 13.2 112.8 4 stiff, SANDY CLAY (CL). _Delmar Formation (Td): Olive green and fight to medium Cal 19 6 reddish - brown, moist, stiff, SILTY CLAY (CL /CH). E.I Expansion Index= 76 (Medium) 19.2 87.0 DS 8 <::::: <: Light to medium greenish- brown, moist, dense to very dense, SILTY Cal 7 10 SAND (SN ), fine to medium - grained. o /�" 11.8 104.7 At 9 feet near vertical precipitate stained fractures observed. 12 At 12 feet becomes very dense. From 12 to 13 feet becomes slightly 14 cemented with shell fragments. Cal 80/9" 16.8 109.6 Boring terminated at 14 feet. 16 M 20 MILY CUSTOM HOME t, Del Mar, California CHRISTIAN WHEELER L7M ATE: F N c i N 1_ I_ R i N C October 2004 LATE NO.: 2 h 0 mw� SUMMARY OF SUBSURFACE CONDITIONS z O �O EW. Topsoil- Aledium to dark brown, damp to moist, loose, SILTY 2 SAND (SA . Subsoil: Olive green to medium grayish- brown, moist, stiff to very Cal 25 13.2 112.8 4 stiff, SANDY CLAY (CL). _Delmar Formation (Td): Olive green and fight to medium Cal 19 6 reddish - brown, moist, stiff, SILTY CLAY (CL /CH). E.I Expansion Index= 76 (Medium) 19.2 87.0 DS 8 <::::: <: Light to medium greenish- brown, moist, dense to very dense, SILTY Cal 7 10 SAND (SN ), fine to medium - grained. o /�" 11.8 104.7 At 9 feet near vertical precipitate stained fractures observed. 12 At 12 feet becomes very dense. From 12 to 13 feet becomes slightly 14 cemented with shell fragments. Cal 80/9" 16.8 109.6 Boring terminated at 14 feet. 16 M 20 MILY CUSTOM HOME t, Del Mar, California CHRISTIAN WHEELER L7M ATE: F N c i N 1_ I_ R i N C October 2004 LATE NO.: 2 LOG OF TEST BORING NUMBER B Date Excavated: 9/15/2004 B -2 Equipment: Beaver L Logged by: T TSW Existing Elevation: N/A P Project I\fanager: C CHC Finish Elevation: N/A D Depth to Water: N N/A Drive Weight: 1 140 lbs. O S SAMPLES W a. SUIDIMARY OF SUBSURFACE CONDITIONS o o F F FO 8 10 12 - 14 - 16 18 20 -----------------•----•------------------- Olive een and a moist, hard, SANDY CLAY CL . gray, 20.3 89.0 Olive brown and moist, very dense, SILTY SAND (SNI), fine . -- -- - - - - -- '• 50 /5" 19.7 99.4 to medium- Cal - - - -- �rarned. � - - - --- ------- ------------------------------------------------------------------ Light reddish - brown, moist, very dense, SILTY SAND - POORLY GRADED SAND SNl -SP ,fine to medium- ained. GRADED - --- ------------------ Olive brown and gray, moist, hard, SANDY CLAY (CL). ._._..__ Cal Nledium reddish- brown, moist, very dense, SILTY SAND (SNI). At 18 feet becomes very moist. Boring terminated at 18 feet. Cal 50/3" i' 18.8_1.102.2_1. 50/3"1 20.9 1 98.8 1 DS PROPOSED SINGLE - FAMILY CUSTOM HOME 2271 Montgomery Street, Del Mar, California CHRISTIAN WHEELER BY: LN<,I Nf_FR -NC. HF DATE: JOB NO. ; October 2004 2040221 PLATE NO.: 3 LOG OF TEST BORING NUMBER B -3 9/15/2004 Beaver Logged by: TSW n- N/A Project Manager: CHC : N/A Depth to Water: N/A Pe Drive Weight: 1401bs. SAMPLES (D SUMMARY OF SUBSURFACE CONDITIONS W a z O �O H Artificial Fill (Qaf)• Medium to dark brown, moist, loose 2 to medium dense, SANDY CLAY (CL). 4 Subsoil: Olive gray, moist, stiff, SANDY CLAY (CL). Cal 22 3.1 105.3 6 Cobbles present at 6 feet. r 8 Delmar Formation (Td): Medium reddish -brown and olive green, moist, medium dense to dense, CLAYEY SAND (SC). 'I 10 At 8/2 feet becomes dense to ve dense. ` .................................... Cal �� 15.5 108.7 Medium reddish brown and light gray, moist, dense, SILTY 1 SAND (SM). Cobbles and gravels present from 10' /2 to 12 feet. 14 Cal 49 11.1 122.2 -- Boring terminated at 13'/2 feet. 16 18 20 PROPOSED SINGLE - FAMILY CUSTOM HOME 2271 Montgomery Street, Del Mar, California CHRISTIAN WHEELER BY: HF F N C i N V 11 it i N C DATE: October 2004 JOB NO.: 2040221 PLATE NO.: 4 3/4 inch Cru Nfiradrain 600 0 Geofab Rock 1% Slor)e Minimum ,rte; rnvu; 6 -inch Nlax. a. . � v shed Rock or a a or Equivalent y QO. d 12" a d a � nc Behveen �d and Soil ° an Minimum 4 -inch Diameter Perforated Pipe PVC Schedule 40 FA' FM I I 6 -inch Minimum Waterproof Back of Wall Per Architect's Specifications RETAINING WALL SUBDRAIN DETAIL No Scale CHRISTIAN WHEELER r G I N C E R I N G 4925 N11 SRCURY S'IRI- F 1, TEL (858) 496 -9760 SAN DIEGO, CALIFORNIA 92111 FAX. (858) 469 -9758 Top of Ground or Concrete Slab e4 PROPOSED DUPLEX 2271 MONTGOMERY AVENUE, ENCINITAS, CALIFORNIA BY: WIN DATE: October 2004 JOB NO.: 2040221 PLATE NO.: 5 6 -inch Minimum LABORATORY TEST RESULTS PROPOSED SINGLE - FAMILY CUSTOM HOME 2271 MONTGOMERYAVENUE CARDIFF BY THE SEA ENCINITAS CALIFORNIA DIRECT SHEAR TEST Sample Number Boring B -1 @ 5' Description Natural Angle of Friction 25 degrees Apparent Cohesion 350 psf Sample Number Boring B -2 @ 5' Description Natural Angle of Friction 36 degrees Apparent Cohesion 350 psf Sample Number Boring B -2 @ 18' Description Natural Angle of Friction 35 degrees Apparent Cohesion 200 psf EXPANSION INDEX TESTS Sample Number Boring B -1 @ 4.5 -8' Initial Moisture 14.5 percent Initial Dry Density 99.0 pcf Final Moisture 29.9 percent Expansion Index 76 (Medium) GRAIN SIZE DISTRIBUTION Sample Number: Boring B -1 @ 4.5' -8' Sieve Size #4 Percent Passing #8 100 #16 99 98 #30 96 #50 92 #100 81 #200 67 0.05 mm 61 0.005 mm 27 0.001 mm 3 CWE 2040221.01 October 27, 2004 Plate No. 6 CW'E 2040221.01 October 27, 2004 Appendix A, Page A -1 REFERENCES Anderson, J.G.; Rockwell, R.K. and Agnew, D.C., 1989, Past and Possible Future Earthquakes of Significance to the San Diego Region, Earthquake Spectra, Volume 5, No. 2, 1989. Boore, David M., Joyner, William B., and Fumal, Thomas E., 1997, "Empirical Near - Source Attenuation Relationships for Horizontal and Vertical Components of Peak Ground Acceleration, Peak Ground Velocity, and Pseudo - Absolute Acceleration Response Spectra ", in Seismological Research Letters, Volume 68, Number 1, January /Februan, 1997. California Division of Mines and Geology, 1998, Maps of Known Active Fault Near Source -Zones in California and Adjacent Portions of Nevada. Countylvide Flood Insurance Rate Map, Map No. 06073C1044F (panel 1044 of 2375), prepared by the Federal Emergency Management Agency, effective date June 19, 1997. Jennings, C.w., 1975, Fault Map of California, California Division of Mines and Geology, Map No. 1, Scale 1:750,000. Kennedy, M.P. and Peterson, G.L., 1975, Geology of the San Diego Metropolitan Area, California; California Division of Mines and Geology, Bulletin 200 Kern, P., 1989, Earthquakes and Faults in San Diego County, Pickle Press, 73 pp. United States Department of Agriculture, 1970, Soil Survey, San Diego Area, California. W'esnousky, S.G., 1986, "Earthquakes, Quaternary Faults, and Seismic Hazards in California ", in Journal of Geophysical Research, Volume 91, No. B12, pp 12,587 to 12,631, November 1986. COY- E 2040221.01 October 27, 2004 Appendix B - 1 RECOMMENDED GRADING SPECIFICATIONS - GENERAL PROVISIONS PROPOSED DUPLEX 2271 MONTGOMERY AVENUE CARDIFF BY THE SEA ENCINITAS CALIFORNIA GENERAL INTENT The intent of these specifications is to establish procedures for clearing, compacting natural ground, preparing areas to be filled, and placing and compacting fill soils to the lines and grades shown on the accepted plans. The recommendations contained in the preliminary geotechnical investigation report and /or the attached Special Provisions are a part of the Recommended Grading Specifications and shall supersede the provisions contained hereinafter in the case of conflict. These specifications shall only be used in conjunction with the geotechnical report for which they area part. No deviation from these specifications will be allowed, except where specified in the geotechnical report or in other written communication signed by the Geotechnical Engineer. OBSERVATION AND TESTING Christian \yv'heeler Engineering shall be retained as the Geotechnical Engineer to observe and test the earthwork in accordance with these specifications. It will be necessary that the Geotechnical Engineer or his representative provide adequate observation so that he may provide his opinion as to whether or not the work was accomplished as specified. It shall be the responsibility of the contractor to assist the Geotechnical Engineer and to keep him appraised of work schedules, changes and new information and data so that he may provide these opinions. In the event that any unusual conditions not covered by the special provisions or preliminary geotechnical report are encountered during the grading operations, the Geotechnical Engineer shall be contacted for further recommendations. If, in the opinion of the Geotechnical Engineer, substandard conditions are encountered, such as questionable or unsuitable soil, unacceptable moisture content, inadequate compaction, adverse weather, etc., construction should be stopped until the conditions are remedied or corrected or he shall recommend rejection of this work. Tests used to determine the degree of compaction should be performed in accordance with the following American Society for Testing and Materials test methods: CW'E 2040221.01 October 27, 2004 Appendix B - 2 Maximum Density & Optimum Moisture Content - ASTM D- 1557 -91 Density of Soil In -Place - ASTM D- 1556 -90 or ASTM D -2922 All densities shall be expressed in terms of Relative Compaction as determined by the foregoing ASTM testing procedures. PREPARATION OF AREAS TO RECEIVE FILL All vegetation, brush and debris derived from clearing operations shall be removed, and legally disposed of. All areas disturbed by site grading should be left in a neat and finished appearance, free from unsightly debris. After clearing or benching the natural ground, the areas to be Filled shall be scarified to a depth of 6 inches, brought to the proper moisture content, compacted and tested for the specified minimum degree of compaction. All loose soils in excess of 6 inches thick should be removed to firm natural ground which is defined as natural soil which possesses an in -situ density of at least 90 percent of its maximum dry density. When the slope of the natural ground receiving fill exceeds 20 percent (5 horizontal units to 1 vertical unit), the original ground shall be stepped or benched. Benches shall be cut to a firm competent formational soil. The lower bench shall be at least 10 feet wide or 1 -1/2 times the equipment width, whichever is greater, and shall be sloped back into the hillside at a gradient of not less than two (2) percent. All other benches should be at least 6 feet wide. The horizontal portion of each bench shall be compacted prior to receiving fill as specified herein for compacted natural ground. Ground slopes flatter than 20 percent shall be benched when considered necessary by the Geotechnical Engineer. Any abandoned buried structures encountered during grading operations must be totally removed. All underground utilities to be abandoned beneath any proposed structure should be removed from within 10 feet of the structure and properly capped off. The resulting depressions from the above described procedure should be backfilled with acceptable soil that is compacted to the requirements of the Geotechnical Engineer. This includes, but is not limited to, septic tanks, fuel tanks, sewer lines or leach lines, storm drains and water lines. Any buried structures or utilities not to be abandoned should be brought to the attention of the Geotechnical Engineer so that he may determine if any special recommendation will be necessary. All water wells which will be abandoned should be backfilled and capped in accordance to the requirements set forth by the Geotechnical Engineer. The top of the cap should be at least 4 feet below finish grade or 3 C\X'E 2040221.01 October 27, 2004 Appendix B - 3 feet below the bottom of footing whichever is greater. The type of cap will depend on the diameter of the well and should be determined by the Geotechnical Engineer and /or a qualified Structural Engineer. FILL MATERIAL Materials to be placed in the fill shall be approved by the Geotechnical Engineer and shall be free of vegetable matter and other deleterious substances. Granular soil shall contain sufficient fine material to fill the voids. The definition and disposition of oversized rocks and expansive or detrimental soils are covered in the geotechnical report or Special Provisions. Expansive soils, soils of poor gradation, or soils with low strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill material, but only with the explicit consent of the Geotechnical Engineer. Any import material shall be approved by the Geotechnical Engineer before being brought to the site. PLACING AND COMPACTION OF FILL Approved fill material shall be placed in areas prepared to receive fill in layers not to exceed 6 inches in compacted thickness. Each layer shall have a uniform moisture content in the range that will allow the compaction effort to be efficiently applied to achieve the specified degree of compaction. Each layer shall be uniformly compacted to the specified minimum degree of compaction with equipment of adequate size to economically compact the layer. Compaction equipment should either be specifically designed for soil compaction or of proven reliability. The minimum degree of compaction to be achieved is specified in either the Special Provisions or the recommendations contained in the preliminary geotechnical investigation report. \Vhen the structural fill material includes rocks, no rocks will be allowed to nest and all voids must be carefully filled with soil such that the minimum degree of compaction recommended in the Special Provisions is achieved. The maximum size and spacing of rock permitted in structural fills and in non - structural fills is discussed in the geotechnical report, when applicable. Field observation and compaction tests to estimate the degree of compaction of the fill will be taken by the Geotechnical Engineer or his representative. The location and frequency of the tests shall be at the Geotechnical Engineer's discretion. When the compaction test indicates that a particular layer is at less than the required degree of compaction, the layer shall be reworked to the satisfaction of the Geotechnical Engineer and until the desired relative compaction has been obtained. C\�E 2040221.01 October 27, 2004 Appendix B - 4 Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction by sheepsfoot roller shall be at vertical intervals of not greater than four feet. In addition, fill slopes at a ratio of two horizontal to one vertical or flatter, should be trackrolled. Steeper fill slopes shall be over -built and cut- back to finish contours after the slope has been constructed. Slope compaction operations shall result in all fill material six or more inches inward from the finished face of the slope having a relative compaction of at least 90 percent of maximum dry density or the degree of compaction specified in the Special Provisions section of this specification. The compaction operation on the slopes shall be continued until the Geotechnical Engineer is of the opinion that the slopes will be surficially stable. Density tests in the slopes will be made by the Geotechnical Engineer during construction of the slopes to determine if the required compaction is being achieved. Where failing tests occur or other field problems arise, the Contractor will be notified that day of such conditions by written communication from the Geotechnical Engineer or his representative in the form of a daily field report. If the method of achieving the required slope compaction selected by the Contractor fails to produce the necessary results, the Contractor shall rework or rebuild such slopes until the required degree of compaction is obtained, at no cost to the Owner or Geotechnical Engineer. CUT SLOPES The Engineering Geologist shall inspect cut slopes excavated in rock or lithified formational material during the grading operations at intervals determined at his discretion. If any conditions not anticipated in the preliminary report such as perched water, seepage, lenticular or confined strata of a potentially adverse nature, unfavorably inclined bedding, joints or fault planes are encountered during grading, these conditions shall be analyzed by the Engineering Geologist and Geotechnical Engineer to determine if mitigating measures are necessary. Unless otherwise specified in the geotechnical report, no cut slopes shall be excavated higher or steeper than that allowed by the ordinances of the controlling governmental agency. ENGINEERING OBSERVATION Field observation by the Geotechnical Engineer or his representative shall be made during the filling and compaction operations so that he can express his opinion regarding the conformance of the grading with acceptable standards of practice. Neither the presence of the Geotechnical Engineer or his representative or CWE 2040221.01 October 27, 2004 Appendix B - 5 the observation and testing shall release the Grading Contractor from his duty to compact all fill material to the specified degree of compaction. SEASON LIMITS Fill shall not be placed during unfavorable weather conditions. When work is interrupted by heavy rain, filling operations shall not be resumed until the proper moisture content and density of the fill materials can be achieved. Damaged site conditions resulting from weather or acts of God shall be repaired before acceptance of work. RECOMMENDED GRADING SPECIFICATIONS - SPECIAL PROVISIONS RELATIVE COMPACTION: The minimum degree of compaction to be obtained in compacted natural ground, compacted fill, and compacted backfill shall be at least 90 percent. For street and parking lot subgrade, the upper twelve inches should be compacted to at least 95 percent relative compaction. EXPANSIVE SOILS: Detrimentally expansive soil is defined as clayey soil which has an expansion index of 50 or greater when tested in accordance with the American Society of Testing Materials (ASTM) Laboratory Test D4829 -95. OVERSIZED MATERIAL: Oversized fill material is generally defined herein as rocks or lumps of soil over six inches in diameter. Oversized materials should not be placed in fill unless recommendations of placement of such material is provided by the Geotechnical Engineer. At least 40 percent of the fill soils shall pass through a No. 4 U.S. Standard Sieve. TRANSITION LOTS: Where transitions between cut and fill occur within the proposed building pad, the cut portion should be undercut a minimum of one foot below the base of the proposed footings and recompacted as structural backfill. In certain cases that would be addressed in the geotechnical report, special footing reinforcement or a combination of special footing reinforcement and undercutting may be required. 11^ CHRISTIAN WHEELER IN(" INC.I R INC November 15, 2006 Mark Bobo 1509 Encinitas Boulevard Encinitas, California 92024 CWE 2040221.03 SUBJECT: UPDATE OF REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION, PROPOSED DUPLEX, 2271 MONTGOMERY AVENUE, ENCINITAS, CALIFORNIA. Reference: Report of Preliminary Geotechnical Investigation, Proposed Duplex, 2271 Montgomery Avenue, Encinitas, California, prepared by Christian Wheeler Engineering, Report No. 2040221.01, dated October 27, 2004. Dear Mr. Bobo: In accordance with your request we have prepared this letter to update the referenced geotechnical investigation. Provided no changes to the project are proposed, it is our opinion that our recommendations in the above referenced geotechnical report remains applicable to the proposed project. If you have any questions after reviewing this report, please do not hesitate to contact this office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted, CHRISTIAN WHEELER ENGINEERING QPpFESS /O� SK Cy9� �Z s Charles H. Christian, RGE #00215 Cl) 2 y Z CHC:wm C7 v No.GE215 z M cc: (3) Submitted .*. Exp. 9-30-07 X � 07ECNN��P �Q F CA�.�FO 4925 Mercury Street + San Diego, CA 921 1 1 + 858- 496 -9760 + FAX 858 -496 -9758 n1i ! CHRISTIAN WHEELER E N C I N E E R I N C November 15, 2006 Mark Bobo 1509 Encinitas Boulevard Encinitas, California 92024 CWE, 2040221.03 SUBJECT: UPDATE OF REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION, PROPOSED DUPLEX, 2271 MONTGOMERY AVENUE, ENCINITAS, CALIFORNIA. Reference: Report of Preliminary Geotechnical Investigation, Proposed Duplex, 2271 Montgomery Avenue, Encinitas, California, prepared by Christian Wheeler Engineering, Report No. 2040221.01, dated October 27, 2004. Dear Mr. Bobo: In accordance with your request we have prepared this letter to update the referenced geotechnical investigation. Provided no changes to the project are proposed, it is our opinion that our recommendations in the above referenced geotechnical report remains applicable to the proposed project. If you have any questions after reviewing this report, please do not hesitate to contact this office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted, CHRISTIAN WHEELER ENGINEERING Q�pFESS g H. Cy/ �Z Z No.GE215 z m w Charles H. Christian, RGE #00215 U Exp. 9-30-07 M CHC:wm cc: (3) Submitted * T cF�IECNN��P� �* 9�OF CN-\ O 4925 Mercury Street f San Diego, CA 92 11 1 ♦ 858 - 496 -9760 ♦ FAX 858- 496 -9758